TOMOYO Linux Cross Reference
Linux/mm/slub.c

   // SPDX-License-Identifier: GPL-2.0
   /*
    * SLUB: A slab allocator that limits cache line use instead of queuing
    * objects in per cpu and per node lists.
    *
    * The allocator synchronizes using per slab locks or atomic operations
    * and only uses a centralized lock to manage a pool of partial slabs.
    *
    * (C) 2007 SGI, Christoph Lameter
   * (C) 2011 Linux Foundation, Christoph Lameter
   */
  
  #include <linux/mm.h>
  #include <linux/swap.h> /* mm_account_reclaimed_pages() */
  #include <linux/module.h>
  #include <linux/bit_spinlock.h>
  #include <linux/interrupt.h>
  #include <linux/swab.h>
  #include <linux/bitops.h>
  #include <linux/slab.h>
  #include "slab.h"
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/kasan.h>
  #include <linux/kmsan.h>
  #include <linux/cpu.h>
  #include <linux/cpuset.h>
  #include <linux/mempolicy.h>
  #include <linux/ctype.h>
  #include <linux/stackdepot.h>
  #include <linux/debugobjects.h>
  #include <linux/kallsyms.h>
  #include <linux/kfence.h>
  #include <linux/memory.h>
  #include <linux/math64.h>
  #include <linux/fault-inject.h>
  #include <linux/kmemleak.h>
  #include <linux/stacktrace.h>
  #include <linux/prefetch.h>
  #include <linux/memcontrol.h>
  #include <linux/random.h>
  #include <kunit/test.h>
  #include <kunit/test-bug.h>
  #include <linux/sort.h>
  
  #include <linux/debugfs.h>
  #include <trace/events/kmem.h>
  
  #include "internal.h"
  
  /*
   * Lock order:
   *   1. slab_mutex (Global Mutex)
   *   2. node->list_lock (Spinlock)
   *   3. kmem_cache->cpu_slab->lock (Local lock)
   *   4. slab_lock(slab) (Only on some arches)
   *   5. object_map_lock (Only for debugging)
   *
   *   slab_mutex
   *
   *   The role of the slab_mutex is to protect the list of all the slabs
   *   and to synchronize major metadata changes to slab cache structures.
   *   Also synchronizes memory hotplug callbacks.
   *
   *   slab_lock
   *
   *   The slab_lock is a wrapper around the page lock, thus it is a bit
   *   spinlock.
   *
   *   The slab_lock is only used on arches that do not have the ability
   *   to do a cmpxchg_double. It only protects:
   *
   *      A. slab->freelist       -> List of free objects in a slab
   *      B. slab->inuse          -> Number of objects in use
   *      C. slab->objects        -> Number of objects in slab
   *      D. slab->frozen         -> frozen state
   *
   *   Frozen slabs
   *
   *   If a slab is frozen then it is exempt from list management. It is
   *   the cpu slab which is actively allocated from by the processor that
   *   froze it and it is not on any list. The processor that froze the
   *   slab is the one who can perform list operations on the slab. Other
   *   processors may put objects onto the freelist but the processor that
   *   froze the slab is the only one that can retrieve the objects from the
   *   slab's freelist.
   *
   *   CPU partial slabs
   *
   *   The partially empty slabs cached on the CPU partial list are used
   *   for performance reasons, which speeds up the allocation process.
   *   These slabs are not frozen, but are also exempt from list management,
   *   by clearing the PG_workingset flag when moving out of the node
   *   partial list. Please see __slab_free() for more details.
   *
   *   To sum up, the current scheme is:
   *   - node partial slab: PG_Workingset && !frozen
   *   - cpu partial slab: !PG_Workingset && !frozen
   *   - cpu slab: !PG_Workingset && frozen
  *   - full slab: !PG_Workingset && !frozen
  *
  *   list_lock
  *
  *   The list_lock protects the partial and full list on each node and
  *   the partial slab counter. If taken then no new slabs may be added or
  *   removed from the lists nor make the number of partial slabs be modified.
  *   (Note that the total number of slabs is an atomic value that may be
  *   modified without taking the list lock).
  *
  *   The list_lock is a centralized lock and thus we avoid taking it as
  *   much as possible. As long as SLUB does not have to handle partial
  *   slabs, operations can continue without any centralized lock. F.e.
  *   allocating a long series of objects that fill up slabs does not require
  *   the list lock.
  *
  *   For debug caches, all allocations are forced to go through a list_lock
  *   protected region to serialize against concurrent validation.
  *
  *   cpu_slab->lock local lock
  *
  *   This locks protect slowpath manipulation of all kmem_cache_cpu fields
  *   except the stat counters. This is a percpu structure manipulated only by
  *   the local cpu, so the lock protects against being preempted or interrupted
  *   by an irq. Fast path operations rely on lockless operations instead.
  *
  *   On PREEMPT_RT, the local lock neither disables interrupts nor preemption
  *   which means the lockless fastpath cannot be used as it might interfere with
  *   an in-progress slow path operations. In this case the local lock is always
  *   taken but it still utilizes the freelist for the common operations.
  *
  *   lockless fastpaths
  *
  *   The fast path allocation (slab_alloc_node()) and freeing (do_slab_free())
  *   are fully lockless when satisfied from the percpu slab (and when
  *   cmpxchg_double is possible to use, otherwise slab_lock is taken).
  *   They also don't disable preemption or migration or irqs. They rely on
  *   the transaction id (tid) field to detect being preempted or moved to
  *   another cpu.
  *
  *   irq, preemption, migration considerations
  *
  *   Interrupts are disabled as part of list_lock or local_lock operations, or
  *   around the slab_lock operation, in order to make the slab allocator safe
  *   to use in the context of an irq.
  *
  *   In addition, preemption (or migration on PREEMPT_RT) is disabled in the
  *   allocation slowpath, bulk allocation, and put_cpu_partial(), so that the
  *   local cpu doesn't change in the process and e.g. the kmem_cache_cpu pointer
  *   doesn't have to be revalidated in each section protected by the local lock.
  *
  * SLUB assigns one slab for allocation to each processor.
  * Allocations only occur from these slabs called cpu slabs.
  *
  * Slabs with free elements are kept on a partial list and during regular
  * operations no list for full slabs is used. If an object in a full slab is
  * freed then the slab will show up again on the partial lists.
  * We track full slabs for debugging purposes though because otherwise we
  * cannot scan all objects.
  *
  * Slabs are freed when they become empty. Teardown and setup is
  * minimal so we rely on the page allocators per cpu caches for
  * fast frees and allocs.
  *
  * slab->frozen         The slab is frozen and exempt from list processing.
  *                      This means that the slab is dedicated to a purpose
  *                      such as satisfying allocations for a specific
  *                      processor. Objects may be freed in the slab while
  *                      it is frozen but slab_free will then skip the usual
  *                      list operations. It is up to the processor holding
  *                      the slab to integrate the slab into the slab lists
  *                      when the slab is no longer needed.
  *
  *                      One use of this flag is to mark slabs that are
  *                      used for allocations. Then such a slab becomes a cpu
  *                      slab. The cpu slab may be equipped with an additional
  *                      freelist that allows lockless access to
  *                      free objects in addition to the regular freelist
  *                      that requires the slab lock.
  *
  * SLAB_DEBUG_FLAGS     Slab requires special handling due to debug
  *                      options set. This moves slab handling out of
  *                      the fast path and disables lockless freelists.
  */
 
 /*
  * We could simply use migrate_disable()/enable() but as long as it's a
  * function call even on !PREEMPT_RT, use inline preempt_disable() there.
  */
 #ifndef CONFIG_PREEMPT_RT
 #define slub_get_cpu_ptr(var)           get_cpu_ptr(var)
 #define slub_put_cpu_ptr(var)           put_cpu_ptr(var)
 #define USE_LOCKLESS_FAST_PATH()        (true)
 #else
 #define slub_get_cpu_ptr(var)           \
 ({                                      \
         migrate_disable();              \
         this_cpu_ptr(var);              \
 })
 #define slub_put_cpu_ptr(var)           \
 do {                                    \
         (void)(var);                    \
         migrate_enable();               \
 } while (0)
 #define USE_LOCKLESS_FAST_PATH()        (false)
 #endif
 
 #ifndef CONFIG_SLUB_TINY
 #define __fastpath_inline __always_inline
 #else
 #define __fastpath_inline
 #endif
 
 #ifdef CONFIG_SLUB_DEBUG
 #ifdef CONFIG_SLUB_DEBUG_ON
 DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
 #else
 DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
 #endif
 #endif          /* CONFIG_SLUB_DEBUG */
 
 /* Structure holding parameters for get_partial() call chain */
 struct partial_context {
         gfp_t flags;
         unsigned int orig_size;
         void *object;
 };
 
 static inline bool kmem_cache_debug(struct kmem_cache *s)
 {
         return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
 }
 
 static inline bool slub_debug_orig_size(struct kmem_cache *s)
 {
         return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
                         (s->flags & SLAB_KMALLOC));
 }
 
 void *fixup_red_left(struct kmem_cache *s, void *p)
 {
         if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
                 p += s->red_left_pad;
 
         return p;
 }
 
 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
 {
 #ifdef CONFIG_SLUB_CPU_PARTIAL
         return !kmem_cache_debug(s);
 #else
         return false;
 #endif
 }
 
 /*
  * Issues still to be resolved:
  *
  * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
  *
  * - Variable sizing of the per node arrays
  */
 
 /* Enable to log cmpxchg failures */
 #undef SLUB_DEBUG_CMPXCHG
 
 #ifndef CONFIG_SLUB_TINY
 /*
  * Minimum number of partial slabs. These will be left on the partial
  * lists even if they are empty. kmem_cache_shrink may reclaim them.
  */
 #define MIN_PARTIAL 5
 
 /*
  * Maximum number of desirable partial slabs.
  * The existence of more partial slabs makes kmem_cache_shrink
  * sort the partial list by the number of objects in use.
  */
 #define MAX_PARTIAL 10
 #else
 #define MIN_PARTIAL 0
 #define MAX_PARTIAL 0
 #endif
 
 #define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
                                 SLAB_POISON | SLAB_STORE_USER)
 
 /*
  * These debug flags cannot use CMPXCHG because there might be consistency
  * issues when checking or reading debug information
  */
 #define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
                                 SLAB_TRACE)
 
 
 /*
  * Debugging flags that require metadata to be stored in the slab.  These get
  * disabled when slab_debug=O is used and a cache's min order increases with
  * metadata.
  */
 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 
 #define OO_SHIFT        16
 #define OO_MASK         ((1 << OO_SHIFT) - 1)
 #define MAX_OBJS_PER_PAGE       32767 /* since slab.objects is u15 */
 
 /* Internal SLUB flags */
 /* Poison object */
 #define __OBJECT_POISON         __SLAB_FLAG_BIT(_SLAB_OBJECT_POISON)
 /* Use cmpxchg_double */
 
 #ifdef system_has_freelist_aba
 #define __CMPXCHG_DOUBLE        __SLAB_FLAG_BIT(_SLAB_CMPXCHG_DOUBLE)
 #else
 #define __CMPXCHG_DOUBLE        __SLAB_FLAG_UNUSED
 #endif
 
 /*
  * Tracking user of a slab.
  */
 #define TRACK_ADDRS_COUNT 16
 struct track {
         unsigned long addr;     /* Called from address */
 #ifdef CONFIG_STACKDEPOT
         depot_stack_handle_t handle;
 #endif
         int cpu;                /* Was running on cpu */
         int pid;                /* Pid context */
         unsigned long when;     /* When did the operation occur */
 };
 
 enum track_item { TRACK_ALLOC, TRACK_FREE };
 
 #ifdef SLAB_SUPPORTS_SYSFS
 static int sysfs_slab_add(struct kmem_cache *);
 static int sysfs_slab_alias(struct kmem_cache *, const char *);
 #else
 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
                                                         { return 0; }
 #endif
 
 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
 static void debugfs_slab_add(struct kmem_cache *);
 #else
 static inline void debugfs_slab_add(struct kmem_cache *s) { }
 #endif
 
 enum stat_item {
         ALLOC_FASTPATH,         /* Allocation from cpu slab */
         ALLOC_SLOWPATH,         /* Allocation by getting a new cpu slab */
         FREE_FASTPATH,          /* Free to cpu slab */
         FREE_SLOWPATH,          /* Freeing not to cpu slab */
         FREE_FROZEN,            /* Freeing to frozen slab */
         FREE_ADD_PARTIAL,       /* Freeing moves slab to partial list */
         FREE_REMOVE_PARTIAL,    /* Freeing removes last object */
         ALLOC_FROM_PARTIAL,     /* Cpu slab acquired from node partial list */
         ALLOC_SLAB,             /* Cpu slab acquired from page allocator */
         ALLOC_REFILL,           /* Refill cpu slab from slab freelist */
         ALLOC_NODE_MISMATCH,    /* Switching cpu slab */
         FREE_SLAB,              /* Slab freed to the page allocator */
         CPUSLAB_FLUSH,          /* Abandoning of the cpu slab */
         DEACTIVATE_FULL,        /* Cpu slab was full when deactivated */
         DEACTIVATE_EMPTY,       /* Cpu slab was empty when deactivated */
         DEACTIVATE_TO_HEAD,     /* Cpu slab was moved to the head of partials */
         DEACTIVATE_TO_TAIL,     /* Cpu slab was moved to the tail of partials */
         DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
         DEACTIVATE_BYPASS,      /* Implicit deactivation */
         ORDER_FALLBACK,         /* Number of times fallback was necessary */
         CMPXCHG_DOUBLE_CPU_FAIL,/* Failures of this_cpu_cmpxchg_double */
         CMPXCHG_DOUBLE_FAIL,    /* Failures of slab freelist update */
         CPU_PARTIAL_ALLOC,      /* Used cpu partial on alloc */
         CPU_PARTIAL_FREE,       /* Refill cpu partial on free */
         CPU_PARTIAL_NODE,       /* Refill cpu partial from node partial */
         CPU_PARTIAL_DRAIN,      /* Drain cpu partial to node partial */
         NR_SLUB_STAT_ITEMS
 };
 
 #ifndef CONFIG_SLUB_TINY
 /*
  * When changing the layout, make sure freelist and tid are still compatible
  * with this_cpu_cmpxchg_double() alignment requirements.
  */
 struct kmem_cache_cpu {
         union {
                 struct {
                         void **freelist;        /* Pointer to next available object */
                         unsigned long tid;      /* Globally unique transaction id */
                 };
                 freelist_aba_t freelist_tid;
         };
         struct slab *slab;      /* The slab from which we are allocating */
 #ifdef CONFIG_SLUB_CPU_PARTIAL
         struct slab *partial;   /* Partially allocated slabs */
 #endif
         local_lock_t lock;      /* Protects the fields above */
 #ifdef CONFIG_SLUB_STATS
         unsigned int stat[NR_SLUB_STAT_ITEMS];
 #endif
 };
 #endif /* CONFIG_SLUB_TINY */
 
 static inline void stat(const struct kmem_cache *s, enum stat_item si)
 {
 #ifdef CONFIG_SLUB_STATS
         /*
          * The rmw is racy on a preemptible kernel but this is acceptable, so
          * avoid this_cpu_add()'s irq-disable overhead.
          */
         raw_cpu_inc(s->cpu_slab->stat[si]);
 #endif
 }
 
 static inline
 void stat_add(const struct kmem_cache *s, enum stat_item si, int v)
 {
 #ifdef CONFIG_SLUB_STATS
         raw_cpu_add(s->cpu_slab->stat[si], v);
 #endif
 }
 
 /*
  * The slab lists for all objects.
  */
 struct kmem_cache_node {
         spinlock_t list_lock;
         unsigned long nr_partial;
         struct list_head partial;
 #ifdef CONFIG_SLUB_DEBUG
         atomic_long_t nr_slabs;
         atomic_long_t total_objects;
         struct list_head full;
 #endif
 };
 
 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 {
         return s->node[node];
 }
 
 /*
  * Iterator over all nodes. The body will be executed for each node that has
  * a kmem_cache_node structure allocated (which is true for all online nodes)
  */
 #define for_each_kmem_cache_node(__s, __node, __n) \
         for (__node = 0; __node < nr_node_ids; __node++) \
                  if ((__n = get_node(__s, __node)))
 
 /*
  * Tracks for which NUMA nodes we have kmem_cache_nodes allocated.
  * Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily
  * differ during memory hotplug/hotremove operations.
  * Protected by slab_mutex.
  */
 static nodemask_t slab_nodes;
 
 #ifndef CONFIG_SLUB_TINY
 /*
  * Workqueue used for flush_cpu_slab().
  */
 static struct workqueue_struct *flushwq;
 #endif
 
 /********************************************************************
  *                      Core slab cache functions
  *******************************************************************/
 
 /*
  * freeptr_t represents a SLUB freelist pointer, which might be encoded
  * and not dereferenceable if CONFIG_SLAB_FREELIST_HARDENED is enabled.
  */
 typedef struct { unsigned long v; } freeptr_t;
 
 /*
  * Returns freelist pointer (ptr). With hardening, this is obfuscated
  * with an XOR of the address where the pointer is held and a per-cache
  * random number.
  */
 static inline freeptr_t freelist_ptr_encode(const struct kmem_cache *s,
                                             void *ptr, unsigned long ptr_addr)
 {
         unsigned long encoded;
 
 #ifdef CONFIG_SLAB_FREELIST_HARDENED
         encoded = (unsigned long)ptr ^ s->random ^ swab(ptr_addr);
 #else
         encoded = (unsigned long)ptr;
 #endif
         return (freeptr_t){.v = encoded};
 }
 
 static inline void *freelist_ptr_decode(const struct kmem_cache *s,
                                         freeptr_t ptr, unsigned long ptr_addr)
 {
         void *decoded;
 
 #ifdef CONFIG_SLAB_FREELIST_HARDENED
         decoded = (void *)(ptr.v ^ s->random ^ swab(ptr_addr));
 #else
         decoded = (void *)ptr.v;
 #endif
         return decoded;
 }
 
 static inline void *get_freepointer(struct kmem_cache *s, void *object)
 {
         unsigned long ptr_addr;
         freeptr_t p;
 
         object = kasan_reset_tag(object);
         ptr_addr = (unsigned long)object + s->offset;
         p = *(freeptr_t *)(ptr_addr);
         return freelist_ptr_decode(s, p, ptr_addr);
 }
 
 #ifndef CONFIG_SLUB_TINY
 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
 {
         prefetchw(object + s->offset);
 }
 #endif
 
 /*
  * When running under KMSAN, get_freepointer_safe() may return an uninitialized
  * pointer value in the case the current thread loses the race for the next
  * memory chunk in the freelist. In that case this_cpu_cmpxchg_double() in
  * slab_alloc_node() will fail, so the uninitialized value won't be used, but
  * KMSAN will still check all arguments of cmpxchg because of imperfect
  * handling of inline assembly.
  * To work around this problem, we apply __no_kmsan_checks to ensure that
  * get_freepointer_safe() returns initialized memory.
  */
 __no_kmsan_checks
 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
 {
         unsigned long freepointer_addr;
         freeptr_t p;
 
         if (!debug_pagealloc_enabled_static())
                 return get_freepointer(s, object);
 
         object = kasan_reset_tag(object);
         freepointer_addr = (unsigned long)object + s->offset;
         copy_from_kernel_nofault(&p, (freeptr_t *)freepointer_addr, sizeof(p));
         return freelist_ptr_decode(s, p, freepointer_addr);
 }
 
 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
 {
         unsigned long freeptr_addr = (unsigned long)object + s->offset;
 
 #ifdef CONFIG_SLAB_FREELIST_HARDENED
         BUG_ON(object == fp); /* naive detection of double free or corruption */
 #endif
 
         freeptr_addr = (unsigned long)kasan_reset_tag((void *)freeptr_addr);
         *(freeptr_t *)freeptr_addr = freelist_ptr_encode(s, fp, freeptr_addr);
 }
 
 /*
  * See comment in calculate_sizes().
  */
 static inline bool freeptr_outside_object(struct kmem_cache *s)
 {
         return s->offset >= s->inuse;
 }
 
 /*
  * Return offset of the end of info block which is inuse + free pointer if
  * not overlapping with object.
  */
 static inline unsigned int get_info_end(struct kmem_cache *s)
 {
         if (freeptr_outside_object(s))
                 return s->inuse + sizeof(void *);
         else
                 return s->inuse;
 }
 
 /* Loop over all objects in a slab */
 #define for_each_object(__p, __s, __addr, __objects) \
         for (__p = fixup_red_left(__s, __addr); \
                 __p < (__addr) + (__objects) * (__s)->size; \
                 __p += (__s)->size)
 
 static inline unsigned int order_objects(unsigned int order, unsigned int size)
 {
         return ((unsigned int)PAGE_SIZE << order) / size;
 }
 
 static inline struct kmem_cache_order_objects oo_make(unsigned int order,
                 unsigned int size)
 {
         struct kmem_cache_order_objects x = {
                 (order << OO_SHIFT) + order_objects(order, size)
         };
 
         return x;
 }
 
 static inline unsigned int oo_order(struct kmem_cache_order_objects x)
 {
         return x.x >> OO_SHIFT;
 }
 
 static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
 {
         return x.x & OO_MASK;
 }
 
 #ifdef CONFIG_SLUB_CPU_PARTIAL
 static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
 {
         unsigned int nr_slabs;
 
         s->cpu_partial = nr_objects;
 
         /*
          * We take the number of objects but actually limit the number of
          * slabs on the per cpu partial list, in order to limit excessive
          * growth of the list. For simplicity we assume that the slabs will
          * be half-full.
          */
         nr_slabs = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
         s->cpu_partial_slabs = nr_slabs;
 }
 
 static inline unsigned int slub_get_cpu_partial(struct kmem_cache *s)
 {
         return s->cpu_partial_slabs;
 }
 #else
 static inline void
 slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
 {
 }
 
 static inline unsigned int slub_get_cpu_partial(struct kmem_cache *s)
 {
         return 0;
 }
 #endif /* CONFIG_SLUB_CPU_PARTIAL */
 
 /*
  * Per slab locking using the pagelock
  */
 static __always_inline void slab_lock(struct slab *slab)
 {
         bit_spin_lock(PG_locked, &slab->__page_flags);
 }
 
 static __always_inline void slab_unlock(struct slab *slab)
 {
         bit_spin_unlock(PG_locked, &slab->__page_flags);
 }
 
 static inline bool
 __update_freelist_fast(struct slab *slab,
                       void *freelist_old, unsigned long counters_old,
                       void *freelist_new, unsigned long counters_new)
 {
 #ifdef system_has_freelist_aba
         freelist_aba_t old = { .freelist = freelist_old, .counter = counters_old };
         freelist_aba_t new = { .freelist = freelist_new, .counter = counters_new };
 
         return try_cmpxchg_freelist(&slab->freelist_counter.full, &old.full, new.full);
 #else
         return false;
 #endif
 }
 
 static inline bool
 __update_freelist_slow(struct slab *slab,
                       void *freelist_old, unsigned long counters_old,
                       void *freelist_new, unsigned long counters_new)
 {
         bool ret = false;
 
         slab_lock(slab);
         if (slab->freelist == freelist_old &&
             slab->counters == counters_old) {
                 slab->freelist = freelist_new;
                 slab->counters = counters_new;
                 ret = true;
         }
         slab_unlock(slab);
 
         return ret;
 }
 
 /*
  * Interrupts must be disabled (for the fallback code to work right), typically
  * by an _irqsave() lock variant. On PREEMPT_RT the preempt_disable(), which is
  * part of bit_spin_lock(), is sufficient because the policy is not to allow any
  * allocation/ free operation in hardirq context. Therefore nothing can
  * interrupt the operation.
  */
 static inline bool __slab_update_freelist(struct kmem_cache *s, struct slab *slab,
                 void *freelist_old, unsigned long counters_old,
                 void *freelist_new, unsigned long counters_new,
                 const char *n)
 {
         bool ret;
 
         if (USE_LOCKLESS_FAST_PATH())
                 lockdep_assert_irqs_disabled();
 
         if (s->flags & __CMPXCHG_DOUBLE) {
                 ret = __update_freelist_fast(slab, freelist_old, counters_old,
                                             freelist_new, counters_new);
         } else {
                 ret = __update_freelist_slow(slab, freelist_old, counters_old,
                                             freelist_new, counters_new);
         }
         if (likely(ret))
                 return true;
 
         cpu_relax();
         stat(s, CMPXCHG_DOUBLE_FAIL);
 
 #ifdef SLUB_DEBUG_CMPXCHG
         pr_info("%s %s: cmpxchg double redo ", n, s->name);
 #endif
 
         return false;
 }
 
 static inline bool slab_update_freelist(struct kmem_cache *s, struct slab *slab,
                 void *freelist_old, unsigned long counters_old,
                 void *freelist_new, unsigned long counters_new,
                 const char *n)
 {
         bool ret;
 
         if (s->flags & __CMPXCHG_DOUBLE) {
                 ret = __update_freelist_fast(slab, freelist_old, counters_old,
                                             freelist_new, counters_new);
         } else {
                 unsigned long flags;
 
                 local_irq_save(flags);
                 ret = __update_freelist_slow(slab, freelist_old, counters_old,
                                             freelist_new, counters_new);
                 local_irq_restore(flags);
         }
         if (likely(ret))
                 return true;
 
         cpu_relax();
         stat(s, CMPXCHG_DOUBLE_FAIL);
 
 #ifdef SLUB_DEBUG_CMPXCHG
         pr_info("%s %s: cmpxchg double redo ", n, s->name);
 #endif
 
         return false;
 }
 
 /*
  * kmalloc caches has fixed sizes (mostly power of 2), and kmalloc() API
  * family will round up the real request size to these fixed ones, so
  * there could be an extra area than what is requested. Save the original
  * request size in the meta data area, for better debug and sanity check.
  */
 static inline void set_orig_size(struct kmem_cache *s,
                                 void *object, unsigned int orig_size)
 {
         void *p = kasan_reset_tag(object);
         unsigned int kasan_meta_size;
 
         if (!slub_debug_orig_size(s))
                 return;
 
         /*
          * KASAN can save its free meta data inside of the object at offset 0.
          * If this meta data size is larger than 'orig_size', it will overlap
          * the data redzone in [orig_size+1, object_size]. Thus, we adjust
          * 'orig_size' to be as at least as big as KASAN's meta data.
          */
         kasan_meta_size = kasan_metadata_size(s, true);
         if (kasan_meta_size > orig_size)
                 orig_size = kasan_meta_size;
 
         p += get_info_end(s);
         p += sizeof(struct track) * 2;
 
         *(unsigned int *)p = orig_size;
 }
 
 static inline unsigned int get_orig_size(struct kmem_cache *s, void *object)
 {
         void *p = kasan_reset_tag(object);
 
         if (!slub_debug_orig_size(s))
                 return s->object_size;
 
         p += get_info_end(s);
         p += sizeof(struct track) * 2;
 
         return *(unsigned int *)p;
 }
 
 #ifdef CONFIG_SLUB_DEBUG
 static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
 static DEFINE_SPINLOCK(object_map_lock);
 
 static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
                        struct slab *slab)
 {
         void *addr = slab_address(slab);
         void *p;
 
         bitmap_zero(obj_map, slab->objects);
 
         for (p = slab->freelist; p; p = get_freepointer(s, p))
                 set_bit(__obj_to_index(s, addr, p), obj_map);
 }
 
 #if IS_ENABLED(CONFIG_KUNIT)
 static bool slab_add_kunit_errors(void)
 {
         struct kunit_resource *resource;
 
         if (!kunit_get_current_test())
                 return false;
 
         resource = kunit_find_named_resource(current->kunit_test, "slab_errors");
         if (!resource)
                 return false;
 
         (*(int *)resource->data)++;
         kunit_put_resource(resource);
         return true;
 }
 
 static bool slab_in_kunit_test(void)
 {
         struct kunit_resource *resource;
 
         if (!kunit_get_current_test())
                 return false;
 
         resource = kunit_find_named_resource(current->kunit_test, "slab_errors");
         if (!resource)
                 return false;
 
         kunit_put_resource(resource);
         return true;
 }
 #else
 static inline bool slab_add_kunit_errors(void) { return false; }
 static inline bool slab_in_kunit_test(void) { return false; }
 #endif
 
 static inline unsigned int size_from_object(struct kmem_cache *s)
 {
         if (s->flags & SLAB_RED_ZONE)
                 return s->size - s->red_left_pad;
 
         return s->size;
 }
 
 static inline void *restore_red_left(struct kmem_cache *s, void *p)
 {
         if (s->flags & SLAB_RED_ZONE)
                 p -= s->red_left_pad;
 
         return p;
 }
 
 /*
  * Debug settings:
  */
 #if defined(CONFIG_SLUB_DEBUG_ON)
 static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
 #else
 static slab_flags_t slub_debug;
 #endif
 
 static char *slub_debug_string;
 static int disable_higher_order_debug;
 
 /*
  * slub is about to manipulate internal object metadata.  This memory lies
  * outside the range of the allocated object, so accessing it would normally
  * be reported by kasan as a bounds error.  metadata_access_enable() is used
  * to tell kasan that these accesses are OK.
  */
 static inline void metadata_access_enable(void)
 {
         kasan_disable_current();
         kmsan_disable_current();
 }
 
 static inline void metadata_access_disable(void)
 {
         kmsan_enable_current();
         kasan_enable_current();
 }
 
 /*
  * Object debugging
  */
 
 /* Verify that a pointer has an address that is valid within a slab page */
 static inline int check_valid_pointer(struct kmem_cache *s,
                                 struct slab *slab, void *object)
 {
         void *base;
 
         if (!object)
                 return 1;
 
         base = slab_address(slab);
         object = kasan_reset_tag(object);
         object = restore_red_left(s, object);
         if (object < base || object >= base + slab->objects * s->size ||
                 (object - base) % s->size) {
                 return 0;
         }
 
         return 1;
 }
 
 static void print_section(char *level, char *text, u8 *addr,
                           unsigned int length)
 {
         metadata_access_enable();
         print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
                         16, 1, kasan_reset_tag((void *)addr), length, 1);
         metadata_access_disable();
 }
 
 static struct track *get_track(struct kmem_cache *s, void *object,
         enum track_item alloc)
 {
         struct track *p;
 
         p = object + get_info_end(s);
 
         return kasan_reset_tag(p + alloc);
 }
 
 #ifdef CONFIG_STACKDEPOT
 static noinline depot_stack_handle_t set_track_prepare(void)
 {
         depot_stack_handle_t handle;
         unsigned long entries[TRACK_ADDRS_COUNT];
         unsigned int nr_entries;
 
         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
         handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
 
         return handle;
 }
 #else
 static inline depot_stack_handle_t set_track_prepare(void)
 {
         return 0;
 }
 #endif
 
 static void set_track_update(struct kmem_cache *s, void *object,
                              enum track_item alloc, unsigned long addr,
                              depot_stack_handle_t handle)
 {
         struct track *p = get_track(s, object, alloc);
 
 #ifdef CONFIG_STACKDEPOT
         p->handle = handle;
 #endif
         p->addr = addr;
         p->cpu = smp_processor_id();
         p->pid = current->pid;
         p->when = jiffies;
 }
 
 static __always_inline void set_track(struct kmem_cache *s, void *object,
                                       enum track_item alloc, unsigned long addr)
 {
         depot_stack_handle_t handle = set_track_prepare();
 
         set_track_update(s, object, alloc, addr, handle);
 }
 
 static void init_tracking(struct kmem_cache *s, void *object)
 {
         struct track *p;
 
         if (!(s->flags & SLAB_STORE_USER))
                 return;
 
         p = get_track(s, object, TRACK_ALLOC);
         memset(p, 0, 2*sizeof(struct track));
 }
 
 static void print_track(const char *s, struct track *t, unsigned long pr_time)
 {
         depot_stack_handle_t handle __maybe_unused;
 
         if (!t->addr)
                 return;
 
         pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
                s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
 #ifdef CONFIG_STACKDEPOT
         handle = READ_ONCE(t->handle);
         if (handle)
                 stack_depot_print(handle);
         else
                 pr_err("object allocation/free stack trace missing\n");
 #endif
 }
 
 void print_tracking(struct kmem_cache *s, void *object)
 {
         unsigned long pr_time = jiffies;
         if (!(s->flags & SLAB_STORE_USER))
                 return;
 
         print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
         print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
 }
 
 static void print_slab_info(const struct slab *slab)
 {
         pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
                slab, slab->objects, slab->inuse, slab->freelist,
                &slab->__page_flags);
 }
 
 void skip_orig_size_check(struct kmem_cache *s, const void *object)
 {
         set_orig_size(s, (void *)object, s->object_size);
 }
 
 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
 {
         struct va_format vaf;
         va_list args;
 
         va_start(args, fmt);
         vaf.fmt = fmt;
         vaf.va = &args;
         pr_err("=============================================================================\n");
         pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
         pr_err("-----------------------------------------------------------------------------\n\n");
         va_end(args);
 }
 
 __printf(2, 3)
 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
 {
         struct va_format vaf;
         va_list args;
 
         if (slab_add_kunit_errors())
                 return;
 
         va_start(args, fmt);
         vaf.fmt = fmt;
         vaf.va = &args;
         pr_err("FIX %s: %pV\n", s->name, &vaf);
         va_end(args);
 }
 
 static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
 {
         unsigned int off;       /* Offset of last byte */
         u8 *addr = slab_address(slab);
 
         print_tracking(s, p);
 
         print_slab_info(slab);
 
         pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
                p, p - addr, get_freepointer(s, p));
 
         if (s->flags & SLAB_RED_ZONE)
                 print_section(KERN_ERR, "Redzone  ", p - s->red_left_pad,
                               s->red_left_pad);
         else if (p > addr + 16)
                 print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
 
         print_section(KERN_ERR,         "Object   ", p,
                       min_t(unsigned int, s->object_size, PAGE_SIZE));
         if (s->flags & SLAB_RED_ZONE)
                 print_section(KERN_ERR, "Redzone  ", p + s->object_size,
                         s->inuse - s->object_size);
 
         off = get_info_end(s);
 
         if (s->flags & SLAB_STORE_USER)
                 off += 2 * sizeof(struct track);
 
         if (slub_debug_orig_size(s))
                 off += sizeof(unsigned int);
 
         off += kasan_metadata_size(s, false);
 
         if (off != size_from_object(s))
                 /* Beginning of the filler is the free pointer */
                 print_section(KERN_ERR, "Padding  ", p + off,
                               size_from_object(s) - off);
 
         dump_stack();
 }
 
 static void object_err(struct kmem_cache *s, struct slab *slab,
                         u8 *object, char *reason)
 {
         if (slab_add_kunit_errors())
                 return;
 
         slab_bug(s, "%s", reason);
         print_trailer(s, slab, object);
         add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
 
 static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
                                void **freelist, void *nextfree)
 {
         if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
             !check_valid_pointer(s, slab, nextfree) && freelist) {
                 object_err(s, slab, *freelist, "Freechain corrupt");
                 *freelist = NULL;
                 slab_fix(s, "Isolate corrupted freechain");
                 return true;
         }
 
         return false;
 }
 
 static __printf(3, 4) void slab_err(struct kmem_cache *s, struct slab *slab,
                         const char *fmt, ...)
 {
         va_list args;
         char buf[100];
 
         if (slab_add_kunit_errors())
                 return;
 
         va_start(args, fmt);
         vsnprintf(buf, sizeof(buf), fmt, args);
         va_end(args);
         slab_bug(s, "%s", buf);
         print_slab_info(slab);
         dump_stack();
         add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
 
 static void init_object(struct kmem_cache *s, void *object, u8 val)
 {
         u8 *p = kasan_reset_tag(object);
         unsigned int poison_size = s->object_size;
 
         if (s->flags & SLAB_RED_ZONE) {
                 /*
                  * Here and below, avoid overwriting the KMSAN shadow. Keeping
                  * the shadow makes it possible to distinguish uninit-value
                  * from use-after-free.
                  */
                 memset_no_sanitize_memory(p - s->red_left_pad, val,
                                           s->red_left_pad);
 
                 if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
                         /*
                          * Redzone the extra allocated space by kmalloc than
                          * requested, and the poison size will be limited to
                          * the original request size accordingly.
                          */
                         poison_size = get_orig_size(s, object);
                 }
         }
 
         if (s->flags & __OBJECT_POISON) {
                 memset_no_sanitize_memory(p, POISON_FREE, poison_size - 1);
                 memset_no_sanitize_memory(p + poison_size - 1, POISON_END, 1);
         }
 
         if (s->flags & SLAB_RED_ZONE)
                 memset_no_sanitize_memory(p + poison_size, val,
                                           s->inuse - poison_size);
 }
 
 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
                                                 void *from, void *to)
 {
         slab_fix(s, "Restoring %s 0x%p-0x%p=0x%x", message, from, to - 1, data);
         memset(from, data, to - from);
 }
 
 #ifdef CONFIG_KMSAN
 #define pad_check_attributes noinline __no_kmsan_checks
 #else
 #define pad_check_attributes
 #endif
 
 static pad_check_attributes int
 check_bytes_and_report(struct kmem_cache *s, struct slab *slab,
                        u8 *object, char *what,
                        u8 *start, unsigned int value, unsigned int bytes)
 {
         u8 *fault;
         u8 *end;
         u8 *addr = slab_address(slab);
 
         metadata_access_enable();
         fault = memchr_inv(kasan_reset_tag(start), value, bytes);
         metadata_access_disable();
         if (!fault)
                 return 1;
 
         end = start + bytes;
         while (end > fault && end[-1] == value)
                 end--;
 
         if (slab_add_kunit_errors())
                 goto skip_bug_print;
 
         slab_bug(s, "%s overwritten", what);
         pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
                                         fault, end - 1, fault - addr,
                                         fault[0], value);
 
 skip_bug_print:
         restore_bytes(s, what, value, fault, end);
         return 0;
 }
 
 /*
  * Object layout:
  *
  * object address
  *      Bytes of the object to be managed.
  *      If the freepointer may overlay the object then the free
  *      pointer is at the middle of the object.
  *
  *      Poisoning uses 0x6b (POISON_FREE) and the last byte is
  *      0xa5 (POISON_END)
  *
  * object + s->object_size
  *      Padding to reach word boundary. This is also used for Redzoning.
  *      Padding is extended by another word if Redzoning is enabled and
  *      object_size == inuse.
  *
  *      We fill with 0xbb (SLUB_RED_INACTIVE) for inactive objects and with
  *      0xcc (SLUB_RED_ACTIVE) for objects in use.
  *
  * object + s->inuse
  *      Meta data starts here.
  *
  *      A. Free pointer (if we cannot overwrite object on free)
  *      B. Tracking data for SLAB_STORE_USER
  *      C. Original request size for kmalloc object (SLAB_STORE_USER enabled)
  *      D. Padding to reach required alignment boundary or at minimum
  *              one word if debugging is on to be able to detect writes
  *              before the word boundary.
  *
  *      Padding is done using 0x5a (POISON_INUSE)
  *
  * object + s->size
  *      Nothing is used beyond s->size.
  *
  * If slabcaches are merged then the object_size and inuse boundaries are mostly
  * ignored. And therefore no slab options that rely on these boundaries
  * may be used with merged slabcaches.
  */
 
 static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p)
 {
         unsigned long off = get_info_end(s);    /* The end of info */
 
         if (s->flags & SLAB_STORE_USER) {
                 /* We also have user information there */
                 off += 2 * sizeof(struct track);
 
                 if (s->flags & SLAB_KMALLOC)
                         off += sizeof(unsigned int);
         }
 
         off += kasan_metadata_size(s, false);
 
         if (size_from_object(s) == off)
                 return 1;
 
         return check_bytes_and_report(s, slab, p, "Object padding",
                         p + off, POISON_INUSE, size_from_object(s) - off);
 }
 
 /* Check the pad bytes at the end of a slab page */
 static pad_check_attributes void
 slab_pad_check(struct kmem_cache *s, struct slab *slab)
 {
         u8 *start;
         u8 *fault;
         u8 *end;
         u8 *pad;
         int length;
         int remainder;
 
         if (!(s->flags & SLAB_POISON))
                 return;
 
         start = slab_address(slab);
         length = slab_size(slab);
         end = start + length;
         remainder = length % s->size;
         if (!remainder)
                 return;
 
         pad = end - remainder;
         metadata_access_enable();
         fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder);
         metadata_access_disable();
         if (!fault)
                 return;
         while (end > fault && end[-1] == POISON_INUSE)
                 end--;
 
         slab_err(s, slab, "Padding overwritten. 0x%p-0x%p @offset=%tu",
                         fault, end - 1, fault - start);
         print_section(KERN_ERR, "Padding ", pad, remainder);
 
         restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
 }
 
 static int check_object(struct kmem_cache *s, struct slab *slab,
                                         void *object, u8 val)
 {
         u8 *p = object;
         u8 *endobject = object + s->object_size;
         unsigned int orig_size, kasan_meta_size;
         int ret = 1;
 
         if (s->flags & SLAB_RED_ZONE) {
                 if (!check_bytes_and_report(s, slab, object, "Left Redzone",
                         object - s->red_left_pad, val, s->red_left_pad))
                         ret = 0;
 
                 if (!check_bytes_and_report(s, slab, object, "Right Redzone",
                         endobject, val, s->inuse - s->object_size))
                         ret = 0;
 
                 if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
                         orig_size = get_orig_size(s, object);
 
                         if (s->object_size > orig_size  &&
                                 !check_bytes_and_report(s, slab, object,
                                         "kmalloc Redzone", p + orig_size,
                                         val, s->object_size - orig_size)) {
                                 ret = 0;
                         }
                 }
         } else {
                 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
                         if (!check_bytes_and_report(s, slab, p, "Alignment padding",
                                 endobject, POISON_INUSE,
                                 s->inuse - s->object_size))
                                 ret = 0;
                 }
         }
 
         if (s->flags & SLAB_POISON) {
                 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON)) {
                         /*
                          * KASAN can save its free meta data inside of the
                          * object at offset 0. Thus, skip checking the part of
                          * the redzone that overlaps with the meta data.
                          */
                         kasan_meta_size = kasan_metadata_size(s, true);
                         if (kasan_meta_size < s->object_size - 1 &&
                             !check_bytes_and_report(s, slab, p, "Poison",
                                         p + kasan_meta_size, POISON_FREE,
                                         s->object_size - kasan_meta_size - 1))
                                 ret = 0;
                         if (kasan_meta_size < s->object_size &&
                             !check_bytes_and_report(s, slab, p, "End Poison",
                                         p + s->object_size - 1, POISON_END, 1))
                                 ret = 0;
                 }
                 /*
                  * check_pad_bytes cleans up on its own.
                  */
                 if (!check_pad_bytes(s, slab, p))
                         ret = 0;
         }
 
         /*
          * Cannot check freepointer while object is allocated if
          * object and freepointer overlap.
          */
         if ((freeptr_outside_object(s) || val != SLUB_RED_ACTIVE) &&
             !check_valid_pointer(s, slab, get_freepointer(s, p))) {
                 object_err(s, slab, p, "Freepointer corrupt");
                 /*
                  * No choice but to zap it and thus lose the remainder
                  * of the free objects in this slab. May cause
                  * another error because the object count is now wrong.
                  */
                 set_freepointer(s, p, NULL);
                 ret = 0;
         }
 
         if (!ret && !slab_in_kunit_test()) {
                 print_trailer(s, slab, object);
                 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
         }
 
         return ret;
 }
 
 static int check_slab(struct kmem_cache *s, struct slab *slab)
 {
         int maxobj;
 
         if (!folio_test_slab(slab_folio(slab))) {
                 slab_err(s, slab, "Not a valid slab page");
                 return 0;
         }
 
         maxobj = order_objects(slab_order(slab), s->size);
         if (slab->objects > maxobj) {
                 slab_err(s, slab, "objects %u > max %u",
                         slab->objects, maxobj);
                 return 0;
         }
         if (slab->inuse > slab->objects) {
                 slab_err(s, slab, "inuse %u > max %u",
                         slab->inuse, slab->objects);
                 return 0;
         }
         /* Slab_pad_check fixes things up after itself */
         slab_pad_check(s, slab);
         return 1;
 }
 
 /*
  * Determine if a certain object in a slab is on the freelist. Must hold the
  * slab lock to guarantee that the chains are in a consistent state.
  */
 static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
 {
         int nr = 0;
         void *fp;
         void *object = NULL;
         int max_objects;
 
         fp = slab->freelist;
         while (fp && nr <= slab->objects) {
                 if (fp == search)
                         return 1;
                 if (!check_valid_pointer(s, slab, fp)) {
                         if (object) {
                                 object_err(s, slab, object,
                                         "Freechain corrupt");
                                 set_freepointer(s, object, NULL);
                         } else {
                                 slab_err(s, slab, "Freepointer corrupt");
                                 slab->freelist = NULL;
                                 slab->inuse = slab->objects;
                                 slab_fix(s, "Freelist cleared");
                                 return 0;
                         }
                         break;
                 }
                 object = fp;
                 fp = get_freepointer(s, object);
                 nr++;
         }
 
         max_objects = order_objects(slab_order(slab), s->size);
         if (max_objects > MAX_OBJS_PER_PAGE)
                 max_objects = MAX_OBJS_PER_PAGE;
 
         if (slab->objects != max_objects) {
                 slab_err(s, slab, "Wrong number of objects. Found %d but should be %d",
                          slab->objects, max_objects);
                 slab->objects = max_objects;
                 slab_fix(s, "Number of objects adjusted");
         }
         if (slab->inuse != slab->objects - nr) {
                 slab_err(s, slab, "Wrong object count. Counter is %d but counted were %d",
                          slab->inuse, slab->objects - nr);
                 slab->inuse = slab->objects - nr;
                 slab_fix(s, "Object count adjusted");
         }
         return search == NULL;
 }
 
 static void trace(struct kmem_cache *s, struct slab *slab, void *object,
                                                                 int alloc)
 {
         if (s->flags & SLAB_TRACE) {
                 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
                         s->name,
                         alloc ? "alloc" : "free",
                         object, slab->inuse,
                         slab->freelist);
 
                 if (!alloc)
                         print_section(KERN_INFO, "Object ", (void *)object,
                                         s->object_size);
 
                 dump_stack();
         }
 }
 
 /*
  * Tracking of fully allocated slabs for debugging purposes.
  */
 static void add_full(struct kmem_cache *s,
         struct kmem_cache_node *n, struct slab *slab)
 {
         if (!(s->flags & SLAB_STORE_USER))
                 return;
 
         lockdep_assert_held(&n->list_lock);
         list_add(&slab->slab_list, &n->full);
 }
 
 static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab)
 {
         if (!(s->flags & SLAB_STORE_USER))
                 return;
 
         lockdep_assert_held(&n->list_lock);
         list_del(&slab->slab_list);
 }
 
 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
 {
         return atomic_long_read(&n->nr_slabs);
 }
 
 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
 {
         struct kmem_cache_node *n = get_node(s, node);
 
         atomic_long_inc(&n->nr_slabs);
         atomic_long_add(objects, &n->total_objects);
 }
 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
 {
         struct kmem_cache_node *n = get_node(s, node);
 
         atomic_long_dec(&n->nr_slabs);
         atomic_long_sub(objects, &n->total_objects);
 }
 
 /* Object debug checks for alloc/free paths */
 static void setup_object_debug(struct kmem_cache *s, void *object)
 {
         if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
                 return;
 
         init_object(s, object, SLUB_RED_INACTIVE);
         init_tracking(s, object);
 }
 
 static
 void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr)
 {
         if (!kmem_cache_debug_flags(s, SLAB_POISON))
                 return;
 
         metadata_access_enable();
         memset(kasan_reset_tag(addr), POISON_INUSE, slab_size(slab));
         metadata_access_disable();
 }
 
 static inline int alloc_consistency_checks(struct kmem_cache *s,
                                         struct slab *slab, void *object)
 {
         if (!check_slab(s, slab))
                 return 0;
 
         if (!check_valid_pointer(s, slab, object)) {
                 object_err(s, slab, object, "Freelist Pointer check fails");
                 return 0;
         }
 
         if (!check_object(s, slab, object, SLUB_RED_INACTIVE))
                 return 0;
 
         return 1;
 }
 
 static noinline bool alloc_debug_processing(struct kmem_cache *s,
                         struct slab *slab, void *object, int orig_size)
 {
         if (s->flags & SLAB_CONSISTENCY_CHECKS) {
                 if (!alloc_consistency_checks(s, slab, object))
                         goto bad;
         }
 
         /* Success. Perform special debug activities for allocs */
         trace(s, slab, object, 1);
         set_orig_size(s, object, orig_size);
         init_object(s, object, SLUB_RED_ACTIVE);
         return true;
 
 bad:
         if (folio_test_slab(slab_folio(slab))) {
                 /*
                  * If this is a slab page then lets do the best we can
                  * to avoid issues in the future. Marking all objects
                  * as used avoids touching the remaining objects.
                  */
                 slab_fix(s, "Marking all objects used");
                 slab->inuse = slab->objects;
                 slab->freelist = NULL;
         }
         return false;
 }
 
 static inline int free_consistency_checks(struct kmem_cache *s,
                 struct slab *slab, void *object, unsigned long addr)
 {
         if (!check_valid_pointer(s, slab, object)) {
                 slab_err(s, slab, "Invalid object pointer 0x%p", object);
                 return 0;
         }
 
         if (on_freelist(s, slab, object)) {
                 object_err(s, slab, object, "Object already free");
                 return 0;
         }
 
         if (!check_object(s, slab, object, SLUB_RED_ACTIVE))
                 return 0;
 
         if (unlikely(s != slab->slab_cache)) {
                 if (!folio_test_slab(slab_folio(slab))) {
                         slab_err(s, slab, "Attempt to free object(0x%p) outside of slab",
                                  object);
                 } else if (!slab->slab_cache) {
                         pr_err("SLUB <none>: no slab for object 0x%p.\n",
                                object);
                         dump_stack();
                 } else
                         object_err(s, slab, object,
                                         "page slab pointer corrupt.");
                 return 0;
         }
         return 1;
 }
 
 /*
  * Parse a block of slab_debug options. Blocks are delimited by ';'
  *
  * @str:    start of block
  * @flags:  returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
  * @slabs:  return start of list of slabs, or NULL when there's no list
  * @init:   assume this is initial parsing and not per-kmem-create parsing
  *
  * returns the start of next block if there's any, or NULL
  */
 static char *
 parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
 {
         bool higher_order_disable = false;
 
         /* Skip any completely empty blocks */
         while (*str && *str == ';')
                 str++;
 
         if (*str == ',') {
                 /*
                  * No options but restriction on slabs. This means full
                  * debugging for slabs matching a pattern.
                  */
                 *flags = DEBUG_DEFAULT_FLAGS;
                 goto check_slabs;
         }
         *flags = 0;
 
         /* Determine which debug features should be switched on */
         for (; *str && *str != ',' && *str != ';'; str++) {
                 switch (tolower(*str)) {
                 case '-':
                         *flags = 0;
                         break;
                 case 'f':
                         *flags |= SLAB_CONSISTENCY_CHECKS;
                         break;
                 case 'z':
                         *flags |= SLAB_RED_ZONE;
                         break;
                 case 'p':
                         *flags |= SLAB_POISON;
                         break;
                 case 'u':
                         *flags |= SLAB_STORE_USER;
                         break;
                 case 't':
                         *flags |= SLAB_TRACE;
                         break;
                 case 'a':
                         *flags |= SLAB_FAILSLAB;
                         break;
                 case 'o':
                         /*
                          * Avoid enabling debugging on caches if its minimum
                          * order would increase as a result.
                          */
                         higher_order_disable = true;
                         break;
                 default:
                         if (init)
                                 pr_err("slab_debug option '%c' unknown. skipped\n", *str);
                 }
         }
 check_slabs:
         if (*str == ',')
                 *slabs = ++str;
         else
                 *slabs = NULL;
 
         /* Skip over the slab list */
         while (*str && *str != ';')
                 str++;
 
         /* Skip any completely empty blocks */
         while (*str && *str == ';')
                 str++;
 
         if (init && higher_order_disable)
                 disable_higher_order_debug = 1;
 
         if (*str)
                 return str;
         else
                 return NULL;
 }
 
 static int __init setup_slub_debug(char *str)
 {
         slab_flags_t flags;
         slab_flags_t global_flags;
         char *saved_str;
         char *slab_list;
         bool global_slub_debug_changed = false;
         bool slab_list_specified = false;
 
         global_flags = DEBUG_DEFAULT_FLAGS;
         if (*str++ != '=' || !*str)
                 /*
                  * No options specified. Switch on full debugging.
                  */
                 goto out;
 
         saved_str = str;
         while (str) {
                 str = parse_slub_debug_flags(str, &flags, &slab_list, true);
 
                 if (!slab_list) {
                         global_flags = flags;
                         global_slub_debug_changed = true;
                 } else {
                         slab_list_specified = true;
                         if (flags & SLAB_STORE_USER)
                                 stack_depot_request_early_init();
                 }
         }
 
         /*
          * For backwards compatibility, a single list of flags with list of
          * slabs means debugging is only changed for those slabs, so the global
          * slab_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
          * on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
          * long as there is no option specifying flags without a slab list.
          */
         if (slab_list_specified) {
                 if (!global_slub_debug_changed)
                         global_flags = slub_debug;
                 slub_debug_string = saved_str;
         }
 out:
         slub_debug = global_flags;
         if (slub_debug & SLAB_STORE_USER)
                 stack_depot_request_early_init();
         if (slub_debug != 0 || slub_debug_string)
                 static_branch_enable(&slub_debug_enabled);
         else
                 static_branch_disable(&slub_debug_enabled);
         if ((static_branch_unlikely(&init_on_alloc) ||
              static_branch_unlikely(&init_on_free)) &&
             (slub_debug & SLAB_POISON))
                 pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
         return 1;
 }
 
 __setup("slab_debug", setup_slub_debug);
 __setup_param("slub_debug", slub_debug, setup_slub_debug, 0);
 
 /*
  * kmem_cache_flags - apply debugging options to the cache
  * @flags:              flags to set
  * @name:               name of the cache
  *
  * Debug option(s) are applied to @flags. In addition to the debug
  * option(s), if a slab name (or multiple) is specified i.e.
  * slab_debug=<Debug-Options>,<slab name1>,<slab name2> ...
  * then only the select slabs will receive the debug option(s).
  */
 slab_flags_t kmem_cache_flags(slab_flags_t flags, const char *name)
 {
         char *iter;
         size_t len;
         char *next_block;
         slab_flags_t block_flags;
         slab_flags_t slub_debug_local = slub_debug;
 
         if (flags & SLAB_NO_USER_FLAGS)
                 return flags;
 
         /*
          * If the slab cache is for debugging (e.g. kmemleak) then
          * don't store user (stack trace) information by default,
          * but let the user enable it via the command line below.
          */
         if (flags & SLAB_NOLEAKTRACE)
                 slub_debug_local &= ~SLAB_STORE_USER;
 
         len = strlen(name);
         next_block = slub_debug_string;
         /* Go through all blocks of debug options, see if any matches our slab's name */
         while (next_block) {
                 next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false);
                 if (!iter)
                         continue;
                 /* Found a block that has a slab list, search it */
                 while (*iter) {
                         char *end, *glob;
                         size_t cmplen;
 
                         end = strchrnul(iter, ',');
                         if (next_block && next_block < end)
                                 end = next_block - 1;
 
                         glob = strnchr(iter, end - iter, '*');
                         if (glob)
                                 cmplen = glob - iter;
                         else
                                 cmplen = max_t(size_t, len, (end - iter));
 
                         if (!strncmp(name, iter, cmplen)) {
                                 flags |= block_flags;
                                 return flags;
                         }
 
                         if (!*end || *end == ';')
                                 break;
                         iter = end + 1;
                 }
         }
 
         return flags | slub_debug_local;
 }
 #else /* !CONFIG_SLUB_DEBUG */
 static inline void setup_object_debug(struct kmem_cache *s, void *object) {}
 static inline
 void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr) {}
 
 static inline bool alloc_debug_processing(struct kmem_cache *s,
         struct slab *slab, void *object, int orig_size) { return true; }
 
 static inline bool free_debug_processing(struct kmem_cache *s,
         struct slab *slab, void *head, void *tail, int *bulk_cnt,
         unsigned long addr, depot_stack_handle_t handle) { return true; }
 
 static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {}
 static inline int check_object(struct kmem_cache *s, struct slab *slab,
                         void *object, u8 val) { return 1; }
 static inline depot_stack_handle_t set_track_prepare(void) { return 0; }
 static inline void set_track(struct kmem_cache *s, void *object,
                              enum track_item alloc, unsigned long addr) {}
 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
                                         struct slab *slab) {}
 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
                                         struct slab *slab) {}
 slab_flags_t kmem_cache_flags(slab_flags_t flags, const char *name)
 {
         return flags;
 }
 #define slub_debug 0
 
 #define disable_higher_order_debug 0
 
 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
                                                         { return 0; }
 static inline void inc_slabs_node(struct kmem_cache *s, int node,
                                                         int objects) {}
 static inline void dec_slabs_node(struct kmem_cache *s, int node,
                                                         int objects) {}
 #ifndef CONFIG_SLUB_TINY
 static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
                                void **freelist, void *nextfree)
 {
         return false;
 }
 #endif
 #endif /* CONFIG_SLUB_DEBUG */
 
 #ifdef CONFIG_SLAB_OBJ_EXT
 
 #ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG
 
 static inline void mark_objexts_empty(struct slabobj_ext *obj_exts)
 {
         struct slabobj_ext *slab_exts;
         struct slab *obj_exts_slab;
 
         obj_exts_slab = virt_to_slab(obj_exts);
         slab_exts = slab_obj_exts(obj_exts_slab);
         if (slab_exts) {
                 unsigned int offs = obj_to_index(obj_exts_slab->slab_cache,
                                                  obj_exts_slab, obj_exts);
                 /* codetag should be NULL */
                 WARN_ON(slab_exts[offs].ref.ct);
                 set_codetag_empty(&slab_exts[offs].ref);
         }
 }
 
 static inline void mark_failed_objexts_alloc(struct slab *slab)
 {
         slab->obj_exts = OBJEXTS_ALLOC_FAIL;
 }
 
 static inline void handle_failed_objexts_alloc(unsigned long obj_exts,
                         struct slabobj_ext *vec, unsigned int objects)
 {
         /*
          * If vector previously failed to allocate then we have live
          * objects with no tag reference. Mark all references in this
          * vector as empty to avoid warnings later on.
          */
         if (obj_exts & OBJEXTS_ALLOC_FAIL) {
                 unsigned int i;
 
                 for (i = 0; i < objects; i++)
                         set_codetag_empty(&vec[i].ref);
         }
 }
 
 #else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
 
 static inline void mark_objexts_empty(struct slabobj_ext *obj_exts) {}
 static inline void mark_failed_objexts_alloc(struct slab *slab) {}
 static inline void handle_failed_objexts_alloc(unsigned long obj_exts,
                         struct slabobj_ext *vec, unsigned int objects) {}
 
 #endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
 
 /*
  * The allocated objcg pointers array is not accounted directly.
  * Moreover, it should not come from DMA buffer and is not readily
  * reclaimable. So those GFP bits should be masked off.
  */
 #define OBJCGS_CLEAR_MASK       (__GFP_DMA | __GFP_RECLAIMABLE | \
                                 __GFP_ACCOUNT | __GFP_NOFAIL)
 
 int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
                         gfp_t gfp, bool new_slab)
 {
         unsigned int objects = objs_per_slab(s, slab);
         unsigned long new_exts;
         unsigned long old_exts;
         struct slabobj_ext *vec;
 
         gfp &= ~OBJCGS_CLEAR_MASK;
         /* Prevent recursive extension vector allocation */
         gfp |= __GFP_NO_OBJ_EXT;
         vec = kcalloc_node(objects, sizeof(struct slabobj_ext), gfp,
                            slab_nid(slab));
         if (!vec) {
                 /* Mark vectors which failed to allocate */
                 if (new_slab)
                         mark_failed_objexts_alloc(slab);
 
                 return -ENOMEM;
         }
 
         new_exts = (unsigned long)vec;
 #ifdef CONFIG_MEMCG
         new_exts |= MEMCG_DATA_OBJEXTS;
 #endif
         old_exts = READ_ONCE(slab->obj_exts);
         handle_failed_objexts_alloc(old_exts, vec, objects);
         if (new_slab) {
                 /*
                  * If the slab is brand new and nobody can yet access its
                  * obj_exts, no synchronization is required and obj_exts can
                  * be simply assigned.
                  */
                 slab->obj_exts = new_exts;
         } else if ((old_exts & ~OBJEXTS_FLAGS_MASK) ||
                    cmpxchg(&slab->obj_exts, old_exts, new_exts) != old_exts) {
                 /*
                  * If the slab is already in use, somebody can allocate and
                  * assign slabobj_exts in parallel. In this case the existing
                  * objcg vector should be reused.
                  */
                 mark_objexts_empty(vec);
                 kfree(vec);
                 return 0;
         }
 
         kmemleak_not_leak(vec);
         return 0;
 }
 
 static inline void free_slab_obj_exts(struct slab *slab)
 {
         struct slabobj_ext *obj_exts;
 
         obj_exts = slab_obj_exts(slab);
         if (!obj_exts)
                 return;
 
         /*
          * obj_exts was created with __GFP_NO_OBJ_EXT flag, therefore its
          * corresponding extension will be NULL. alloc_tag_sub() will throw a
          * warning if slab has extensions but the extension of an object is
          * NULL, therefore replace NULL with CODETAG_EMPTY to indicate that
          * the extension for obj_exts is expected to be NULL.
          */
         mark_objexts_empty(obj_exts);
         kfree(obj_exts);
         slab->obj_exts = 0;
 }
 
 static inline bool need_slab_obj_ext(void)
 {
         if (mem_alloc_profiling_enabled())
                 return true;
 
         /*
          * CONFIG_MEMCG creates vector of obj_cgroup objects conditionally
          * inside memcg_slab_post_alloc_hook. No other users for now.
          */
         return false;
 }
 
 #else /* CONFIG_SLAB_OBJ_EXT */
 
 static int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
                                gfp_t gfp, bool new_slab)
 {
         return 0;
 }
 
 static inline void free_slab_obj_exts(struct slab *slab)
 {
 }
 
 static inline bool need_slab_obj_ext(void)
 {
         return false;
 }
 
 #endif /* CONFIG_SLAB_OBJ_EXT */
 
 #ifdef CONFIG_MEM_ALLOC_PROFILING
 
 static inline struct slabobj_ext *
 prepare_slab_obj_exts_hook(struct kmem_cache *s, gfp_t flags, void *p)
 {
         struct slab *slab;
 
         if (!p)
                 return NULL;
 
         if (s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE))
                 return NULL;
 
         if (flags & __GFP_NO_OBJ_EXT)
                 return NULL;
 
         slab = virt_to_slab(p);
         if (!slab_obj_exts(slab) &&
             WARN(alloc_slab_obj_exts(slab, s, flags, false),
                  "%s, %s: Failed to create slab extension vector!\n",
                  __func__, s->name))
                 return NULL;
 
         return slab_obj_exts(slab) + obj_to_index(s, slab, p);
 }
 
 static inline void
 alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags)
 {
         if (need_slab_obj_ext()) {
                 struct slabobj_ext *obj_exts;
 
                 obj_exts = prepare_slab_obj_exts_hook(s, flags, object);
                 /*
                  * Currently obj_exts is used only for allocation profiling.
                  * If other users appear then mem_alloc_profiling_enabled()
                  * check should be added before alloc_tag_add().
                  */
                 if (likely(obj_exts))
                         alloc_tag_add(&obj_exts->ref, current->alloc_tag, s->size);
         }
 }
 
 static inline void
 alloc_tagging_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p,
                              int objects)
 {
         struct slabobj_ext *obj_exts;
         int i;
 
         if (!mem_alloc_profiling_enabled())
                 return;
 
         /* slab->obj_exts might not be NULL if it was created for MEMCG accounting. */
         if (s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE))
                 return;
 
         obj_exts = slab_obj_exts(slab);
         if (!obj_exts)
                 return;
 
         for (i = 0; i < objects; i++) {
                 unsigned int off = obj_to_index(s, slab, p[i]);
 
                 alloc_tag_sub(&obj_exts[off].ref, s->size);
         }
 }
 
 #else /* CONFIG_MEM_ALLOC_PROFILING */
 
 static inline void
 alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags)
 {
 }
 
 static inline void
 alloc_tagging_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p,
                              int objects)
 {
 }
 
 #endif /* CONFIG_MEM_ALLOC_PROFILING */
 
 
 #ifdef CONFIG_MEMCG
 
 static void memcg_alloc_abort_single(struct kmem_cache *s, void *object);
 
 static __fastpath_inline
 bool memcg_slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru,
                                 gfp_t flags, size_t size, void **p)
 {
         if (likely(!memcg_kmem_online()))
                 return true;
 
         if (likely(!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT)))
                 return true;
 
         if (likely(__memcg_slab_post_alloc_hook(s, lru, flags, size, p)))
                 return true;
 
         if (likely(size == 1)) {
                 memcg_alloc_abort_single(s, *p);
                 *p = NULL;
         } else {
                 kmem_cache_free_bulk(s, size, p);
         }
 
         return false;
 }
 
 static __fastpath_inline
 void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p,
                           int objects)
 {
         struct slabobj_ext *obj_exts;
 
         if (!memcg_kmem_online())
                 return;
 
         obj_exts = slab_obj_exts(slab);
         if (likely(!obj_exts))
                 return;
 
         __memcg_slab_free_hook(s, slab, p, objects, obj_exts);
 }
 #else /* CONFIG_MEMCG */
 static inline bool memcg_slab_post_alloc_hook(struct kmem_cache *s,
                                               struct list_lru *lru,
                                               gfp_t flags, size_t size,
                                               void **p)
 {
         return true;
 }
 
 static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
                                         void **p, int objects)
 {
 }
 #endif /* CONFIG_MEMCG */
 
 /*
  * Hooks for other subsystems that check memory allocations. In a typical
  * production configuration these hooks all should produce no code at all.
  *
  * Returns true if freeing of the object can proceed, false if its reuse
  * was delayed by KASAN quarantine, or it was returned to KFENCE.
  */
 static __always_inline
 bool slab_free_hook(struct kmem_cache *s, void *x, bool init)
 {
         kmemleak_free_recursive(x, s->flags);
         kmsan_slab_free(s, x);
 
         debug_check_no_locks_freed(x, s->object_size);
 
         if (!(s->flags & SLAB_DEBUG_OBJECTS))
                 debug_check_no_obj_freed(x, s->object_size);
 
         /* Use KCSAN to help debug racy use-after-free. */
         if (!(s->flags & SLAB_TYPESAFE_BY_RCU))
                 __kcsan_check_access(x, s->object_size,
                                      KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
 
         if (kfence_free(x))
                 return false;
 
         /*
          * As memory initialization might be integrated into KASAN,
          * kasan_slab_free and initialization memset's must be
          * kept together to avoid discrepancies in behavior.
          *
          * The initialization memset's clear the object and the metadata,
          * but don't touch the SLAB redzone.
          *
          * The object's freepointer is also avoided if stored outside the
          * object.
          */
         if (unlikely(init)) {
                 int rsize;
                 unsigned int inuse, orig_size;
 
                 inuse = get_info_end(s);
                 orig_size = get_orig_size(s, x);
                 if (!kasan_has_integrated_init())
                         memset(kasan_reset_tag(x), 0, orig_size);
                 rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad : 0;
                 memset((char *)kasan_reset_tag(x) + inuse, 0,
                        s->size - inuse - rsize);
                 /*
                  * Restore orig_size, otherwize kmalloc redzone overwritten
                  * would be reported
                  */
                 set_orig_size(s, x, orig_size);
 
         }
         /* KASAN might put x into memory quarantine, delaying its reuse. */
         return !kasan_slab_free(s, x, init);
 }
 
 static __fastpath_inline
 bool slab_free_freelist_hook(struct kmem_cache *s, void **head, void **tail,
                              int *cnt)
 {
 
         void *object;
         void *next = *head;
         void *old_tail = *tail;
         bool init;
 
         if (is_kfence_address(next)) {
                 slab_free_hook(s, next, false);
                 return false;
         }
 
         /* Head and tail of the reconstructed freelist */
         *head = NULL;
         *tail = NULL;
 
         init = slab_want_init_on_free(s);
 
         do {
                 object = next;
                 next = get_freepointer(s, object);
 
                 /* If object's reuse doesn't have to be delayed */
                 if (likely(slab_free_hook(s, object, init))) {
                         /* Move object to the new freelist */
                         set_freepointer(s, object, *head);
                         *head = object;
                         if (!*tail)
                                 *tail = object;
                 } else {
                         /*
                          * Adjust the reconstructed freelist depth
                          * accordingly if object's reuse is delayed.
                          */
                         --(*cnt);
                 }
         } while (object != old_tail);
 
         return *head != NULL;
 }
 
 static void *setup_object(struct kmem_cache *s, void *object)
 {
         setup_object_debug(s, object);
         object = kasan_init_slab_obj(s, object);
         if (unlikely(s->ctor)) {
                 kasan_unpoison_new_object(s, object);
                 s->ctor(object);
                 kasan_poison_new_object(s, object);
         }
         return object;
 }
 
 /*
  * Slab allocation and freeing
  */
 static inline struct slab *alloc_slab_page(gfp_t flags, int node,
                 struct kmem_cache_order_objects oo)
 {
         struct folio *folio;
         struct slab *slab;
         unsigned int order = oo_order(oo);
 
         folio = (struct folio *)alloc_pages_node(node, flags, order);
         if (!folio)
                 return NULL;
 
         slab = folio_slab(folio);
         __folio_set_slab(folio);
         /* Make the flag visible before any changes to folio->mapping */
         smp_wmb();
         if (folio_is_pfmemalloc(folio))
                 slab_set_pfmemalloc(slab);
 
         return slab;
 }
 
 #ifdef CONFIG_SLAB_FREELIST_RANDOM
 /* Pre-initialize the random sequence cache */
 static int init_cache_random_seq(struct kmem_cache *s)
 {
         unsigned int count = oo_objects(s->oo);
         int err;
 
         /* Bailout if already initialised */
         if (s->random_seq)
                 return 0;
 
         err = cache_random_seq_create(s, count, GFP_KERNEL);
         if (err) {
                 pr_err("SLUB: Unable to initialize free list for %s\n",
                         s->name);
                 return err;
         }
 
         /* Transform to an offset on the set of pages */
         if (s->random_seq) {
                 unsigned int i;
 
                 for (i = 0; i < count; i++)
                         s->random_seq[i] *= s->size;
         }
         return 0;
 }
 
 /* Initialize each random sequence freelist per cache */
 static void __init init_freelist_randomization(void)
 {
         struct kmem_cache *s;
 
         mutex_lock(&slab_mutex);
 
         list_for_each_entry(s, &slab_caches, list)
                 init_cache_random_seq(s);
 
         mutex_unlock(&slab_mutex);
 }
 
 /* Get the next entry on the pre-computed freelist randomized */
 static void *next_freelist_entry(struct kmem_cache *s,
                                 unsigned long *pos, void *start,
                                 unsigned long page_limit,
                                 unsigned long freelist_count)
 {
         unsigned int idx;
 
         /*
          * If the target page allocation failed, the number of objects on the
          * page might be smaller than the usual size defined by the cache.
          */
         do {
                 idx = s->random_seq[*pos];
                 *pos += 1;
                 if (*pos >= freelist_count)
                         *pos = 0;
         } while (unlikely(idx >= page_limit));
 
         return (char *)start + idx;
 }
 
 /* Shuffle the single linked freelist based on a random pre-computed sequence */
 static bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
 {
         void *start;
         void *cur;
         void *next;
         unsigned long idx, pos, page_limit, freelist_count;
 
         if (slab->objects < 2 || !s->random_seq)
                 return false;
 
         freelist_count = oo_objects(s->oo);
         pos = get_random_u32_below(freelist_count);
 
         page_limit = slab->objects * s->size;
         start = fixup_red_left(s, slab_address(slab));
 
         /* First entry is used as the base of the freelist */
         cur = next_freelist_entry(s, &pos, start, page_limit, freelist_count);
         cur = setup_object(s, cur);
         slab->freelist = cur;
 
         for (idx = 1; idx < slab->objects; idx++) {
                 next = next_freelist_entry(s, &pos, start, page_limit,
                         freelist_count);
                 next = setup_object(s, next);
                 set_freepointer(s, cur, next);
                 cur = next;
         }
         set_freepointer(s, cur, NULL);
 
         return true;
 }
 #else
 static inline int init_cache_random_seq(struct kmem_cache *s)
 {
         return 0;
 }
 static inline void init_freelist_randomization(void) { }
 static inline bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
 {
         return false;
 }
 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
 
 static __always_inline void account_slab(struct slab *slab, int order,
                                          struct kmem_cache *s, gfp_t gfp)
 {
         if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT))
                 alloc_slab_obj_exts(slab, s, gfp, true);
 
         mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
                             PAGE_SIZE << order);
 }
 
 static __always_inline void unaccount_slab(struct slab *slab, int order,
                                            struct kmem_cache *s)
 {
         if (memcg_kmem_online() || need_slab_obj_ext())
                 free_slab_obj_exts(slab);
 
         mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
                             -(PAGE_SIZE << order));
 }
 
 static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 {
         struct slab *slab;
         struct kmem_cache_order_objects oo = s->oo;
         gfp_t alloc_gfp;
         void *start, *p, *next;
         int idx;
         bool shuffle;
 
         flags &= gfp_allowed_mask;
 
         flags |= s->allocflags;
 
         /*
          * Let the initial higher-order allocation fail under memory pressure
          * so we fall-back to the minimum order allocation.
          */
         alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
         if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
                 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_RECLAIM;
 
         slab = alloc_slab_page(alloc_gfp, node, oo);
         if (unlikely(!slab)) {
                 oo = s->min;
                 alloc_gfp = flags;
                 /*
                  * Allocation may have failed due to fragmentation.
                  * Try a lower order alloc if possible
                  */
                 slab = alloc_slab_page(alloc_gfp, node, oo);
                 if (unlikely(!slab))
                         return NULL;
                 stat(s, ORDER_FALLBACK);
         }
 
         slab->objects = oo_objects(oo);
         slab->inuse = 0;
         slab->frozen = 0;
 
         account_slab(slab, oo_order(oo), s, flags);
 
         slab->slab_cache = s;
 
         kasan_poison_slab(slab);
 
         start = slab_address(slab);
 
         setup_slab_debug(s, slab, start);
 
         shuffle = shuffle_freelist(s, slab);
 
         if (!shuffle) {
                 start = fixup_red_left(s, start);
                 start = setup_object(s, start);
                 slab->freelist = start;
                 for (idx = 0, p = start; idx < slab->objects - 1; idx++) {
                         next = p + s->size;
                         next = setup_object(s, next);
                         set_freepointer(s, p, next);
                         p = next;
                 }
                 set_freepointer(s, p, NULL);
         }
 
         return slab;
 }
 
 static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node)
 {
         if (unlikely(flags & GFP_SLAB_BUG_MASK))
                 flags = kmalloc_fix_flags(flags);
 
         WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
 
         return allocate_slab(s,
                 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
 }
 
 static void __free_slab(struct kmem_cache *s, struct slab *slab)
 {
         struct folio *folio = slab_folio(slab);
         int order = folio_order(folio);
         int pages = 1 << order;
 
         __slab_clear_pfmemalloc(slab);
         folio->mapping = NULL;
         /* Make the mapping reset visible before clearing the flag */
         smp_wmb();
         __folio_clear_slab(folio);
         mm_account_reclaimed_pages(pages);
         unaccount_slab(slab, order, s);
         __free_pages(&folio->page, order);
 }
 
 static void rcu_free_slab(struct rcu_head *h)
 {
         struct slab *slab = container_of(h, struct slab, rcu_head);
 
         __free_slab(slab->slab_cache, slab);
 }
 
 static void free_slab(struct kmem_cache *s, struct slab *slab)
 {
         if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
                 void *p;
 
                 slab_pad_check(s, slab);
                 for_each_object(p, s, slab_address(slab), slab->objects)
                         check_object(s, slab, p, SLUB_RED_INACTIVE);
         }
 
         if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU))
                 call_rcu(&slab->rcu_head, rcu_free_slab);
         else
                 __free_slab(s, slab);
 }
 
 static void discard_slab(struct kmem_cache *s, struct slab *slab)
 {
         dec_slabs_node(s, slab_nid(slab), slab->objects);
         free_slab(s, slab);
 }
 
 /*
  * SLUB reuses PG_workingset bit to keep track of whether it's on
  * the per-node partial list.
  */
 static inline bool slab_test_node_partial(const struct slab *slab)
 {
         return folio_test_workingset(slab_folio(slab));
 }
 
 static inline void slab_set_node_partial(struct slab *slab)
 {
         set_bit(PG_workingset, folio_flags(slab_folio(slab), 0));
 }
 
 static inline void slab_clear_node_partial(struct slab *slab)
 {
         clear_bit(PG_workingset, folio_flags(slab_folio(slab), 0));
 }
 
 /*
  * Management of partially allocated slabs.
  */
 static inline void
 __add_partial(struct kmem_cache_node *n, struct slab *slab, int tail)
 {
         n->nr_partial++;
         if (tail == DEACTIVATE_TO_TAIL)
                 list_add_tail(&slab->slab_list, &n->partial);
         else
                 list_add(&slab->slab_list, &n->partial);
         slab_set_node_partial(slab);
 }
 
 static inline void add_partial(struct kmem_cache_node *n,
                                 struct slab *slab, int tail)
 {
         lockdep_assert_held(&n->list_lock);
         __add_partial(n, slab, tail);
 }
 
 static inline void remove_partial(struct kmem_cache_node *n,
                                         struct slab *slab)
 {
         lockdep_assert_held(&n->list_lock);
         list_del(&slab->slab_list);
         slab_clear_node_partial(slab);
         n->nr_partial--;
 }
 
 /*
  * Called only for kmem_cache_debug() caches instead of remove_partial(), with a
  * slab from the n->partial list. Remove only a single object from the slab, do
  * the alloc_debug_processing() checks and leave the slab on the list, or move
  * it to full list if it was the last free object.
  */
 static void *alloc_single_from_partial(struct kmem_cache *s,
                 struct kmem_cache_node *n, struct slab *slab, int orig_size)
 {
         void *object;
 
         lockdep_assert_held(&n->list_lock);
 
         object = slab->freelist;
         slab->freelist = get_freepointer(s, object);
         slab->inuse++;
 
         if (!alloc_debug_processing(s, slab, object, orig_size)) {
                 remove_partial(n, slab);
                 return NULL;
         }
 
         if (slab->inuse == slab->objects) {
                 remove_partial(n, slab);
                 add_full(s, n, slab);
         }
 
         return object;
 }
 
 /*
  * Called only for kmem_cache_debug() caches to allocate from a freshly
  * allocated slab. Allocate a single object instead of whole freelist
  * and put the slab to the partial (or full) list.
  */
 static void *alloc_single_from_new_slab(struct kmem_cache *s,
                                         struct slab *slab, int orig_size)
 {
         int nid = slab_nid(slab);
         struct kmem_cache_node *n = get_node(s, nid);
         unsigned long flags;
         void *object;
 
 
         object = slab->freelist;
         slab->freelist = get_freepointer(s, object);
         slab->inuse = 1;
 
         if (!alloc_debug_processing(s, slab, object, orig_size))
                 /*
                  * It's not really expected that this would fail on a
                  * freshly allocated slab, but a concurrent memory
                  * corruption in theory could cause that.
                  */
                 return NULL;
 
         spin_lock_irqsave(&n->list_lock, flags);
 
         if (slab->inuse == slab->objects)
                 add_full(s, n, slab);
         else
                 add_partial(n, slab, DEACTIVATE_TO_HEAD);
 
         inc_slabs_node(s, nid, slab->objects);
         spin_unlock_irqrestore(&n->list_lock, flags);
 
         return object;
 }
 
 #ifdef CONFIG_SLUB_CPU_PARTIAL
 static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain);
 #else
 static inline void put_cpu_partial(struct kmem_cache *s, struct slab *slab,
                                    int drain) { }
 #endif
 static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
 
 /*
  * Try to allocate a partial slab from a specific node.
  */
 static struct slab *get_partial_node(struct kmem_cache *s,
                                      struct kmem_cache_node *n,
                                      struct partial_context *pc)
 {
         struct slab *slab, *slab2, *partial = NULL;
         unsigned long flags;
         unsigned int partial_slabs = 0;
 
         /*
          * Racy check. If we mistakenly see no partial slabs then we
          * just allocate an empty slab. If we mistakenly try to get a
          * partial slab and there is none available then get_partial()
          * will return NULL.
          */
         if (!n || !n->nr_partial)
                 return NULL;
 
         spin_lock_irqsave(&n->list_lock, flags);
         list_for_each_entry_safe(slab, slab2, &n->partial, slab_list) {
                 if (!pfmemalloc_match(slab, pc->flags))
                         continue;
 
                 if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
                         void *object = alloc_single_from_partial(s, n, slab,
                                                         pc->orig_size);
                         if (object) {
                                 partial = slab;
                                 pc->object = object;
                                 break;
                         }
                         continue;
                 }
 
                 remove_partial(n, slab);
 
                 if (!partial) {
                         partial = slab;
                         stat(s, ALLOC_FROM_PARTIAL);
 
                         if ((slub_get_cpu_partial(s) == 0)) {
                                 break;
                         }
                 } else {
                         put_cpu_partial(s, slab, 0);
                         stat(s, CPU_PARTIAL_NODE);
 
                         if (++partial_slabs > slub_get_cpu_partial(s) / 2) {
                                 break;
                         }
                 }
         }
         spin_unlock_irqrestore(&n->list_lock, flags);
         return partial;
 }
 
 /*
  * Get a slab from somewhere. Search in increasing NUMA distances.
  */
 static struct slab *get_any_partial(struct kmem_cache *s,
                                     struct partial_context *pc)
 {
 #ifdef CONFIG_NUMA
         struct zonelist *zonelist;
         struct zoneref *z;
         struct zone *zone;
         enum zone_type highest_zoneidx = gfp_zone(pc->flags);
         struct slab *slab;
         unsigned int cpuset_mems_cookie;
 
         /*
          * The defrag ratio allows a configuration of the tradeoffs between
          * inter node defragmentation and node local allocations. A lower
          * defrag_ratio increases the tendency to do local allocations
          * instead of attempting to obtain partial slabs from other nodes.
          *
          * If the defrag_ratio is set to 0 then kmalloc() always
          * returns node local objects. If the ratio is higher then kmalloc()
          * may return off node objects because partial slabs are obtained
          * from other nodes and filled up.
          *
          * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
          * (which makes defrag_ratio = 1000) then every (well almost)
          * allocation will first attempt to defrag slab caches on other nodes.
          * This means scanning over all nodes to look for partial slabs which
          * may be expensive if we do it every time we are trying to find a slab
          * with available objects.
          */
         if (!s->remote_node_defrag_ratio ||
                         get_cycles() % 1024 > s->remote_node_defrag_ratio)
                 return NULL;
 
         do {
                 cpuset_mems_cookie = read_mems_allowed_begin();
                 zonelist = node_zonelist(mempolicy_slab_node(), pc->flags);
                 for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
                         struct kmem_cache_node *n;
 
                         n = get_node(s, zone_to_nid(zone));
 
                         if (n && cpuset_zone_allowed(zone, pc->flags) &&
                                         n->nr_partial > s->min_partial) {
                                 slab = get_partial_node(s, n, pc);
                                 if (slab) {
                                         /*
                                          * Don't check read_mems_allowed_retry()
                                          * here - if mems_allowed was updated in
                                          * parallel, that was a harmless race
                                          * between allocation and the cpuset
                                          * update
                                          */
                                         return slab;
                                 }
                         }
                 }
         } while (read_mems_allowed_retry(cpuset_mems_cookie));
 #endif  /* CONFIG_NUMA */
         return NULL;
 }
 
 /*
  * Get a partial slab, lock it and return it.
  */
 static struct slab *get_partial(struct kmem_cache *s, int node,
                                 struct partial_context *pc)
 {
         struct slab *slab;
         int searchnode = node;
 
         if (node == NUMA_NO_NODE)
                 searchnode = numa_mem_id();
 
         slab = get_partial_node(s, get_node(s, searchnode), pc);
         if (slab || (node != NUMA_NO_NODE && (pc->flags & __GFP_THISNODE)))
                 return slab;
 
         return get_any_partial(s, pc);
 }
 
 #ifndef CONFIG_SLUB_TINY
 
 #ifdef CONFIG_PREEMPTION
 /*
  * Calculate the next globally unique transaction for disambiguation
  * during cmpxchg. The transactions start with the cpu number and are then
  * incremented by CONFIG_NR_CPUS.
  */
 #define TID_STEP  roundup_pow_of_two(CONFIG_NR_CPUS)
 #else
 /*
  * No preemption supported therefore also no need to check for
  * different cpus.
  */
 #define TID_STEP 1
 #endif /* CONFIG_PREEMPTION */
 
 static inline unsigned long next_tid(unsigned long tid)
 {
         return tid + TID_STEP;
 }
 
 #ifdef SLUB_DEBUG_CMPXCHG
 static inline unsigned int tid_to_cpu(unsigned long tid)
 {
         return tid % TID_STEP;
 }
 
 static inline unsigned long tid_to_event(unsigned long tid)
 {
         return tid / TID_STEP;
 }
 #endif
 
 static inline unsigned int init_tid(int cpu)
 {
         return cpu;
 }
 
 static inline void note_cmpxchg_failure(const char *n,
                 const struct kmem_cache *s, unsigned long tid)
 {
 #ifdef SLUB_DEBUG_CMPXCHG
         unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
 
         pr_info("%s %s: cmpxchg redo ", n, s->name);
 
 #ifdef CONFIG_PREEMPTION
         if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
                 pr_warn("due to cpu change %d -> %d\n",
                         tid_to_cpu(tid), tid_to_cpu(actual_tid));
         else
 #endif
         if (tid_to_event(tid) != tid_to_event(actual_tid))
                 pr_warn("due to cpu running other code. Event %ld->%ld\n",
                         tid_to_event(tid), tid_to_event(actual_tid));
         else
                 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
                         actual_tid, tid, next_tid(tid));
 #endif
         stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
 }
 
 static void init_kmem_cache_cpus(struct kmem_cache *s)
 {
         int cpu;
         struct kmem_cache_cpu *c;
 
         for_each_possible_cpu(cpu) {
                 c = per_cpu_ptr(s->cpu_slab, cpu);
                 local_lock_init(&c->lock);
                 c->tid = init_tid(cpu);
         }
 }
 
 /*
  * Finishes removing the cpu slab. Merges cpu's freelist with slab's freelist,
  * unfreezes the slabs and puts it on the proper list.
  * Assumes the slab has been already safely taken away from kmem_cache_cpu
  * by the caller.
  */
 static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
                             void *freelist)
 {
         struct kmem_cache_node *n = get_node(s, slab_nid(slab));
         int free_delta = 0;
         void *nextfree, *freelist_iter, *freelist_tail;
         int tail = DEACTIVATE_TO_HEAD;
         unsigned long flags = 0;
         struct slab new;
         struct slab old;
 
         if (READ_ONCE(slab->freelist)) {
                 stat(s, DEACTIVATE_REMOTE_FREES);
                 tail = DEACTIVATE_TO_TAIL;
         }
 
         /*
          * Stage one: Count the objects on cpu's freelist as free_delta and
          * remember the last object in freelist_tail for later splicing.
          */
         freelist_tail = NULL;
         freelist_iter = freelist;
         while (freelist_iter) {
                 nextfree = get_freepointer(s, freelist_iter);
 
                 /*
                  * If 'nextfree' is invalid, it is possible that the object at
                  * 'freelist_iter' is already corrupted.  So isolate all objects
                  * starting at 'freelist_iter' by skipping them.
                  */
                 if (freelist_corrupted(s, slab, &freelist_iter, nextfree))
                         break;
 
                 freelist_tail = freelist_iter;
                 free_delta++;
 
                 freelist_iter = nextfree;
         }
 
         /*
          * Stage two: Unfreeze the slab while splicing the per-cpu
          * freelist to the head of slab's freelist.
          */
         do {
                 old.freelist = READ_ONCE(slab->freelist);
                 old.counters = READ_ONCE(slab->counters);
                 VM_BUG_ON(!old.frozen);
 
                 /* Determine target state of the slab */
                 new.counters = old.counters;
                 new.frozen = 0;
                 if (freelist_tail) {
                         new.inuse -= free_delta;
                         set_freepointer(s, freelist_tail, old.freelist);
                         new.freelist = freelist;
                 } else {
                         new.freelist = old.freelist;
                 }
         } while (!slab_update_freelist(s, slab,
                 old.freelist, old.counters,
                 new.freelist, new.counters,
                 "unfreezing slab"));
 
         /*
          * Stage three: Manipulate the slab list based on the updated state.
          */
         if (!new.inuse && n->nr_partial >= s->min_partial) {
                 stat(s, DEACTIVATE_EMPTY);
                 discard_slab(s, slab);
                 stat(s, FREE_SLAB);
         } else if (new.freelist) {
                 spin_lock_irqsave(&n->list_lock, flags);
                 add_partial(n, slab, tail);
                 spin_unlock_irqrestore(&n->list_lock, flags);
                 stat(s, tail);
         } else {
                 stat(s, DEACTIVATE_FULL);
         }
 }
 
 #ifdef CONFIG_SLUB_CPU_PARTIAL
 static void __put_partials(struct kmem_cache *s, struct slab *partial_slab)
 {
         struct kmem_cache_node *n = NULL, *n2 = NULL;
         struct slab *slab, *slab_to_discard = NULL;
         unsigned long flags = 0;
 
         while (partial_slab) {
                 slab = partial_slab;
                 partial_slab = slab->next;
 
                 n2 = get_node(s, slab_nid(slab));
                 if (n != n2) {
                         if (n)
                                 spin_unlock_irqrestore(&n->list_lock, flags);
 
                         n = n2;
                         spin_lock_irqsave(&n->list_lock, flags);
                 }
 
                 if (unlikely(!slab->inuse && n->nr_partial >= s->min_partial)) {
                         slab->next = slab_to_discard;
                         slab_to_discard = slab;
                 } else {
                         add_partial(n, slab, DEACTIVATE_TO_TAIL);
                         stat(s, FREE_ADD_PARTIAL);
                 }
         }
 
         if (n)
                 spin_unlock_irqrestore(&n->list_lock, flags);
 
         while (slab_to_discard) {
                 slab = slab_to_discard;
                 slab_to_discard = slab_to_discard->next;
 
                 stat(s, DEACTIVATE_EMPTY);
                 discard_slab(s, slab);
                 stat(s, FREE_SLAB);
         }
 }
 
 /*
  * Put all the cpu partial slabs to the node partial list.
  */
 static void put_partials(struct kmem_cache *s)
 {
         struct slab *partial_slab;
         unsigned long flags;
 
         local_lock_irqsave(&s->cpu_slab->lock, flags);
         partial_slab = this_cpu_read(s->cpu_slab->partial);
         this_cpu_write(s->cpu_slab->partial, NULL);
         local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 
         if (partial_slab)
                 __put_partials(s, partial_slab);
 }
 
 static void put_partials_cpu(struct kmem_cache *s,
                              struct kmem_cache_cpu *c)
 {
         struct slab *partial_slab;
 
         partial_slab = slub_percpu_partial(c);
         c->partial = NULL;
 
         if (partial_slab)
                 __put_partials(s, partial_slab);
 }
 
 /*
  * Put a slab into a partial slab slot if available.
  *
  * If we did not find a slot then simply move all the partials to the
  * per node partial list.
  */
 static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain)
 {
         struct slab *oldslab;
         struct slab *slab_to_put = NULL;
         unsigned long flags;
         int slabs = 0;
 
         local_lock_irqsave(&s->cpu_slab->lock, flags);
 
         oldslab = this_cpu_read(s->cpu_slab->partial);
 
         if (oldslab) {
                 if (drain && oldslab->slabs >= s->cpu_partial_slabs) {
                         /*
                          * Partial array is full. Move the existing set to the
                          * per node partial list. Postpone the actual unfreezing
                          * outside of the critical section.
                          */
                         slab_to_put = oldslab;
                         oldslab = NULL;
                 } else {
                         slabs = oldslab->slabs;
                 }
         }
 
         slabs++;
 
         slab->slabs = slabs;
         slab->next = oldslab;
 
         this_cpu_write(s->cpu_slab->partial, slab);
 
         local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 
         if (slab_to_put) {
                 __put_partials(s, slab_to_put);
                 stat(s, CPU_PARTIAL_DRAIN);
         }
 }
 
 #else   /* CONFIG_SLUB_CPU_PARTIAL */
 
 static inline void put_partials(struct kmem_cache *s) { }
 static inline void put_partials_cpu(struct kmem_cache *s,
                                     struct kmem_cache_cpu *c) { }
 
 #endif  /* CONFIG_SLUB_CPU_PARTIAL */
 
 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
 {
         unsigned long flags;
         struct slab *slab;
         void *freelist;
 
         local_lock_irqsave(&s->cpu_slab->lock, flags);
 
         slab = c->slab;
         freelist = c->freelist;
 
         c->slab = NULL;
         c->freelist = NULL;
         c->tid = next_tid(c->tid);
 
         local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 
         if (slab) {
                 deactivate_slab(s, slab, freelist);
                 stat(s, CPUSLAB_FLUSH);
         }
 }
 
 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
 {
         struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
         void *freelist = c->freelist;
         struct slab *slab = c->slab;
 
         c->slab = NULL;
         c->freelist = NULL;
         c->tid = next_tid(c->tid);
 
         if (slab) {
                 deactivate_slab(s, slab, freelist);
                 stat(s, CPUSLAB_FLUSH);
         }
 
         put_partials_cpu(s, c);
 }
 
 struct slub_flush_work {
         struct work_struct work;
         struct kmem_cache *s;
         bool skip;
 };
 
 /*
  * Flush cpu slab.
  *
  * Called from CPU work handler with migration disabled.
  */
 static void flush_cpu_slab(struct work_struct *w)
 {
         struct kmem_cache *s;
         struct kmem_cache_cpu *c;
         struct slub_flush_work *sfw;
 
         sfw = container_of(w, struct slub_flush_work, work);
 
         s = sfw->s;
         c = this_cpu_ptr(s->cpu_slab);
 
         if (c->slab)
                 flush_slab(s, c);
 
         put_partials(s);
 }
 
 static bool has_cpu_slab(int cpu, struct kmem_cache *s)
 {
         struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
 
         return c->slab || slub_percpu_partial(c);
 }
 
 static DEFINE_MUTEX(flush_lock);
 static DEFINE_PER_CPU(struct slub_flush_work, slub_flush);
 
 static void flush_all_cpus_locked(struct kmem_cache *s)
 {
         struct slub_flush_work *sfw;
         unsigned int cpu;
 
         lockdep_assert_cpus_held();
         mutex_lock(&flush_lock);
 
         for_each_online_cpu(cpu) {
                 sfw = &per_cpu(slub_flush, cpu);
                 if (!has_cpu_slab(cpu, s)) {
                         sfw->skip = true;
                         continue;
                 }
                 INIT_WORK(&sfw->work, flush_cpu_slab);
                 sfw->skip = false;
                 sfw->s = s;
                 queue_work_on(cpu, flushwq, &sfw->work);
         }
 
         for_each_online_cpu(cpu) {
                 sfw = &per_cpu(slub_flush, cpu);
                 if (sfw->skip)
                         continue;
                 flush_work(&sfw->work);
         }
 
         mutex_unlock(&flush_lock);
 }
 
 static void flush_all(struct kmem_cache *s)
 {
         cpus_read_lock();
         flush_all_cpus_locked(s);
         cpus_read_unlock();
 }
 
 /*
  * Use the cpu notifier to insure that the cpu slabs are flushed when
  * necessary.
  */
 static int slub_cpu_dead(unsigned int cpu)
 {
         struct kmem_cache *s;
 
         mutex_lock(&slab_mutex);
         list_for_each_entry(s, &slab_caches, list)
                 __flush_cpu_slab(s, cpu);
         mutex_unlock(&slab_mutex);
         return 0;
 }
 
 #else /* CONFIG_SLUB_TINY */
 static inline void flush_all_cpus_locked(struct kmem_cache *s) { }
 static inline void flush_all(struct kmem_cache *s) { }
 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) { }
 static inline int slub_cpu_dead(unsigned int cpu) { return 0; }
 #endif /* CONFIG_SLUB_TINY */
 
 /*
  * Check if the objects in a per cpu structure fit numa
  * locality expectations.
  */
 static inline int node_match(struct slab *slab, int node)
 {
 #ifdef CONFIG_NUMA
         if (node != NUMA_NO_NODE && slab_nid(slab) != node)
                 return 0;
 #endif
         return 1;
 }
 
 #ifdef CONFIG_SLUB_DEBUG
 static int count_free(struct slab *slab)
 {
         return slab->objects - slab->inuse;
 }
 
 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
 {
         return atomic_long_read(&n->total_objects);
 }
 
 /* Supports checking bulk free of a constructed freelist */
 static inline bool free_debug_processing(struct kmem_cache *s,
         struct slab *slab, void *head, void *tail, int *bulk_cnt,
         unsigned long addr, depot_stack_handle_t handle)
 {
         bool checks_ok = false;
         void *object = head;
         int cnt = 0;
 
         if (s->flags & SLAB_CONSISTENCY_CHECKS) {
                 if (!check_slab(s, slab))
                         goto out;
         }
 
         if (slab->inuse < *bulk_cnt) {
                 slab_err(s, slab, "Slab has %d allocated objects but %d are to be freed\n",
                          slab->inuse, *bulk_cnt);
                 goto out;
         }
 
 next_object:
 
         if (++cnt > *bulk_cnt)
                 goto out_cnt;
 
         if (s->flags & SLAB_CONSISTENCY_CHECKS) {
                 if (!free_consistency_checks(s, slab, object, addr))
                         goto out;
         }
 
         if (s->flags & SLAB_STORE_USER)
                 set_track_update(s, object, TRACK_FREE, addr, handle);
         trace(s, slab, object, 0);
         /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
         init_object(s, object, SLUB_RED_INACTIVE);
 
         /* Reached end of constructed freelist yet? */
         if (object != tail) {
                 object = get_freepointer(s, object);
                 goto next_object;
         }
         checks_ok = true;
 
 out_cnt:
         if (cnt != *bulk_cnt) {
                 slab_err(s, slab, "Bulk free expected %d objects but found %d\n",
                          *bulk_cnt, cnt);
                 *bulk_cnt = cnt;
         }
 
 out:
 
         if (!checks_ok)
                 slab_fix(s, "Object at 0x%p not freed", object);
 
         return checks_ok;
 }
 #endif /* CONFIG_SLUB_DEBUG */
 
 #if defined(CONFIG_SLUB_DEBUG) || defined(SLAB_SUPPORTS_SYSFS)
 static unsigned long count_partial(struct kmem_cache_node *n,
                                         int (*get_count)(struct slab *))
 {
         unsigned long flags;
         unsigned long x = 0;
         struct slab *slab;
 
         spin_lock_irqsave(&n->list_lock, flags);
         list_for_each_entry(slab, &n->partial, slab_list)
                 x += get_count(slab);
         spin_unlock_irqrestore(&n->list_lock, flags);
         return x;
 }
 #endif /* CONFIG_SLUB_DEBUG || SLAB_SUPPORTS_SYSFS */
 
 #ifdef CONFIG_SLUB_DEBUG
 #define MAX_PARTIAL_TO_SCAN 10000
 
 static unsigned long count_partial_free_approx(struct kmem_cache_node *n)
 {
         unsigned long flags;
         unsigned long x = 0;
         struct slab *slab;
 
         spin_lock_irqsave(&n->list_lock, flags);
         if (n->nr_partial <= MAX_PARTIAL_TO_SCAN) {
                 list_for_each_entry(slab, &n->partial, slab_list)
                         x += slab->objects - slab->inuse;
         } else {
                 /*
                  * For a long list, approximate the total count of objects in
                  * it to meet the limit on the number of slabs to scan.
                  * Scan from both the list's head and tail for better accuracy.
                  */
                 unsigned long scanned = 0;
 
                 list_for_each_entry(slab, &n->partial, slab_list) {
                         x += slab->objects - slab->inuse;
                         if (++scanned == MAX_PARTIAL_TO_SCAN / 2)
                                 break;
                 }
                 list_for_each_entry_reverse(slab, &n->partial, slab_list) {
                         x += slab->objects - slab->inuse;
                         if (++scanned == MAX_PARTIAL_TO_SCAN)
                                 break;
                 }
                 x = mult_frac(x, n->nr_partial, scanned);
                 x = min(x, node_nr_objs(n));
         }
         spin_unlock_irqrestore(&n->list_lock, flags);
         return x;
 }
 
 static noinline void
 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
 {
         static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
                                       DEFAULT_RATELIMIT_BURST);
         int node;
         struct kmem_cache_node *n;
 
         if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
                 return;
 
         pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
                 nid, gfpflags, &gfpflags);
         pr_warn("  cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
                 s->name, s->object_size, s->size, oo_order(s->oo),
                 oo_order(s->min));
 
         if (oo_order(s->min) > get_order(s->object_size))
                 pr_warn("  %s debugging increased min order, use slab_debug=O to disable.\n",
                         s->name);
 
         for_each_kmem_cache_node(s, node, n) {
                 unsigned long nr_slabs;
                 unsigned long nr_objs;
                 unsigned long nr_free;
 
                 nr_free  = count_partial_free_approx(n);
                 nr_slabs = node_nr_slabs(n);
                 nr_objs  = node_nr_objs(n);
 
                 pr_warn("  node %d: slabs: %ld, objs: %ld, free: %ld\n",
                         node, nr_slabs, nr_objs, nr_free);
         }
 }
 #else /* CONFIG_SLUB_DEBUG */
 static inline void
 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) { }
 #endif
 
 static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
 {
         if (unlikely(slab_test_pfmemalloc(slab)))
                 return gfp_pfmemalloc_allowed(gfpflags);
 
         return true;
 }
 
 #ifndef CONFIG_SLUB_TINY
 static inline bool
 __update_cpu_freelist_fast(struct kmem_cache *s,
                            void *freelist_old, void *freelist_new,
                            unsigned long tid)
 {
         freelist_aba_t old = { .freelist = freelist_old, .counter = tid };
         freelist_aba_t new = { .freelist = freelist_new, .counter = next_tid(tid) };
 
         return this_cpu_try_cmpxchg_freelist(s->cpu_slab->freelist_tid.full,
                                              &old.full, new.full);
 }
 
 /*
  * Check the slab->freelist and either transfer the freelist to the
  * per cpu freelist or deactivate the slab.
  *
  * The slab is still frozen if the return value is not NULL.
  *
  * If this function returns NULL then the slab has been unfrozen.
  */
 static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
 {
         struct slab new;
         unsigned long counters;
         void *freelist;
 
         lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
 
         do {
                 freelist = slab->freelist;
                 counters = slab->counters;
 
                 new.counters = counters;
 
                 new.inuse = slab->objects;
                 new.frozen = freelist != NULL;
 
         } while (!__slab_update_freelist(s, slab,
                 freelist, counters,
                 NULL, new.counters,
                 "get_freelist"));
 
         return freelist;
 }
 
 /*
  * Freeze the partial slab and return the pointer to the freelist.
  */
 static inline void *freeze_slab(struct kmem_cache *s, struct slab *slab)
 {
         struct slab new;
         unsigned long counters;
         void *freelist;
 
         do {
                 freelist = slab->freelist;
                 counters = slab->counters;
 
                 new.counters = counters;
                 VM_BUG_ON(new.frozen);
 
                 new.inuse = slab->objects;
                 new.frozen = 1;
 
         } while (!slab_update_freelist(s, slab,
                 freelist, counters,
                 NULL, new.counters,
                 "freeze_slab"));
 
         return freelist;
 }
 
 /*
  * Slow path. The lockless freelist is empty or we need to perform
  * debugging duties.
  *
  * Processing is still very fast if new objects have been freed to the
  * regular freelist. In that case we simply take over the regular freelist
  * as the lockless freelist and zap the regular freelist.
  *
  * If that is not working then we fall back to the partial lists. We take the
  * first element of the freelist as the object to allocate now and move the
  * rest of the freelist to the lockless freelist.
  *
  * And if we were unable to get a new slab from the partial slab lists then
  * we need to allocate a new slab. This is the slowest path since it involves
  * a call to the page allocator and the setup of a new slab.
  *
  * Version of __slab_alloc to use when we know that preemption is
  * already disabled (which is the case for bulk allocation).
  */
 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
                           unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
 {
         void *freelist;
         struct slab *slab;
         unsigned long flags;
         struct partial_context pc;
         bool try_thisnode = true;
 
         stat(s, ALLOC_SLOWPATH);
 
 reread_slab:
 
         slab = READ_ONCE(c->slab);
         if (!slab) {
                 /*
                  * if the node is not online or has no normal memory, just
                  * ignore the node constraint
                  */
                 if (unlikely(node != NUMA_NO_NODE &&
                              !node_isset(node, slab_nodes)))
                         node = NUMA_NO_NODE;
                 goto new_slab;
         }
 
         if (unlikely(!node_match(slab, node))) {
                 /*
                  * same as above but node_match() being false already
                  * implies node != NUMA_NO_NODE
                  */
                 if (!node_isset(node, slab_nodes)) {
                         node = NUMA_NO_NODE;
                 } else {
                         stat(s, ALLOC_NODE_MISMATCH);
                         goto deactivate_slab;
                 }
         }
 
         /*
          * By rights, we should be searching for a slab page that was
          * PFMEMALLOC but right now, we are losing the pfmemalloc
          * information when the page leaves the per-cpu allocator
          */
         if (unlikely(!pfmemalloc_match(slab, gfpflags)))
                 goto deactivate_slab;
 
         /* must check again c->slab in case we got preempted and it changed */
         local_lock_irqsave(&s->cpu_slab->lock, flags);
         if (unlikely(slab != c->slab)) {
                 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
                 goto reread_slab;
         }
         freelist = c->freelist;
         if (freelist)
                 goto load_freelist;
 
         freelist = get_freelist(s, slab);
 
         if (!freelist) {
                 c->slab = NULL;
                 c->tid = next_tid(c->tid);
                 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
                 stat(s, DEACTIVATE_BYPASS);
                 goto new_slab;
         }
 
         stat(s, ALLOC_REFILL);
 
 load_freelist:
 
         lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
 
         /*
          * freelist is pointing to the list of objects to be used.
          * slab is pointing to the slab from which the objects are obtained.
          * That slab must be frozen for per cpu allocations to work.
          */
         VM_BUG_ON(!c->slab->frozen);
         c->freelist = get_freepointer(s, freelist);
         c->tid = next_tid(c->tid);
         local_unlock_irqrestore(&s->cpu_slab->lock, flags);
         return freelist;
 
 deactivate_slab:
 
         local_lock_irqsave(&s->cpu_slab->lock, flags);
         if (slab != c->slab) {
                 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
                 goto reread_slab;
         }
         freelist = c->freelist;
         c->slab = NULL;
         c->freelist = NULL;
         c->tid = next_tid(c->tid);
         local_unlock_irqrestore(&s->cpu_slab->lock, flags);
         deactivate_slab(s, slab, freelist);
 
 new_slab:
 
 #ifdef CONFIG_SLUB_CPU_PARTIAL
         while (slub_percpu_partial(c)) {
                 local_lock_irqsave(&s->cpu_slab->lock, flags);
                 if (unlikely(c->slab)) {
                         local_unlock_irqrestore(&s->cpu_slab->lock, flags);
                         goto reread_slab;
                 }
                 if (unlikely(!slub_percpu_partial(c))) {
                         local_unlock_irqrestore(&s->cpu_slab->lock, flags);
                         /* we were preempted and partial list got empty */
                         goto new_objects;
                 }
 
                 slab = slub_percpu_partial(c);
                 slub_set_percpu_partial(c, slab);
 
                 if (likely(node_match(slab, node) &&
                            pfmemalloc_match(slab, gfpflags))) {
                         c->slab = slab;
                         freelist = get_freelist(s, slab);
                         VM_BUG_ON(!freelist);
                         stat(s, CPU_PARTIAL_ALLOC);
                         goto load_freelist;
                 }
 
                 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 
                 slab->next = NULL;
                 __put_partials(s, slab);
         }
 #endif
 
 new_objects:
 
         pc.flags = gfpflags;
         /*
          * When a preferred node is indicated but no __GFP_THISNODE
          *
          * 1) try to get a partial slab from target node only by having
          *    __GFP_THISNODE in pc.flags for get_partial()
          * 2) if 1) failed, try to allocate a new slab from target node with
          *    GPF_NOWAIT | __GFP_THISNODE opportunistically
          * 3) if 2) failed, retry with original gfpflags which will allow
          *    get_partial() try partial lists of other nodes before potentially
          *    allocating new page from other nodes
          */
         if (unlikely(node != NUMA_NO_NODE && !(gfpflags & __GFP_THISNODE)
                      && try_thisnode))
                 pc.flags = GFP_NOWAIT | __GFP_THISNODE;
 
         pc.orig_size = orig_size;
         slab = get_partial(s, node, &pc);
         if (slab) {
                 if (kmem_cache_debug(s)) {
                         freelist = pc.object;
                         /*
                          * For debug caches here we had to go through
                          * alloc_single_from_partial() so just store the
                          * tracking info and return the object.
                          */
                         if (s->flags & SLAB_STORE_USER)
                                 set_track(s, freelist, TRACK_ALLOC, addr);
 
                         return freelist;
                 }
 
                 freelist = freeze_slab(s, slab);
                 goto retry_load_slab;
         }
 
         slub_put_cpu_ptr(s->cpu_slab);
         slab = new_slab(s, pc.flags, node);
         c = slub_get_cpu_ptr(s->cpu_slab);
 
         if (unlikely(!slab)) {
                 if (node != NUMA_NO_NODE && !(gfpflags & __GFP_THISNODE)
                     && try_thisnode) {
                         try_thisnode = false;
                         goto new_objects;
                 }
                 slab_out_of_memory(s, gfpflags, node);
                 return NULL;
         }
 
         stat(s, ALLOC_SLAB);
 
         if (kmem_cache_debug(s)) {
                 freelist = alloc_single_from_new_slab(s, slab, orig_size);
 
                 if (unlikely(!freelist))
                         goto new_objects;
 
                 if (s->flags & SLAB_STORE_USER)
                         set_track(s, freelist, TRACK_ALLOC, addr);
 
                 return freelist;
         }
 
         /*
          * No other reference to the slab yet so we can
          * muck around with it freely without cmpxchg
          */
         freelist = slab->freelist;
         slab->freelist = NULL;
         slab->inuse = slab->objects;
         slab->frozen = 1;
 
         inc_slabs_node(s, slab_nid(slab), slab->objects);
 
         if (unlikely(!pfmemalloc_match(slab, gfpflags))) {
                 /*
                  * For !pfmemalloc_match() case we don't load freelist so that
                  * we don't make further mismatched allocations easier.
                  */
                 deactivate_slab(s, slab, get_freepointer(s, freelist));
                 return freelist;
         }
 
 retry_load_slab:
 
         local_lock_irqsave(&s->cpu_slab->lock, flags);
         if (unlikely(c->slab)) {
                 void *flush_freelist = c->freelist;
                 struct slab *flush_slab = c->slab;
 
                 c->slab = NULL;
                 c->freelist = NULL;
                 c->tid = next_tid(c->tid);
 
                 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 
                 deactivate_slab(s, flush_slab, flush_freelist);
 
                 stat(s, CPUSLAB_FLUSH);
 
                 goto retry_load_slab;
         }
         c->slab = slab;
 
         goto load_freelist;
 }
 
 /*
  * A wrapper for ___slab_alloc() for contexts where preemption is not yet
  * disabled. Compensates for possible cpu changes by refetching the per cpu area
  * pointer.
  */
 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
                           unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
 {
         void *p;
 
 #ifdef CONFIG_PREEMPT_COUNT
         /*
          * We may have been preempted and rescheduled on a different
          * cpu before disabling preemption. Need to reload cpu area
          * pointer.
          */
         c = slub_get_cpu_ptr(s->cpu_slab);
 #endif
 
         p = ___slab_alloc(s, gfpflags, node, addr, c, orig_size);
 #ifdef CONFIG_PREEMPT_COUNT
         slub_put_cpu_ptr(s->cpu_slab);
 #endif
         return p;
 }
 
 static __always_inline void *__slab_alloc_node(struct kmem_cache *s,
                 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
 {
         struct kmem_cache_cpu *c;
         struct slab *slab;
         unsigned long tid;
         void *object;
 
 redo:
         /*
          * Must read kmem_cache cpu data via this cpu ptr. Preemption is
          * enabled. We may switch back and forth between cpus while
          * reading from one cpu area. That does not matter as long
          * as we end up on the original cpu again when doing the cmpxchg.
          *
          * We must guarantee that tid and kmem_cache_cpu are retrieved on the
          * same cpu. We read first the kmem_cache_cpu pointer and use it to read
          * the tid. If we are preempted and switched to another cpu between the
          * two reads, it's OK as the two are still associated with the same cpu
          * and cmpxchg later will validate the cpu.
          */
         c = raw_cpu_ptr(s->cpu_slab);
         tid = READ_ONCE(c->tid);
 
         /*
          * Irqless object alloc/free algorithm used here depends on sequence
          * of fetching cpu_slab's data. tid should be fetched before anything
          * on c to guarantee that object and slab associated with previous tid
          * won't be used with current tid. If we fetch tid first, object and
          * slab could be one associated with next tid and our alloc/free
          * request will be failed. In this case, we will retry. So, no problem.
          */
         barrier();
 
         /*
          * The transaction ids are globally unique per cpu and per operation on
          * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
          * occurs on the right processor and that there was no operation on the
          * linked list in between.
          */
 
         object = c->freelist;
         slab = c->slab;
 
         if (!USE_LOCKLESS_FAST_PATH() ||
             unlikely(!object || !slab || !node_match(slab, node))) {
                 object = __slab_alloc(s, gfpflags, node, addr, c, orig_size);
         } else {
                 void *next_object = get_freepointer_safe(s, object);
 
                 /*
                  * The cmpxchg will only match if there was no additional
                  * operation and if we are on the right processor.
                  *
                  * The cmpxchg does the following atomically (without lock
                  * semantics!)
                  * 1. Relocate first pointer to the current per cpu area.
                  * 2. Verify that tid and freelist have not been changed
                  * 3. If they were not changed replace tid and freelist
                  *
                  * Since this is without lock semantics the protection is only
                  * against code executing on this cpu *not* from access by
                  * other cpus.
                  */
                 if (unlikely(!__update_cpu_freelist_fast(s, object, next_object, tid))) {
                         note_cmpxchg_failure("slab_alloc", s, tid);
                         goto redo;
                 }
                 prefetch_freepointer(s, next_object);
                 stat(s, ALLOC_FASTPATH);
         }
 
         return object;
 }
 #else /* CONFIG_SLUB_TINY */
 static void *__slab_alloc_node(struct kmem_cache *s,
                 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
 {
         struct partial_context pc;
         struct slab *slab;
         void *object;
 
         pc.flags = gfpflags;
         pc.orig_size = orig_size;
         slab = get_partial(s, node, &pc);
 
         if (slab)
                 return pc.object;
 
         slab = new_slab(s, gfpflags, node);
         if (unlikely(!slab)) {
                 slab_out_of_memory(s, gfpflags, node);
                 return NULL;
         }
 
         object = alloc_single_from_new_slab(s, slab, orig_size);
 
         return object;
 }
 #endif /* CONFIG_SLUB_TINY */
 
 /*
  * If the object has been wiped upon free, make sure it's fully initialized by
  * zeroing out freelist pointer.
  */
 static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
                                                    void *obj)
 {
         if (unlikely(slab_want_init_on_free(s)) && obj &&
             !freeptr_outside_object(s))
                 memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
                         0, sizeof(void *));
 }
 
 static __fastpath_inline
 struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
 {
         flags &= gfp_allowed_mask;
 
         might_alloc(flags);
 
         if (unlikely(should_failslab(s, flags)))
                 return NULL;
 
         return s;
 }
 
 static __fastpath_inline
 bool slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru,
                           gfp_t flags, size_t size, void **p, bool init,
                           unsigned int orig_size)
 {
         unsigned int zero_size = s->object_size;
         bool kasan_init = init;
         size_t i;
         gfp_t init_flags = flags & gfp_allowed_mask;
 
         /*
          * For kmalloc object, the allocated memory size(object_size) is likely
          * larger than the requested size(orig_size). If redzone check is
          * enabled for the extra space, don't zero it, as it will be redzoned
          * soon. The redzone operation for this extra space could be seen as a
          * replacement of current poisoning under certain debug option, and
          * won't break other sanity checks.
          */
         if (kmem_cache_debug_flags(s, SLAB_STORE_USER | SLAB_RED_ZONE) &&
             (s->flags & SLAB_KMALLOC))
                 zero_size = orig_size;
 
         /*
          * When slab_debug is enabled, avoid memory initialization integrated
          * into KASAN and instead zero out the memory via the memset below with
          * the proper size. Otherwise, KASAN might overwrite SLUB redzones and
          * cause false-positive reports. This does not lead to a performance
          * penalty on production builds, as slab_debug is not intended to be
          * enabled there.
          */
         if (__slub_debug_enabled())
                 kasan_init = false;
 
         /*
          * As memory initialization might be integrated into KASAN,
          * kasan_slab_alloc and initialization memset must be
          * kept together to avoid discrepancies in behavior.
          *
          * As p[i] might get tagged, memset and kmemleak hook come after KASAN.
          */
         for (i = 0; i < size; i++) {
                 p[i] = kasan_slab_alloc(s, p[i], init_flags, kasan_init);
                 if (p[i] && init && (!kasan_init ||
                                      !kasan_has_integrated_init()))
                         memset(p[i], 0, zero_size);
                 kmemleak_alloc_recursive(p[i], s->object_size, 1,
                                          s->flags, init_flags);
                 kmsan_slab_alloc(s, p[i], init_flags);
                 alloc_tagging_slab_alloc_hook(s, p[i], flags);
         }
 
         return memcg_slab_post_alloc_hook(s, lru, flags, size, p);
 }
 
 /*
  * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
  * have the fastpath folded into their functions. So no function call
  * overhead for requests that can be satisfied on the fastpath.
  *
  * The fastpath works by first checking if the lockless freelist can be used.
  * If not then __slab_alloc is called for slow processing.
  *
  * Otherwise we can simply pick the next object from the lockless free list.
  */
 static __fastpath_inline void *slab_alloc_node(struct kmem_cache *s, struct list_lru *lru,
                 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
 {
         void *object;
         bool init = false;
 
         s = slab_pre_alloc_hook(s, gfpflags);
         if (unlikely(!s))
                 return NULL;
 
         object = kfence_alloc(s, orig_size, gfpflags);
         if (unlikely(object))
                 goto out;
 
         object = __slab_alloc_node(s, gfpflags, node, addr, orig_size);
 
         maybe_wipe_obj_freeptr(s, object);
         init = slab_want_init_on_alloc(gfpflags, s);
 
 out:
         /*
          * When init equals 'true', like for kzalloc() family, only
          * @orig_size bytes might be zeroed instead of s->object_size
          * In case this fails due to memcg_slab_post_alloc_hook(),
          * object is set to NULL
          */
         slab_post_alloc_hook(s, lru, gfpflags, 1, &object, init, orig_size);
 
         return object;
 }
 
 void *kmem_cache_alloc_noprof(struct kmem_cache *s, gfp_t gfpflags)
 {
         void *ret = slab_alloc_node(s, NULL, gfpflags, NUMA_NO_NODE, _RET_IP_,
                                     s->object_size);
 
         trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
 
         return ret;
 }
 EXPORT_SYMBOL(kmem_cache_alloc_noprof);
 
 void *kmem_cache_alloc_lru_noprof(struct kmem_cache *s, struct list_lru *lru,
                            gfp_t gfpflags)
 {
         void *ret = slab_alloc_node(s, lru, gfpflags, NUMA_NO_NODE, _RET_IP_,
                                     s->object_size);
 
         trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
 
         return ret;
 }
 EXPORT_SYMBOL(kmem_cache_alloc_lru_noprof);
 
 /**
  * kmem_cache_alloc_node - Allocate an object on the specified node
  * @s: The cache to allocate from.
  * @gfpflags: See kmalloc().
  * @node: node number of the target node.
  *
  * Identical to kmem_cache_alloc but it will allocate memory on the given
  * node, which can improve the performance for cpu bound structures.
  *
  * Fallback to other node is possible if __GFP_THISNODE is not set.
  *
  * Return: pointer to the new object or %NULL in case of error
  */
 void *kmem_cache_alloc_node_noprof(struct kmem_cache *s, gfp_t gfpflags, int node)
 {
         void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);
 
         trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, node);
 
         return ret;
 }
 EXPORT_SYMBOL(kmem_cache_alloc_node_noprof);
 
 /*
  * To avoid unnecessary overhead, we pass through large allocation requests
  * directly to the page allocator. We use __GFP_COMP, because we will need to
  * know the allocation order to free the pages properly in kfree.
  */
 static void *___kmalloc_large_node(size_t size, gfp_t flags, int node)
 {
         struct folio *folio;
         void *ptr = NULL;
         unsigned int order = get_order(size);
 
         if (unlikely(flags & GFP_SLAB_BUG_MASK))
                 flags = kmalloc_fix_flags(flags);
 
         flags |= __GFP_COMP;
         folio = (struct folio *)alloc_pages_node_noprof(node, flags, order);
         if (folio) {
                 ptr = folio_address(folio);
                 lruvec_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B,
                                       PAGE_SIZE << order);
         }
 
         ptr = kasan_kmalloc_large(ptr, size, flags);
         /* As ptr might get tagged, call kmemleak hook after KASAN. */
         kmemleak_alloc(ptr, size, 1, flags);
         kmsan_kmalloc_large(ptr, size, flags);
 
         return ptr;
 }
 
 void *__kmalloc_large_noprof(size_t size, gfp_t flags)
 {
         void *ret = ___kmalloc_large_node(size, flags, NUMA_NO_NODE);
 
         trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
                       flags, NUMA_NO_NODE);
         return ret;
 }
 EXPORT_SYMBOL(__kmalloc_large_noprof);
 
 void *__kmalloc_large_node_noprof(size_t size, gfp_t flags, int node)
 {
         void *ret = ___kmalloc_large_node(size, flags, node);
 
         trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
                       flags, node);
         return ret;
 }
 EXPORT_SYMBOL(__kmalloc_large_node_noprof);
 
 static __always_inline
 void *__do_kmalloc_node(size_t size, kmem_buckets *b, gfp_t flags, int node,
                         unsigned long caller)
 {
         struct kmem_cache *s;
         void *ret;
 
         if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
                 ret = __kmalloc_large_node_noprof(size, flags, node);
                 trace_kmalloc(caller, ret, size,
                               PAGE_SIZE << get_order(size), flags, node);
                 return ret;
         }
 
         if (unlikely(!size))
                 return ZERO_SIZE_PTR;
 
         s = kmalloc_slab(size, b, flags, caller);
 
         ret = slab_alloc_node(s, NULL, flags, node, caller, size);
         ret = kasan_kmalloc(s, ret, size, flags);
         trace_kmalloc(caller, ret, size, s->size, flags, node);
         return ret;
 }
 void *__kmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node)
 {
         return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags, node, _RET_IP_);
 }
 EXPORT_SYMBOL(__kmalloc_node_noprof);
 
 void *__kmalloc_noprof(size_t size, gfp_t flags)
 {
         return __do_kmalloc_node(size, NULL, flags, NUMA_NO_NODE, _RET_IP_);
 }
 EXPORT_SYMBOL(__kmalloc_noprof);
 
 void *__kmalloc_node_track_caller_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags,
                                          int node, unsigned long caller)
 {
         return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags, node, caller);
 
 }
 EXPORT_SYMBOL(__kmalloc_node_track_caller_noprof);
 
 void *__kmalloc_cache_noprof(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 {
         void *ret = slab_alloc_node(s, NULL, gfpflags, NUMA_NO_NODE,
                                             _RET_IP_, size);
 
         trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, NUMA_NO_NODE);
 
         ret = kasan_kmalloc(s, ret, size, gfpflags);
         return ret;
 }
 EXPORT_SYMBOL(__kmalloc_cache_noprof);
 
 void *__kmalloc_cache_node_noprof(struct kmem_cache *s, gfp_t gfpflags,
                                   int node, size_t size)
 {
         void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, size);
 
         trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, node);
 
         ret = kasan_kmalloc(s, ret, size, gfpflags);
         return ret;
 }
 EXPORT_SYMBOL(__kmalloc_cache_node_noprof);
 
 static noinline void free_to_partial_list(
         struct kmem_cache *s, struct slab *slab,
         void *head, void *tail, int bulk_cnt,
         unsigned long addr)
 {
         struct kmem_cache_node *n = get_node(s, slab_nid(slab));
         struct slab *slab_free = NULL;
         int cnt = bulk_cnt;
         unsigned long flags;
         depot_stack_handle_t handle = 0;
 
         if (s->flags & SLAB_STORE_USER)
                 handle = set_track_prepare();
 
         spin_lock_irqsave(&n->list_lock, flags);
 
         if (free_debug_processing(s, slab, head, tail, &cnt, addr, handle)) {
                 void *prior = slab->freelist;
 
                 /* Perform the actual freeing while we still hold the locks */
                 slab->inuse -= cnt;
                 set_freepointer(s, tail, prior);
                 slab->freelist = head;
 
                 /*
                  * If the slab is empty, and node's partial list is full,
                  * it should be discarded anyway no matter it's on full or
                  * partial list.
                  */
                 if (slab->inuse == 0 && n->nr_partial >= s->min_partial)
                         slab_free = slab;
 
                 if (!prior) {
                         /* was on full list */
                         remove_full(s, n, slab);
                         if (!slab_free) {
                                 add_partial(n, slab, DEACTIVATE_TO_TAIL);
                                 stat(s, FREE_ADD_PARTIAL);
                         }
                 } else if (slab_free) {
                         remove_partial(n, slab);
                         stat(s, FREE_REMOVE_PARTIAL);
                 }
         }
 
         if (slab_free) {
                 /*
                  * Update the counters while still holding n->list_lock to
                  * prevent spurious validation warnings
                  */
                 dec_slabs_node(s, slab_nid(slab_free), slab_free->objects);
         }
 
         spin_unlock_irqrestore(&n->list_lock, flags);
 
         if (slab_free) {
                 stat(s, FREE_SLAB);
                 free_slab(s, slab_free);
         }
 }
 
 /*
  * Slow path handling. This may still be called frequently since objects
  * have a longer lifetime than the cpu slabs in most processing loads.
  *
  * So we still attempt to reduce cache line usage. Just take the slab
  * lock and free the item. If there is no additional partial slab
  * handling required then we can return immediately.
  */
 static void __slab_free(struct kmem_cache *s, struct slab *slab,
                         void *head, void *tail, int cnt,
                         unsigned long addr)
 
 {
         void *prior;
         int was_frozen;
         struct slab new;
         unsigned long counters;
         struct kmem_cache_node *n = NULL;
         unsigned long flags;
         bool on_node_partial;
 
         stat(s, FREE_SLOWPATH);
 
         if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
                 free_to_partial_list(s, slab, head, tail, cnt, addr);
                 return;
         }
 
         do {
                 if (unlikely(n)) {
                         spin_unlock_irqrestore(&n->list_lock, flags);
                         n = NULL;
                 }
                 prior = slab->freelist;
                 counters = slab->counters;
                 set_freepointer(s, tail, prior);
                 new.counters = counters;
                 was_frozen = new.frozen;
                 new.inuse -= cnt;
                 if ((!new.inuse || !prior) && !was_frozen) {
                         /* Needs to be taken off a list */
                         if (!kmem_cache_has_cpu_partial(s) || prior) {
 
                                 n = get_node(s, slab_nid(slab));
                                 /*
                                  * Speculatively acquire the list_lock.
                                  * If the cmpxchg does not succeed then we may
                                  * drop the list_lock without any processing.
                                  *
                                  * Otherwise the list_lock will synchronize with
                                  * other processors updating the list of slabs.
                                  */
                                 spin_lock_irqsave(&n->list_lock, flags);
 
                                 on_node_partial = slab_test_node_partial(slab);
                         }
                 }
 
         } while (!slab_update_freelist(s, slab,
                 prior, counters,
                 head, new.counters,
                 "__slab_free"));
 
         if (likely(!n)) {
 
                 if (likely(was_frozen)) {
                         /*
                          * The list lock was not taken therefore no list
                          * activity can be necessary.
                          */
                         stat(s, FREE_FROZEN);
                 } else if (kmem_cache_has_cpu_partial(s) && !prior) {
                         /*
                          * If we started with a full slab then put it onto the
                          * per cpu partial list.
                          */
                         put_cpu_partial(s, slab, 1);
                         stat(s, CPU_PARTIAL_FREE);
                 }
 
                 return;
         }
 
         /*
          * This slab was partially empty but not on the per-node partial list,
          * in which case we shouldn't manipulate its list, just return.
          */
         if (prior && !on_node_partial) {
                 spin_unlock_irqrestore(&n->list_lock, flags);
                 return;
         }
 
         if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
                 goto slab_empty;
 
         /*
          * Objects left in the slab. If it was not on the partial list before
          * then add it.
          */
         if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
                 add_partial(n, slab, DEACTIVATE_TO_TAIL);
                 stat(s, FREE_ADD_PARTIAL);
         }
         spin_unlock_irqrestore(&n->list_lock, flags);
         return;
 
 slab_empty:
         if (prior) {
                 /*
                  * Slab on the partial list.
                  */
                 remove_partial(n, slab);
                 stat(s, FREE_REMOVE_PARTIAL);
         }
 
         spin_unlock_irqrestore(&n->list_lock, flags);
         stat(s, FREE_SLAB);
         discard_slab(s, slab);
 }
 
 #ifndef CONFIG_SLUB_TINY
 /*
  * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
  * can perform fastpath freeing without additional function calls.
  *
  * The fastpath is only possible if we are freeing to the current cpu slab
  * of this processor. This typically the case if we have just allocated
  * the item before.
  *
  * If fastpath is not possible then fall back to __slab_free where we deal
  * with all sorts of special processing.
  *
  * Bulk free of a freelist with several objects (all pointing to the
  * same slab) possible by specifying head and tail ptr, plus objects
  * count (cnt). Bulk free indicated by tail pointer being set.
  */
 static __always_inline void do_slab_free(struct kmem_cache *s,
                                 struct slab *slab, void *head, void *tail,
                                 int cnt, unsigned long addr)
 {
         struct kmem_cache_cpu *c;
         unsigned long tid;
         void **freelist;
 
 redo:
         /*
          * Determine the currently cpus per cpu slab.
          * The cpu may change afterward. However that does not matter since
          * data is retrieved via this pointer. If we are on the same cpu
          * during the cmpxchg then the free will succeed.
          */
         c = raw_cpu_ptr(s->cpu_slab);
         tid = READ_ONCE(c->tid);
 
         /* Same with comment on barrier() in __slab_alloc_node() */
         barrier();
 
         if (unlikely(slab != c->slab)) {
                 __slab_free(s, slab, head, tail, cnt, addr);
                 return;
         }
 
         if (USE_LOCKLESS_FAST_PATH()) {
                 freelist = READ_ONCE(c->freelist);
 
                 set_freepointer(s, tail, freelist);
 
                 if (unlikely(!__update_cpu_freelist_fast(s, freelist, head, tid))) {
                         note_cmpxchg_failure("slab_free", s, tid);
                         goto redo;
                 }
         } else {
                 /* Update the free list under the local lock */
                 local_lock(&s->cpu_slab->lock);
                 c = this_cpu_ptr(s->cpu_slab);
                 if (unlikely(slab != c->slab)) {
                         local_unlock(&s->cpu_slab->lock);
                         goto redo;
                 }
                 tid = c->tid;
                 freelist = c->freelist;
 
                 set_freepointer(s, tail, freelist);
                 c->freelist = head;
                 c->tid = next_tid(tid);
 
                 local_unlock(&s->cpu_slab->lock);
         }
         stat_add(s, FREE_FASTPATH, cnt);
 }
 #else /* CONFIG_SLUB_TINY */
 static void do_slab_free(struct kmem_cache *s,
                                 struct slab *slab, void *head, void *tail,
                                 int cnt, unsigned long addr)
 {
         __slab_free(s, slab, head, tail, cnt, addr);
 }
 #endif /* CONFIG_SLUB_TINY */
 
 static __fastpath_inline
 void slab_free(struct kmem_cache *s, struct slab *slab, void *object,
                unsigned long addr)
 {
         memcg_slab_free_hook(s, slab, &object, 1);
         alloc_tagging_slab_free_hook(s, slab, &object, 1);
 
         if (likely(slab_free_hook(s, object, slab_want_init_on_free(s))))
                 do_slab_free(s, slab, object, object, 1, addr);
 }
 
 #ifdef CONFIG_MEMCG
 /* Do not inline the rare memcg charging failed path into the allocation path */
 static noinline
 void memcg_alloc_abort_single(struct kmem_cache *s, void *object)
 {
         if (likely(slab_free_hook(s, object, slab_want_init_on_free(s))))
                 do_slab_free(s, virt_to_slab(object), object, object, 1, _RET_IP_);
 }
 #endif
 
 static __fastpath_inline
 void slab_free_bulk(struct kmem_cache *s, struct slab *slab, void *head,
                     void *tail, void **p, int cnt, unsigned long addr)
 {
         memcg_slab_free_hook(s, slab, p, cnt);
         alloc_tagging_slab_free_hook(s, slab, p, cnt);
         /*
          * With KASAN enabled slab_free_freelist_hook modifies the freelist
          * to remove objects, whose reuse must be delayed.
          */
         if (likely(slab_free_freelist_hook(s, &head, &tail, &cnt)))
                 do_slab_free(s, slab, head, tail, cnt, addr);
 }
 
 #ifdef CONFIG_KASAN_GENERIC
 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
 {
         do_slab_free(cache, virt_to_slab(x), x, x, 1, addr);
 }
 #endif
 
 static inline struct kmem_cache *virt_to_cache(const void *obj)
 {
         struct slab *slab;
 
         slab = virt_to_slab(obj);
         if (WARN_ONCE(!slab, "%s: Object is not a Slab page!\n", __func__))
                 return NULL;
         return slab->slab_cache;
 }
 
 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 {
         struct kmem_cache *cachep;
 
         if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
             !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
                 return s;
 
         cachep = virt_to_cache(x);
         if (WARN(cachep && cachep != s,
                  "%s: Wrong slab cache. %s but object is from %s\n",
                  __func__, s->name, cachep->name))
                 print_tracking(cachep, x);
         return cachep;
 }
 
 /**
  * kmem_cache_free - Deallocate an object
  * @s: The cache the allocation was from.
  * @x: The previously allocated object.
  *
  * Free an object which was previously allocated from this
  * cache.
  */
 void kmem_cache_free(struct kmem_cache *s, void *x)
 {
         s = cache_from_obj(s, x);
         if (!s)
                 return;
         trace_kmem_cache_free(_RET_IP_, x, s);
         slab_free(s, virt_to_slab(x), x, _RET_IP_);
 }
 EXPORT_SYMBOL(kmem_cache_free);
 
 static void free_large_kmalloc(struct folio *folio, void *object)
 {
         unsigned int order = folio_order(folio);
 
         if (WARN_ON_ONCE(order == 0))
                 pr_warn_once("object pointer: 0x%p\n", object);
 
         kmemleak_free(object);
         kasan_kfree_large(object);
         kmsan_kfree_large(object);
 
         lruvec_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B,
                               -(PAGE_SIZE << order));
         folio_put(folio);
 }
 
 /**
  * kfree - free previously allocated memory
  * @object: pointer returned by kmalloc() or kmem_cache_alloc()
  *
  * If @object is NULL, no operation is performed.
  */
 void kfree(const void *object)
 {
         struct folio *folio;
         struct slab *slab;
         struct kmem_cache *s;
         void *x = (void *)object;
 
         trace_kfree(_RET_IP_, object);
 
         if (unlikely(ZERO_OR_NULL_PTR(object)))
                 return;
 
         folio = virt_to_folio(object);
         if (unlikely(!folio_test_slab(folio))) {
                 free_large_kmalloc(folio, (void *)object);
                 return;
         }
 
         slab = folio_slab(folio);
         s = slab->slab_cache;
         slab_free(s, slab, x, _RET_IP_);
 }
 EXPORT_SYMBOL(kfree);
 
 struct detached_freelist {
         struct slab *slab;
         void *tail;
         void *freelist;
         int cnt;
         struct kmem_cache *s;
 };
 
 /*
  * This function progressively scans the array with free objects (with
  * a limited look ahead) and extract objects belonging to the same
  * slab.  It builds a detached freelist directly within the given
  * slab/objects.  This can happen without any need for
  * synchronization, because the objects are owned by running process.
  * The freelist is build up as a single linked list in the objects.
  * The idea is, that this detached freelist can then be bulk
  * transferred to the real freelist(s), but only requiring a single
  * synchronization primitive.  Look ahead in the array is limited due
  * to performance reasons.
  */
 static inline
 int build_detached_freelist(struct kmem_cache *s, size_t size,
                             void **p, struct detached_freelist *df)
 {
         int lookahead = 3;
         void *object;
         struct folio *folio;
         size_t same;
 
         object = p[--size];
         folio = virt_to_folio(object);
         if (!s) {
                 /* Handle kalloc'ed objects */
                 if (unlikely(!folio_test_slab(folio))) {
                         free_large_kmalloc(folio, object);
                         df->slab = NULL;
                         return size;
                 }
                 /* Derive kmem_cache from object */
                 df->slab = folio_slab(folio);
                 df->s = df->slab->slab_cache;
         } else {
                 df->slab = folio_slab(folio);
                 df->s = cache_from_obj(s, object); /* Support for memcg */
         }
 
         /* Start new detached freelist */
         df->tail = object;
         df->freelist = object;
         df->cnt = 1;
 
         if (is_kfence_address(object))
                 return size;
 
         set_freepointer(df->s, object, NULL);
 
         same = size;
         while (size) {
                 object = p[--size];
                 /* df->slab is always set at this point */
                 if (df->slab == virt_to_slab(object)) {
                         /* Opportunity build freelist */
                         set_freepointer(df->s, object, df->freelist);
                         df->freelist = object;
                         df->cnt++;
                         same--;
                         if (size != same)
                                 swap(p[size], p[same]);
                         continue;
                 }
 
                 /* Limit look ahead search */
                 if (!--lookahead)
                         break;
         }
 
         return same;
 }
 
 /*
  * Internal bulk free of objects that were not initialised by the post alloc
  * hooks and thus should not be processed by the free hooks
  */
 static void __kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
 {
         if (!size)
                 return;
 
         do {
                 struct detached_freelist df;
 
                 size = build_detached_freelist(s, size, p, &df);
                 if (!df.slab)
                         continue;
 
                 if (kfence_free(df.freelist))
                         continue;
 
                 do_slab_free(df.s, df.slab, df.freelist, df.tail, df.cnt,
                              _RET_IP_);
         } while (likely(size));
 }
 
 /* Note that interrupts must be enabled when calling this function. */
 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
 {
         if (!size)
                 return;
 
         do {
                 struct detached_freelist df;
 
                 size = build_detached_freelist(s, size, p, &df);
                 if (!df.slab)
                         continue;
 
                 slab_free_bulk(df.s, df.slab, df.freelist, df.tail, &p[size],
                                df.cnt, _RET_IP_);
         } while (likely(size));
 }
 EXPORT_SYMBOL(kmem_cache_free_bulk);
 
 #ifndef CONFIG_SLUB_TINY
 static inline
 int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
                             void **p)
 {
         struct kmem_cache_cpu *c;
         unsigned long irqflags;
         int i;
 
         /*
          * Drain objects in the per cpu slab, while disabling local
          * IRQs, which protects against PREEMPT and interrupts
          * handlers invoking normal fastpath.
          */
         c = slub_get_cpu_ptr(s->cpu_slab);
         local_lock_irqsave(&s->cpu_slab->lock, irqflags);
 
         for (i = 0; i < size; i++) {
                 void *object = kfence_alloc(s, s->object_size, flags);
 
                 if (unlikely(object)) {
                         p[i] = object;
                         continue;
                 }
 
                 object = c->freelist;
                 if (unlikely(!object)) {
                         /*
                          * We may have removed an object from c->freelist using
                          * the fastpath in the previous iteration; in that case,
                          * c->tid has not been bumped yet.
                          * Since ___slab_alloc() may reenable interrupts while
                          * allocating memory, we should bump c->tid now.
                          */
                         c->tid = next_tid(c->tid);
 
                         local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);
 
                         /*
                          * Invoking slow path likely have side-effect
                          * of re-populating per CPU c->freelist
                          */
                         p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
                                             _RET_IP_, c, s->object_size);
                         if (unlikely(!p[i]))
                                 goto error;
 
                         c = this_cpu_ptr(s->cpu_slab);
                         maybe_wipe_obj_freeptr(s, p[i]);
 
                         local_lock_irqsave(&s->cpu_slab->lock, irqflags);
 
                         continue; /* goto for-loop */
                 }
                 c->freelist = get_freepointer(s, object);
                 p[i] = object;
                 maybe_wipe_obj_freeptr(s, p[i]);
                 stat(s, ALLOC_FASTPATH);
         }
         c->tid = next_tid(c->tid);
         local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);
         slub_put_cpu_ptr(s->cpu_slab);
 
         return i;
 
 error:
         slub_put_cpu_ptr(s->cpu_slab);
         __kmem_cache_free_bulk(s, i, p);
         return 0;
 
 }
 #else /* CONFIG_SLUB_TINY */
 static int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags,
                                    size_t size, void **p)
 {
         int i;
 
         for (i = 0; i < size; i++) {
                 void *object = kfence_alloc(s, s->object_size, flags);
 
                 if (unlikely(object)) {
                         p[i] = object;
                         continue;
                 }
 
                 p[i] = __slab_alloc_node(s, flags, NUMA_NO_NODE,
                                          _RET_IP_, s->object_size);
                 if (unlikely(!p[i]))
                         goto error;
 
                 maybe_wipe_obj_freeptr(s, p[i]);
         }
 
         return i;
 
 error:
         __kmem_cache_free_bulk(s, i, p);
         return 0;
 }
 #endif /* CONFIG_SLUB_TINY */
 
 /* Note that interrupts must be enabled when calling this function. */
 int kmem_cache_alloc_bulk_noprof(struct kmem_cache *s, gfp_t flags, size_t size,
                                  void **p)
 {
         int i;
 
         if (!size)
                 return 0;
 
         s = slab_pre_alloc_hook(s, flags);
         if (unlikely(!s))
                 return 0;
 
         i = __kmem_cache_alloc_bulk(s, flags, size, p);
         if (unlikely(i == 0))
                 return 0;
 
         /*
          * memcg and kmem_cache debug support and memory initialization.
          * Done outside of the IRQ disabled fastpath loop.
          */
         if (unlikely(!slab_post_alloc_hook(s, NULL, flags, size, p,
                     slab_want_init_on_alloc(flags, s), s->object_size))) {
                 return 0;
         }
         return i;
 }
 EXPORT_SYMBOL(kmem_cache_alloc_bulk_noprof);
 
 
 /*
  * Object placement in a slab is made very easy because we always start at
  * offset 0. If we tune the size of the object to the alignment then we can
  * get the required alignment by putting one properly sized object after
  * another.
  *
  * Notice that the allocation order determines the sizes of the per cpu
  * caches. Each processor has always one slab available for allocations.
  * Increasing the allocation order reduces the number of times that slabs
  * must be moved on and off the partial lists and is therefore a factor in
  * locking overhead.
  */
 
 /*
  * Minimum / Maximum order of slab pages. This influences locking overhead
  * and slab fragmentation. A higher order reduces the number of partial slabs
  * and increases the number of allocations possible without having to
  * take the list_lock.
  */
 static unsigned int slub_min_order;
 static unsigned int slub_max_order =
         IS_ENABLED(CONFIG_SLUB_TINY) ? 1 : PAGE_ALLOC_COSTLY_ORDER;
 static unsigned int slub_min_objects;
 
 /*
  * Calculate the order of allocation given an slab object size.
  *
  * The order of allocation has significant impact on performance and other
  * system components. Generally order 0 allocations should be preferred since
  * order 0 does not cause fragmentation in the page allocator. Larger objects
  * be problematic to put into order 0 slabs because there may be too much
  * unused space left. We go to a higher order if more than 1/16th of the slab
  * would be wasted.
  *
  * In order to reach satisfactory performance we must ensure that a minimum
  * number of objects is in one slab. Otherwise we may generate too much
  * activity on the partial lists which requires taking the list_lock. This is
  * less a concern for large slabs though which are rarely used.
  *
  * slab_max_order specifies the order where we begin to stop considering the
  * number of objects in a slab as critical. If we reach slab_max_order then
  * we try to keep the page order as low as possible. So we accept more waste
  * of space in favor of a small page order.
  *
  * Higher order allocations also allow the placement of more objects in a
  * slab and thereby reduce object handling overhead. If the user has
  * requested a higher minimum order then we start with that one instead of
  * the smallest order which will fit the object.
  */
 static inline unsigned int calc_slab_order(unsigned int size,
                 unsigned int min_order, unsigned int max_order,
                 unsigned int fract_leftover)
 {
         unsigned int order;
 
         for (order = min_order; order <= max_order; order++) {
 
                 unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
                 unsigned int rem;
 
                 rem = slab_size % size;
 
                 if (rem <= slab_size / fract_leftover)
                         break;
         }
 
         return order;
 }
 
 static inline int calculate_order(unsigned int size)
 {
         unsigned int order;
         unsigned int min_objects;
         unsigned int max_objects;
         unsigned int min_order;
 
         min_objects = slub_min_objects;
         if (!min_objects) {
                 /*
                  * Some architectures will only update present cpus when
                  * onlining them, so don't trust the number if it's just 1. But
                  * we also don't want to use nr_cpu_ids always, as on some other
                  * architectures, there can be many possible cpus, but never
                  * onlined. Here we compromise between trying to avoid too high
                  * order on systems that appear larger than they are, and too
                  * low order on systems that appear smaller than they are.
                  */
                 unsigned int nr_cpus = num_present_cpus();
                 if (nr_cpus <= 1)
                         nr_cpus = nr_cpu_ids;
                 min_objects = 4 * (fls(nr_cpus) + 1);
         }
         /* min_objects can't be 0 because get_order(0) is undefined */
         max_objects = max(order_objects(slub_max_order, size), 1U);
         min_objects = min(min_objects, max_objects);
 
         min_order = max_t(unsigned int, slub_min_order,
                           get_order(min_objects * size));
         if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
                 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
 
         /*
          * Attempt to find best configuration for a slab. This works by first
          * attempting to generate a layout with the best possible configuration
          * and backing off gradually.
          *
          * We start with accepting at most 1/16 waste and try to find the
          * smallest order from min_objects-derived/slab_min_order up to
          * slab_max_order that will satisfy the constraint. Note that increasing
          * the order can only result in same or less fractional waste, not more.
          *
          * If that fails, we increase the acceptable fraction of waste and try
          * again. The last iteration with fraction of 1/2 would effectively
          * accept any waste and give us the order determined by min_objects, as
          * long as at least single object fits within slab_max_order.
          */
         for (unsigned int fraction = 16; fraction > 1; fraction /= 2) {
                 order = calc_slab_order(size, min_order, slub_max_order,
                                         fraction);
                 if (order <= slub_max_order)
                         return order;
         }
 
         /*
          * Doh this slab cannot be placed using slab_max_order.
          */
         order = get_order(size);
         if (order <= MAX_PAGE_ORDER)
                 return order;
         return -ENOSYS;
 }
 
 static void
 init_kmem_cache_node(struct kmem_cache_node *n)
 {
         n->nr_partial = 0;
         spin_lock_init(&n->list_lock);
         INIT_LIST_HEAD(&n->partial);
 #ifdef CONFIG_SLUB_DEBUG
         atomic_long_set(&n->nr_slabs, 0);
         atomic_long_set(&n->total_objects, 0);
         INIT_LIST_HEAD(&n->full);
 #endif
 }
 
 #ifndef CONFIG_SLUB_TINY
 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
 {
         BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
                         NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH *
                         sizeof(struct kmem_cache_cpu));
 
         /*
          * Must align to double word boundary for the double cmpxchg
          * instructions to work; see __pcpu_double_call_return_bool().
          */
         s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
                                      2 * sizeof(void *));
 
         if (!s->cpu_slab)
                 return 0;
 
         init_kmem_cache_cpus(s);
 
         return 1;
 }
 #else
 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
 {
         return 1;
 }
 #endif /* CONFIG_SLUB_TINY */
 
 static struct kmem_cache *kmem_cache_node;
 
 /*
  * No kmalloc_node yet so do it by hand. We know that this is the first
  * slab on the node for this slabcache. There are no concurrent accesses
  * possible.
  *
  * Note that this function only works on the kmem_cache_node
  * when allocating for the kmem_cache_node. This is used for bootstrapping
  * memory on a fresh node that has no slab structures yet.
  */
 static void early_kmem_cache_node_alloc(int node)
 {
         struct slab *slab;
         struct kmem_cache_node *n;
 
         BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
 
         slab = new_slab(kmem_cache_node, GFP_NOWAIT, node);
 
         BUG_ON(!slab);
         if (slab_nid(slab) != node) {
                 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
                 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
         }
 
         n = slab->freelist;
         BUG_ON(!n);
 #ifdef CONFIG_SLUB_DEBUG
         init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
 #endif
         n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false);
         slab->freelist = get_freepointer(kmem_cache_node, n);
         slab->inuse = 1;
         kmem_cache_node->node[node] = n;
         init_kmem_cache_node(n);
         inc_slabs_node(kmem_cache_node, node, slab->objects);
 
         /*
          * No locks need to be taken here as it has just been
          * initialized and there is no concurrent access.
          */
         __add_partial(n, slab, DEACTIVATE_TO_HEAD);
 }
 
 static void free_kmem_cache_nodes(struct kmem_cache *s)
 {
         int node;
         struct kmem_cache_node *n;
 
         for_each_kmem_cache_node(s, node, n) {
                 s->node[node] = NULL;
                 kmem_cache_free(kmem_cache_node, n);
         }
 }
 
 void __kmem_cache_release(struct kmem_cache *s)
 {
         cache_random_seq_destroy(s);
 #ifndef CONFIG_SLUB_TINY
         free_percpu(s->cpu_slab);
 #endif
         free_kmem_cache_nodes(s);
 }
 
 static int init_kmem_cache_nodes(struct kmem_cache *s)
 {
         int node;
 
         for_each_node_mask(node, slab_nodes) {
                 struct kmem_cache_node *n;
 
                 if (slab_state == DOWN) {
                         early_kmem_cache_node_alloc(node);
                         continue;
                 }
                 n = kmem_cache_alloc_node(kmem_cache_node,
                                                 GFP_KERNEL, node);
 
                 if (!n) {
                         free_kmem_cache_nodes(s);
                         return 0;
                 }
 
                 init_kmem_cache_node(n);
                 s->node[node] = n;
         }
         return 1;
 }
 
 static void set_cpu_partial(struct kmem_cache *s)
 {
 #ifdef CONFIG_SLUB_CPU_PARTIAL
         unsigned int nr_objects;
 
         /*
          * cpu_partial determined the maximum number of objects kept in the
          * per cpu partial lists of a processor.
          *
          * Per cpu partial lists mainly contain slabs that just have one
          * object freed. If they are used for allocation then they can be
          * filled up again with minimal effort. The slab will never hit the
          * per node partial lists and therefore no locking will be required.
          *
          * For backwards compatibility reasons, this is determined as number
          * of objects, even though we now limit maximum number of pages, see
          * slub_set_cpu_partial()
          */
         if (!kmem_cache_has_cpu_partial(s))
                 nr_objects = 0;
         else if (s->size >= PAGE_SIZE)
                 nr_objects = 6;
         else if (s->size >= 1024)
                 nr_objects = 24;
         else if (s->size >= 256)
                 nr_objects = 52;
         else
                 nr_objects = 120;
 
         slub_set_cpu_partial(s, nr_objects);
 #endif
 }
 
 /*
  * calculate_sizes() determines the order and the distribution of data within
  * a slab object.
  */
 static int calculate_sizes(struct kmem_cache *s)
 {
         slab_flags_t flags = s->flags;
         unsigned int size = s->object_size;
         unsigned int order;
 
         /*
          * Round up object size to the next word boundary. We can only
          * place the free pointer at word boundaries and this determines
          * the possible location of the free pointer.
          */
         size = ALIGN(size, sizeof(void *));
 
 #ifdef CONFIG_SLUB_DEBUG
         /*
          * Determine if we can poison the object itself. If the user of
          * the slab may touch the object after free or before allocation
          * then we should never poison the object itself.
          */
         if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
                         !s->ctor)
                 s->flags |= __OBJECT_POISON;
         else
                 s->flags &= ~__OBJECT_POISON;
 
 
         /*
          * If we are Redzoning then check if there is some space between the
          * end of the object and the free pointer. If not then add an
          * additional word to have some bytes to store Redzone information.
          */
         if ((flags & SLAB_RED_ZONE) && size == s->object_size)
                 size += sizeof(void *);
 #endif
 
         /*
          * With that we have determined the number of bytes in actual use
          * by the object and redzoning.
          */
         s->inuse = size;
 
         if ((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) || s->ctor ||
             ((flags & SLAB_RED_ZONE) &&
              (s->object_size < sizeof(void *) || slub_debug_orig_size(s)))) {
                 /*
                  * Relocate free pointer after the object if it is not
                  * permitted to overwrite the first word of the object on
                  * kmem_cache_free.
                  *
                  * This is the case if we do RCU, have a constructor or
                  * destructor, are poisoning the objects, or are
                  * redzoning an object smaller than sizeof(void *) or are
                  * redzoning an object with slub_debug_orig_size() enabled,
                  * in which case the right redzone may be extended.
                  *
                  * The assumption that s->offset >= s->inuse means free
                  * pointer is outside of the object is used in the
                  * freeptr_outside_object() function. If that is no
                  * longer true, the function needs to be modified.
                  */
                 s->offset = size;
                 size += sizeof(void *);
         } else {
                 /*
                  * Store freelist pointer near middle of object to keep
                  * it away from the edges of the object to avoid small
                  * sized over/underflows from neighboring allocations.
                  */
                 s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *));
         }
 
 #ifdef CONFIG_SLUB_DEBUG
         if (flags & SLAB_STORE_USER) {
                 /*
                  * Need to store information about allocs and frees after
                  * the object.
                  */
                 size += 2 * sizeof(struct track);
 
                 /* Save the original kmalloc request size */
                 if (flags & SLAB_KMALLOC)
                         size += sizeof(unsigned int);
         }
 #endif
 
         kasan_cache_create(s, &size, &s->flags);
 #ifdef CONFIG_SLUB_DEBUG
         if (flags & SLAB_RED_ZONE) {
                 /*
                  * Add some empty padding so that we can catch
                  * overwrites from earlier objects rather than let
                  * tracking information or the free pointer be
                  * corrupted if a user writes before the start
                  * of the object.
                  */
                 size += sizeof(void *);
 
                 s->red_left_pad = sizeof(void *);
                 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
                 size += s->red_left_pad;
         }
 #endif
 
         /*
          * SLUB stores one object immediately after another beginning from
          * offset 0. In order to align the objects we have to simply size
          * each object to conform to the alignment.
          */
         size = ALIGN(size, s->align);
         s->size = size;
         s->reciprocal_size = reciprocal_value(size);
         order = calculate_order(size);
 
         if ((int)order < 0)
                 return 0;
 
         s->allocflags = __GFP_COMP;
 
         if (s->flags & SLAB_CACHE_DMA)
                 s->allocflags |= GFP_DMA;
 
         if (s->flags & SLAB_CACHE_DMA32)
                 s->allocflags |= GFP_DMA32;
 
         if (s->flags & SLAB_RECLAIM_ACCOUNT)
                 s->allocflags |= __GFP_RECLAIMABLE;
 
         /*
          * Determine the number of objects per slab
          */
         s->oo = oo_make(order, size);
         s->min = oo_make(get_order(size), size);
 
         return !!oo_objects(s->oo);
 }
 
 static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
 {
         s->flags = kmem_cache_flags(flags, s->name);
 #ifdef CONFIG_SLAB_FREELIST_HARDENED
         s->random = get_random_long();
 #endif
 
         if (!calculate_sizes(s))
                 goto error;
         if (disable_higher_order_debug) {
                 /*
                  * Disable debugging flags that store metadata if the min slab
                  * order increased.
                  */
                 if (get_order(s->size) > get_order(s->object_size)) {
                         s->flags &= ~DEBUG_METADATA_FLAGS;
                         s->offset = 0;
                         if (!calculate_sizes(s))
                                 goto error;
                 }
         }
 
 #ifdef system_has_freelist_aba
         if (system_has_freelist_aba() && !(s->flags & SLAB_NO_CMPXCHG)) {
                 /* Enable fast mode */
                 s->flags |= __CMPXCHG_DOUBLE;
         }
 #endif
 
         /*
          * The larger the object size is, the more slabs we want on the partial
          * list to avoid pounding the page allocator excessively.
          */
         s->min_partial = min_t(unsigned long, MAX_PARTIAL, ilog2(s->size) / 2);
         s->min_partial = max_t(unsigned long, MIN_PARTIAL, s->min_partial);
 
         set_cpu_partial(s);
 
 #ifdef CONFIG_NUMA
         s->remote_node_defrag_ratio = 1000;
 #endif
 
         /* Initialize the pre-computed randomized freelist if slab is up */
         if (slab_state >= UP) {
                 if (init_cache_random_seq(s))
                         goto error;
         }
 
         if (!init_kmem_cache_nodes(s))
                 goto error;
 
         if (alloc_kmem_cache_cpus(s))
                 return 0;
 
 error:
         __kmem_cache_release(s);
         return -EINVAL;
 }
 
 static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
                               const char *text)
 {
 #ifdef CONFIG_SLUB_DEBUG
         void *addr = slab_address(slab);
         void *p;
 
         slab_err(s, slab, text, s->name);
 
         spin_lock(&object_map_lock);
         __fill_map(object_map, s, slab);
 
         for_each_object(p, s, addr, slab->objects) {
 
                 if (!test_bit(__obj_to_index(s, addr, p), object_map)) {
                         pr_err("Object 0x%p @offset=%tu\n", p, p - addr);
                         print_tracking(s, p);
                 }
         }
         spin_unlock(&object_map_lock);
 #endif
 }
 
 /*
  * Attempt to free all partial slabs on a node.
  * This is called from __kmem_cache_shutdown(). We must take list_lock
  * because sysfs file might still access partial list after the shutdowning.
  */
 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
 {
         LIST_HEAD(discard);
         struct slab *slab, *h;
 
         BUG_ON(irqs_disabled());
         spin_lock_irq(&n->list_lock);
         list_for_each_entry_safe(slab, h, &n->partial, slab_list) {
                 if (!slab->inuse) {
                         remove_partial(n, slab);
                         list_add(&slab->slab_list, &discard);
                 } else {
                         list_slab_objects(s, slab,
                           "Objects remaining in %s on __kmem_cache_shutdown()");
                 }
         }
         spin_unlock_irq(&n->list_lock);
 
         list_for_each_entry_safe(slab, h, &discard, slab_list)
                 discard_slab(s, slab);
 }
 
 bool __kmem_cache_empty(struct kmem_cache *s)
 {
         int node;
         struct kmem_cache_node *n;
 
         for_each_kmem_cache_node(s, node, n)
                 if (n->nr_partial || node_nr_slabs(n))
                         return false;
         return true;
 }
 
 /*
  * Release all resources used by a slab cache.
  */
 int __kmem_cache_shutdown(struct kmem_cache *s)
 {
         int node;
         struct kmem_cache_node *n;
 
         flush_all_cpus_locked(s);
         /* Attempt to free all objects */
         for_each_kmem_cache_node(s, node, n) {
                 free_partial(s, n);
                 if (n->nr_partial || node_nr_slabs(n))
                         return 1;
         }
         return 0;
 }
 
 #ifdef CONFIG_PRINTK
 void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
 {
         void *base;
         int __maybe_unused i;
         unsigned int objnr;
         void *objp;
         void *objp0;
         struct kmem_cache *s = slab->slab_cache;
         struct track __maybe_unused *trackp;
 
         kpp->kp_ptr = object;
         kpp->kp_slab = slab;
         kpp->kp_slab_cache = s;
         base = slab_address(slab);
         objp0 = kasan_reset_tag(object);
 #ifdef CONFIG_SLUB_DEBUG
         objp = restore_red_left(s, objp0);
 #else
         objp = objp0;
 #endif
         objnr = obj_to_index(s, slab, objp);
         kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
         objp = base + s->size * objnr;
         kpp->kp_objp = objp;
         if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size
                          || (objp - base) % s->size) ||
             !(s->flags & SLAB_STORE_USER))
                 return;
 #ifdef CONFIG_SLUB_DEBUG
         objp = fixup_red_left(s, objp);
         trackp = get_track(s, objp, TRACK_ALLOC);
         kpp->kp_ret = (void *)trackp->addr;
 #ifdef CONFIG_STACKDEPOT
         {
                 depot_stack_handle_t handle;
                 unsigned long *entries;
                 unsigned int nr_entries;
 
                 handle = READ_ONCE(trackp->handle);
                 if (handle) {
                         nr_entries = stack_depot_fetch(handle, &entries);
                         for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
                                 kpp->kp_stack[i] = (void *)entries[i];
                 }
 
                 trackp = get_track(s, objp, TRACK_FREE);
                 handle = READ_ONCE(trackp->handle);
                 if (handle) {
                         nr_entries = stack_depot_fetch(handle, &entries);
                         for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
                                 kpp->kp_free_stack[i] = (void *)entries[i];
                 }
         }
 #endif
 #endif
 }
 #endif
 
 /********************************************************************
  *              Kmalloc subsystem
  *******************************************************************/
 
 static int __init setup_slub_min_order(char *str)
 {
         get_option(&str, (int *)&slub_min_order);
 
         if (slub_min_order > slub_max_order)
                 slub_max_order = slub_min_order;
 
         return 1;
 }
 
 __setup("slab_min_order=", setup_slub_min_order);
 __setup_param("slub_min_order=", slub_min_order, setup_slub_min_order, 0);
 
 
 static int __init setup_slub_max_order(char *str)
 {
         get_option(&str, (int *)&slub_max_order);
         slub_max_order = min_t(unsigned int, slub_max_order, MAX_PAGE_ORDER);
 
         if (slub_min_order > slub_max_order)
                 slub_min_order = slub_max_order;
 
         return 1;
 }
 
 __setup("slab_max_order=", setup_slub_max_order);
 __setup_param("slub_max_order=", slub_max_order, setup_slub_max_order, 0);
 
 static int __init setup_slub_min_objects(char *str)
 {
         get_option(&str, (int *)&slub_min_objects);
 
         return 1;
 }
 
 __setup("slab_min_objects=", setup_slub_min_objects);
 __setup_param("slub_min_objects=", slub_min_objects, setup_slub_min_objects, 0);
 
 #ifdef CONFIG_HARDENED_USERCOPY
 /*
  * Rejects incorrectly sized objects and objects that are to be copied
  * to/from userspace but do not fall entirely within the containing slab
  * cache's usercopy region.
  *
  * Returns NULL if check passes, otherwise const char * to name of cache
  * to indicate an error.
  */
 void __check_heap_object(const void *ptr, unsigned long n,
                          const struct slab *slab, bool to_user)
 {
         struct kmem_cache *s;
         unsigned int offset;
         bool is_kfence = is_kfence_address(ptr);
 
         ptr = kasan_reset_tag(ptr);
 
         /* Find object and usable object size. */
         s = slab->slab_cache;
 
         /* Reject impossible pointers. */
         if (ptr < slab_address(slab))
                 usercopy_abort("SLUB object not in SLUB page?!", NULL,
                                to_user, 0, n);
 
         /* Find offset within object. */
         if (is_kfence)
                 offset = ptr - kfence_object_start(ptr);
         else
                 offset = (ptr - slab_address(slab)) % s->size;
 
         /* Adjust for redzone and reject if within the redzone. */
         if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
                 if (offset < s->red_left_pad)
                         usercopy_abort("SLUB object in left red zone",
                                        s->name, to_user, offset, n);
                 offset -= s->red_left_pad;
         }
 
         /* Allow address range falling entirely within usercopy region. */
         if (offset >= s->useroffset &&
             offset - s->useroffset <= s->usersize &&
             n <= s->useroffset - offset + s->usersize)
                 return;
 
         usercopy_abort("SLUB object", s->name, to_user, offset, n);
 }
 #endif /* CONFIG_HARDENED_USERCOPY */
 
 #define SHRINK_PROMOTE_MAX 32
 
 /*
  * kmem_cache_shrink discards empty slabs and promotes the slabs filled
  * up most to the head of the partial lists. New allocations will then
  * fill those up and thus they can be removed from the partial lists.
  *
  * The slabs with the least items are placed last. This results in them
  * being allocated from last increasing the chance that the last objects
  * are freed in them.
  */
 static int __kmem_cache_do_shrink(struct kmem_cache *s)
 {
         int node;
         int i;
         struct kmem_cache_node *n;
         struct slab *slab;
         struct slab *t;
         struct list_head discard;
         struct list_head promote[SHRINK_PROMOTE_MAX];
         unsigned long flags;
         int ret = 0;
 
         for_each_kmem_cache_node(s, node, n) {
                 INIT_LIST_HEAD(&discard);
                 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
                         INIT_LIST_HEAD(promote + i);
 
                 spin_lock_irqsave(&n->list_lock, flags);
 
                 /*
                  * Build lists of slabs to discard or promote.
                  *
                  * Note that concurrent frees may occur while we hold the
                  * list_lock. slab->inuse here is the upper limit.
                  */
                 list_for_each_entry_safe(slab, t, &n->partial, slab_list) {
                         int free = slab->objects - slab->inuse;
 
                         /* Do not reread slab->inuse */
                         barrier();
 
                         /* We do not keep full slabs on the list */
                         BUG_ON(free <= 0);
 
                         if (free == slab->objects) {
                                 list_move(&slab->slab_list, &discard);
                                 slab_clear_node_partial(slab);
                                 n->nr_partial--;
                                 dec_slabs_node(s, node, slab->objects);
                         } else if (free <= SHRINK_PROMOTE_MAX)
                                 list_move(&slab->slab_list, promote + free - 1);
                 }
 
                 /*
                  * Promote the slabs filled up most to the head of the
                  * partial list.
                  */
                 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
                         list_splice(promote + i, &n->partial);
 
                 spin_unlock_irqrestore(&n->list_lock, flags);
 
                 /* Release empty slabs */
                 list_for_each_entry_safe(slab, t, &discard, slab_list)
                         free_slab(s, slab);
 
                 if (node_nr_slabs(n))
                         ret = 1;
         }
 
         return ret;
 }
 
 int __kmem_cache_shrink(struct kmem_cache *s)
 {
         flush_all(s);
         return __kmem_cache_do_shrink(s);
 }
 
 static int slab_mem_going_offline_callback(void *arg)
 {
         struct kmem_cache *s;
 
         mutex_lock(&slab_mutex);
         list_for_each_entry(s, &slab_caches, list) {
                 flush_all_cpus_locked(s);
                 __kmem_cache_do_shrink(s);
         }
         mutex_unlock(&slab_mutex);
 
         return 0;
 }
 
 static void slab_mem_offline_callback(void *arg)
 {
         struct memory_notify *marg = arg;
         int offline_node;
 
         offline_node = marg->status_change_nid_normal;
 
         /*
          * If the node still has available memory. we need kmem_cache_node
          * for it yet.
          */
         if (offline_node < 0)
                 return;
 
         mutex_lock(&slab_mutex);
         node_clear(offline_node, slab_nodes);
         /*
          * We no longer free kmem_cache_node structures here, as it would be
          * racy with all get_node() users, and infeasible to protect them with
          * slab_mutex.
          */
         mutex_unlock(&slab_mutex);
 }
 
 static int slab_mem_going_online_callback(void *arg)
 {
         struct kmem_cache_node *n;
         struct kmem_cache *s;
         struct memory_notify *marg = arg;
         int nid = marg->status_change_nid_normal;
         int ret = 0;
 
         /*
          * If the node's memory is already available, then kmem_cache_node is
          * already created. Nothing to do.
          */
         if (nid < 0)
                 return 0;
 
         /*
          * We are bringing a node online. No memory is available yet. We must
          * allocate a kmem_cache_node structure in order to bring the node
          * online.
          */
         mutex_lock(&slab_mutex);
         list_for_each_entry(s, &slab_caches, list) {
                 /*
                  * The structure may already exist if the node was previously
                  * onlined and offlined.
                  */
                 if (get_node(s, nid))
                         continue;
                 /*
                  * XXX: kmem_cache_alloc_node will fallback to other nodes
                  *      since memory is not yet available from the node that
                  *      is brought up.
                  */
                 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
                 if (!n) {
                         ret = -ENOMEM;
                         goto out;
                 }
                 init_kmem_cache_node(n);
                 s->node[nid] = n;
         }
         /*
          * Any cache created after this point will also have kmem_cache_node
          * initialized for the new node.
          */
         node_set(nid, slab_nodes);
 out:
         mutex_unlock(&slab_mutex);
         return ret;
 }
 
 static int slab_memory_callback(struct notifier_block *self,
                                 unsigned long action, void *arg)
 {
         int ret = 0;
 
         switch (action) {
         case MEM_GOING_ONLINE:
                 ret = slab_mem_going_online_callback(arg);
                 break;
         case MEM_GOING_OFFLINE:
                 ret = slab_mem_going_offline_callback(arg);
                 break;
         case MEM_OFFLINE:
         case MEM_CANCEL_ONLINE:
                 slab_mem_offline_callback(arg);
                 break;
         case MEM_ONLINE:
         case MEM_CANCEL_OFFLINE:
                 break;
         }
         if (ret)
                 ret = notifier_from_errno(ret);
         else
                 ret = NOTIFY_OK;
         return ret;
 }
 
 /********************************************************************
  *                      Basic setup of slabs
  *******************************************************************/
 
 /*
  * Used for early kmem_cache structures that were allocated using
  * the page allocator. Allocate them properly then fix up the pointers
  * that may be pointing to the wrong kmem_cache structure.
  */
 
 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
 {
         int node;
         struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
         struct kmem_cache_node *n;
 
         memcpy(s, static_cache, kmem_cache->object_size);
 
         /*
          * This runs very early, and only the boot processor is supposed to be
          * up.  Even if it weren't true, IRQs are not up so we couldn't fire
          * IPIs around.
          */
         __flush_cpu_slab(s, smp_processor_id());
         for_each_kmem_cache_node(s, node, n) {
                 struct slab *p;
 
                 list_for_each_entry(p, &n->partial, slab_list)
                         p->slab_cache = s;
 
 #ifdef CONFIG_SLUB_DEBUG
                 list_for_each_entry(p, &n->full, slab_list)
                         p->slab_cache = s;
 #endif
         }
         list_add(&s->list, &slab_caches);
         return s;
 }
 
 void __init kmem_cache_init(void)
 {
         static __initdata struct kmem_cache boot_kmem_cache,
                 boot_kmem_cache_node;
         int node;
 
         if (debug_guardpage_minorder())
                 slub_max_order = 0;
 
         /* Print slub debugging pointers without hashing */
         if (__slub_debug_enabled())
                 no_hash_pointers_enable(NULL);
 
         kmem_cache_node = &boot_kmem_cache_node;
         kmem_cache = &boot_kmem_cache;
 
         /*
          * Initialize the nodemask for which we will allocate per node
          * structures. Here we don't need taking slab_mutex yet.
          */
         for_each_node_state(node, N_NORMAL_MEMORY)
                 node_set(node, slab_nodes);
 
         create_boot_cache(kmem_cache_node, "kmem_cache_node",
                         sizeof(struct kmem_cache_node),
                         SLAB_HWCACHE_ALIGN | SLAB_NO_OBJ_EXT, 0, 0);
 
         hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
 
         /* Able to allocate the per node structures */
         slab_state = PARTIAL;
 
         create_boot_cache(kmem_cache, "kmem_cache",
                         offsetof(struct kmem_cache, node) +
                                 nr_node_ids * sizeof(struct kmem_cache_node *),
                         SLAB_HWCACHE_ALIGN | SLAB_NO_OBJ_EXT, 0, 0);
 
         kmem_cache = bootstrap(&boot_kmem_cache);
         kmem_cache_node = bootstrap(&boot_kmem_cache_node);
 
         /* Now we can use the kmem_cache to allocate kmalloc slabs */
         setup_kmalloc_cache_index_table();
         create_kmalloc_caches();
 
         /* Setup random freelists for each cache */
         init_freelist_randomization();
 
         cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
                                   slub_cpu_dead);
 
         pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
                 cache_line_size(),
                 slub_min_order, slub_max_order, slub_min_objects,
                 nr_cpu_ids, nr_node_ids);
 }
 
 void __init kmem_cache_init_late(void)
 {
 #ifndef CONFIG_SLUB_TINY
         flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM, 0);
         WARN_ON(!flushwq);
 #endif
 }
 
 struct kmem_cache *
 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
                    slab_flags_t flags, void (*ctor)(void *))
 {
         struct kmem_cache *s;
 
         s = find_mergeable(size, align, flags, name, ctor);
         if (s) {
                 if (sysfs_slab_alias(s, name))
                         return NULL;
 
                 s->refcount++;
 
                 /*
                  * Adjust the object sizes so that we clear
                  * the complete object on kzalloc.
                  */
                 s->object_size = max(s->object_size, size);
                 s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
         }
 
         return s;
 }
 
 int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
 {
         int err;
 
         err = kmem_cache_open(s, flags);
         if (err)
                 return err;
 
         /* Mutex is not taken during early boot */
         if (slab_state <= UP)
                 return 0;
 
         err = sysfs_slab_add(s);
         if (err) {
                 __kmem_cache_release(s);
                 return err;
         }
 
         if (s->flags & SLAB_STORE_USER)
                 debugfs_slab_add(s);
 
         return 0;
 }
 
 #ifdef SLAB_SUPPORTS_SYSFS
 static int count_inuse(struct slab *slab)
 {
         return slab->inuse;
 }
 
 static int count_total(struct slab *slab)
 {
         return slab->objects;
 }
 #endif
 
 #ifdef CONFIG_SLUB_DEBUG
 static void validate_slab(struct kmem_cache *s, struct slab *slab,
                           unsigned long *obj_map)
 {
         void *p;
         void *addr = slab_address(slab);
 
         if (!check_slab(s, slab) || !on_freelist(s, slab, NULL))
                 return;
 
         /* Now we know that a valid freelist exists */
         __fill_map(obj_map, s, slab);
         for_each_object(p, s, addr, slab->objects) {
                 u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ?
                          SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
 
                 if (!check_object(s, slab, p, val))
                         break;
         }
 }
 
 static int validate_slab_node(struct kmem_cache *s,
                 struct kmem_cache_node *n, unsigned long *obj_map)
 {
         unsigned long count = 0;
         struct slab *slab;
         unsigned long flags;
 
         spin_lock_irqsave(&n->list_lock, flags);
 
         list_for_each_entry(slab, &n->partial, slab_list) {
                 validate_slab(s, slab, obj_map);
                 count++;
         }
         if (count != n->nr_partial) {
                 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
                        s->name, count, n->nr_partial);
                 slab_add_kunit_errors();
         }
 
         if (!(s->flags & SLAB_STORE_USER))
                 goto out;
 
         list_for_each_entry(slab, &n->full, slab_list) {
                 validate_slab(s, slab, obj_map);
                 count++;
         }
         if (count != node_nr_slabs(n)) {
                 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
                        s->name, count, node_nr_slabs(n));
                 slab_add_kunit_errors();
         }
 
 out:
         spin_unlock_irqrestore(&n->list_lock, flags);
         return count;
 }
 
 long validate_slab_cache(struct kmem_cache *s)
 {
         int node;
         unsigned long count = 0;
         struct kmem_cache_node *n;
         unsigned long *obj_map;
 
         obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
         if (!obj_map)
                 return -ENOMEM;
 
         flush_all(s);
         for_each_kmem_cache_node(s, node, n)
                 count += validate_slab_node(s, n, obj_map);
 
         bitmap_free(obj_map);
 
         return count;
 }
 EXPORT_SYMBOL(validate_slab_cache);
 
 #ifdef CONFIG_DEBUG_FS
 /*
  * Generate lists of code addresses where slabcache objects are allocated
  * and freed.
  */
 
 struct location {
         depot_stack_handle_t handle;
         unsigned long count;
         unsigned long addr;
         unsigned long waste;
         long long sum_time;
         long min_time;
         long max_time;
         long min_pid;
         long max_pid;
         DECLARE_BITMAP(cpus, NR_CPUS);
         nodemask_t nodes;
 };
 
 struct loc_track {
         unsigned long max;
         unsigned long count;
         struct location *loc;
         loff_t idx;
 };
 
 static struct dentry *slab_debugfs_root;
 
 static void free_loc_track(struct loc_track *t)
 {
         if (t->max)
                 free_pages((unsigned long)t->loc,
                         get_order(sizeof(struct location) * t->max));
 }
 
 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
 {
         struct location *l;
         int order;
 
         order = get_order(sizeof(struct location) * max);
 
         l = (void *)__get_free_pages(flags, order);
         if (!l)
                 return 0;
 
         if (t->count) {
                 memcpy(l, t->loc, sizeof(struct location) * t->count);
                 free_loc_track(t);
         }
         t->max = max;
         t->loc = l;
         return 1;
 }
 
 static int add_location(struct loc_track *t, struct kmem_cache *s,
                                 const struct track *track,
                                 unsigned int orig_size)
 {
         long start, end, pos;
         struct location *l;
         unsigned long caddr, chandle, cwaste;
         unsigned long age = jiffies - track->when;
         depot_stack_handle_t handle = 0;
         unsigned int waste = s->object_size - orig_size;
 
 #ifdef CONFIG_STACKDEPOT
         handle = READ_ONCE(track->handle);
 #endif
         start = -1;
         end = t->count;
 
         for ( ; ; ) {
                 pos = start + (end - start + 1) / 2;
 
                 /*
                  * There is nothing at "end". If we end up there
                  * we need to add something to before end.
                  */
                 if (pos == end)
                         break;
 
                 l = &t->loc[pos];
                 caddr = l->addr;
                 chandle = l->handle;
                 cwaste = l->waste;
                 if ((track->addr == caddr) && (handle == chandle) &&
                         (waste == cwaste)) {
 
                         l->count++;
                         if (track->when) {
                                 l->sum_time += age;
                                 if (age < l->min_time)
                                         l->min_time = age;
                                 if (age > l->max_time)
                                         l->max_time = age;
 
                                 if (track->pid < l->min_pid)
                                         l->min_pid = track->pid;
                                 if (track->pid > l->max_pid)
                                         l->max_pid = track->pid;
 
                                 cpumask_set_cpu(track->cpu,
                                                 to_cpumask(l->cpus));
                         }
                         node_set(page_to_nid(virt_to_page(track)), l->nodes);
                         return 1;
                 }
 
                 if (track->addr < caddr)
                         end = pos;
                 else if (track->addr == caddr && handle < chandle)
                         end = pos;
                 else if (track->addr == caddr && handle == chandle &&
                                 waste < cwaste)
                         end = pos;
                 else
                         start = pos;
         }
 
         /*
          * Not found. Insert new tracking element.
          */
         if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
                 return 0;
 
         l = t->loc + pos;
         if (pos < t->count)
                 memmove(l + 1, l,
                         (t->count - pos) * sizeof(struct location));
         t->count++;
         l->count = 1;
         l->addr = track->addr;
         l->sum_time = age;
         l->min_time = age;
         l->max_time = age;
         l->min_pid = track->pid;
         l->max_pid = track->pid;
         l->handle = handle;
         l->waste = waste;
         cpumask_clear(to_cpumask(l->cpus));
         cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
         nodes_clear(l->nodes);
         node_set(page_to_nid(virt_to_page(track)), l->nodes);
         return 1;
 }
 
 static void process_slab(struct loc_track *t, struct kmem_cache *s,
                 struct slab *slab, enum track_item alloc,
                 unsigned long *obj_map)
 {
         void *addr = slab_address(slab);
         bool is_alloc = (alloc == TRACK_ALLOC);
         void *p;
 
         __fill_map(obj_map, s, slab);
 
         for_each_object(p, s, addr, slab->objects)
                 if (!test_bit(__obj_to_index(s, addr, p), obj_map))
                         add_location(t, s, get_track(s, p, alloc),
                                      is_alloc ? get_orig_size(s, p) :
                                                 s->object_size);
 }
 #endif  /* CONFIG_DEBUG_FS   */
 #endif  /* CONFIG_SLUB_DEBUG */
 
 #ifdef SLAB_SUPPORTS_SYSFS
 enum slab_stat_type {
         SL_ALL,                 /* All slabs */
         SL_PARTIAL,             /* Only partially allocated slabs */
         SL_CPU,                 /* Only slabs used for cpu caches */
         SL_OBJECTS,             /* Determine allocated objects not slabs */
         SL_TOTAL                /* Determine object capacity not slabs */
 };
 
 #define SO_ALL          (1 << SL_ALL)
 #define SO_PARTIAL      (1 << SL_PARTIAL)
 #define SO_CPU          (1 << SL_CPU)
 #define SO_OBJECTS      (1 << SL_OBJECTS)
 #define SO_TOTAL        (1 << SL_TOTAL)
 
 static ssize_t show_slab_objects(struct kmem_cache *s,
                                  char *buf, unsigned long flags)
 {
         unsigned long total = 0;
         int node;
         int x;
         unsigned long *nodes;
         int len = 0;
 
         nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
         if (!nodes)
                 return -ENOMEM;
 
         if (flags & SO_CPU) {
                 int cpu;
 
                 for_each_possible_cpu(cpu) {
                         struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
                                                                cpu);
                         int node;
                         struct slab *slab;
 
                         slab = READ_ONCE(c->slab);
                         if (!slab)
                                 continue;
 
                         node = slab_nid(slab);
                         if (flags & SO_TOTAL)
                                 x = slab->objects;
                         else if (flags & SO_OBJECTS)
                                 x = slab->inuse;
                         else
                                 x = 1;
 
                         total += x;
                         nodes[node] += x;
 
 #ifdef CONFIG_SLUB_CPU_PARTIAL
                         slab = slub_percpu_partial_read_once(c);
                         if (slab) {
                                 node = slab_nid(slab);
                                 if (flags & SO_TOTAL)
                                         WARN_ON_ONCE(1);
                                 else if (flags & SO_OBJECTS)
                                         WARN_ON_ONCE(1);
                                 else
                                         x = data_race(slab->slabs);
                                 total += x;
                                 nodes[node] += x;
                         }
 #endif
                 }
         }
 
         /*
          * It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
          * already held which will conflict with an existing lock order:
          *
          * mem_hotplug_lock->slab_mutex->kernfs_mutex
          *
          * We don't really need mem_hotplug_lock (to hold off
          * slab_mem_going_offline_callback) here because slab's memory hot
          * unplug code doesn't destroy the kmem_cache->node[] data.
          */
 
 #ifdef CONFIG_SLUB_DEBUG
         if (flags & SO_ALL) {
                 struct kmem_cache_node *n;
 
                 for_each_kmem_cache_node(s, node, n) {
 
                         if (flags & SO_TOTAL)
                                 x = node_nr_objs(n);
                         else if (flags & SO_OBJECTS)
                                 x = node_nr_objs(n) - count_partial(n, count_free);
                         else
                                 x = node_nr_slabs(n);
                         total += x;
                         nodes[node] += x;
                 }
 
         } else
 #endif
         if (flags & SO_PARTIAL) {
                 struct kmem_cache_node *n;
 
                 for_each_kmem_cache_node(s, node, n) {
                         if (flags & SO_TOTAL)
                                 x = count_partial(n, count_total);
                         else if (flags & SO_OBJECTS)
                                 x = count_partial(n, count_inuse);
                         else
                                 x = n->nr_partial;
                         total += x;
                         nodes[node] += x;
                 }
         }
 
         len += sysfs_emit_at(buf, len, "%lu", total);
 #ifdef CONFIG_NUMA
         for (node = 0; node < nr_node_ids; node++) {
                 if (nodes[node])
                         len += sysfs_emit_at(buf, len, " N%d=%lu",
                                              node, nodes[node]);
         }
 #endif
         len += sysfs_emit_at(buf, len, "\n");
         kfree(nodes);
 
         return len;
 }
 
 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
 
 struct slab_attribute {
         struct attribute attr;
         ssize_t (*show)(struct kmem_cache *s, char *buf);
         ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
 };
 
 #define SLAB_ATTR_RO(_name) \
         static struct slab_attribute _name##_attr = __ATTR_RO_MODE(_name, 0400)
 
 #define SLAB_ATTR(_name) \
         static struct slab_attribute _name##_attr = __ATTR_RW_MODE(_name, 0600)
 
 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%u\n", s->size);
 }
 SLAB_ATTR_RO(slab_size);
 
 static ssize_t align_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%u\n", s->align);
 }
 SLAB_ATTR_RO(align);
 
 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%u\n", s->object_size);
 }
 SLAB_ATTR_RO(object_size);
 
 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%u\n", oo_objects(s->oo));
 }
 SLAB_ATTR_RO(objs_per_slab);
 
 static ssize_t order_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%u\n", oo_order(s->oo));
 }
 SLAB_ATTR_RO(order);
 
 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%lu\n", s->min_partial);
 }
 
 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
                                  size_t length)
 {
         unsigned long min;
         int err;
 
         err = kstrtoul(buf, 10, &min);
         if (err)
                 return err;
 
         s->min_partial = min;
         return length;
 }
 SLAB_ATTR(min_partial);
 
 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
 {
         unsigned int nr_partial = 0;
 #ifdef CONFIG_SLUB_CPU_PARTIAL
         nr_partial = s->cpu_partial;
 #endif
 
         return sysfs_emit(buf, "%u\n", nr_partial);
 }
 
 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
                                  size_t length)
 {
         unsigned int objects;
         int err;
 
         err = kstrtouint(buf, 10, &objects);
         if (err)
                 return err;
         if (objects && !kmem_cache_has_cpu_partial(s))
                 return -EINVAL;
 
         slub_set_cpu_partial(s, objects);
         flush_all(s);
         return length;
 }
 SLAB_ATTR(cpu_partial);
 
 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
 {
         if (!s->ctor)
                 return 0;
         return sysfs_emit(buf, "%pS\n", s->ctor);
 }
 SLAB_ATTR_RO(ctor);
 
 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
 }
 SLAB_ATTR_RO(aliases);
 
 static ssize_t partial_show(struct kmem_cache *s, char *buf)
 {
         return show_slab_objects(s, buf, SO_PARTIAL);
 }
 SLAB_ATTR_RO(partial);
 
 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
 {
         return show_slab_objects(s, buf, SO_CPU);
 }
 SLAB_ATTR_RO(cpu_slabs);
 
 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
 {
         return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
 }
 SLAB_ATTR_RO(objects_partial);
 
 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
 {
         int objects = 0;
         int slabs = 0;
         int cpu __maybe_unused;
         int len = 0;
 
 #ifdef CONFIG_SLUB_CPU_PARTIAL
         for_each_online_cpu(cpu) {
                 struct slab *slab;
 
                 slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
 
                 if (slab)
                         slabs += data_race(slab->slabs);
         }
 #endif
 
         /* Approximate half-full slabs, see slub_set_cpu_partial() */
         objects = (slabs * oo_objects(s->oo)) / 2;
         len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
 
 #ifdef CONFIG_SLUB_CPU_PARTIAL
         for_each_online_cpu(cpu) {
                 struct slab *slab;
 
                 slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
                 if (slab) {
                         slabs = data_race(slab->slabs);
                         objects = (slabs * oo_objects(s->oo)) / 2;
                         len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
                                              cpu, objects, slabs);
                 }
         }
 #endif
         len += sysfs_emit_at(buf, len, "\n");
 
         return len;
 }
 SLAB_ATTR_RO(slabs_cpu_partial);
 
 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
 }
 SLAB_ATTR_RO(reclaim_account);
 
 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
 }
 SLAB_ATTR_RO(hwcache_align);
 
 #ifdef CONFIG_ZONE_DMA
 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
 }
 SLAB_ATTR_RO(cache_dma);
 #endif
 
 #ifdef CONFIG_HARDENED_USERCOPY
 static ssize_t usersize_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%u\n", s->usersize);
 }
 SLAB_ATTR_RO(usersize);
 #endif
 
 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
 }
 SLAB_ATTR_RO(destroy_by_rcu);
 
 #ifdef CONFIG_SLUB_DEBUG
 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
 {
         return show_slab_objects(s, buf, SO_ALL);
 }
 SLAB_ATTR_RO(slabs);
 
 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
 {
         return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
 }
 SLAB_ATTR_RO(total_objects);
 
 static ssize_t objects_show(struct kmem_cache *s, char *buf)
 {
         return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
 }
 SLAB_ATTR_RO(objects);
 
 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
 }
 SLAB_ATTR_RO(sanity_checks);
 
 static ssize_t trace_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TRACE));
 }
 SLAB_ATTR_RO(trace);
 
 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
 }
 
 SLAB_ATTR_RO(red_zone);
 
 static ssize_t poison_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_POISON));
 }
 
 SLAB_ATTR_RO(poison);
 
 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
 }
 
 SLAB_ATTR_RO(store_user);
 
 static ssize_t validate_show(struct kmem_cache *s, char *buf)
 {
         return 0;
 }
 
 static ssize_t validate_store(struct kmem_cache *s,
                         const char *buf, size_t length)
 {
         int ret = -EINVAL;
 
         if (buf[0] == '1' && kmem_cache_debug(s)) {
                 ret = validate_slab_cache(s);
                 if (ret >= 0)
                         ret = length;
         }
         return ret;
 }
 SLAB_ATTR(validate);
 
 #endif /* CONFIG_SLUB_DEBUG */
 
 #ifdef CONFIG_FAILSLAB
 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
 }
 
 static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
                                 size_t length)
 {
         if (s->refcount > 1)
                 return -EINVAL;
 
         if (buf[0] == '1')
                 WRITE_ONCE(s->flags, s->flags | SLAB_FAILSLAB);
         else
                 WRITE_ONCE(s->flags, s->flags & ~SLAB_FAILSLAB);
 
         return length;
 }
 SLAB_ATTR(failslab);
 #endif
 
 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
 {
         return 0;
 }
 
 static ssize_t shrink_store(struct kmem_cache *s,
                         const char *buf, size_t length)
 {
         if (buf[0] == '1')
                 kmem_cache_shrink(s);
         else
                 return -EINVAL;
         return length;
 }
 SLAB_ATTR(shrink);
 
 #ifdef CONFIG_NUMA
 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%u\n", s->remote_node_defrag_ratio / 10);
 }
 
 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
                                 const char *buf, size_t length)
 {
         unsigned int ratio;
         int err;
 
         err = kstrtouint(buf, 10, &ratio);
         if (err)
                 return err;
         if (ratio > 100)
                 return -ERANGE;
 
         s->remote_node_defrag_ratio = ratio * 10;
 
         return length;
 }
 SLAB_ATTR(remote_node_defrag_ratio);
 #endif
 
 #ifdef CONFIG_SLUB_STATS
 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
 {
         unsigned long sum  = 0;
         int cpu;
         int len = 0;
         int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
 
         if (!data)
                 return -ENOMEM;
 
         for_each_online_cpu(cpu) {
                 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
 
                 data[cpu] = x;
                 sum += x;
         }
 
         len += sysfs_emit_at(buf, len, "%lu", sum);
 
 #ifdef CONFIG_SMP
         for_each_online_cpu(cpu) {
                 if (data[cpu])
                         len += sysfs_emit_at(buf, len, " C%d=%u",
                                              cpu, data[cpu]);
         }
 #endif
         kfree(data);
         len += sysfs_emit_at(buf, len, "\n");
 
         return len;
 }
 
 static void clear_stat(struct kmem_cache *s, enum stat_item si)
 {
         int cpu;
 
         for_each_online_cpu(cpu)
                 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
 }
 
 #define STAT_ATTR(si, text)                                     \
 static ssize_t text##_show(struct kmem_cache *s, char *buf)     \
 {                                                               \
         return show_stat(s, buf, si);                           \
 }                                                               \
 static ssize_t text##_store(struct kmem_cache *s,               \
                                 const char *buf, size_t length) \
 {                                                               \
         if (buf[0] != '')                                      \
                 return -EINVAL;                                 \
         clear_stat(s, si);                                      \
         return length;                                          \
 }                                                               \
 SLAB_ATTR(text);                                                \
 
 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
 STAT_ATTR(FREE_FASTPATH, free_fastpath);
 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
 STAT_ATTR(FREE_FROZEN, free_frozen);
 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
 STAT_ATTR(ALLOC_SLAB, alloc_slab);
 STAT_ATTR(ALLOC_REFILL, alloc_refill);
 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
 STAT_ATTR(FREE_SLAB, free_slab);
 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
 STAT_ATTR(ORDER_FALLBACK, order_fallback);
 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
 #endif  /* CONFIG_SLUB_STATS */
 
 #ifdef CONFIG_KFENCE
 static ssize_t skip_kfence_show(struct kmem_cache *s, char *buf)
 {
         return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_SKIP_KFENCE));
 }
 
 static ssize_t skip_kfence_store(struct kmem_cache *s,
                         const char *buf, size_t length)
 {
         int ret = length;
 
         if (buf[0] == '')
                 s->flags &= ~SLAB_SKIP_KFENCE;
         else if (buf[0] == '1')
                 s->flags |= SLAB_SKIP_KFENCE;
         else
                 ret = -EINVAL;
 
         return ret;
 }
 SLAB_ATTR(skip_kfence);
 #endif
 
 static struct attribute *slab_attrs[] = {
         &slab_size_attr.attr,
         &object_size_attr.attr,
         &objs_per_slab_attr.attr,
         &order_attr.attr,
         &min_partial_attr.attr,
         &cpu_partial_attr.attr,
         &objects_partial_attr.attr,
         &partial_attr.attr,
         &cpu_slabs_attr.attr,
         &ctor_attr.attr,
         &aliases_attr.attr,
         &align_attr.attr,
         &hwcache_align_attr.attr,
         &reclaim_account_attr.attr,
         &destroy_by_rcu_attr.attr,
         &shrink_attr.attr,
         &slabs_cpu_partial_attr.attr,
 #ifdef CONFIG_SLUB_DEBUG
         &total_objects_attr.attr,
         &objects_attr.attr,
         &slabs_attr.attr,
         &sanity_checks_attr.attr,
         &trace_attr.attr,
         &red_zone_attr.attr,
         &poison_attr.attr,
         &store_user_attr.attr,
         &validate_attr.attr,
 #endif
 #ifdef CONFIG_ZONE_DMA
         &cache_dma_attr.attr,
 #endif
 #ifdef CONFIG_NUMA
         &remote_node_defrag_ratio_attr.attr,
 #endif
 #ifdef CONFIG_SLUB_STATS
         &alloc_fastpath_attr.attr,
         &alloc_slowpath_attr.attr,
         &free_fastpath_attr.attr,
         &free_slowpath_attr.attr,
         &free_frozen_attr.attr,
         &free_add_partial_attr.attr,
         &free_remove_partial_attr.attr,
         &alloc_from_partial_attr.attr,
         &alloc_slab_attr.attr,
         &alloc_refill_attr.attr,
         &alloc_node_mismatch_attr.attr,
         &free_slab_attr.attr,
         &cpuslab_flush_attr.attr,
         &deactivate_full_attr.attr,
         &deactivate_empty_attr.attr,
         &deactivate_to_head_attr.attr,
         &deactivate_to_tail_attr.attr,
         &deactivate_remote_frees_attr.attr,
         &deactivate_bypass_attr.attr,
         &order_fallback_attr.attr,
         &cmpxchg_double_fail_attr.attr,
         &cmpxchg_double_cpu_fail_attr.attr,
         &cpu_partial_alloc_attr.attr,
         &cpu_partial_free_attr.attr,
         &cpu_partial_node_attr.attr,
         &cpu_partial_drain_attr.attr,
 #endif
 #ifdef CONFIG_FAILSLAB
         &failslab_attr.attr,
 #endif
 #ifdef CONFIG_HARDENED_USERCOPY
         &usersize_attr.attr,
 #endif
 #ifdef CONFIG_KFENCE
         &skip_kfence_attr.attr,
 #endif
 
         NULL
 };
 
 static const struct attribute_group slab_attr_group = {
         .attrs = slab_attrs,
 };
 
 static ssize_t slab_attr_show(struct kobject *kobj,
                                 struct attribute *attr,
                                 char *buf)
 {
         struct slab_attribute *attribute;
         struct kmem_cache *s;
 
         attribute = to_slab_attr(attr);
         s = to_slab(kobj);
 
         if (!attribute->show)
                 return -EIO;
 
         return attribute->show(s, buf);
 }
 
 static ssize_t slab_attr_store(struct kobject *kobj,
                                 struct attribute *attr,
                                 const char *buf, size_t len)
 {
         struct slab_attribute *attribute;
         struct kmem_cache *s;
 
         attribute = to_slab_attr(attr);
         s = to_slab(kobj);
 
         if (!attribute->store)
                 return -EIO;
 
         return attribute->store(s, buf, len);
 }
 
 static void kmem_cache_release(struct kobject *k)
 {
         slab_kmem_cache_release(to_slab(k));
 }
 
 static const struct sysfs_ops slab_sysfs_ops = {
         .show = slab_attr_show,
         .store = slab_attr_store,
 };
 
 static const struct kobj_type slab_ktype = {
         .sysfs_ops = &slab_sysfs_ops,
         .release = kmem_cache_release,
 };
 
 static struct kset *slab_kset;
 
 static inline struct kset *cache_kset(struct kmem_cache *s)
 {
         return slab_kset;
 }
 
 #define ID_STR_LENGTH 32
 
 /* Create a unique string id for a slab cache:
  *
  * Format       :[flags-]size
  */
 static char *create_unique_id(struct kmem_cache *s)
 {
         char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
         char *p = name;
 
         if (!name)
                 return ERR_PTR(-ENOMEM);
 
         *p++ = ':';
         /*
          * First flags affecting slabcache operations. We will only
          * get here for aliasable slabs so we do not need to support
          * too many flags. The flags here must cover all flags that
          * are matched during merging to guarantee that the id is
          * unique.
          */
         if (s->flags & SLAB_CACHE_DMA)
                 *p++ = 'd';
         if (s->flags & SLAB_CACHE_DMA32)
                 *p++ = 'D';
         if (s->flags & SLAB_RECLAIM_ACCOUNT)
                 *p++ = 'a';
         if (s->flags & SLAB_CONSISTENCY_CHECKS)
                 *p++ = 'F';
         if (s->flags & SLAB_ACCOUNT)
                 *p++ = 'A';
         if (p != name + 1)
                 *p++ = '-';
         p += snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size);
 
         if (WARN_ON(p > name + ID_STR_LENGTH - 1)) {
                 kfree(name);
                 return ERR_PTR(-EINVAL);
         }
         kmsan_unpoison_memory(name, p - name);
         return name;
 }
 
 static int sysfs_slab_add(struct kmem_cache *s)
 {
         int err;
         const char *name;
         struct kset *kset = cache_kset(s);
         int unmergeable = slab_unmergeable(s);
 
         if (!unmergeable && disable_higher_order_debug &&
                         (slub_debug & DEBUG_METADATA_FLAGS))
                 unmergeable = 1;
 
         if (unmergeable) {
                 /*
                  * Slabcache can never be merged so we can use the name proper.
                  * This is typically the case for debug situations. In that
                  * case we can catch duplicate names easily.
                  */
                 sysfs_remove_link(&slab_kset->kobj, s->name);
                 name = s->name;
         } else {
                 /*
                  * Create a unique name for the slab as a target
                  * for the symlinks.
                  */
                 name = create_unique_id(s);
                 if (IS_ERR(name))
                         return PTR_ERR(name);
         }
 
         s->kobj.kset = kset;
         err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
         if (err)
                 goto out;
 
         err = sysfs_create_group(&s->kobj, &slab_attr_group);
         if (err)
                 goto out_del_kobj;
 
         if (!unmergeable) {
                 /* Setup first alias */
                 sysfs_slab_alias(s, s->name);
         }
 out:
         if (!unmergeable)
                 kfree(name);
         return err;
 out_del_kobj:
         kobject_del(&s->kobj);
         goto out;
 }
 
 void sysfs_slab_unlink(struct kmem_cache *s)
 {
         kobject_del(&s->kobj);
 }
 
 void sysfs_slab_release(struct kmem_cache *s)
 {
         kobject_put(&s->kobj);
 }
 
 /*
  * Need to buffer aliases during bootup until sysfs becomes
  * available lest we lose that information.
  */
 struct saved_alias {
         struct kmem_cache *s;
         const char *name;
         struct saved_alias *next;
 };
 
 static struct saved_alias *alias_list;
 
 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
 {
         struct saved_alias *al;
 
         if (slab_state == FULL) {
                 /*
                  * If we have a leftover link then remove it.
                  */
                 sysfs_remove_link(&slab_kset->kobj, name);
                 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
         }
 
         al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
         if (!al)
                 return -ENOMEM;
 
         al->s = s;
         al->name = name;
         al->next = alias_list;
         alias_list = al;
         kmsan_unpoison_memory(al, sizeof(*al));
         return 0;
 }
 
 static int __init slab_sysfs_init(void)
 {
         struct kmem_cache *s;
         int err;
 
         mutex_lock(&slab_mutex);
 
         slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
         if (!slab_kset) {
                 mutex_unlock(&slab_mutex);
                 pr_err("Cannot register slab subsystem.\n");
                 return -ENOMEM;
         }
 
         slab_state = FULL;
 
         list_for_each_entry(s, &slab_caches, list) {
                 err = sysfs_slab_add(s);
                 if (err)
                         pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
                                s->name);
         }
 
         while (alias_list) {
                 struct saved_alias *al = alias_list;
 
                 alias_list = alias_list->next;
                 err = sysfs_slab_alias(al->s, al->name);
                 if (err)
                         pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
                                al->name);
                 kfree(al);
         }
 
         mutex_unlock(&slab_mutex);
         return 0;
 }
 late_initcall(slab_sysfs_init);
 #endif /* SLAB_SUPPORTS_SYSFS */
 
 #if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
 static int slab_debugfs_show(struct seq_file *seq, void *v)
 {
         struct loc_track *t = seq->private;
         struct location *l;
         unsigned long idx;
 
         idx = (unsigned long) t->idx;
         if (idx < t->count) {
                 l = &t->loc[idx];
 
                 seq_printf(seq, "%7ld ", l->count);
 
                 if (l->addr)
                         seq_printf(seq, "%pS", (void *)l->addr);
                 else
                         seq_puts(seq, "<not-available>");
 
                 if (l->waste)
                         seq_printf(seq, " waste=%lu/%lu",
                                 l->count * l->waste, l->waste);
 
                 if (l->sum_time != l->min_time) {
                         seq_printf(seq, " age=%ld/%llu/%ld",
                                 l->min_time, div_u64(l->sum_time, l->count),
                                 l->max_time);
                 } else
                         seq_printf(seq, " age=%ld", l->min_time);
 
                 if (l->min_pid != l->max_pid)
                         seq_printf(seq, " pid=%ld-%ld", l->min_pid, l->max_pid);
                 else
                         seq_printf(seq, " pid=%ld",
                                 l->min_pid);
 
                 if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus)))
                         seq_printf(seq, " cpus=%*pbl",
                                  cpumask_pr_args(to_cpumask(l->cpus)));
 
                 if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
                         seq_printf(seq, " nodes=%*pbl",
                                  nodemask_pr_args(&l->nodes));
 
 #ifdef CONFIG_STACKDEPOT
                 {
                         depot_stack_handle_t handle;
                         unsigned long *entries;
                         unsigned int nr_entries, j;
 
                         handle = READ_ONCE(l->handle);
                         if (handle) {
                                 nr_entries = stack_depot_fetch(handle, &entries);
                                 seq_puts(seq, "\n");
                                 for (j = 0; j < nr_entries; j++)
                                         seq_printf(seq, "        %pS\n", (void *)entries[j]);
                         }
                 }
 #endif
                 seq_puts(seq, "\n");
         }
 
         if (!idx && !t->count)
                 seq_puts(seq, "No data\n");
 
         return 0;
 }
 
 static void slab_debugfs_stop(struct seq_file *seq, void *v)
 {
 }
 
 static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
 {
         struct loc_track *t = seq->private;
 
         t->idx = ++(*ppos);
         if (*ppos <= t->count)
                 return ppos;
 
         return NULL;
 }
 
 static int cmp_loc_by_count(const void *a, const void *b, const void *data)
 {
         struct location *loc1 = (struct location *)a;
         struct location *loc2 = (struct location *)b;
 
         if (loc1->count > loc2->count)
                 return -1;
         else
                 return 1;
 }
 
 static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
 {
         struct loc_track *t = seq->private;
 
         t->idx = *ppos;
         return ppos;
 }
 
 static const struct seq_operations slab_debugfs_sops = {
         .start  = slab_debugfs_start,
         .next   = slab_debugfs_next,
         .stop   = slab_debugfs_stop,
         .show   = slab_debugfs_show,
 };
 
 static int slab_debug_trace_open(struct inode *inode, struct file *filep)
 {
 
         struct kmem_cache_node *n;
         enum track_item alloc;
         int node;
         struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
                                                 sizeof(struct loc_track));
         struct kmem_cache *s = file_inode(filep)->i_private;
         unsigned long *obj_map;
 
         if (!t)
                 return -ENOMEM;
 
         obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
         if (!obj_map) {
                 seq_release_private(inode, filep);
                 return -ENOMEM;
         }
 
         if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
                 alloc = TRACK_ALLOC;
         else
                 alloc = TRACK_FREE;
 
         if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
                 bitmap_free(obj_map);
                 seq_release_private(inode, filep);
                 return -ENOMEM;
         }
 
         for_each_kmem_cache_node(s, node, n) {
                 unsigned long flags;
                 struct slab *slab;
 
                 if (!node_nr_slabs(n))
                         continue;
 
                 spin_lock_irqsave(&n->list_lock, flags);
                 list_for_each_entry(slab, &n->partial, slab_list)
                         process_slab(t, s, slab, alloc, obj_map);
                 list_for_each_entry(slab, &n->full, slab_list)
                         process_slab(t, s, slab, alloc, obj_map);
                 spin_unlock_irqrestore(&n->list_lock, flags);
         }
 
         /* Sort locations by count */
         sort_r(t->loc, t->count, sizeof(struct location),
                 cmp_loc_by_count, NULL, NULL);
 
         bitmap_free(obj_map);
         return 0;
 }
 
 static int slab_debug_trace_release(struct inode *inode, struct file *file)
 {
         struct seq_file *seq = file->private_data;
         struct loc_track *t = seq->private;
 
         free_loc_track(t);
         return seq_release_private(inode, file);
 }
 
 static const struct file_operations slab_debugfs_fops = {
         .open    = slab_debug_trace_open,
         .read    = seq_read,
         .llseek  = seq_lseek,
         .release = slab_debug_trace_release,
 };
 
 static void debugfs_slab_add(struct kmem_cache *s)
 {
         struct dentry *slab_cache_dir;
 
         if (unlikely(!slab_debugfs_root))
                 return;
 
         slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root);
 
         debugfs_create_file("alloc_traces", 0400,
                 slab_cache_dir, s, &slab_debugfs_fops);
 
         debugfs_create_file("free_traces", 0400,
                 slab_cache_dir, s, &slab_debugfs_fops);
 }
 
 void debugfs_slab_release(struct kmem_cache *s)
 {
         debugfs_lookup_and_remove(s->name, slab_debugfs_root);
 }
 
 static int __init slab_debugfs_init(void)
 {
         struct kmem_cache *s;
 
         slab_debugfs_root = debugfs_create_dir("slab", NULL);
 
         list_for_each_entry(s, &slab_caches, list)
                 if (s->flags & SLAB_STORE_USER)
                         debugfs_slab_add(s);
 
         return 0;
 
 }
 __initcall(slab_debugfs_init);
 #endif
 /*
  * The /proc/slabinfo ABI
  */
 #ifdef CONFIG_SLUB_DEBUG
 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
 {
         unsigned long nr_slabs = 0;
         unsigned long nr_objs = 0;
         unsigned long nr_free = 0;
         int node;
         struct kmem_cache_node *n;
 
         for_each_kmem_cache_node(s, node, n) {
                 nr_slabs += node_nr_slabs(n);
                 nr_objs += node_nr_objs(n);
                 nr_free += count_partial_free_approx(n);
         }
 
         sinfo->active_objs = nr_objs - nr_free;
         sinfo->num_objs = nr_objs;
         sinfo->active_slabs = nr_slabs;
         sinfo->num_slabs = nr_slabs;
         sinfo->objects_per_slab = oo_objects(s->oo);
         sinfo->cache_order = oo_order(s->oo);
 }
 #endif /* CONFIG_SLUB_DEBUG */