1 # SPDX-License-Identifier: GPL-2.0-only
2 config PAGE_EXTENSION
3 bool "Extend memmap on extra space for
4 help
5 Extend memmap on extra space for mor
6 could be used for debugging features
7 field for every page. This extension
8 by not allocating this extra memory
9 configuration.
10
11 config DEBUG_PAGEALLOC
12 bool "Debug page memory allocations"
13 depends on DEBUG_KERNEL
14 depends on !HIBERNATION || ARCH_SUPPOR
15 select PAGE_POISONING if !ARCH_SUPPORT
16 help
17 Unmap pages from the kernel linear m
18 Depending on runtime enablement, thi
19 slowdown, but helps to find certain
20
21 Also, the state of page tracking str
22 pages are being allocated and freed,
23 often happen for same reasons as mem
24 use-after-free). The error reports f
25 with stack traces of last allocation
26 PAGE_OWNER is also selected and enab
27
28 For architectures which don't enable
29 fill the pages with poison patterns
30 the patterns before alloc_pages(). A
31 be enabled in combination with hiber
32 incorrect warnings of memory corrupt
33 pages are not saved to the suspend i
34
35 By default this option will have a s
36 allowing the kernel mapping to be ba
37 architectures. Even bigger overhead
38 enabled by DEBUG_PAGEALLOC_ENABLE_DE
39 command line parameter.
40
41 config DEBUG_PAGEALLOC_ENABLE_DEFAULT
42 bool "Enable debug page memory allocat
43 depends on DEBUG_PAGEALLOC
44 help
45 Enable debug page memory allocations
46 can be overridden by debug_pagealloc
47
48 config SLUB_DEBUG
49 default y
50 bool "Enable SLUB debugging support" i
51 depends on SYSFS && !SLUB_TINY
52 select STACKDEPOT if STACKTRACE_SUPPOR
53 help
54 SLUB has extensive debug support fea
55 result in significant savings in cod
56 will still exist (with SYSFS enabled
57 validation.
58
59 config SLUB_DEBUG_ON
60 bool "SLUB debugging on by default"
61 depends on SLUB_DEBUG
62 select STACKDEPOT_ALWAYS_INIT if STACK
63 default n
64 help
65 Boot with debugging on by default. S
66 the runtime debug capabilities switc
67 equivalent to specifying the "slab_d
68 There is no support for more fine gr
69 possible with slab_debug=xxx. SLUB d
70 off in a kernel built with CONFIG_SL
71 "slab_debug=-".
72
73 config PAGE_OWNER
74 bool "Track page owner"
75 depends on DEBUG_KERNEL && STACKTRACE_
76 select DEBUG_FS
77 select STACKTRACE
78 select STACKDEPOT
79 select PAGE_EXTENSION
80 help
81 This keeps track of what call chain
82 help to find bare alloc_page(s) leak
83 feature on your build, it is disable
84 "page_owner=on" to boot parameter in
85 a fair amount of memory if enabled.
86 for user-space helper.
87
88 If unsure, say N.
89
90 config PAGE_TABLE_CHECK
91 bool "Check for invalid mappings in us
92 depends on ARCH_SUPPORTS_PAGE_TABLE_CH
93 depends on EXCLUSIVE_SYSTEM_RAM
94 select PAGE_EXTENSION
95 help
96 Check that anonymous page is not bei
97 permissions. Check that anonymous an
98 erroneously shared. Since the checki
99 entries are added and removed to use
100 and double mapping problems are dete
101
102 If unsure say "n".
103
104 config PAGE_TABLE_CHECK_ENFORCED
105 bool "Enforce the page table checking
106 depends on PAGE_TABLE_CHECK
107 help
108 Always enable page table checking.
109 is disabled, and can be optionally e
110 kernel parameter. This config enforc
111 enabled.
112
113 If unsure say "n".
114
115 config PAGE_POISONING
116 bool "Poison pages after freeing"
117 help
118 Fill the pages with poison patterns
119 the patterns before alloc_pages. The
120 reduce the risk of information leaks
121 have a potential performance impact
122 "page_poison=1" kernel boot option.
123
124 Note that "poison" here is not the s
125 for CONFIG_MEMORY_FAILURE. This is s
126
127 If you are only interested in saniti
128 checking the poison pattern on alloc
129 "init_on_free=1" instead of enabling
130
131 If unsure, say N
132
133 config DEBUG_PAGE_REF
134 bool "Enable tracepoint to track down
135 depends on DEBUG_KERNEL
136 depends on TRACEPOINTS
137 help
138 This is a feature to add tracepoint
139 manipulation. This tracking is usefu
140 due to migration failures caused by
141 careful when enabling this feature b
142 kernel code. However the runtime pe
143 nil until the tracepoints are actual
144
145 config DEBUG_RODATA_TEST
146 bool "Testcase for the marking rodata read
147 depends on STRICT_KERNEL_RWX
148 help
149 This option enables a testcase for the s
150
151 config ARCH_HAS_DEBUG_WX
152 bool
153
154 config DEBUG_WX
155 bool "Warn on W+X mappings at boot"
156 depends on ARCH_HAS_DEBUG_WX
157 depends on MMU
158 select PTDUMP_CORE
159 help
160 Generate a warning if any W+X mappin
161
162 This is useful for discovering cases
163 mappings after applying NX, as such
164
165 Look for a message in dmesg output l
166
167 <arch>/mm: Checked W+X mappings: p
168
169 or like this, if the check failed:
170
171 <arch>/mm: Checked W+X mappings: f
172
173 Note that even if the check fails, y
174 still fine, as W+X mappings are not
175 themselves, what they do is that the
176 of other unfixed kernel bugs easier.
177
178 There is no runtime or memory usage
179 once the kernel has booted up - it's
180
181 If in doubt, say "Y".
182
183 config GENERIC_PTDUMP
184 bool
185
186 config PTDUMP_CORE
187 bool
188
189 config PTDUMP_DEBUGFS
190 bool "Export kernel pagetable layout t
191 depends on DEBUG_KERNEL
192 depends on DEBUG_FS
193 depends on GENERIC_PTDUMP
194 select PTDUMP_CORE
195 help
196 Say Y here if you want to show the k
197 debugfs file. This information is on
198 who are working in architecture spec
199 It is probably not a good idea to en
200 kernel.
201
202 If in doubt, say N.
203
204 config HAVE_DEBUG_KMEMLEAK
205 bool
206
207 config DEBUG_KMEMLEAK
208 bool "Kernel memory leak detector"
209 depends on DEBUG_KERNEL && HAVE_DEBUG_
210 select DEBUG_FS
211 select STACKTRACE if STACKTRACE_SUPPOR
212 select KALLSYMS
213 select CRC32
214 select STACKDEPOT
215 select STACKDEPOT_ALWAYS_INIT if !DEBU
216 help
217 Say Y here if you want to enable the
218 detector. The memory allocation/free
219 similar to the Boehm's conservative
220 difference being that the orphan obj
221 only shown in /sys/kernel/debug/kmem
222 feature will introduce an overhead t
223 allocations. See Documentation/dev-t
224 details.
225
226 Enabling SLUB_DEBUG may increase the
227 due to the slab objects poisoning.
228
229 In order to access the kmemleak file
230 mounted (usually at /sys/kernel/debu
231
232 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
233 int "Kmemleak memory pool size"
234 depends on DEBUG_KMEMLEAK
235 range 200 1000000
236 default 16000
237 help
238 Kmemleak must track all the memory a
239 reporting false positives. Since mem
240 freed before kmemleak is fully initi
241 of metadata objects to track such ca
242 fully initialised, this memory pool
243 if slab allocations fail.
244
245 config DEBUG_KMEMLEAK_DEFAULT_OFF
246 bool "Default kmemleak to off"
247 depends on DEBUG_KMEMLEAK
248 help
249 Say Y here to disable kmemleak by de
250 on the command line via kmemleak=on.
251
252 config DEBUG_KMEMLEAK_AUTO_SCAN
253 bool "Enable kmemleak auto scan thread
254 default y
255 depends on DEBUG_KMEMLEAK
256 help
257 Depending on the cpu, kmemleak scan
258 stall user tasks at times. This opti
259 kmemleak scan at boot up.
260
261 Say N here to disable kmemleak auto
262 scanning. Disabling this option disa
263 memory leaks.
264
265 If unsure, say Y.
266
267 config PER_VMA_LOCK_STATS
268 bool "Statistics for per-vma locks"
269 depends on PER_VMA_LOCK
270 help
271 Say Y here to enable success, retry
272 faults handled under protection of p
273 counters are exposed in /proc/vmstat
274 kernel developers to evaluate effect
275 identify pathological cases. Countin
276 overhead in the page fault path.
277
278 If in doubt, say N.
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