1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Provide a default dump_stack() function for architectures
4 * which don't implement their own.
5 */
6
7 #include <linux/kernel.h>
8 #include <linux/buildid.h>
9 #include <linux/export.h>
10 #include <linux/sched.h>
11 #include <linux/sched/debug.h>
12 #include <linux/smp.h>
13 #include <linux/atomic.h>
14 #include <linux/kexec.h>
15 #include <linux/utsname.h>
16 #include <linux/stop_machine.h>
17
18 static char dump_stack_arch_desc_str[128];
19
20 /**
21 * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
22 * @fmt: printf-style format string
23 * @...: arguments for the format string
24 *
25 * The configured string will be printed right after utsname during task
26 * dumps. Usually used to add arch-specific system identifiers. If an
27 * arch wants to make use of such an ID string, it should initialize this
28 * as soon as possible during boot.
29 */
30 void __init dump_stack_set_arch_desc(const char *fmt, ...)
31 {
32 va_list args;
33
34 va_start(args, fmt);
35 vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
36 fmt, args);
37 va_end(args);
38 }
39
40 #if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
41 #define BUILD_ID_FMT " %20phN"
42 #define BUILD_ID_VAL vmlinux_build_id
43 #else
44 #define BUILD_ID_FMT "%s"
45 #define BUILD_ID_VAL ""
46 #endif
47
48 /**
49 * dump_stack_print_info - print generic debug info for dump_stack()
50 * @log_lvl: log level
51 *
52 * Arch-specific dump_stack() implementations can use this function to
53 * print out the same debug information as the generic dump_stack().
54 */
55 void dump_stack_print_info(const char *log_lvl)
56 {
57 printk("%sCPU: %d UID: %u PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_FMT "\n",
58 log_lvl, raw_smp_processor_id(),
59 __kuid_val(current_real_cred()->euid),
60 current->pid, current->comm,
61 kexec_crash_loaded() ? "Kdump: loaded " : "",
62 print_tainted(),
63 init_utsname()->release,
64 (int)strcspn(init_utsname()->version, " "),
65 init_utsname()->version, BUILD_ID_VAL);
66
67 if (get_taint())
68 printk("%s%s\n", log_lvl, print_tainted_verbose());
69
70 if (dump_stack_arch_desc_str[0] != '\0')
71 printk("%sHardware name: %s\n",
72 log_lvl, dump_stack_arch_desc_str);
73
74 print_worker_info(log_lvl, current);
75 print_stop_info(log_lvl, current);
76 }
77
78 /**
79 * show_regs_print_info - print generic debug info for show_regs()
80 * @log_lvl: log level
81 *
82 * show_regs() implementations can use this function to print out generic
83 * debug information.
84 */
85 void show_regs_print_info(const char *log_lvl)
86 {
87 dump_stack_print_info(log_lvl);
88 }
89
90 static void __dump_stack(const char *log_lvl)
91 {
92 dump_stack_print_info(log_lvl);
93 show_stack(NULL, NULL, log_lvl);
94 }
95
96 /**
97 * dump_stack_lvl - dump the current task information and its stack trace
98 * @log_lvl: log level
99 *
100 * Architectures can override this implementation by implementing its own.
101 */
102 asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
103 {
104 bool in_panic = this_cpu_in_panic();
105 unsigned long flags;
106
107 /*
108 * Permit this cpu to perform nested stack dumps while serialising
109 * against other CPUs, unless this CPU is in panic.
110 *
111 * When in panic, non-panic CPUs are not permitted to store new
112 * printk messages so there is no need to synchronize the output.
113 * This avoids potential deadlock in panic() if another CPU is
114 * holding and unable to release the printk_cpu_sync.
115 */
116 if (!in_panic)
117 printk_cpu_sync_get_irqsave(flags);
118
119 __dump_stack(log_lvl);
120
121 if (!in_panic)
122 printk_cpu_sync_put_irqrestore(flags);
123 }
124 EXPORT_SYMBOL(dump_stack_lvl);
125
126 asmlinkage __visible void dump_stack(void)
127 {
128 dump_stack_lvl(KERN_DEFAULT);
129 }
130 EXPORT_SYMBOL(dump_stack);
131
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