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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
18static 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 */
30void __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 */
55void dump_stack_print_info(const char *log_lvl)
56{
57 printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_FMT "\n",
58 log_lvl, raw_smp_processor_id(), current->pid, current->comm,
59 kexec_crash_loaded() ? "Kdump: loaded " : "",
60 print_tainted(),
61 init_utsname()->release,
62 (int)strcspn(init_utsname()->version, " "),
63 init_utsname()->version, BUILD_ID_VAL);
64
65 if (dump_stack_arch_desc_str[0] != '\0')
66 printk("%sHardware name: %s\n",
67 log_lvl, dump_stack_arch_desc_str);
68
69 print_worker_info(log_lvl, current);
70 print_stop_info(log_lvl, current);
71}
72
73/**
74 * show_regs_print_info - print generic debug info for show_regs()
75 * @log_lvl: log level
76 *
77 * show_regs() implementations can use this function to print out generic
78 * debug information.
79 */
80void show_regs_print_info(const char *log_lvl)
81{
82 dump_stack_print_info(log_lvl);
83}
84
85static void __dump_stack(const char *log_lvl)
86{
87 dump_stack_print_info(log_lvl);
88 show_stack(NULL, NULL, log_lvl);
89}
90
91/**
92 * dump_stack - dump the current task information and its stack trace
93 *
94 * Architectures can override this implementation by implementing its own.
95 */
96asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
97{
98 unsigned long flags;
99
100 /*
101 * Permit this cpu to perform nested stack dumps while serialising
102 * against other CPUs
103 */
104 printk_cpu_lock_irqsave(flags);
105 __dump_stack(log_lvl);
106 printk_cpu_unlock_irqrestore(flags);
107}
108EXPORT_SYMBOL(dump_stack_lvl);
109
110asmlinkage __visible void dump_stack(void)
111{
112 dump_stack_lvl(KERN_DEFAULT);
113}
114EXPORT_SYMBOL(dump_stack);
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/export.h>
9#include <linux/sched.h>
10#include <linux/sched/debug.h>
11#include <linux/smp.h>
12#include <linux/atomic.h>
13#include <linux/kexec.h>
14#include <linux/utsname.h>
15
16static char dump_stack_arch_desc_str[128];
17
18/**
19 * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
20 * @fmt: printf-style format string
21 * @...: arguments for the format string
22 *
23 * The configured string will be printed right after utsname during task
24 * dumps. Usually used to add arch-specific system identifiers. If an
25 * arch wants to make use of such an ID string, it should initialize this
26 * as soon as possible during boot.
27 */
28void __init dump_stack_set_arch_desc(const char *fmt, ...)
29{
30 va_list args;
31
32 va_start(args, fmt);
33 vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
34 fmt, args);
35 va_end(args);
36}
37
38/**
39 * dump_stack_print_info - print generic debug info for dump_stack()
40 * @log_lvl: log level
41 *
42 * Arch-specific dump_stack() implementations can use this function to
43 * print out the same debug information as the generic dump_stack().
44 */
45void dump_stack_print_info(const char *log_lvl)
46{
47 printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n",
48 log_lvl, raw_smp_processor_id(), current->pid, current->comm,
49 kexec_crash_loaded() ? "Kdump: loaded " : "",
50 print_tainted(),
51 init_utsname()->release,
52 (int)strcspn(init_utsname()->version, " "),
53 init_utsname()->version);
54
55 if (dump_stack_arch_desc_str[0] != '\0')
56 printk("%sHardware name: %s\n",
57 log_lvl, dump_stack_arch_desc_str);
58
59 print_worker_info(log_lvl, current);
60}
61
62/**
63 * show_regs_print_info - print generic debug info for show_regs()
64 * @log_lvl: log level
65 *
66 * show_regs() implementations can use this function to print out generic
67 * debug information.
68 */
69void show_regs_print_info(const char *log_lvl)
70{
71 dump_stack_print_info(log_lvl);
72}
73
74static void __dump_stack(void)
75{
76 dump_stack_print_info(KERN_DEFAULT);
77 show_stack(NULL, NULL, KERN_DEFAULT);
78}
79
80/**
81 * dump_stack - dump the current task information and its stack trace
82 *
83 * Architectures can override this implementation by implementing its own.
84 */
85#ifdef CONFIG_SMP
86static atomic_t dump_lock = ATOMIC_INIT(-1);
87
88asmlinkage __visible void dump_stack(void)
89{
90 unsigned long flags;
91 int was_locked;
92 int old;
93 int cpu;
94
95 /*
96 * Permit this cpu to perform nested stack dumps while serialising
97 * against other CPUs
98 */
99retry:
100 local_irq_save(flags);
101 cpu = smp_processor_id();
102 old = atomic_cmpxchg(&dump_lock, -1, cpu);
103 if (old == -1) {
104 was_locked = 0;
105 } else if (old == cpu) {
106 was_locked = 1;
107 } else {
108 local_irq_restore(flags);
109 /*
110 * Wait for the lock to release before jumping to
111 * atomic_cmpxchg() in order to mitigate the thundering herd
112 * problem.
113 */
114 do { cpu_relax(); } while (atomic_read(&dump_lock) != -1);
115 goto retry;
116 }
117
118 __dump_stack();
119
120 if (!was_locked)
121 atomic_set(&dump_lock, -1);
122
123 local_irq_restore(flags);
124}
125#else
126asmlinkage __visible void dump_stack(void)
127{
128 __dump_stack();
129}
130#endif
131EXPORT_SYMBOL(dump_stack);