1/*
 2 * Provide a default dump_stack() function for architectures
 3 * which don't implement their own.
 4 */
 5
 6#include <linux/kernel.h>
 
 7#include <linux/export.h>
 8#include <linux/sched.h>
 
 9#include <linux/smp.h>
10#include <linux/atomic.h>
 
 
 
11
12static void __dump_stack(void)
 
 
 
 
 
 
 
 
 
 
 
 
13{
14	dump_stack_print_info(KERN_DEFAULT);
15	show_stack(NULL, NULL);
 
 
 
 
16}
17
 
 
 
 
 
 
 
 
18/**
19 * dump_stack - dump the current task information and its stack trace
 
20 *
21 * Architectures can override this implementation by implementing its own.
 
22 */
23#ifdef CONFIG_SMP
24static atomic_t dump_lock = ATOMIC_INIT(-1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
25
26asmlinkage __visible void dump_stack(void)
 
 
 
 
 
 
 
27{
28	int was_locked;
29	int old;
30	int cpu;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
31
32	/*
33	 * Permit this cpu to perform nested stack dumps while serialising
34	 * against other CPUs
 
 
 
 
 
35	 */
36	preempt_disable();
37
38retry:
39	cpu = smp_processor_id();
40	old = atomic_cmpxchg(&dump_lock, -1, cpu);
41	if (old == -1) {
42		was_locked = 0;
43	} else if (old == cpu) {
44		was_locked = 1;
45	} else {
46		cpu_relax();
47		goto retry;
48	}
49
50	__dump_stack();
51
52	if (!was_locked)
53		atomic_set(&dump_lock, -1);
54
55	preempt_enable();
 
56}
57#else
 
58asmlinkage __visible void dump_stack(void)
59{
60	__dump_stack();
61}
62#endif
63EXPORT_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/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 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	print_scx_info(log_lvl, current);
 77}
 78
 79/**
 80 * show_regs_print_info - print generic debug info for show_regs()
 81 * @log_lvl: log level
 82 *
 83 * show_regs() implementations can use this function to print out generic
 84 * debug information.
 85 */
 86void show_regs_print_info(const char *log_lvl)
 87{
 88	dump_stack_print_info(log_lvl);
 89}
 90
 91static void __dump_stack(const char *log_lvl)
 92{
 93	dump_stack_print_info(log_lvl);
 94	show_stack(NULL, NULL, log_lvl);
 95}
 96
 97/**
 98 * dump_stack_lvl - dump the current task information and its stack trace
 99 * @log_lvl: log level
100 *
101 * Architectures can override this implementation by implementing its own.
102 */
103asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
104{
105	bool in_panic = this_cpu_in_panic();
106	unsigned long flags;
107
108	/*
109	 * Permit this cpu to perform nested stack dumps while serialising
110	 * against other CPUs, unless this CPU is in panic.
111	 *
112	 * When in panic, non-panic CPUs are not permitted to store new
113	 * printk messages so there is no need to synchronize the output.
114	 * This avoids potential deadlock in panic() if another CPU is
115	 * holding and unable to release the printk_cpu_sync.
116	 */
117	if (!in_panic)
118		printk_cpu_sync_get_irqsave(flags);
 
 
 
 
 
 
 
 
 
 
 
 
 
119
120	__dump_stack(log_lvl);
 
121
122	if (!in_panic)
123		printk_cpu_sync_put_irqrestore(flags);
124}
125EXPORT_SYMBOL(dump_stack_lvl);
126
127asmlinkage __visible void dump_stack(void)
128{
129	dump_stack_lvl(KERN_DEFAULT);
130}
 
131EXPORT_SYMBOL(dump_stack);