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(buf: dump_stack_arch_desc_str, size: 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 %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, preempt_model_str(), 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, loglvl: 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 = panic_on_this_cpu();
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);
132