summaryrefslogtreecommitdiffstats
path: root/lib/dump_stack.c
blob: 1a996fbbf50a038829ee7b9439f9eabafa866ff3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
// SPDX-License-Identifier: GPL-2.0
/*
 * Provide a default dump_stack() function for architectures
 * which don't implement their own.
 */

#include <linux/kernel.h>
#include <linux/buildid.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/smp.h>
#include <linux/atomic.h>
#include <linux/kexec.h>
#include <linux/utsname.h>
#include <linux/stop_machine.h>

static char dump_stack_arch_desc_str[128];

/**
 * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
 * @fmt: printf-style format string
 * @...: arguments for the format string
 *
 * The configured string will be printed right after utsname during task
 * dumps.  Usually used to add arch-specific system identifiers.  If an
 * arch wants to make use of such an ID string, it should initialize this
 * as soon as possible during boot.
 */
void __init dump_stack_set_arch_desc(const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
		  fmt, args);
	va_end(args);
}

#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
#define BUILD_ID_FMT " %20phN"
#define BUILD_ID_VAL vmlinux_build_id
#else
#define BUILD_ID_FMT "%s"
#define BUILD_ID_VAL ""
#endif

/**
 * dump_stack_print_info - print generic debug info for dump_stack()
 * @log_lvl: log level
 *
 * Arch-specific dump_stack() implementations can use this function to
 * print out the same debug information as the generic dump_stack().
 */
void dump_stack_print_info(const char *log_lvl)
{
	printk("%sCPU: %d UID: %u PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_FMT "\n",
	       log_lvl, raw_smp_processor_id(),
	       __kuid_val(current_real_cred()->euid),
	       current->pid, current->comm,
	       kexec_crash_loaded() ? "Kdump: loaded " : "",
	       print_tainted(),
	       init_utsname()->release,
	       (int)strcspn(init_utsname()->version, " "),
	       init_utsname()->version, BUILD_ID_VAL);

	if (get_taint())
		printk("%s%s\n", log_lvl, print_tainted_verbose());

	if (dump_stack_arch_desc_str[0] != '\0')
		printk("%sHardware name: %s\n",
		       log_lvl, dump_stack_arch_desc_str);

	print_worker_info(log_lvl, current);
	print_stop_info(log_lvl, current);
}

/**
 * show_regs_print_info - print generic debug info for show_regs()
 * @log_lvl: log level
 *
 * show_regs() implementations can use this function to print out generic
 * debug information.
 */
void show_regs_print_info(const char *log_lvl)
{
	dump_stack_print_info(log_lvl);
}

static void __dump_stack(const char *log_lvl)
{
	dump_stack_print_info(log_lvl);
	show_stack(NULL, NULL, log_lvl);
}

/**
 * dump_stack_lvl - dump the current task information and its stack trace
 * @log_lvl: log level
 *
 * Architectures can override this implementation by implementing its own.
 */
asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
{
	bool in_panic = this_cpu_in_panic();
	unsigned long flags;

	/*
	 * Permit this cpu to perform nested stack dumps while serialising
	 * against other CPUs, unless this CPU is in panic.
	 *
	 * When in panic, non-panic CPUs are not permitted to store new
	 * printk messages so there is no need to synchronize the output.
	 * This avoids potential deadlock in panic() if another CPU is
	 * holding and unable to release the printk_cpu_sync.
	 */
	if (!in_panic)
		printk_cpu_sync_get_irqsave(flags);

	__dump_stack(log_lvl);

	if (!in_panic)
		printk_cpu_sync_put_irqrestore(flags);
}
EXPORT_SYMBOL(dump_stack_lvl);

asmlinkage __visible void dump_stack(void)
{
	dump_stack_lvl(KERN_DEFAULT);
}
EXPORT_SYMBOL(dump_stack);