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 */
dump_stack_set_arch_desc(const char * fmt,...)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 */
dump_stack_print_info(const char * log_lvl)55 void 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 */
show_regs_print_info(const char * log_lvl)80 void show_regs_print_info(const char *log_lvl)
81 {
82 dump_stack_print_info(log_lvl);
83 }
84
__dump_stack(const char * log_lvl)85 static 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_lvl - dump the current task information and its stack trace
93 * @log_lvl: log level
94 *
95 * Architectures can override this implementation by implementing its own.
96 */
dump_stack_lvl(const char * log_lvl)97 asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
98 {
99 bool in_panic = this_cpu_in_panic();
100 unsigned long flags;
101
102 /*
103 * Permit this cpu to perform nested stack dumps while serialising
104 * against other CPUs, unless this CPU is in panic.
105 *
106 * When in panic, non-panic CPUs are not permitted to store new
107 * printk messages so there is no need to synchronize the output.
108 * This avoids potential deadlock in panic() if another CPU is
109 * holding and unable to release the printk_cpu_sync.
110 */
111 if (!in_panic)
112 printk_cpu_sync_get_irqsave(flags);
113
114 __dump_stack(log_lvl);
115
116 if (!in_panic)
117 printk_cpu_sync_put_irqrestore(flags);
118 }
119 EXPORT_SYMBOL(dump_stack_lvl);
120
dump_stack(void)121 asmlinkage __visible void dump_stack(void)
122 {
123 dump_stack_lvl(KERN_DEFAULT);
124 }
125 EXPORT_SYMBOL(dump_stack);
126