Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * Provide a default dump_stack() function for architectures | |
4 | * which don't implement their own. | |
5 | */ | |
6 | ||
7 | #include <linux/kernel.h> | |
8bc3bcc9 | 8 | #include <linux/export.h> |
196779b9 | 9 | #include <linux/sched.h> |
b17b0153 | 10 | #include <linux/sched/debug.h> |
b58d9774 AT |
11 | #include <linux/smp.h> |
12 | #include <linux/atomic.h> | |
e36df28f DY |
13 | #include <linux/kexec.h> |
14 | #include <linux/utsname.h> | |
a8b62fd0 | 15 | #include <linux/stop_machine.h> |
e36df28f DY |
16 | |
17 | static char dump_stack_arch_desc_str[128]; | |
18 | ||
19 | /** | |
20 | * dump_stack_set_arch_desc - set arch-specific str to show with task dumps | |
21 | * @fmt: printf-style format string | |
22 | * @...: arguments for the format string | |
23 | * | |
24 | * The configured string will be printed right after utsname during task | |
25 | * dumps. Usually used to add arch-specific system identifiers. If an | |
26 | * arch wants to make use of such an ID string, it should initialize this | |
27 | * as soon as possible during boot. | |
28 | */ | |
29 | void __init dump_stack_set_arch_desc(const char *fmt, ...) | |
30 | { | |
31 | va_list args; | |
32 | ||
33 | va_start(args, fmt); | |
34 | vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), | |
35 | fmt, args); | |
36 | va_end(args); | |
37 | } | |
38 | ||
39 | /** | |
40 | * dump_stack_print_info - print generic debug info for dump_stack() | |
41 | * @log_lvl: log level | |
42 | * | |
43 | * Arch-specific dump_stack() implementations can use this function to | |
44 | * print out the same debug information as the generic dump_stack(). | |
45 | */ | |
46 | void dump_stack_print_info(const char *log_lvl) | |
47 | { | |
48 | printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n", | |
49 | log_lvl, raw_smp_processor_id(), current->pid, current->comm, | |
50 | kexec_crash_loaded() ? "Kdump: loaded " : "", | |
51 | print_tainted(), | |
52 | init_utsname()->release, | |
53 | (int)strcspn(init_utsname()->version, " "), | |
54 | init_utsname()->version); | |
55 | ||
56 | if (dump_stack_arch_desc_str[0] != '\0') | |
57 | printk("%sHardware name: %s\n", | |
58 | log_lvl, dump_stack_arch_desc_str); | |
59 | ||
60 | print_worker_info(log_lvl, current); | |
a8b62fd0 | 61 | print_stop_info(log_lvl, current); |
e36df28f DY |
62 | } |
63 | ||
64 | /** | |
65 | * show_regs_print_info - print generic debug info for show_regs() | |
66 | * @log_lvl: log level | |
67 | * | |
68 | * show_regs() implementations can use this function to print out generic | |
69 | * debug information. | |
70 | */ | |
71 | void show_regs_print_info(const char *log_lvl) | |
72 | { | |
73 | dump_stack_print_info(log_lvl); | |
74 | } | |
b58d9774 AT |
75 | |
76 | static void __dump_stack(void) | |
77 | { | |
78 | dump_stack_print_info(KERN_DEFAULT); | |
9cb8f069 | 79 | show_stack(NULL, NULL, KERN_DEFAULT); |
b58d9774 | 80 | } |
1da177e4 | 81 | |
196779b9 TH |
82 | /** |
83 | * dump_stack - dump the current task information and its stack trace | |
84 | * | |
85 | * Architectures can override this implementation by implementing its own. | |
86 | */ | |
b58d9774 AT |
87 | #ifdef CONFIG_SMP |
88 | static atomic_t dump_lock = ATOMIC_INIT(-1); | |
89 | ||
722a9f92 | 90 | asmlinkage __visible void dump_stack(void) |
1da177e4 | 91 | { |
d7ce3692 | 92 | unsigned long flags; |
b58d9774 AT |
93 | int was_locked; |
94 | int old; | |
95 | int cpu; | |
96 | ||
97 | /* | |
98 | * Permit this cpu to perform nested stack dumps while serialising | |
99 | * against other CPUs | |
100 | */ | |
b58d9774 | 101 | retry: |
d7ce3692 | 102 | local_irq_save(flags); |
b58d9774 AT |
103 | cpu = smp_processor_id(); |
104 | old = atomic_cmpxchg(&dump_lock, -1, cpu); | |
105 | if (old == -1) { | |
106 | was_locked = 0; | |
107 | } else if (old == cpu) { | |
108 | was_locked = 1; | |
109 | } else { | |
d7ce3692 | 110 | local_irq_restore(flags); |
5cbf2fff KH |
111 | /* |
112 | * Wait for the lock to release before jumping to | |
113 | * atomic_cmpxchg() in order to mitigate the thundering herd | |
114 | * problem. | |
115 | */ | |
116 | do { cpu_relax(); } while (atomic_read(&dump_lock) != -1); | |
b58d9774 AT |
117 | goto retry; |
118 | } | |
119 | ||
120 | __dump_stack(); | |
121 | ||
122 | if (!was_locked) | |
123 | atomic_set(&dump_lock, -1); | |
124 | ||
d7ce3692 | 125 | local_irq_restore(flags); |
b58d9774 AT |
126 | } |
127 | #else | |
722a9f92 | 128 | asmlinkage __visible void dump_stack(void) |
b58d9774 AT |
129 | { |
130 | __dump_stack(); | |
1da177e4 | 131 | } |
b58d9774 | 132 | #endif |
1da177e4 | 133 | EXPORT_SYMBOL(dump_stack); |