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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/export.h> | |
9 | #include <linux/sched.h> | |
10 | #include <linux/sched/debug.h> | |
11 | #include <linux/smp.h> | |
12 | #include <linux/atomic.h> | |
13 | #include <linux/kexec.h> | |
14 | #include <linux/utsname.h> | |
15 | ||
16 | static char dump_stack_arch_desc_str[128]; | |
17 | ||
18 | /** | |
19 | * dump_stack_set_arch_desc - set arch-specific str to show with task dumps | |
20 | * @fmt: printf-style format string | |
21 | * @...: arguments for the format string | |
22 | * | |
23 | * The configured string will be printed right after utsname during task | |
24 | * dumps. Usually used to add arch-specific system identifiers. If an | |
25 | * arch wants to make use of such an ID string, it should initialize this | |
26 | * as soon as possible during boot. | |
27 | */ | |
28 | void __init dump_stack_set_arch_desc(const char *fmt, ...) | |
29 | { | |
30 | va_list args; | |
31 | ||
32 | va_start(args, fmt); | |
33 | vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), | |
34 | fmt, args); | |
35 | va_end(args); | |
36 | } | |
37 | ||
38 | /** | |
39 | * dump_stack_print_info - print generic debug info for dump_stack() | |
40 | * @log_lvl: log level | |
41 | * | |
42 | * Arch-specific dump_stack() implementations can use this function to | |
43 | * print out the same debug information as the generic dump_stack(). | |
44 | */ | |
45 | void dump_stack_print_info(const char *log_lvl) | |
46 | { | |
47 | printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n", | |
48 | log_lvl, raw_smp_processor_id(), current->pid, current->comm, | |
49 | kexec_crash_loaded() ? "Kdump: loaded " : "", | |
50 | print_tainted(), | |
51 | init_utsname()->release, | |
52 | (int)strcspn(init_utsname()->version, " "), | |
53 | init_utsname()->version); | |
54 | ||
55 | if (dump_stack_arch_desc_str[0] != '\0') | |
56 | printk("%sHardware name: %s\n", | |
57 | log_lvl, dump_stack_arch_desc_str); | |
58 | ||
59 | print_worker_info(log_lvl, current); | |
60 | } | |
61 | ||
62 | /** | |
63 | * show_regs_print_info - print generic debug info for show_regs() | |
64 | * @log_lvl: log level | |
65 | * | |
66 | * show_regs() implementations can use this function to print out generic | |
67 | * debug information. | |
68 | */ | |
69 | void show_regs_print_info(const char *log_lvl) | |
70 | { | |
71 | dump_stack_print_info(log_lvl); | |
72 | } | |
73 | ||
74 | static void __dump_stack(void) | |
75 | { | |
76 | dump_stack_print_info(KERN_DEFAULT); | |
77 | show_stack(NULL, NULL); | |
78 | } | |
79 | ||
80 | /** | |
81 | * dump_stack - dump the current task information and its stack trace | |
82 | * | |
83 | * Architectures can override this implementation by implementing its own. | |
84 | */ | |
85 | #ifdef CONFIG_SMP | |
86 | static atomic_t dump_lock = ATOMIC_INIT(-1); | |
87 | ||
88 | asmlinkage __visible void dump_stack(void) | |
89 | { | |
90 | unsigned long flags; | |
91 | int was_locked; | |
92 | int old; | |
93 | int cpu; | |
94 | ||
95 | /* | |
96 | * Permit this cpu to perform nested stack dumps while serialising | |
97 | * against other CPUs | |
98 | */ | |
99 | retry: | |
100 | local_irq_save(flags); | |
101 | cpu = smp_processor_id(); | |
102 | old = atomic_cmpxchg(&dump_lock, -1, cpu); | |
103 | if (old == -1) { | |
104 | was_locked = 0; | |
105 | } else if (old == cpu) { | |
106 | was_locked = 1; | |
107 | } else { | |
108 | local_irq_restore(flags); | |
109 | cpu_relax(); | |
110 | goto retry; | |
111 | } | |
112 | ||
113 | __dump_stack(); | |
114 | ||
115 | if (!was_locked) | |
116 | atomic_set(&dump_lock, -1); | |
117 | ||
118 | local_irq_restore(flags); | |
119 | } | |
120 | #else | |
121 | asmlinkage __visible void dump_stack(void) | |
122 | { | |
123 | __dump_stack(); | |
124 | } | |
125 | #endif | |
126 | EXPORT_SYMBOL(dump_stack); |