]>
Commit | Line | Data |
---|---|---|
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 | ||
14 | static void __dump_stack(void) | |
15 | { | |
16 | dump_stack_print_info(KERN_DEFAULT); | |
17 | show_stack(NULL, NULL); | |
18 | } | |
19 | ||
20 | /** | |
21 | * dump_stack - dump the current task information and its stack trace | |
22 | * | |
23 | * Architectures can override this implementation by implementing its own. | |
24 | */ | |
25 | #ifdef CONFIG_SMP | |
26 | static atomic_t dump_lock = ATOMIC_INIT(-1); | |
27 | ||
28 | asmlinkage __visible void dump_stack(void) | |
29 | { | |
30 | unsigned long flags; | |
31 | int was_locked; | |
32 | int old; | |
33 | int cpu; | |
34 | ||
35 | /* | |
36 | * Permit this cpu to perform nested stack dumps while serialising | |
37 | * against other CPUs | |
38 | */ | |
39 | retry: | |
40 | local_irq_save(flags); | |
41 | cpu = smp_processor_id(); | |
42 | old = atomic_cmpxchg(&dump_lock, -1, cpu); | |
43 | if (old == -1) { | |
44 | was_locked = 0; | |
45 | } else if (old == cpu) { | |
46 | was_locked = 1; | |
47 | } else { | |
48 | local_irq_restore(flags); | |
49 | cpu_relax(); | |
50 | goto retry; | |
51 | } | |
52 | ||
53 | __dump_stack(); | |
54 | ||
55 | if (!was_locked) | |
56 | atomic_set(&dump_lock, -1); | |
57 | ||
58 | local_irq_restore(flags); | |
59 | } | |
60 | #else | |
61 | asmlinkage __visible void dump_stack(void) | |
62 | { | |
63 | __dump_stack(); | |
64 | } | |
65 | #endif | |
66 | EXPORT_SYMBOL(dump_stack); |