1/*
 2 * Provide a default dump_stack() function for architectures
 3 * which don't implement their own.
 4 */
 5
 6#include <linux/kernel.h>
 7#include <linux/export.h>
 8#include <linux/sched.h>
 9#include <linux/smp.h>
10#include <linux/atomic.h>
11
12static void __dump_stack(void)
13{
14	dump_stack_print_info(KERN_DEFAULT);
15	show_stack(NULL, NULL);
16}
17
18/**
19 * dump_stack - dump the current task information and its stack trace
20 *
21 * Architectures can override this implementation by implementing its own.
22 */
23#ifdef CONFIG_SMP
24static atomic_t dump_lock = ATOMIC_INIT(-1);
25
26asmlinkage __visible void dump_stack(void)
27{
 
28	int was_locked;
29	int old;
30	int cpu;
31
32	/*
33	 * Permit this cpu to perform nested stack dumps while serialising
34	 * against other CPUs
35	 */
36	preempt_disable();
37
38retry:
 
39	cpu = smp_processor_id();
40	old = atomic_cmpxchg(&dump_lock, -1, cpu);
41	if (old == -1) {
42		was_locked = 0;
43	} else if (old == cpu) {
44		was_locked = 1;
45	} else {
 
46		cpu_relax();
47		goto retry;
48	}
49
50	__dump_stack();
51
52	if (!was_locked)
53		atomic_set(&dump_lock, -1);
54
55	preempt_enable();
56}
57#else
58asmlinkage __visible void dump_stack(void)
59{
60	__dump_stack();
61}
62#endif
63EXPORT_SYMBOL(dump_stack);

 1/*
 2 * Provide a default dump_stack() function for architectures
 3 * which don't implement their own.
 4 */
 5
 6#include <linux/kernel.h>
 7#include <linux/export.h>
 8#include <linux/sched.h>
 9#include <linux/smp.h>
10#include <linux/atomic.h>
11
12static void __dump_stack(void)
13{
14	dump_stack_print_info(KERN_DEFAULT);
15	show_stack(NULL, NULL);
16}
17
18/**
19 * dump_stack - dump the current task information and its stack trace
20 *
21 * Architectures can override this implementation by implementing its own.
22 */
23#ifdef CONFIG_SMP
24static atomic_t dump_lock = ATOMIC_INIT(-1);
25
26asmlinkage __visible void dump_stack(void)
27{
28	unsigned long flags;
29	int was_locked;
30	int old;
31	int cpu;
32
33	/*
34	 * Permit this cpu to perform nested stack dumps while serialising
35	 * against other CPUs
36	 */
 
 
37retry:
38	local_irq_save(flags);
39	cpu = smp_processor_id();
40	old = atomic_cmpxchg(&dump_lock, -1, cpu);
41	if (old == -1) {
42		was_locked = 0;
43	} else if (old == cpu) {
44		was_locked = 1;
45	} else {
46		local_irq_restore(flags);
47		cpu_relax();
48		goto retry;
49	}
50
51	__dump_stack();
52
53	if (!was_locked)
54		atomic_set(&dump_lock, -1);
55
56	local_irq_restore(flags);
57}
58#else
59asmlinkage __visible void dump_stack(void)
60{
61	__dump_stack();
62}
63#endif
64EXPORT_SYMBOL(dump_stack);