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