Line data    Source code

       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             : 
      12           0 : static void __dump_stack(void)
      13             : {
      14           0 :         dump_stack_print_info(KERN_DEFAULT);
      15           0 :         show_stack(NULL, NULL);
      16           0 : }
      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
      24             : static atomic_t dump_lock = ATOMIC_INIT(-1);
      25             : 
      26             : asmlinkage __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             : 
      38             : retry:
      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
      58           0 : asmlinkage __visible void dump_stack(void)
      59             : {
      60           0 :         __dump_stack();
      61           0 : }
      62             : #endif
      63             : EXPORT_SYMBOL(dump_stack);