kernel/stacktrace.c

   1 /*
   2  * kernel/stacktrace.c
   3  *
   4  * Stack trace management functions
   5  *
   6  *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
   7  */
   8 #include <linux/sched.h>
   9 #include <linux/kernel.h>
  10 #include <linux/export.h>
  11 #include <linux/kallsyms.h>
  12 #include <linux/stacktrace.h>
  13
  14 void print_stack_trace(struct stack_trace *trace, int spaces)
  15 {
  16         int i;
  17
  18         if (WARN_ON(!trace->entries))
  19                 return;
  20
  21         for (i = 0; i < trace->nr_entries; i++)
  22                 printk("%*c%pS\n", 1 + spaces, ' ', (void *)trace->entries[i]);
  23 }
  24 EXPORT_SYMBOL_GPL(print_stack_trace);
  25
  26 int snprint_stack_trace(char *buf, size_t size,
  27                         struct stack_trace *trace, int spaces)
  28 {
  29         int i;
  30         int generated;
  31         int total = 0;
  32
  33         if (WARN_ON(!trace->entries))
  34                 return 0;
  35
  36         for (i = 0; i < trace->nr_entries; i++) {
  37                 generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
  38                                      (void *)trace->entries[i]);
  39
  40                 total += generated;
  41
  42                 /* Assume that generated isn't a negative number */
  43                 if (generated >= size) {
  44                         buf += size;
  45                         size = 0;
  46                 } else {
  47                         buf += generated;
  48                         size -= generated;
  49                 }
  50         }
  51
  52         return total;
  53 }
  54 EXPORT_SYMBOL_GPL(snprint_stack_trace);
  55
  56 /*
  57  * Architectures that do not implement save_stack_trace_*()
  58  * get these weak aliases and once-per-bootup warnings
  59  * (whenever this facility is utilized - for example by procfs):
  60  */
  61 __weak void
  62 save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  63 {
  64         WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
  65 }
  66
  67 __weak void
  68 save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
  69 {
  70         WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
  71 }
  72
  73 __weak int
  74 save_stack_trace_tsk_reliable(struct task_struct *tsk,
  75                               struct stack_trace *trace)
  76 {
  77         WARN_ONCE(1, KERN_INFO "save_stack_tsk_reliable() not implemented yet.\n");
  78         return -ENOSYS;
  79 }