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", 1 + spaces, ' ');
  23                 print_ip_sym(trace->entries[i]);
  24         }
  25 }
  26 EXPORT_SYMBOL_GPL(print_stack_trace);
  27
  28 int snprint_stack_trace(char *buf, size_t size,
  29                         struct stack_trace *trace, int spaces)
  30 {
  31         int i;
  32         unsigned long ip;
  33         int generated;
  34         int total = 0;
  35
  36         if (WARN_ON(!trace->entries))
  37                 return 0;
  38
  39         for (i = 0; i < trace->nr_entries; i++) {
  40                 ip = trace->entries[i];
  41                 generated = snprintf(buf, size, "%*c[<%p>] %pS\n",
  42                                 1 + spaces, ' ', (void *) ip, (void *) ip);
  43
  44                 total += generated;
  45
  46                 /* Assume that generated isn't a negative number */
  47                 if (generated >= size) {
  48                         buf += size;
  49                         size = 0;
  50                 } else {
  51                         buf += generated;
  52                         size -= generated;
  53                 }
  54         }
  55
  56         return total;
  57 }
  58 EXPORT_SYMBOL_GPL(snprint_stack_trace);
  59
  60 /*
  61  * Architectures that do not implement save_stack_trace_tsk or
  62  * save_stack_trace_regs get this weak alias and a once-per-bootup warning
  63  * (whenever this facility is utilized - for example by procfs):
  64  */
  65 __weak void
  66 save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  67 {
  68         WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
  69 }
  70
  71 __weak void
  72 save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
  73 {
  74         WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
  75 }