x86: don't save unreliable stack trace entries
[sfrench/cifs-2.6.git] / arch / x86 / kernel / stacktrace.c
1 /*
2  * Stack trace management functions
3  *
4  *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
5  */
6 #include <linux/sched.h>
7 #include <linux/stacktrace.h>
8 #include <linux/module.h>
9 #include <asm/stacktrace.h>
10
11 static void save_stack_warning(void *data, char *msg)
12 {
13 }
14
15 static void
16 save_stack_warning_symbol(void *data, char *msg, unsigned long symbol)
17 {
18 }
19
20 static int save_stack_stack(void *data, char *name)
21 {
22         return -1;
23 }
24
25 static void save_stack_address(void *data, unsigned long addr, int reliable)
26 {
27         struct stack_trace *trace = data;
28         if (!reliable)
29                 return;
30         if (trace->skip > 0) {
31                 trace->skip--;
32                 return;
33         }
34         if (trace->nr_entries < trace->max_entries)
35                 trace->entries[trace->nr_entries++] = addr;
36 }
37
38 static void
39 save_stack_address_nosched(void *data, unsigned long addr, int reliable)
40 {
41         struct stack_trace *trace = (struct stack_trace *)data;
42         if (!reliable)
43                 return;
44         if (in_sched_functions(addr))
45                 return;
46         if (trace->skip > 0) {
47                 trace->skip--;
48                 return;
49         }
50         if (trace->nr_entries < trace->max_entries)
51                 trace->entries[trace->nr_entries++] = addr;
52 }
53
54 static const struct stacktrace_ops save_stack_ops = {
55         .warning = save_stack_warning,
56         .warning_symbol = save_stack_warning_symbol,
57         .stack = save_stack_stack,
58         .address = save_stack_address,
59 };
60
61 static const struct stacktrace_ops save_stack_ops_nosched = {
62         .warning = save_stack_warning,
63         .warning_symbol = save_stack_warning_symbol,
64         .stack = save_stack_stack,
65         .address = save_stack_address_nosched,
66 };
67
68 /*
69  * Save stack-backtrace addresses into a stack_trace buffer.
70  */
71 void save_stack_trace(struct stack_trace *trace)
72 {
73         dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);
74         if (trace->nr_entries < trace->max_entries)
75                 trace->entries[trace->nr_entries++] = ULONG_MAX;
76 }
77
78 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
79 {
80         dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
81         if (trace->nr_entries < trace->max_entries)
82                 trace->entries[trace->nr_entries++] = ULONG_MAX;
83 }