diff options
| author | Steven Rostedt <srostedt@redhat.com> | 2009-03-12 19:42:29 -0400 |
|---|---|---|
| committer | Steven Rostedt <srostedt@redhat.com> | 2009-03-12 21:15:01 -0400 |
| commit | e447e1df2e568cd43d1918963c9f09fae85aea57 (patch) | |
| tree | a73edfcc1b603a921ed7e332ce614e1345385100 | |
| parent | 2da03ecee6308ea174e8a02b92a3c4ec92e886c8 (diff) | |
tracing: explain why stack tracer is empty
If the stack tracing is disabled (by default) the stack_trace file
will only contain the header:
# cat /debug/tracing/stack_trace
Depth Size Location (0 entries)
----- ---- --------
This can be frustrating to a developer that does not realize that the
stack tracer is disabled. This patch adds the following text:
# cat /debug/tracing/stack_trace
Depth Size Location (0 entries)
----- ---- --------
#
# Stack tracer disabled
#
# To enable the stack tracer, either add 'stacktrace' to the
# kernel command line
# or 'echo 1 > /proc/sys/kernel/stack_tracer_enabled'
#
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| -rw-r--r-- | kernel/trace/trace_stack.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 4564fd94b0c..91ccbf396c9 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -245,6 +245,17 @@ static int trace_lookup_stack(struct seq_file *m, long i) #endif } +static void print_disabled(struct seq_file *m) +{ + seq_puts(m, "#\n" + "# Stack tracer disabled\n" + "#\n" + "# To enable the stack tracer, either add 'stacktrace' to the\n" + "# kernel command line\n" + "# or 'echo 1 > /proc/sys/kernel/stack_tracer_enabled'\n" + "#\n"); +} + static int t_show(struct seq_file *m, void *v) { long i; @@ -255,6 +266,10 @@ static int t_show(struct seq_file *m, void *v) " (%d entries)\n" " ----- ---- --------\n", max_stack_trace.nr_entries); + + if (!stack_tracer_enabled && !max_stack_size) + print_disabled(m); + return 0; } |