tracing: Add function probe to trigger a ftrace dump to console

Add the "dump" command to have the ftrace buffer dumped to console if
a function is hit. This is useful when debugging a tripple fault,
where you have an idea of a function that is called just before the
tripple fault occurs, and can tell ftrace to dump its content out
to the console before it continues.

Format is:

  <function>:dump

echo 'bad_address:dump' > /debug/tracing/set_ftrace_filter

To remove this:

echo '!bad_address:dump' > /debug/tracing/set_ftrace_filter

Requested-by: Luis Claudio R. Goncalves <lclaudio@uudg.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat)
2013-04-30 15:46:14 -04:00
committed by Steven Rostedt
parent 317ddd256b
commit ad71d889b8
2 changed files with 61 additions and 5 deletions
+7
View File
@@ -2430,6 +2430,13 @@ The following commands are supported:
echo '!schedule:disable_event:sched:sched_switch' > \
set_ftrace_filter
- dump
When the function is hit, it will dump the contents of the ftrace
ring buffer to the console. This is useful if you need to debug
something, and want to dump the trace when a certain function
is hit. Perhaps its a function that is called before a tripple
fault happens and does not allow you to get a regular dump.
trace_pipe
----------