diff options
| author | Frederic Weisbecker <fweisbec@gmail.com> | 2009-03-22 23:10:46 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-03-23 09:22:14 +0100 |
| commit | 07edf7121374609709ef1b0889f6e7b8d6a62ec1 (patch) | |
| tree | ad1649c9546dc3ce23bb2f8609a7459a7ca2006e /kernel/trace/trace.c | |
| parent | 9bd7d099ab3f10dd666da399c064999bae427cd9 (diff) | |
tracing/events: don't use wake up for events
Impact: fix hard-lockup with sched switch events
Some ftrace events, such as sched wakeup, can be traced
while the runqueue lock is hold. Since they are using
trace_current_buffer_unlock_commit(), they call wake_up()
which can try to grab the runqueue lock too, resulting in
a deadlock.
Now for all event, we call a new helper:
trace_nowake_buffer_unlock_commit() which do pretty the same than
trace_current_buffer_unlock_commit() except than it doesn't call
trace_wake_up().
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237759847-21025-4-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 26 |
1 files changed, 21 insertions, 5 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e6fac0ffe6f..6bad12819eb 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -860,15 +860,25 @@ static void ftrace_trace_stack(struct trace_array *tr, static void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, int pc); -void trace_buffer_unlock_commit(struct trace_array *tr, - struct ring_buffer_event *event, - unsigned long flags, int pc) +static inline void __trace_buffer_unlock_commit(struct trace_array *tr, + struct ring_buffer_event *event, + unsigned long flags, int pc, + int wake) { ring_buffer_unlock_commit(tr->buffer, event); ftrace_trace_stack(tr, flags, 6, pc); ftrace_trace_userstack(tr, flags, pc); - trace_wake_up(); + + if (wake) + trace_wake_up(); +} + +void trace_buffer_unlock_commit(struct trace_array *tr, + struct ring_buffer_event *event, + unsigned long flags, int pc) +{ + __trace_buffer_unlock_commit(tr, event, flags, pc, 1); } struct ring_buffer_event * @@ -882,7 +892,13 @@ trace_current_buffer_lock_reserve(unsigned char type, unsigned long len, void trace_current_buffer_unlock_commit(struct ring_buffer_event *event, unsigned long flags, int pc) { - return trace_buffer_unlock_commit(&global_trace, event, flags, pc); + return __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 1); +} + +void trace_nowake_buffer_unlock_commit(struct ring_buffer_event *event, + unsigned long flags, int pc) +{ + return __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 0); } void |