tracing: use nowakeup version of commit for function event trace tests

The startup tests for the event tracer also runs with the function
tracer enabled. The "wakeup" version of the trace commit was used
which can grab spinlocks. If a task was preempted by an NMI
that called a function being traced, it could deadlock due to the
function tracer trying to grab the same lock.

Thanks to Frederic Weisbecker for pointing out where the bug was.

Reported-by: Ingo Molnar <mingo@elte.hu>
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 98daf5d..672b195 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1164,7 +1164,7 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip)
        entry->ip                       = ip;
        entry->parent_ip                = parent_ip;
 
-       trace_current_buffer_unlock_commit(event, flags, pc);
+       trace_nowake_buffer_unlock_commit(event, flags, pc);
 
  out:
        atomic_dec(&per_cpu(test_event_disable, cpu));