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Commit 1027fcb2 authored by Steven Rostedt's avatar Steven Rostedt
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tracing: protect ring_buffer_expanded with trace_types_lock 



Impact: prevent races with ring_buffer_expanded

This patch places the expanding of the tracing buffer under the
protection of the trace_types_lock mutex. It is highly unlikely
that there would be any contention, but better safe than sorry.

Reported-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
parent a123c52b

kernel/trace/trace.c

+4 −1
Original line number Diff line number Diff line
@@ -2391,8 +2391,10 @@ int tracing_update_buffers(void) 
{

	int ret = 0;



	mutex_lock(&trace_types_lock);

	if (!ring_buffer_expanded)

		ret = tracing_resize_ring_buffer(trace_buf_size);

	mutex_unlock(&trace_types_lock);



	return ret;

}
@@ -2412,6 +2414,8 @@ static int tracing_set_tracer(const char *buf) 
	struct tracer *t;

	int ret = 0;



	mutex_lock(&trace_types_lock);



	if (!ring_buffer_expanded) {

		ret = tracing_resize_ring_buffer(trace_buf_size);

		if (ret < 0)
@@ -2419,7 +2423,6 @@ static int tracing_set_tracer(const char *buf) 
		ret = 0;

	}



	mutex_lock(&trace_types_lock);

	for (t = trace_types; t; t = t->next) {

		if (strcmp(t->name, buf) == 0)

			break;