Commit 47e74f2b authored Nov 12, 2008 by Steven Rostedt Committed by Ingo Molnar Nov 12, 2008

ring-buffer: no preempt for sched_clock()



Impact: disable preemption when calling sched_clock()

The ring_buffer_time_stamp still uses sched_clock as its counter.
But it is a bug to call it with preemption enabled. This requirement
should not be pushed to the ring_buffer_time_stamp callers, so
the ring_buffer_time_stamp needs to disable preemption when calling
sched_clock.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent c1e7abbc

kernel/trace/ring_buffer.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -51,8 +51,14 @@ void tracing_off(void)
		/* FIXME!!! */
		u64 ring_buffer_time_stamp(int cpu)
		{
		u64 time;

		preempt_disable_notrace();
		/* shift to debug/test normalization and TIME_EXTENTS */
		return sched_clock() << DEBUG_SHIFT;
		time = sched_clock() << DEBUG_SHIFT;
		preempt_enable_notrace();

		return time;
		}

		void ring_buffer_normalize_time_stamp(int cpu, u64 *ts)