Commit 970892a9 authored Aug 13, 2009 by Peter Zijlstra Committed by Ingo Molnar Aug 13, 2009

perf_counter: Fix an ipi-deadlock



perf_pending_counter() is called from IRQ context and will call
perf_counter_disable(), however perf_counter_disable() uses
smp_call_function_single() which doesn't fancy being used with
IRQs disabled due to IPI deadlocks.

Fix this by making it use the local __perf_counter_disable()
call and teaching the counter_sched_out() code about pending
disables as well.

This should cover the case where a counter migrates before the
pending queue gets processed.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey J Ashford <cjashfor@us.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: stephane eranian <eranian@googlemail.com>
LKML-Reference: <20090813103655.244097721@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 3dab77fb

kernel/perf_counter.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -307,6 +307,10 @@ counter_sched_out(struct perf_counter *counter,
		return;

		counter->state = PERF_COUNTER_STATE_INACTIVE;
		if (counter->pending_disable) {
		counter->pending_disable = 0;
		counter->state = PERF_COUNTER_STATE_OFF;
		}
		counter->tstamp_stopped = ctx->time;
		counter->pmu->disable(counter);
		counter->oncpu = -1;
		@@ -2343,7 +2347,7 @@ static void perf_pending_counter(struct perf_pending_entry *entry)

		if (counter->pending_disable) {
		counter->pending_disable = 0;
		perf_counter_disable(counter);
		__perf_counter_disable(counter);
		}

		if (counter->pending_wakeup) {