@@ -1770,6 +1770,8 @@ group_sched_out(struct perf_event *group_event,
struct perf_event *event;
int state = group_event->state;
+ perf_pmu_disable(ctx->pmu);
+
event_sched_out(group_event, cpuctx, ctx);
/*
@@ -1778,6 +1780,8 @@ group_sched_out(struct perf_event *group_event,
list_for_each_entry(event, &group_event->sibling_list, group_entry)
event_sched_out(event, cpuctx, ctx);
+ perf_pmu_enable(ctx->pmu);
+
if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
cpuctx->exclusive = 0;
}
Groups of events are supposed to be scheduled atomically, such that it is possible to derive meaningful ratios between their values. We take great pains to achieve this when scheduling event groups to a PMU in group_sched_in(), calling {start,commit}_txn() (which fall back to perf_pmu_{disable,enable}() if necessary) to provide this guarantee. However we don't mirror this in group_sched_out(), and in some cases events will not be scheduled out atomically. For example, if we disable an event group with PERF_EVENT_IOC_DISABLE, we'll cross-call __perf_event_disable() for the group leader, and will call group_sched_out() without having first disabled the relevant PMU. We will disable/enable the PMU around each pmu->del() call, but between each call the PMU will be enabled and events may count. Avoid this by explicitly disabling and enabling the PMU around event removal in group_sched_out(), mirroring what we do in group_sched_in(). Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: linux-kernel@vger.kernel.org --- kernel/events/core.c | 4 ++++ 1 file changed, 4 insertions(+) -- 1.9.1