Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix double start/stop in x86_pmu_start()
  perf evsel: Fix an issue where perf report fails to show the proper percentage
  perf tools: Fix prefix matching for kernel maps
  perf tools: Fix perf stack to non executable on x86_64
  perf: Remove deprecated WARN_ON_ONCE()

1 files changed, 14 insertions, 5 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index ba36013cfb21..1b5c081d8b9f 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2303,7 +2303,7 @@ do {					\
 static DEFINE_PER_CPU(int, perf_throttled_count);
 static DEFINE_PER_CPU(u64, perf_throttled_seq);
 
-static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
+static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
 {
 	struct hw_perf_event *hwc = &event->hw;
 	s64 period, sample_period;
@@ -2322,9 +2322,13 @@ static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
 	hwc->sample_period = sample_period;
 
 	if (local64_read(&hwc->period_left) > 8*sample_period) {
-		event->pmu->stop(event, PERF_EF_UPDATE);
+		if (disable)
+			event->pmu->stop(event, PERF_EF_UPDATE);
+
 		local64_set(&hwc->period_left, 0);
-		event->pmu->start(event, PERF_EF_RELOAD);
+
+		if (disable)
+			event->pmu->start(event, PERF_EF_RELOAD);
 	}
 }
 
@@ -2350,6 +2354,7 @@ static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
 		return;
 
 	raw_spin_lock(&ctx->lock);
+	perf_pmu_disable(ctx->pmu);
 
 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
 		if (event->state != PERF_EVENT_STATE_ACTIVE)
@@ -2381,13 +2386,17 @@ static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
 		/*
 		 * restart the event
 		 * reload only if value has changed
+		 * we have stopped the event so tell that
+		 * to perf_adjust_period() to avoid stopping it
+		 * twice.
 		 */
 		if (delta > 0)
-			perf_adjust_period(event, period, delta);
+			perf_adjust_period(event, period, delta, false);
 
 		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
 	}
 
+	perf_pmu_enable(ctx->pmu);
 	raw_spin_unlock(&ctx->lock);
 }
 
@@ -4562,7 +4571,7 @@ static int __perf_event_overflow(struct perf_event *event,
 		hwc->freq_time_stamp = now;
 
 		if (delta > 0 && delta < 2*TICK_NSEC)
-			perf_adjust_period(event, delta, hwc->last_period);
+			perf_adjust_period(event, delta, hwc->last_period, true);
 	}
 
 	/*