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perf events fix

GIT PULL Merged Ingo Molnar 2 participants 2 messages Apr 6, 2025 perf events

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Ingo Molnar

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Linus,

Please pull the latest perf/urgent Git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf-urgent-2025-04-06

# HEAD: a3c3c66670cee11eb13aa43905904bf29cb92d32 perf/core: Fix child_total_time_enabled accounting bug at task exit

Fix a perf events time accounting bug.

Thanks,

Ingo

------------------>
Yeoreum Yun (1):
perf/core: Fix child_total_time_enabled accounting bug at task exit

 kernel/events/core.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)
kernel/events/core.c +9 -9
index 0bb21659e252..128db74e9eab 100644
@@ -2451,6 +2451,7 @@ ctx_time_update_event(struct perf_event_context *ctx, struct perf_event *event)
 #define DETACH_GROUP	0x01UL
 #define DETACH_CHILD	0x02UL
 #define DETACH_DEAD	0x04UL
+#define DETACH_EXIT	0x08UL
 
 /*
  * Cross CPU call to remove a performance event

@@ -2465,6 +2466,7 @@ __perf_remove_from_context(struct perf_event *event,
 			   void *info)
 {
 	struct perf_event_pmu_context *pmu_ctx = event->pmu_ctx;
+	enum perf_event_state state = PERF_EVENT_STATE_OFF;
 	unsigned long flags = (unsigned long)info;
 
 	ctx_time_update(cpuctx, ctx);

@@ -2473,16 +2475,19 @@ __perf_remove_from_context(struct perf_event *event,
 	 * Ensure event_sched_out() switches to OFF, at the very least
 	 * this avoids raising perf_pending_task() at this time.
 	 */
-	if (flags & DETACH_DEAD)
+	if (flags & DETACH_EXIT)
+		state = PERF_EVENT_STATE_EXIT;
+	if (flags & DETACH_DEAD) {
 		event->pending_disable = 1;
+		state = PERF_EVENT_STATE_DEAD;
+	}
 	event_sched_out(event, ctx);
+	perf_event_set_state(event, min(event->state, state));
 	if (flags & DETACH_GROUP)
 		perf_group_detach(event);
 	if (flags & DETACH_CHILD)
 		perf_child_detach(event);
 	list_del_event(event, ctx);
-	if (flags & DETACH_DEAD)
-		event->state = PERF_EVENT_STATE_DEAD;
 
 	if (!pmu_ctx->nr_events) {
 		pmu_ctx->rotate_necessary = 0;

@@ -13731,12 +13736,7 @@ perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
 		mutex_lock(&parent_event->child_mutex);
 	}
 
-	perf_remove_from_context(event, detach_flags);
-
-	raw_spin_lock_irq(&ctx->lock);
-	if (event->state > PERF_EVENT_STATE_EXIT)
-		perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
-	raw_spin_unlock_irq(&ctx->lock);
+	perf_remove_from_context(event, detach_flags | DETACH_EXIT);
 
 	/*
 	 * Child events can be freed.