perf/core: Fix __perf_read_group_add() locking (a9cd8194) · Commits · 戴 / test

Event timestamps are serialized using ctx->lock, make sure to hold it over reading all values. Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by:

Ingo Molnar <mingo@kernel.org>

kernel/events/core.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -4453,6 +4453,8 @@ static int __perf_read_group_add(struct perf_event *leader,
		if (ret)
		return ret;

		raw_spin_lock_irqsave(&ctx->lock, flags);

		/*
		* Since we co-schedule groups, {enabled,running} times of siblings
		* will be identical to those of the leader, so we only publish one
		@@ -4475,8 +4477,6 @@ static int __perf_read_group_add(struct perf_event *leader,
		if (read_format & PERF_FORMAT_ID)
		values[n++] = primary_event_id(leader);

		raw_spin_lock_irqsave(&ctx->lock, flags);

		list_for_each_entry(sub, &leader->sibling_list, group_entry) {
		values[n++] += perf_event_count(sub);
		if (read_format & PERF_FORMAT_ID)

Admin message