perf: Fix pmu_filter_match()

Mark reported that the new for_each_sibling_event() assertion triggers
in pmu_filter_match() -- which isn't always called with IRQs disabled
or ctx->mutex held.

Fixes: f3c0eba ("perf: Add a few assertions")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YvvJq2f/7eFVcnNy@FVFF77S0Q05N

kernel/events/core.c

@@ -2226,16 +2226,22 @@ static inline int __pmu_filter_match(struct perf_event *event)
 static inline int pmu_filter_match(struct perf_event *event)
 {
 	struct perf_event *sibling;
+	unsigned long flags;
+	int ret = 1;
 
 	if (!__pmu_filter_match(event))
 		return 0;
 
+	local_irq_save(flags);
 	for_each_sibling_event(sibling, event) {
-		if (!__pmu_filter_match(sibling))
-			return 0;
+		if (!__pmu_filter_match(sibling)) {
+			ret = 0;
+			break;
+		}
 	}
+	local_irq_restore(flags);
 
-	return 1;
+	return ret;
 }
 
 static inline int