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: f3c0eba28704 ("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

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 49bc3b5e6c8aa02db09fcb15ae728c90d640b127..b981b879bcd860d2dfd369af8f6d8e0e02834759 100644 (file)
--- a/kernel/events/core.c
+++ b/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