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

Pull perf fix from Ingo Molnar:
 "A perf kernel side fix for a fuzzer triggered lockup"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix irq_work 'tail' recursion

1 files changed, 10 insertions, 0 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 453ef61311d4..2fabc0627165 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4574,6 +4574,13 @@ static void perf_pending_event(struct irq_work *entry)
 {
         struct perf_event *event = container_of(entry,
                         struct perf_event, pending);
+        int rctx;
+
+        rctx = perf_swevent_get_recursion_context();
+        /*
+         * If we 'fail' here, that's OK, it means recursion is already disabled
+         * and we won't recurse 'further'.
+         */
 
         if (event->pending_disable) {
                 event->pending_disable = 0;
@@ -4584,6 +4591,9 @@ static void perf_pending_event(struct irq_work *entry)
                 event->pending_wakeup = 0;
                 perf_event_wakeup(event);
         }
+
+        if (rctx >= 0)
+                perf_swevent_put_recursion_context(rctx);
 }
 
 /*