perf/core: Fix potential NULL deref

commit a71ef31485bb51b846e8db8b3a35e432cc15afb5 upstream.

Smatch is awesome.

Fixes: 32671e3799ca ("perf: Disallow mis-matched inherited group reads")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 7ece49c14b744f7bbbaae834f3bd0b97e2d006fc..262079890b134dc995738bfd4740f92dafac68b1 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11059,7 +11059,8 @@ static int inherit_group(struct perf_event *parent_event,
                if (IS_ERR(child_ctr))
                        return PTR_ERR(child_ctr);
        }
-       leader->group_generation = parent_event->group_generation;
+       if (leader)
+               leader->group_generation = parent_event->group_generation;
        return 0;
 }