perf/core: Fix potential NULL deref

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>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index d0663b9..a2f2a95 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -13372,7 +13372,8 @@ static int inherit_group(struct perf_event *parent_event,
                    !perf_get_aux_event(child_ctr, leader))
                        return -EINVAL;
        }
-       leader->group_generation = parent_event->group_generation;
+       if (leader)
+               leader->group_generation = parent_event->group_generation;
        return 0;
 }