[tip: perf/urgent] perf/core: Fix potential NULL deref

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the perf/urgent branch of tip:

Commit-ID:     a71ef31485bb51b846e8db8b3a35e432cc15afb5
Gitweb:        https://git.kernel.org/tip/a71ef31485bb51b846e8db8b3a35e432cc15afb5
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Tue, 24 Oct 2023 11:42:21 +02:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 24 Oct 2023 12:15:12 +02:00

perf/core: Fix potential NULL deref

Smatch is awesome.

Fixes: 32671e3799ca ("perf: Disallow mis-matched inherited group reads")
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 kernel/events/core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index d0663b9..a2f2a95 100644
--- 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;
 }