From 511f3e9bbb0a7abe15d6c4852fb774b814b07b60 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Tue, 24 Oct 2023 11:42:21 +0200
Subject: [PATCH] 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>
---
 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 884cb4aaf342..cd32c7e55568 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -12015,7 +12015,8 @@ 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;
 }