From 514bdc80b9d2cda5201730045cad6e65c4153f67 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Tue, 24 Oct 2023 11:42:21 +0200
Subject: [PATCH] UPSTREAM: perf/core: Fix potential NULL deref
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Smatch is awesome.

BUG: 361274701
(cherry picked from commit a71ef31485bb51b846e8db8b3a35e432cc15afb5)
Fixes: 32671e3799ca ("perf: Disallow mis-matched inherited group reads")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Change-Id: I7691e0aaaee70f1d0db3d1e33983d7236f72ed0c
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: 杨辉 <yanghui10@xiaomi.corp-partner.google.com>
---
 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 c488c778b9f0..88fc24a2dbf8 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -13318,7 +13318,8 @@ 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;
 }