From dd8b17eff1686a86f89b06958f1dd4488b1b7d85 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

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>
(cherry picked from commit 511f3e9bbb0a7abe15d6c4852fb774b814b07b60)
Change-Id: I6d2005d6c186cfc7ff41ed2615e37ee9f01da6a5
Bug: 442358987
Signed-off-by: Greg Kroah-Hartman <gregkh@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 e2c7251219b4..36b60ef0ac6c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -12115,7 +12115,8 @@ 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;
 }