Received-SPF: pass (google.com: domain of linux-kernel+bounces-65115-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
From: Hillf Danton <hdanton@sina.com>
To: syzbot <syzbot+0f999d26a4fd79c3a23b@syzkaller.appspotmail.com>
Cc: linux-kernel@vger.kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [dri?] KASAN: slab-use-after-free Read in drm_atomic_helper_wait_for_vblanks (2)
Date: Wed, 14 Feb 2024 19:18:55 +0800
Message-ID: <20240214111856.168-1-hdanton@sina.com>
In-Reply-To: <000000000000ec4c32061143ec95@google.com>
References: 
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

On Tue, 13 Feb 2024 06:08:15 -0800
> HEAD commit:    c664e16bb1ba Merge tag 'docs-6.8-fixes2' of git://git.lwn...
> git tree:       upstream
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11fcdba2180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git  master

--- x/drivers/gpu/drm/drm_atomic_helper.c
+++ y/drivers/gpu/drm/drm_atomic_helper.c
@@ -1849,7 +1849,11 @@ static void commit_work(struct work_stru
 	struct drm_atomic_state *state = container_of(work,
 						      struct drm_atomic_state,
 						      commit_work);
+	struct drm_device *dev = state->dev;
+
+	mutex_lock(&dev->master_mutex);
 	commit_tail(state);
+	mutex_unlock(&dev->master_mutex);
 }
 
 /**
--