From 6990570f7e0a6078e11b9c5dc13f4b6e3f49a398 Mon Sep 17 00:00:00 2001
From: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Date: Wed, 19 Feb 2020 16:25:54 +0100
Subject: [PATCH] media: v4l2-core: fix a use-after-free bug of sd->devnode
Git-commit: 6990570f7e0a6078e11b9c5dc13f4b6e3f49a398
Patch-mainline: v5.7-rc1
References: git-fixes

sd->devnode is released after calling
v4l2_subdev_release. Therefore it should be set
to NULL so that the subdev won't hold a pointer
to a released object. This fixes a reference
after free bug in function
v4l2_device_unregister_subdev

Fixes: 0e43734d4c46e ("media: v4l2-subdev: add release() internal op")

Cc: stable@vger.kernel.org
Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Reviewed-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/media/v4l2-core/v4l2-device.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
index 63d6b147b21e..41da73ce2e98 100644
--- a/drivers/media/v4l2-core/v4l2-device.c
+++ b/drivers/media/v4l2-core/v4l2-device.c
@@ -179,6 +179,7 @@ static void v4l2_subdev_release(struct v4l2_subdev *sd)
 
 	if (sd->internal_ops && sd->internal_ops->release)
 		sd->internal_ops->release(sd);
+	sd->devnode = NULL;
 	module_put(owner);
 }
 
-- 
2.16.4