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([101.76.249.46]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2bd791e0b11sm91758165ad.18.2026.05.17.04.12.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 17 May 2026 04:12:32 -0700 (PDT) From: Guangshuo Li To: Parthiban Veerasooran , Christian Gromm , Greg Kroah-Hartman , Laurent Pinchart , Hans Verkuil , Guangshuo Li , Dan Carpenter , Kees Cook , Minu Jin , Andrey Shvetsov , linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH] staging: most: video: avoid double free on video register failure Date: Sun, 17 May 2026 19:12:18 +0800 Message-ID: <20260517111218.945796-1-lgs201920130244@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" comp_register_videodev() allocates a video_device with video_device_alloc() and releases it if video_register_device() fails. This can double free the video_device when __video_register_device() reaches device_register() and that call fails: video_register_device() -> __video_register_device() -> device_register() fails -> put_device(&vdev->dev) -> v4l2_device_release() -> vdev->release(vdev) -> video_device_release(vdev) comp_register_videodev() -> video_device_release(mdev->vdev) Use video_device_release_empty() while registering the device so that registration failure paths do not free mdev->vdev through vdev->release(). comp_register_videodev() then releases mdev->vdev exactly once on failure. Restore video_device_release() after successful registration so the registered device keeps its normal lifetime handling. This issue was found by a static analysis tool I am developing. Fixes: eab231c0398a ("staging: most: v4l2-aim: remove unnecessary label err= _vbi_dev") Signed-off-by: Guangshuo Li --- drivers/staging/most/video/video.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/staging/most/video/video.c b/drivers/staging/most/vide= o/video.c index 04351f8ccccf..aab57768f4f7 100644 --- a/drivers/staging/most/video/video.c +++ b/drivers/staging/most/video/video.c @@ -420,6 +420,7 @@ static int comp_register_videodev(struct most_video_dev= *mdev) =20 /* Fill the video capture device struct */ *mdev->vdev =3D comp_videodev_template; + mdev->vdev->release =3D video_device_release_empty; mdev->vdev->v4l2_dev =3D &mdev->v4l2_dev; mdev->vdev->lock =3D &mdev->lock; snprintf(mdev->vdev->name, sizeof(mdev->vdev->name), "MOST: %s", @@ -432,9 +433,13 @@ static int comp_register_videodev(struct most_video_de= v *mdev) v4l2_err(&mdev->v4l2_dev, "video_register_device failed (%d)\n", ret); video_device_release(mdev->vdev); + return ret; } =20 - return ret; + mdev->vdev->release =3D video_device_release; + + return 0; + } =20 static void comp_unregister_videodev(struct most_video_dev *mdev) --=20 2.43.0