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Wed, 12 Aug 2026 20:14:38 -0700 (PDT) Received: from i4-l-hqh5357-03.ad.psu.edu ([130.203.139.71]) by smtp.gmail.com with ESMTPSA id af79cd13be357-936c1b12283sm52741285a.23.2026.08.12.20.14.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Aug 2026 20:14:38 -0700 (PDT) From: Shuangpeng Bai To: hverkuil@kernel.org, mchehab@kernel.org Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Shuangpeng Bai Subject: [PATCH v2] media: gspca: use vb2_video_unregister_device() on disconnect Date: Wed, 12 Aug 2026 23:12:35 -0400 Message-ID: <20260813031235.2468144-1-shuangpeng.kernel@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" gspca uses vb2_fop_release(), but gspca_disconnect() only unregisters the video device. If the queue owner closes the device after USB disconnect, vb2_fop_release() releases the queue and invokes gspca_stop_streaming() at that point. gspca_stream_off() calls subdriver stop callbacks and usb_set_interface() through gspca_dev->dev. By the time the late close runs, the USB core can have freed the usb_device, resulting in a use-after-free. This was observed as a KASAN use-after-free in sd_stopN(). Use vb2_video_unregister_device() so the queue is released and streaming is stopped synchronously during disconnect, while the usb_device is still valid. Since the helper takes the queue lock, which is usb_lock, call it after dropping that lock. Fixes: f729ef5796d8 ("media: videobuf2-v4l2.c: add vb2_video_unregister_dev= ice helper function") Cc: stable@vger.kernel.org # 5.10.x Suggested-by: Hans Verkuil Signed-off-by: Shuangpeng Bai --- Changes in v2: - Use vb2_video_unregister_device() to stop streaming during disconnect, as suggested by Hans. - Drop the usb_get_dev()/usb_put_dev() lifetime workaround. - Call the helper after releasing usb_lock since it takes the queue lock internally. v1: https://lore.kernel.org/r/20260718025434.2259756-1-shuangpeng.kernel@gm= ail.com/ drivers/media/usb/gspca/gspca.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/media/usb/gspca/gspca.c b/drivers/media/usb/gspca/gspc= a.c index 594d73e50b9f..4185c9047241 100644 --- a/drivers/media/usb/gspca/gspca.c +++ b/drivers/media/usb/gspca/gspca.c @@ -1636,9 +1636,8 @@ void gspca_disconnect(struct usb_interface *intf) #endif =20 v4l2_device_disconnect(&gspca_dev->v4l2_dev); - video_unregister_device(&gspca_dev->vdev); - mutex_unlock(&gspca_dev->usb_lock); + vb2_video_unregister_device(&gspca_dev->vdev); =20 /* (this will call gspca_release() immediately or on last close) */ v4l2_device_put(&gspca_dev->v4l2_dev); --=20 2.43.0