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Ricardo Ribalda 6ab6705463 media: uvcvideo: Fix race condition with usb_kill_urb

commit 619d9b710cf06f7a00a17120ca92333684ac45a8 upstream.

usb_kill_urb warranties that all the handlers are finished when it
returns, but does not protect against threads that might be handling
asynchronously the urb.

For UVC, the function uvc_ctrl_status_event_async() takes care of
control changes asynchronously.

If the code is executed in the following order:

CPU 0					CPU 1
===== 					=====
uvc_status_complete()
					uvc_status_stop()
uvc_ctrl_status_event_work()
					uvc_status_start() -> FAIL

Then uvc_status_start will keep failing and this error will be shown:

<4>[    5.540139] URB 0000000000000000 submitted while active
drivers/usb/core/urb.c:378 usb_submit_urb+0x4c3/0x528

Let's improve the current situation, by not re-submiting the urb if
we are stopping the status event. Also process the queued work
(if any) during stop.

CPU 0					CPU 1
===== 					=====
uvc_status_complete()
					uvc_status_stop()
					uvc_status_start()
uvc_ctrl_status_event_work() -> FAIL

Hopefully, with the usb layer protection this should be enough to cover
all the cases.

Cc: stable@vger.kernel.org
Fixes: e5225c820c05 ("media: uvcvideo: Send a control event when a Control Change interrupt arrives")
Reviewed-by: Yunke Cao <yunkec@chromium.org>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2023-03-11 16:44:16 +01:00

cec

media: cec-adap.c: fix is_configuring state

2022-06-14 18:11:28 +02:00

common

media: saa7146: hexium_gemini: Fix a NULL pointer dereference in hexium_attach()

2022-01-27 09:19:43 +01:00

dvb-core

media: dvb-core: Fix UAF due to refcount races at releasing

2023-01-18 11:41:48 +01:00

dvb-frontends

media: stv0288: use explicitly signed char