Re: [PATCH 4/5] media: uvcvideo: Protect uvc queue file operations against disconnect

[kernel test robot]

Hi Guenter,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linuxtv-media/master]
[also build test WARNING on v5.9-rc3 next-20200828]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Guenter-Roeck/media-uvcvideo-Fix-race-conditions/20200830-230715
base:   git://linuxtv.org/media_tree.git master
config: x86_64-randconfig-s031-20200901 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.2-191-g10164920-dirty
        # save the attached .config to linux build tree
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>


sparse warnings: (new ones prefixed by >>)

>> drivers/media/usb/uvc/uvc_queue.c:402:21: sparse: sparse: incorrect type in assignment (different base types) @@     expected restricted __poll_t [usertype] ret @@     got int @@
>> drivers/media/usb/uvc/uvc_queue.c:402:21: sparse:     expected restricted __poll_t [usertype] ret
>> drivers/media/usb/uvc/uvc_queue.c:402:21: sparse:     got int

# https://github.com/0day-ci/linux/commit/9128827e77bc077a6fefd3ca886a8466e84f7154
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Guenter-Roeck/media-uvcvideo-Fix-race-conditions/20200830-230715
git checkout 9128827e77bc077a6fefd3ca886a8466e84f7154
vim +402 drivers/media/usb/uvc/uvc_queue.c

   393	
   394	__poll_t uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
   395				    poll_table *wait)
   396	{
   397		struct uvc_streaming *stream = uvc_queue_to_stream(queue);
   398		__poll_t ret;
   399	
   400		mutex_lock(&queue->mutex);
   401		if (!video_is_registered(&stream->vdev)) {
 > 402			ret = -ENODEV;
   403			goto unlock;
   404		}
   405		ret = vb2_poll(&queue->queue, file, wait);
   406	unlock:
   407		mutex_unlock(&queue->mutex);
   408	
   409		return ret;
   410	}
   411	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

Attachment: .config.gz
Description: application/gzip