* [PATCH] media: em28xx: use video_unregister_device for radio_dev
@ 2026-09-23 7:20 Rohinthan P
2026-09-23 12:12 ` Hans Verkuil
0 siblings, 1 reply; 2+ messages in thread
From: Rohinthan P @ 2026-09-23 7:20 UTC (permalink / raw)
To: Mauro Carvalho Chehab, Hans Verkuil, linux-media, linux-kernel,
syzbot+f26bc23e42eeb548dee1
Commit 7c8bf63b7937 ("media: em28xx: use vb2_video_unregister_device")
converted device unregistrations in em28xx to use
vb2_video_unregister_device() instead of video_unregister_device().
However, radio devices do not have an associated videobuf2 queue
(v4l2->radio_dev.queue is NULL). Calling vb2_video_unregister_device()
on a radio device triggers a WARNING in vb2_video_unregister_device():
!vdev->queue
WARNING: drivers/media/common/videobuf2/videobuf2-v4l2.c:1264 at vb2_video_unregister_device+0x1f8/0x200
Call Trace:
em28xx_v4l2_init+0x1c39/0x3150 drivers/media/usb/em28xx/em28xx-video.c:3085
As documented in vb2_video_unregister_device(), video_unregister_device()
should be used instead when vdev->queue is NULL.
Revert to calling video_unregister_device() for v4l2->radio_dev in both
em28xx_v4l2_fini() and the em28xx_v4l2_init() error unwind path.
Fixes: 7c8bf63b7937 ("media: em28xx: use vb2_video_unregister_device")
Reported-by: syzbot+f26bc23e42eeb548dee1@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f26bc23e42eeb548dee1
Signed-off-by: Rohinthan P <rokinthanp03@gmail.com>
---
drivers/media/usb/em28xx/em28xx-video.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c
index c418add..79af154 100644
--- a/drivers/media/usb/em28xx/em28xx-video.c
+++ b/drivers/media/usb/em28xx/em28xx-video.c
@@ -2416,7 +2416,7 @@ static int em28xx_v4l2_fini(struct em28xx *dev)
if (video_is_registered(&v4l2->radio_dev)) {
dev_info(&dev->intf->dev, "V4L2 device %s deregistered\n",
video_device_node_name(&v4l2->radio_dev));
- vb2_video_unregister_device(&v4l2->radio_dev);
+ video_unregister_device(&v4l2->radio_dev);
}
if (video_is_registered(&v4l2->vbi_dev)) {
dev_info(&dev->intf->dev, "V4L2 device %s deregistered\n",
@@ -3082,7 +3082,7 @@ static int em28xx_v4l2_init(struct em28xx *dev)
dev_info(&dev->intf->dev,
"V4L2 device %s deregistered\n",
video_device_node_name(&v4l2->radio_dev));
- vb2_video_unregister_device(&v4l2->radio_dev);
+ video_unregister_device(&v4l2->radio_dev);
}
if (video_is_registered(&v4l2->vbi_dev)) {
dev_info(&dev->intf->dev,
--
2.53.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] media: em28xx: use video_unregister_device for radio_dev
2026-09-23 7:20 [PATCH] media: em28xx: use video_unregister_device for radio_dev Rohinthan P
@ 2026-09-23 12:12 ` Hans Verkuil
0 siblings, 0 replies; 2+ messages in thread
From: Hans Verkuil @ 2026-09-23 12:12 UTC (permalink / raw)
To: Rohinthan P, Mauro Carvalho Chehab, Hans Verkuil, linux-media,
linux-kernel, syzbot+f26bc23e42eeb548dee1
On 23/09/2026 09:20, Rohinthan P wrote:
> Commit 7c8bf63b7937 ("media: em28xx: use vb2_video_unregister_device")
> converted device unregistrations in em28xx to use
> vb2_video_unregister_device() instead of video_unregister_device().
>
> However, radio devices do not have an associated videobuf2 queue
> (v4l2->radio_dev.queue is NULL). Calling vb2_video_unregister_device()
> on a radio device triggers a WARNING in vb2_video_unregister_device():
>
> !vdev->queue
> WARNING: drivers/media/common/videobuf2/videobuf2-v4l2.c:1264 at vb2_video_unregister_device+0x1f8/0x200
> Call Trace:
> em28xx_v4l2_init+0x1c39/0x3150 drivers/media/usb/em28xx/em28xx-video.c:3085
>
> As documented in vb2_video_unregister_device(), video_unregister_device()
> should be used instead when vdev->queue is NULL.
>
> Revert to calling video_unregister_device() for v4l2->radio_dev in both
> em28xx_v4l2_fini() and the em28xx_v4l2_init() error unwind path.
Good catch!
This is actually a fix for the 7.3-rcX mainline.
I'll handle this.
Regards,
Hans
>
> Fixes: 7c8bf63b7937 ("media: em28xx: use vb2_video_unregister_device")
> Reported-by: syzbot+f26bc23e42eeb548dee1@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=f26bc23e42eeb548dee1
> Signed-off-by: Rohinthan P <rokinthanp03@gmail.com>
> ---
> drivers/media/usb/em28xx/em28xx-video.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c
> index c418add..79af154 100644
> --- a/drivers/media/usb/em28xx/em28xx-video.c
> +++ b/drivers/media/usb/em28xx/em28xx-video.c
> @@ -2416,7 +2416,7 @@ static int em28xx_v4l2_fini(struct em28xx *dev)
> if (video_is_registered(&v4l2->radio_dev)) {
> dev_info(&dev->intf->dev, "V4L2 device %s deregistered\n",
> video_device_node_name(&v4l2->radio_dev));
> - vb2_video_unregister_device(&v4l2->radio_dev);
> + video_unregister_device(&v4l2->radio_dev);
> }
> if (video_is_registered(&v4l2->vbi_dev)) {
> dev_info(&dev->intf->dev, "V4L2 device %s deregistered\n",
> @@ -3082,7 +3082,7 @@ static int em28xx_v4l2_init(struct em28xx *dev)
> dev_info(&dev->intf->dev,
> "V4L2 device %s deregistered\n",
> video_device_node_name(&v4l2->radio_dev));
> - vb2_video_unregister_device(&v4l2->radio_dev);
> + video_unregister_device(&v4l2->radio_dev);
> }
> if (video_is_registered(&v4l2->vbi_dev)) {
> dev_info(&dev->intf->dev,
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-09-23 12:12 UTC | newest]
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2026-09-23 7:20 [PATCH] media: em28xx: use video_unregister_device for radio_dev Rohinthan P
2026-09-23 12:12 ` Hans Verkuil
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