Re: [PATCH] drm/virtio: add timeout to virtqueue wait to avoid hung task

From: syzbot

Date: Wed May 13 2026 - 17:41:42 EST


> Hi,
>
> On 5/12/26 11:59, Ryosuke Yasuoka wrote:
>> virtio_gpu_queue_ctrl_sgs() and virtio_gpu_queue_cursor() use
>> wait_event() without timeout when waiting for virtqueue space. If the
>> host device stops processing commands, these waits block indefinitely.
>> Since callers may hold DRM locks, this can make the entire system
>> unresponsive.
>>
>> Replace wait_event() with wait_event_timeout() using a 5-second timeout,
>> consistent with the existing timeout pattern in the driver. On timeout,
>> clean up and return -ENODEV, following the same error path as
>> drm_dev_enter() failure.
>>
>> Reported-by: syzbot+d6dd6f86d3aaf7eebe7406e45c1c6e549453f224@xxxxxxxxxxxxxxxxxxxxxxxxx
>> Closes: https://syzkaller.appspot.com/bug?id=d6dd6f86d3aaf7eebe7406e45c1c6e549453f224
>> Reported-by: syzbot+908bd910da5dd79b88de4cf7baf376cc873a922e@xxxxxxxxxxxxxxxxxxxxxxxxx
>> Closes: https://syzkaller.appspot.com/bug?id=908bd910da5dd79b88de4cf7baf376cc873a922e
>> Signed-off-by: Ryosuke Yasuoka <ryasuoka@xxxxxxxxxx>
>> ---
>> drivers/gpu/drm/virtio/virtgpu_vq.c | 20 ++++++++++++++++++--
>> 1 file changed, 18 insertions(+), 2 deletions(-)
>
> If host stops processing commands, this is a problem on host side. Isn't it?
>
> --
> Best regards,
> Dmitry

I see the command but can't find the corresponding bug.
The email is sent to syzbot+HASH@xxxxxxxxxxxxxxxxxxxxxxxxx address
but the HASH does not correspond to any known bug.
Please double check the address.