Re: [External] Re: [syzbot] [block?] WARNING in blk_mq_start_request

[Bart Van Assche]

On 11/13/23 07:05, Chengming Zhou wrote:
> Ok, I reviewed the code of virtio_queue_rqs(), found the main difference
> is that request won't fail after blk_mq_start_request().
>
> But in null_blk case, the request will fail after blk_mq_start_request(),
> return BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE. If we return these rqs
> back to the block layer core, they will be queued individually once again.
> So caused the warning.

I think it is safe to move the blk_mq_start_request() call under the if-block
that decides whether or not to requeue a request in null_queue_rq()

Thanks,

Bart.