On Wed, Aug 23, 2017 at 09:03:04AM +0900, Byungchul Park wrote: > On Tue, Aug 22, 2017 at 09:43:56PM +0000, Bart Van Assche wrote: > The report is talking about the following lockup: > > A work in a worker A task work on exit to user > ------------------ --------------------------- > mutex_lock(&bdev->bd_mutex) > mutext_lock(&bdev->bd_mutex) > blk_execute_rq() > wait_for_completion_io_timeout(&A) > complete(&A) > > Is this impossible? > > To Peterz, > > Anyway I wanted to avoid lockdep reports in the case using a timeout > interface. Do you think it's still worth reporting the kind of lockup? Yes, people might not have expected to hit the timeout on this. They might think timeout means a dead device or something like that. I'd like to heard from the block folks if this was constructed thus on purpose though.
