Jens Axboe <axboe@xxxxxxxxx> writes: > On 07/27/2017 08:47 AM, Bart Van Assche wrote: >> On Thu, 2017-07-27 at 08:02 -0600, Jens Axboe wrote: >>> The bug looks like SCSI running the queue inline from IRQ >>> context, that's not a good idea. ... >> >> scsi_run_queue() works fine if no scheduler is configured. Additionally, that >> code predates the introduction of blk-mq I/O schedulers. I think it is >> nontrivial for block driver authors to figure out that a queue has to be run >> from process context if a scheduler has been configured that does not support >> to be run from interrupt context. > > No it doesn't, you could never run the queue from interrupt context with > async == false. So I don't think that's confusing at all, you should > always be aware of the context. > >> How about adding WARN_ON_ONCE(in_interrupt()) to >> blk_mq_start_hw_queue() or replacing the above patch by the following: > > No, I hate having dependencies like that, because they always just catch > one of them. Looks like the IPR path that hits this should just offload > to a workqueue or similar, you don't have to make any scsi_run_queue() > async. OK, so the resolution is "fix it in IPR" ? cheers
