On Fri, 4 May 2012 20:22:04 +0800, Asias He <asias@xxxxxxxxxx> wrote: > If we reset the virtio-blk device before the requests already dispatched > to the virtio-blk driver from the block layer are finised, we will stuck > in blk_cleanup_queue() and the remove will fail. > > blk_cleanup_queue() calls blk_drain_queue() to drain all requests queued > before DEAD marking. However it will never success if the device is > already stopped. We'll have q->in_flight[] > 0, so the drain will not > finish. > > How to reproduce the race: > 1. hot-plug a virtio-blk device > 2. keep reading/writing the device in guest > 3. hot-unplug while the device is busy serving I/O > > Test: > ~1000 rounds of hot-plug/hot-unplug test passed with this patch. > > Changes in v3: > - Drop blk_abort_queue and blk_abort_request > - Use __blk_end_request_all to complete request dispatched to driver OK, replaced v2 with this one. Thanks, Rusty. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
