On Tue, Nov 19 2013, Jens Axboe wrote: > On Tue, Nov 19 2013, Dave Chinner wrote: > > Hi Jens, > > > > I was just running xfstests on a 3.13 kernel that has had the block > > layer changed merged into it. generic/269 on XFS is hanging on a 2 > > CPU VM using virtio,cache=none for the block devices under test, > > with many (130+) threads stuck below submit_bio() like this: > > > > Call Trace: > > [<ffffffff81adb1c9>] schedule+0x29/0x70 > > [<ffffffff817833ee>] percpu_ida_alloc+0x16e/0x330 > > [<ffffffff81759bef>] blk_mq_wait_for_tags+0x1f/0x40 > > [<ffffffff81758bee>] blk_mq_alloc_request_pinned+0x4e/0xf0 > > [<ffffffff8175931b>] blk_mq_make_request+0x3bb/0x4a0 > > [<ffffffff8174d2b2>] generic_make_request+0xc2/0x110 > > [<ffffffff8174e40c>] submit_bio+0x6c/0x120 > > > > reads and writes are hung, both data (direct and buffered) and > > metadata. > > > > Some IOs are sitting in io_schedule, waiting for IO completion (both > > buffered and direct IO, both reads and writes) so it looks like IO > > completion has stalled in some manner, too. > > Can I get a recipe to reproduce this? I haven't had any luck so far.
OK, I reproduced it. Looks weird, basically all 64 commands are in flight, but haven't completed. So the next one that comes in just sits there forever. I can't find any sysfs debug entries for virtio, would be nice to inspect its queue as well... -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
