Re: [Regression x2, 3.13-git] virtio block mq hang, iostat busted onvirtio devices

[Jens Axboe]

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.

-- 
Jens Axboe

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