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Re: [Qemu-block] [Qemu-devel] [PATCH 1/9] blockdev: hold AioContext for
From: |
Eric Blake |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH 1/9] blockdev: hold AioContext for bdrv_unref() in external_snapshot_clean() |
Date: |
Tue, 5 Dec 2017 08:36:32 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 |
On 12/05/2017 04:41 AM, Stefan Hajnoczi wrote:
> bdrv_unref() requires the AioContext lock because bdrv_flush() uses
> BDRV_POLL_WHILE(), which assumes the AioContext is currently held. If
> BDRV_POLL_WHILE() runs without AioContext held the
> pthread_mutex_unlock() call in aio_context_release() fails.
>
> This patch moves bdrv_unref() into the AioContext locked region to solve
> the following pthread_mutex_unlock() failure:
>
> #0 0x00007f566181969b in raise () at /lib64/libc.so.6
> #1 0x00007f566181b3b1 in abort () at /lib64/libc.so.6
> #2 0x00005592cd590458 in error_exit (err=<optimized out>, address@hidden
> <__func__.23977> "qemu_mutex_unlock") at util/qemu-thread-posix.c:36
> #3 0x00005592cd96e738 in qemu_mutex_unlock (address@hidden) at
> util/qemu-thread-posix.c:96
> #4 0x00005592cd969b69 in aio_context_release (address@hidden) at
> util/async.c:507
> #5 0x00005592cd8ead78 in bdrv_flush (address@hidden) at block/io.c:2478
> #6 0x00005592cd89df30 in bdrv_close (bs=0x5592cfa87210) at block.c:3207
> #7 0x00005592cd89df30 in bdrv_delete (bs=0x5592cfa87210) at block.c:3395
> #8 0x00005592cd89df30 in bdrv_unref (bs=0x5592cfa87210) at block.c:4418
> #9 0x00005592cd6b7f86 in qmp_transaction (dev_list=<optimized out>,
> has_props=<optimized out>, props=<optimized out>, address@hidden) at
> blockdev.c:2308
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
> blockdev.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Eric Blake <address@hidden>
I know the series is too big/late for 2.11, but is this one patch worth
having?
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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- [Qemu-block] [PATCH 0/9] blockdev: fix QMP 'transaction' with IOThreads, Stefan Hajnoczi, 2017/12/05
- [Qemu-block] [PATCH 1/9] blockdev: hold AioContext for bdrv_unref() in external_snapshot_clean(), Stefan Hajnoczi, 2017/12/05
- Re: [Qemu-block] [Qemu-devel] [PATCH 1/9] blockdev: hold AioContext for bdrv_unref() in external_snapshot_clean(),
Eric Blake <=
- [Qemu-block] [PATCH 2/9] block: don't keep AioContext acquired after external_snapshot_prepare(), Stefan Hajnoczi, 2017/12/05
- [Qemu-block] [PATCH 3/9] block: don't keep AioContext acquired after drive_backup_prepare(), Stefan Hajnoczi, 2017/12/05
- [Qemu-block] [PATCH 4/9] block: don't keep AioContext acquired after blockdev_backup_prepare(), Stefan Hajnoczi, 2017/12/05
- [Qemu-block] [PATCH 5/9] block: don't keep AioContext acquired after internal_snapshot_prepare(), Stefan Hajnoczi, 2017/12/05
- [Qemu-block] [PATCH 6/9] block: drop unused BlockDirtyBitmapState->aio_context field, Stefan Hajnoczi, 2017/12/05
- [Qemu-block] [PATCH 7/9] iothread: add iothread_by_id() API, Stefan Hajnoczi, 2017/12/05
- [Qemu-block] [PATCH 8/9] blockdev: add x-blockdev-set-iothread testing command, Stefan Hajnoczi, 2017/12/05