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Re: [Qemu-block] forward of qemu bug regarding random qemu hangs at shut
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-block] forward of qemu bug regarding random qemu hangs at shutdown |
Date: |
Fri, 7 Sep 2018 11:34:02 +0200 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
Am 06.09.2018 um 21:29 hat Christian Borntraeger geschrieben:
> Kevin,
>
> for reference, it seems that his bug report somehow got lost.
> https://bugs.launchpad.net/qemu/+bug/1788582
That looks... interesting. The reproducer doesn't even seem to use a
block device, and the backtrace shows a QEMU that is just sitting in the
main loop waiting for events, not somewhere in the shutdown process
after exiting the main loop where bdrv_drain_all() would be called. I
fail to even come up with a theory about any connection between this and
commit 0f12264e7.
I think we need more information there. Can you set a breakpoint on
bdrv_drain_all_begin() to see where it's even called? When I start a
qemu instance without a block device, the first time this is called is
during shutdown after the mainloop (i.e. after the place where you're
seeing a hang).
Maybe bisect within the commit that seems to cause the bug, by
selectively disabling some hunks in it?
Kevin