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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Fri, 18 Mar 2016 16:03:03 +0100
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Subject: Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop
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To: Christian Borntraeger <borntraeger@de.ibm.com>, tu bo <tubo@linux.vnet.ibm.com>, Fam Zheng <famz@redhat.com>, qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>, cornelia.huck@de.ibm.com, Stefan Hajnoczi <stefanha@redhat.com>, qemu-block@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>



On 17/03/2016 17:08, Christian Borntraeger wrote:
> Good (or bad?) news is the assert also triggers on F23, it just seems
> to take longer.

I guess good news, because we can rule out the kernel (not that I
believed it was a kernel problem, but the thought is always there in
the background...).

The interaction between ioeventfd and dataplane is too complicated.  I
think if we get rid of the start/stop ioeventfd calls (just set up the
ioeventfd as soon as possible and then only set/clear the handlers)
things would be much simpler.

I'll see if I can produce something based on Conny's patches, which are
already a start.  Today I had a short day so I couldn't play with the
bug; out of curiosity, does the bug reproduce with her work + patch 4
from this series + the reentrancy assertion?

Paolo