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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
In-Reply-To: <20140903104121.GF28095@stefanha-thinkpad.redhat.com>
References: <5405C24D.4000304@ilande.co.uk>
	<20140903104121.GF28095@stefanha-thinkpad.redhat.com>
Date: Wed, 03 Sep 2014 12:38:41 -0500
Message-ID: <871trsfvtq.fsf@linux.vnet.ibm.com>
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Subject: Re: [Qemu-devel] qemu-system-sparc64 hang (possibly virtio
	related?) with 2.1
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To: Stefan Hajnoczi <stefanha@gmail.com>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, Alexey Kardashevskiy <aik@ozlabs.ru>, Alexander Graf <agraf@suse.de>
Cc: Waldemar Brodkorb <mail@waldemar-brodkorb.de>, qemu-devel <qemu-devel@nongnu.org>

Stefan Hajnoczi <stefanha@gmail.com> writes:

> On Tue, Sep 02, 2014 at 02:12:45PM +0100, Mark Cave-Ayland wrote:
>> Fortunately I can reproduce the issue with a debug-enabled build of
>> qemu-system-sparc64, and I've posted a backtrace obtained during the hung
>> state at http://www.ilande.co.uk/tmp/sparc64-gdb-bt.txt. I can't see
>> anything too obvious, other than that the ppoll() could possibly be waiting
>> for a bad file descriptor?
>
> The backtrace looks like a normal QEMU run.  Nothing obvious there.
>
> This suggests the QEMU monitor is still operational and the guest is
> still executing code.
>
> Does the I/O time out inside the guest?  Normally messages are printed
> in dmesg if I/O requests are pending for too long.

I am also finding this on ppc64. The system hang even with virtio-9p, so
it may not be virtio blk related. git bisect is complicated because few
commits in between cause other boot failures with ppc64.

-aneesh