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From: Olaf Hering <olaf@aepfle.de>
To: xen-devel@lists.xen.org
Subject: migration regression in xen-4.11 and qemu-2.11 and qcow2
Date: Mon, 7 May 2018 17:19:47 +0200	[thread overview]
Message-ID: <20180507151940.GA31926@aepfle.de> (raw)


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I assume OSS test does not test realworld live migration,
therefore the following regression remained unnoticed:

name="hvm"
builder="hvm"
memory=555
vcpus=4
serial="pty"
boot="c"
disk=[ 'qcow2:/nfs/vdisk.qcow2,hda,w', ]
device_model_version="qemu-xen"

xl create -cf hvm.cfg
sleep N
xl migrate hvm $host

On $host the domU becomes unusable, qemu reports:
xen be: qdisk-768: xen be: qdisk-768: error: Failed to get "write" lock

With qemu-2.10 the sender noticed the error somehow, and migration was aborted:
qemu-system-i386: Failed to get "write" lock

With qemu-2.11 the sender thinks everything is alright and the domU is moved.

What I gathered during debugging so far is that somehow qemu on the receiving side locks a region twice:

2018-05-07T09:49:45.810930Z qemu-system-i386: qemu_lock_fcntl: 39 c9 1 F_UNLCK>F_UNLCK 0 Success
2018-05-07T09:49:45.813717Z qemu-system-i386: qemu_lock_fcntl: 39 c9 1 F_RDLCK>F_RDLCK 0 Success
2018-05-07T09:49:45.814591Z qemu-system-i386: qemu_lock_fd_test: 39 c9 1 F_WRLCK>F_RDLCK 0 Success
raw_check_lock_bytes: fcntl on 39 returned -11/0

I do not know how raw_apply_lock_bytes() is supposed to be used. In its current form it does not work.
Anyone else seeing this?

Olaf

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             reply	other threads:[~2018-05-07 15:19 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-07 15:19 Olaf Hering [this message]
2018-05-08 11:31 ` migration regression in xen-4.11 and qemu-2.11 and qcow2 Olaf Hering
2018-05-08 16:40   ` Olaf Hering
2018-05-09 12:23     ` Olaf Hering
2018-05-09 21:08       ` Stefano Stabellini
2018-05-09 21:13         ` Olaf Hering
2018-05-09 21:43           ` Stefano Stabellini
2018-05-10  6:04             ` Olaf Hering
2018-05-10 16:03               ` Stefano Stabellini
2018-05-16 13:13                 ` Olaf Hering
2018-05-10 10:40   ` Anthony PERARD
2018-05-14 14:15     ` Olaf Hering
2018-05-16 14:53     ` Olaf Hering
2018-05-17  6:30       ` Olaf Hering
2018-05-17  9:08         ` Olaf Hering
2018-05-17  8:31 ` Olaf Hering

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