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From: Gerd Hoffmann <kraxel@redhat.com>
To: uril@redhat.com
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	qemu-devel@nongnu.org, spice-devel <spice-devel@freedesktop.org>
Subject: Re: [Qemu-devel] [Spice-devel] Postcopy+spice crash
Date: Tue, 06 Dec 2016 07:59:30 +0100	[thread overview]
Message-ID: <1481007570.20373.3.camel@redhat.com> (raw)
In-Reply-To: <62f28da2-a81b-e0f8-32b7-6e75f197750b@redhat.com>

  Hi,

> >> On a quick glance I'd blame the guest for sending corrupted commands.
> >> Strange though that it happens on migration only, so there could be
> >> a host issue too.  Or a timing issue triggered by migration.
> >>
> >> Which migration phase?
> >
> > This is the point at which it switches over in postcopy.
> 
> It looks like it's the vmstate (post) load phase of the qxl device on
> destination host.

Dave, can you try "thread apply all bt" so we see the other threads too?
That should show whenever it happens in post_load

> Maybe if you trace qxl device save/load related functions
> on both src and dst hosts you'll see a difference.

qxl keeps references to certain commands (create surface for example) in
qxl device memory, so it can replay them in post_load.  That possibly
doesn't work correctly with postcopy.

cheers,
  Gerd

  reply	other threads:[~2016-12-06  6:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-02 17:44 [Qemu-devel] Postcopy+spice crash Dr. David Alan Gilbert
2016-12-05  8:33 ` Gerd Hoffmann
2016-12-05  9:46   ` Dr. David Alan Gilbert
2016-12-05 12:06     ` [Qemu-devel] [Spice-devel] " Uri Lublin
2016-12-06  6:59       ` Gerd Hoffmann [this message]
2016-12-06 10:53         ` Dr. David Alan Gilbert
2016-12-06 12:37           ` Gerd Hoffmann
2016-12-06 16:47             ` Dr. David Alan Gilbert

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