From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([140.186.70.92]:39694)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1Rwfpz-0002UY-Oz
	for qemu-devel@nongnu.org; Sun, 12 Feb 2012 15:15:56 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1Rwfpp-0000am-Na
	for qemu-devel@nongnu.org; Sun, 12 Feb 2012 15:15:55 -0500
Received: from mx1.redhat.com ([209.132.183.28]:5783)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <mst@redhat.com>) id 1Rwfpp-0000aY-H2
	for qemu-devel@nongnu.org; Sun, 12 Feb 2012 15:15:45 -0500
Date: Sun, 12 Feb 2012 22:15:48 +0200
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20120212201547.GC4199@redhat.com>
References: <20120212170743.GA3375@redhat.com>
	<20120212173140.GB3375@redhat.com> <4F37F910.5030400@codemonkey.ws>
	<20120212175659.GA4199@redhat.com> <4F381B4D.2000108@codemonkey.ws>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4F381B4D.2000108@codemonkey.ws>
Subject: Re: [Qemu-devel] weird qdev error
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: qemu-devel@nongnu.org

On Sun, Feb 12, 2012 at 02:04:29PM -0600, Anthony Liguori wrote:
> On 02/12/2012 11:57 AM, Michael S. Tsirkin wrote:
> >On Sun, Feb 12, 2012 at 11:38:24AM -0600, Anthony Liguori wrote:
> >>From: Anthony Liguori<aliguori@us.ibm.com>
> >>Date: Sun, 12 Feb 2012 11:36:24 -0600
> >>Subject: [PATCH] device_add: don't add a /peripheral link until init is complete
> >>
> >>Otherwise we end up with a dangling reference which causes qdev_free() to fail.
> >>
> >>Reported-by: Michael Tsirkin<mst@redhat.com>
> >>Signed-off-by: Anthony Liguori<aliguori@us.ibm.com>
> >
> >This handles the option parsing but what about hotplug
> >failures (when bus->hotplug returns an error)?
> 
> Sorry, I don't follow.
> 
> The assert you reported was that object_free() noted a reference
> count of !0 which indicates something else was holding the reference
> to the object.  In this case, it was the child link in /peripheral.
> 
> By delaying creating the link in /peripheral, we eliminate the problem completely.

Th other problem was internal in pci which calls ->hostplug
during initialization. This doesn't seem affected?
But I didn't try, maybe I misundertand.

> BTW, the explicit calls to do_pci_unregister are redundant.
> finalize() will be called during cleanup which means exit() will be
> invoked (which already calls do_pci_unregister).  I'm not sure why
> this isn't failing more aggressively but it looks clearly wrong to
> me.
> 
> Regards,
> 
> Anthony Liguori

Me too. Want to try to drop them?