Re: [Qemu-devel] qemu 2.0.0-rc2 crash

[Cole Robinson]

On 04/10/2014 12:39 PM, Marcel Apfelbaum wrote:
> On Thu, 2014-04-10 at 18:24 +0200, Marcin Gibuła wrote:
>> W dniu 2014-04-10 15:43, Marcel Apfelbaum pisze:
>>> On Thu, 2014-04-10 at 14:55 +0200, Marcin Gibuła wrote:
>>>> Hi,
>>>>
>>>> I've been playing with QEMU 2.0-rc2 and found a crash that isn't there
>>>> in 1.7.1.
>>> Hi Marcin,
>>> Thanks for reporting the bug!
>>>
>>> Do you have a development environment?
>>> If you do, and the reproduction is fast (and you already have a setup),
>>> a git bisect to find the problematic commit would be appreciated,
>>
>> Hi,
>>
>> yes, it's on development environment. If you could point me to some 
>> quick guide to bisecting qemu, I'll be happy to do it.
> 
> Sure! Thanks for helping.
> 
> 1. Start:
>      git bisect start
>      git bisect good <commit hash or tag name of the version that works> (Ex: 
> v1.7.1)
>      git bisect bad <commit hash or tag name of the non working version> (Ex: 
> HEAD)
> 2. Git will checkout commits for you and you have to check and answer:
>      git bisect good or git bisect bad 
> 3. Git will show you the first bad commit.
> 
> A more detailed version here:
> http://git-scm.com/book/en/Git-Tools-Debugging-with-Git
> Look for git-bisect.

Actually I was just independently bisecting this :) Culprit is:

commit 9561fda8d90e176bef598ba87c42a1bd6ad03ef7
Author: Stefan Hajnoczi <address@hidden>
Date:   Wed Mar 19 08:58:55 2014 +0100

    qom: Make QOM link property unref optional

Simple reproducer:

./x86_64-softmmu/qemu-system-x86_64 -qmp unix:./qmp.sock,server

./scripts/qmp/qmp-shell ./qmp.sock
(QEMU) qom-list path=//machine/i440fx/pci.0/child[2]

Seems like trying to qom-list any link property will crash

- Cole