Re: race between kvm-kmod-3.0 and kvm-kmod-3.3 // was: race condition in qemu-kvm-1.0.1

[Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>]

On 07/05/2012 07:12 AM, Peter Lieven wrote:
> On 07/03/12 15:13, Avi Kivity wrote:
>> On 07/03/2012 04:01 PM, Peter Lieven wrote:
>>> Further output from my testing.
>>>
>>> Working:
>>> Linux 2.6.38 with included kvm module
>>> Linux 3.0.0 with included kvm module
>>>
>>> Not-Working:
>>> Linux 3.2.0 with included kvm module
>>> Linux 2.6.28 with kvm-kmod 3.4
>>> Linux 3.0.0 with kvm-kmod 3.4
>>> Linux 3.2.0 with kvm-kmod 3.4
>>>
>>> I can trigger the race with any of qemu-kvm 0.12.5, 1.0 or 1.0.1.
>>> It might be that the code was introduced somewhere between 3.0.0
>>> and 3.2.0 in the kvm kernel module and that the flaw is not
>>> in qemu-kvm.
>>>
>>> Any hints?
>>>
>> A bisect could tell us where the problem is.
>>
>> To avoid bisecting all of linux, try
>>
>>     git bisect v3.2 v3.0 virt/kvm arch/x86/kvm
> here we go:
> 
> commit ca7d58f375c650cf36900cb1da1ca2cc99b13393
> Author: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
> Date:   Wed Jul 13 14:31:08 2011 +0800
> 
>     KVM: x86: fix broken read emulation spans a page boundary

Ah, i will try to reproduce it and fix it.

Thanks for your work.