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

[Peter Lieven <pl@dlhnet.de>]

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