Re: [GIT PULL] First batch of KVM changes for 4.1

Andy Lutomirski
2015-04-20T20:28:22Z

On Mon, Apr 20, 2015 at 9:59 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
>
> On 17/04/2015 22:18, Marcelo Tosatti wrote:
>> The bug which this is fixing is very rare, have no memory of a report.
>>
>> In fact, its even difficult to create a synthetic reproducer.
>
> But then why was the task migration notifier even in Jeremy's original
> code for Xen? Was it supposed to work even on non-synchronized TSC?
>
> If that's the case, then it could be reverted indeed; but then why did
> you commit this patch to 4.1? Did you think of something that would
> cause the seqcount-like protocol to fail, and that turned out not to be
> the case later? I was only following the mailing list sparsely in March.

I don't think anyone ever tried that hard to test this stuff. There
was an infinte loop that Firefox was triggering as a KVM guest
somewhat reliably until a couple months ago in the same vdso code. :(

--Andy