Messages in this thread | | | Date | Fri, 14 Feb 2014 18:33:33 +0100 | From | Borislav Petkov <> | Subject | Re: Another preempt folding issue? |
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On Fri, Feb 14, 2014 at 06:02:32PM +0100, Stefan Bader wrote: > Okaaay, I think I did what you asked. So yes, there is sse2 in the cpu info. And > there is a mfence in the disassembly:
Btw, I just realized booting the kernel in the guest was a dumb idea, because, doh, the guest is not baremetal. The only reliable thing we can say is that sse2 is present and that MFENCE alternative replacement works :)
But for simplicity's sake let's just assume the machine can do MFENCE just fine and it gets replaced by the alternatives code.
Besides, if that weren't true, we'd have a whole lot of other problems on those boxes.
> Thinking about it, I guess Peter is quite right saying that I likely > will end on the patch that converted preempt_count to percpu.
Yeah, c2daa3bed53a81171cf8c1a36db798e82b91afe8 et al.
> One thing I likely should do is to reinstall the exact same laptop > with 64bit kernel and userspace... maybe only 64bit kernel first... > and make sure on my side that this does not show up on 64bit, too. I > took the word of reporters for that (and the impression that otherwise > many more people would have complained).
Yeah, that should be a prudent thing to do.
Also, Paolo and I were wondering whether you can trigger this thing without kvm, i.e. virtualization involved... do you have any data on that?
Thanks.
-- Regards/Gruss, Boris.
Sent from a fat crate under my desk. Formatting is fine. --
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