Messages in this thread | | | Subject | Re: [PATCH] x86/vdso/pvclock: Protect STABLE check with the seqcount | From | Paolo Bonzini <> | Date | Thu, 7 Jan 2016 22:47:47 +0100 |
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On 07/01/2016 22:13, Andy Lutomirski wrote: > I don't understand what you mean. > > In the old code (4.3 and 4.4), the vdso checks STABLE_BIT at the end, > which is correct as long as STABLE_BIT can never change from 0 to 1. > > In the -tip code, it's clearly wrong. > > In the code in this patch, it should be correct regardless of how > STABLE_BIT changes as long as the seqcount works. Given that the > performance cost of doing that is zero, I'd rather keep it that way. > If we're really paranoid, we could move it after the rest of the pvti > reads and add a barrier, but is there really any host on which that > matters?
I agree that your patch is fine.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo
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