Messages in this thread | | | Date | Tue, 13 Sep 2016 16:58:09 +0200 | From | Greg KH <> | Subject | Re: KVM patches applied in weird order in -stable |
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[adding stable@ as this is a stable issue, not a 'normal' issue]
On Tue, Sep 13, 2016 at 03:51:00PM +0100, Matt Fleming wrote: > Folks, > > While hunting down a performance issue involving KVM I was surprised > to see "native_set_debugreg()" as the first entry in `perf top`. > > Digging deeper, it looks as though the following patches were applied > in the wrong order in -stable. This is the order as they appear in > Linus' tree, > > [0] commit 4e422bdd2f84 ("KVM: x86: fix missed hardware breakpoints") > [1] commit 172b2386ed16 ("KVM: x86: fix missed hardware breakpoints") > [2] commit 70e4da7a8ff6 ("KVM: x86: fix root cause for missed hardware breakpoints") > > but this is the order for linux-4.4.y > > [1] commit fc90441e728a ("KVM: x86: fix missed hardware breakpoints") > [2] commit 25e8618619a5 ("KVM: x86: fix root cause for missed hardware breakpoints") > [0] commit 0f6e5e26e68f ("KVM: x86: fix missed hardware breakpoints") > > The upshot is that KVM_DEBUGREG_RELOAD is always set when returning > from kvm_arch_vcpu_load() in stable, but not in Linus' tree.
How would applying these in a different order cause breakage?
And if this is a problem, can you please send me a patch to fix it up?
thanks,
greg k-h
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