linux-kernel - KVM patches applied in weird order in -stable

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Message-ID: <20160913145100.GK3872@codeblueprint.co.uk>
Date:   Tue, 13 Sep 2016 15:51:00 +0100
From:   Matt Fleming <matt@...eblueprint.co.uk>
To:     Greg KH <gregkh@...uxfoundation.org>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     linux-kernel@...r.kernel.org
Subject: KVM patches applied in weird order in -stable

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.