From: Paolo Bonzini <pbonzini@redhat.com>
To: "Radim Krčmář" <rkrcmar@redhat.com>, linux-kernel@vger.kernel.org
Cc: kvm@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>,
Andy Lutomirski <luto@amacapital.net>,
stable@vger.kernel.org
Subject: Re: [PATCH] x86: vdso: fix pvclock races with task migration
Date: Tue, 07 Apr 2015 13:11:13 +0200 [thread overview]
Message-ID: <5523BB51.8090703@redhat.com> (raw)
In-Reply-To: <1428000263-11892-1-git-send-email-rkrcmar@redhat.com>
On 02/04/2015 20:44, Radim Krčmář wrote:
> If we were migrated right after __getcpu, but before reading the
> migration_count, we wouldn't notice that we read TSC of a different
> VCPU, nor that KVM's bug made pvti invalid, as only migration_count
> on source VCPU is increased.
>
> Change vdso instead of updating migration_count on destination.
>
> Fixes: 0a4e6be9ca17 ("x86: kvm: Revert "remove sched notifier for cross-cpu migrations"")
> Cc: stable@vger.kernel.org
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Applying this, but removing the "Fixes" tag because a guest patch cannot
fix a host patch (it can work around it or complement it).
Paolo
next prev parent reply other threads:[~2015-04-07 11:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-02 18:44 [PATCH] x86: vdso: fix pvclock races with task migration Radim Krčmář
2015-04-02 18:59 ` Andy Lutomirski
2015-04-06 20:07 ` Andy Lutomirski
2015-04-06 22:04 ` Paolo Bonzini
2015-04-06 20:57 ` Marcelo Tosatti
2015-04-07 11:11 ` Paolo Bonzini [this message]
2015-04-07 12:47 ` Radim Krčmář
2015-04-07 13:57 ` Paolo Bonzini
2015-04-29 12:07 ` Patch "x86: vdso: fix pvclock races with task migration" has been added to the 4.0-stable tree gregkh
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