From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752444Ab3FYSdw (ORCPT ); Tue, 25 Jun 2013 14:33:52 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40904 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752252Ab3FYSdp (ORCPT ); Tue, 25 Jun 2013 14:33:45 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Igor Mammedov , Paolo Bonzini Subject: [ 31/95] x86: kvmclock: zero initialize pvclock shared memory area Date: Tue, 25 Jun 2013 11:32:18 -0700 Message-Id: <20130625182157.154126570@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130625182153.605455184@linuxfoundation.org> References: <20130625182153.605455184@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Igor Mammedov commit 07868fc6aaf57847b0f3a3d53086b7556eb83f4a upstream. kernel might hung in pvclock_clocksource_read() due to uninitialized memory might contain odd version value in following cycle: do { version = __pvclock_read_cycles(src, &ret, &flags); } while ((src->version & 1) || version != src->version); if secondary kvmclock is accessed before it's registered with kvm. Clear garbage in pvclock shared memory area right after it's allocated to avoid this issue. Ref: https://bugzilla.kernel.org/show_bug.cgi?id=59521 Signed-off-by: Igor Mammedov [See BZ for analysis. We may want a different fix for 3.11, but this is the safest for now - Paolo] Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/kvmclock.c | 1 + 1 file changed, 1 insertion(+) --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -238,6 +238,7 @@ void __init kvmclock_init(void) if (!mem) return; hv_clock = __va(mem); + memset(hv_clock, 0, size); if (kvm_register_clock("boot clock")) { hv_clock = NULL;