Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754490Ab3F1S77 (ORCPT ); Fri, 28 Jun 2013 14:59:59 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:42013 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752851Ab3F1S6t (ORCPT ); Fri, 28 Jun 2013 14:58:49 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Igor Mammedov , Paolo Bonzini , Kamal Mostafa Subject: [PATCH 060/105] x86: kvmclock: zero initialize pvclock shared memory area Date: Fri, 28 Jun 2013 11:51:22 -0700 Message-Id: <1372445527-24414-61-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1372445527-24414-1-git-send-email-kamal@canonical.com> References: <1372445527-24414-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1638 Lines: 51 3.8.13.4 -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: Kamal Mostafa --- arch/x86/kernel/kvmclock.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 5bedbdd..a855a2e 100644 --- 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; -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/