From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.92] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1K3bmz-00063T-4G for user-mode-linux-devel@lists.sourceforge.net; Tue, 03 Jun 2008 12:03:21 -0700 Received: from [198.99.130.12] (helo=saraswathi.solana.com) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1K3bmx-0004wK-Hi for user-mode-linux-devel@lists.sourceforge.net; Tue, 03 Jun 2008 12:03:21 -0700 Date: Tue, 3 Jun 2008 15:02:35 -0400 From: Jeff Dike Message-ID: <20080603190235.GA9511@c2.user-mode-linux.org> MIME-Version: 1.0 Content-Disposition: inline Subject: [uml-devel] [PATCH 1/6] UML - Deal with host time going backwards List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: user-mode-linux-devel-bounces@lists.sourceforge.net Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net To: Andrew Morton , LKML , uml-devel Cc: Nix Protection against the host's time going backwards - keep track of the time at the last tick and if it's greater than the current time, keep time stopped until the host catches up. Cc: Nix Signed-off-by: Jeff Dike --- arch/um/os-Linux/time.c | 7 +++++++ 1 file changed, 7 insertions(+) Index: linux-2.6-git/arch/um/os-Linux/time.c =================================================================== --- linux-2.6-git.orig/arch/um/os-Linux/time.c 2008-05-14 10:44:02.000000000 -0400 +++ linux-2.6-git/arch/um/os-Linux/time.c 2008-06-02 15:43:53.000000000 -0400 @@ -106,6 +106,10 @@ static void deliver_alarm(void) unsigned long long this_tick = os_nsecs(); int one_tick = UM_NSEC_PER_SEC / UM_HZ; + /* Protection against the host's time going backwards */ + if ((last_tick != 0) && (this_tick < last_tick)) + this_tick = last_tick; + if (last_tick == 0) last_tick = this_tick - one_tick; @@ -148,6 +152,9 @@ static int after_sleep_interval(struct t start_usecs = usec; start_usecs -= skew / UM_NSEC_PER_USEC; + if (start_usecs < 0) + start_usecs = 0; + tv = ((struct timeval) { .tv_sec = start_usecs / UM_USEC_PER_SEC, .tv_usec = start_usecs % UM_USEC_PER_SEC }); interval = ((struct itimerval) { { 0, usec }, tv }); ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758967AbYFCTFt (ORCPT ); Tue, 3 Jun 2008 15:05:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758668AbYFCTEW (ORCPT ); Tue, 3 Jun 2008 15:04:22 -0400 Received: from saraswathi.solana.com ([198.99.130.12]:58523 "EHLO saraswathi.solana.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758626AbYFCTEV (ORCPT ); Tue, 3 Jun 2008 15:04:21 -0400 Date: Tue, 3 Jun 2008 15:02:35 -0400 From: Jeff Dike To: Andrew Morton , LKML , uml-devel Cc: Nix Subject: [PATCH 1/6] UML - Deal with host time going backwards Message-ID: <20080603190235.GA9511@c2.user-mode-linux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Protection against the host's time going backwards - keep track of the time at the last tick and if it's greater than the current time, keep time stopped until the host catches up. Cc: Nix Signed-off-by: Jeff Dike --- arch/um/os-Linux/time.c | 7 +++++++ 1 file changed, 7 insertions(+) Index: linux-2.6-git/arch/um/os-Linux/time.c =================================================================== --- linux-2.6-git.orig/arch/um/os-Linux/time.c 2008-05-14 10:44:02.000000000 -0400 +++ linux-2.6-git/arch/um/os-Linux/time.c 2008-06-02 15:43:53.000000000 -0400 @@ -106,6 +106,10 @@ static void deliver_alarm(void) unsigned long long this_tick = os_nsecs(); int one_tick = UM_NSEC_PER_SEC / UM_HZ; + /* Protection against the host's time going backwards */ + if ((last_tick != 0) && (this_tick < last_tick)) + this_tick = last_tick; + if (last_tick == 0) last_tick = this_tick - one_tick; @@ -148,6 +152,9 @@ static int after_sleep_interval(struct t start_usecs = usec; start_usecs -= skew / UM_NSEC_PER_USEC; + if (start_usecs < 0) + start_usecs = 0; + tv = ((struct timeval) { .tv_sec = start_usecs / UM_USEC_PER_SEC, .tv_usec = start_usecs % UM_USEC_PER_SEC }); interval = ((struct itimerval) { { 0, usec }, tv });