From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE3A1C5CFC0 for ; Mon, 18 Jun 2018 12:51:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 716892086A for ; Mon, 18 Jun 2018 12:51:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 716892086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933346AbeFRMvO (ORCPT ); Mon, 18 Jun 2018 08:51:14 -0400 Received: from mail.skyhub.de ([5.9.137.197]:54608 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752765AbeFRMvL (ORCPT ); Mon, 18 Jun 2018 08:51:11 -0400 X-Virus-Scanned: Nedap ESD1 at mail.skyhub.de Received: from mail.skyhub.de ([127.0.0.1]) by localhost (blast.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id zrYsy2geVC7P; Mon, 18 Jun 2018 14:51:09 +0200 (CEST) Received: from zn.tnic (p200300EC2BE29C00329C23FFFEA6A903.dip0.t-ipconnect.de [IPv6:2003:ec:2be2:9c00:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id C64951EC00EE; Mon, 18 Jun 2018 14:51:09 +0200 (CEST) Date: Mon, 18 Jun 2018 14:51:06 +0200 From: Borislav Petkov To: Arnd Bergmann Cc: Tony Luck , Thomas Gleixner , Ingo Molnar , x86@kernel.org, y2038@lists.linaro.org, "H. Peter Anvin" , Yazen Ghannam , linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: mce: always use 64-bit timestamps Message-ID: <20180618125106.GB24921@zn.tnic> References: <20180618100759.1921750-1-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20180618100759.1921750-1-arnd@arndb.de> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 18, 2018 at 12:06:46PM +0200, Arnd Bergmann wrote: > The machine check timestamp uses get_seconds(), which returns an 'unsigned long' > number that might overflow on 32-bit architectures (in the distant future) > and is therefore deprecated. > > The normal replacement would be ktime_get_real_seconds(), but that needs to > use a sequence lock that might cause a deadlock if the mce happens at just > the wrong moment. The __ktime_get_real_seconds() skips that lock and is > safer here, but has a miniscule risk of returning the wrong time when we read > it on a 32-bit architecture at the same time as updating the epoch, i.e. > from before y2106 overflow time to after, or vice versa. > > This seems to be an acceptable risk in this particular case, and is the > same thing we do in kdb. > > Signed-off-by: Arnd Bergmann > --- > arch/x86/kernel/cpu/mcheck/mce.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) Applied, thanks. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.