From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754145AbaETRdc (ORCPT ); Tue, 20 May 2014 13:33:32 -0400 Received: from mail.skyhub.de ([78.46.96.112]:37528 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752704AbaETRda (ORCPT ); Tue, 20 May 2014 13:33:30 -0400 Date: Tue, 20 May 2014 19:33:08 +0200 From: Borislav Petkov To: Chen Yucong Cc: tony.luck@intel.com, ak@linux.intel.com, ying.huang@intel.com, seto.hidetoshi@jp.fujitsu.com, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org Subject: Re: [PATCH v2] x86/mce: Distirbute the clear operation of mces_seen to Per-CPU rather than only monarch CPU Message-ID: <20140520173308.GE16428@pd.tnic> References: <1400551885-13828-1-git-send-email-slaoub@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1400551885-13828-1-git-send-email-slaoub@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 20, 2014 at 10:11:25AM +0800, Chen Yucong wrote: > mces_seen is a Per-CPU variable which should only be accessed by > Per-CPU as possible. So the clear operation of mces_seen should also > be lcoal to Per-CPU rather than monarch CPU. > > Meanwhile, there is also a potential risk that mces_seen will not > be be cleared if a timeout occors in mce_end for monarch CPU. As a > reuslt, the stale value of mces_seen will reappear on the next mce. I don't know how many times I have to tell you this already: if we reach the timeout, we have a much bigger friggin' problem! What you could do instead is make the machine panic in the tolerant==1, i.e., the default case, in mce_timed_out(). Basically, in the case any core is stuck and we reach a timeout, we want to panic the whole box immediately. There's a very little chance we can recover so panic is the only sane thing left to do. Ok? -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --