Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752880Ab1FNRNH (ORCPT ); Tue, 14 Jun 2011 13:13:07 -0400 Received: from mga11.intel.com ([192.55.52.93]:14561 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752420Ab1FNRNE convert rfc822-to-8bit (ORCPT ); Tue, 14 Jun 2011 13:13:04 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.65,365,1304319600"; d="scan'208";a="16138089" From: "Luck, Tony" To: Avi Kivity , Borislav Petkov CC: Ingo Molnar , "linux-kernel@vger.kernel.org" , "Huang, Ying" , Hidetoshi Seto Date: Tue, 14 Jun 2011 10:13:02 -0700 Subject: RE: [PATCH 08/10] NOTIFIER: Take over TIF_MCE_NOTIFY and implement task return notifier Thread-Topic: [PATCH 08/10] NOTIFIER: Take over TIF_MCE_NOTIFY and implement task return notifier Thread-Index: AcwqmR3KlRiZ19hVRVWsuUlwzctK3gAHF+lw Message-ID: <987664A83D2D224EAE907B061CE93D5301E7280DF7@orsmsx505.amr.corp.intel.com> References: <4DF5C36A.1040707@redhat.com> <20110613095521.GA26316@aftab> <4DF5F729.4060609@redhat.com> <20110613124003.GA27918@aftab> <4DF606C9.90308@redhat.com> <20110613151208.GA29045@aftab> <4DF63B7A.1030805@redhat.com> <4DF748C2.10009@redhat.com> <20110614133323.GB2830@aftab> <4DF76586.1090308@redhat.com> In-Reply-To: <4DF76586.1090308@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1046 Lines: 21 >Since we can't have nested #MC (due to the IST mechanism resetting %rsp >and clobbering the previous invocation's stack), we have to clear MCIP >outside the #MC handler. And that means irq_work_queue() > >(note that this changes the behaviour from memory corruption to shutdown >state; both suck, but one more than the other). Hmm. We currently clear MCIP inside the handler (at the very end, but still inside). Deferring clearing would make sense - but we'd have to be sure to do so a.s.a.p on all processors. It also would change how we look at the possibility of a process being able to run and re-execute an instruction that causes a machine check. If we defer clearing MCIP this won't just be annoying, it will be fatal (if any cpu hasn't yet got to the work queue to clear MCIP). -Tony -- 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/