Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755333Ab3DVUh4 (ORCPT ); Mon, 22 Apr 2013 16:37:56 -0400 Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:40384 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755238Ab3DVUhy (ORCPT ); Mon, 22 Apr 2013 16:37:54 -0400 Message-ID: <1366663056.8337.7.camel@laptop> Subject: Re: [PATCH v2] NMI: fix NMI period is not correct when cpu frequency changes issue. From: Peter Zijlstra To: "Pan, Zhenjie" Cc: Don Zickus , Stephane Eranian , "paulus@samba.org" , "mingo@redhat.com" , "acme@ghostprotocols.net" , "akpm@linux-foundation.org" , "tglx@linutronix.de" , "Liu, Chuansheng" , "linux-kernel@vger.kernel.org" Date: Mon, 22 Apr 2013 22:37:36 +0200 In-Reply-To: References: <1366285369.19383.19.camel@laptop> <20130418133927.GJ79013@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.2-0ubuntu0.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 783 Lines: 19 On Mon, 2013-04-22 at 00:50 +0000, Pan, Zhenjie wrote: > This make watchdog reset happen before hard lockup detect. Doesn't your watchdog trigger an NMI you can use to print the panic? ISTR some people (hi Don!) spending quite a lot of time to make this work for some other platforms. IIRC those things would fire an NMI at some point and then hard-reset the machine not much later.. the difficulty was detecting this 'unclaimed' nmi and allowing drivers to register for it. NMI_UNKNOWN and unknown_nmi_panic are the result of that. -- 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/