From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754809AbYIVSt3 (ORCPT ); Mon, 22 Sep 2008 14:49:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754361AbYIVSsw (ORCPT ); Mon, 22 Sep 2008 14:48:52 -0400 Received: from ug-out-1314.google.com ([66.249.92.173]:1551 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754239AbYIVSsu (ORCPT ); Mon, 22 Sep 2008 14:48:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=UG4Vc36vbIMTrU096IiuNLKpeMlvnSALF/QmotLSy67G1Wga93+By5jIiDFcd+xP+U zHMI1AGd3yZA4d4nnQJdBE0xGrtVZ+M6+4wBlaNsQZRnDWxS//F7pUmO72yMPOA4ivYm iaLgaIfVhcS8jY8Yr9fOWtHAzgujOgFHLNhXQ= Date: Mon, 22 Sep 2008 22:48:54 +0400 From: Cyrill Gorcunov To: Aristeu Rozanski Cc: Ingo Molnar , linux-kernel@vger.kernel.org, dzickus@redhat.com, prarit@redhat.com, vgoyal@redhat.com Subject: Re: [PATCH] NMI watchdog: setup before enabling NMI watchdog Message-ID: <20080922184854.GC22024@localhost> References: <20080922171347.GI16840@redhat.com> <20080922180535.GB22024@localhost> <20080922183504.GN16840@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080922183504.GN16840@redhat.com> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Aristeu Rozanski - Mon, Sep 22, 2008 at 02:35:05PM -0400] | > Hi Aristeu, | > | > thanks for the patch! I may be _absolutely_ wrong but could you | > explain me how we reach this site in traps | > | > --- | > if (!(reason & 0xc0)) { | > if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, | > 2, SIGINT) == NOTIFY_STOP) | > return; | > /* | > * Ok, so this is none of the documented NMI sources, | > * so it must be the NMI watchdog. | > ^^^^ | > */ | > if (nmi_watchdog_tick(regs, reason)) | > return; | > if (!do_nmi_callback(regs, cpu)) | > unknown_nmi_error(reason, regs); | > | > return; | > } | > --- | > | > not having masked APIC registers as NMI entry yet (which is done during | > perfctl initialization)? | actually the comment is a bit misleading. we can get other "undocumented" | NMIs from different sources. Notice that if the nmi_watchdog_tick() doesn't | identifies it as a performance counter generated NMI (if LAPIC based, IOAPIC | always assume that the NMI is for the NMI watchdog), a default NMI callback | will be tried and if it fails, unknown_nmi_error() will be called. The first | case comes to my head is those NMI buttons present on development machines. | | -- | Aristeu | Thanks Aristeu! - Cyrill -