Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753310AbbLJGg0 (ORCPT ); Thu, 10 Dec 2015 01:36:26 -0500 Received: from mail7.hitachi.co.jp ([133.145.228.42]:49420 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752757AbbLJGgZ (ORCPT ); Thu, 10 Dec 2015 01:36:25 -0500 From: =?utf-8?B?5rKz5ZCI6Iux5a6PIC8gS0FXQUnvvIxISURFSElSTw==?= To: Steven Rostedt CC: "kbuild-all@01.org" , Jonathan Corbet , Peter Zijlstra , Ingo Molnar , "Eric W. Biederman" , "H. Peter Anvin" , Andrew Morton , Thomas Gleixner , Vivek Goyal , Baoquan He , "linux-doc@vger.kernel.org" , "x86@kernel.org" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Michal Hocko , Ingo Molnar , Borislav Petkov , =?utf-8?B?5bmz5p2+6ZuF5bezIC8gSElSQU1BVFXvvIxNQVNBTUk=?= Subject: RE: Re: [V6 PATCH 5/6] x86/nmi: Fix to save registers for crash dump on external NMI broadcast Thread-Topic: [!]Re: [V6 PATCH 5/6] x86/nmi: Fix to save registers for crash dump on external NMI broadcast Thread-Index: AQHRMv7Cs81ecU15WEqH+7twDtG0a57DvZfA Date: Thu, 10 Dec 2015 06:36:20 +0000 Message-ID: <04EAB7311EE43145B2D3536183D1A84454A4EA10@GSjpTKYDCembx31.service.hitachi.net> References: <20151210014634.25437.217.stgit@softrs> <201512101102.6UNkKzbX%fengguang.wu@intel.com> In-Reply-To: <201512101102.6UNkKzbX%fengguang.wu@intel.com> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.198.219.30] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id tBA6aVrq031606 Content-Length: 2017 Lines: 49 Hi Steven, > From: Steven Rostedt [mailto:rostedt@goodmis.org] > On Tue, Nov 24, 2015 at 11:48:53AM +0100, Borislav Petkov wrote: > > > + */ > > > + while (!raw_spin_trylock(&nmi_reason_lock)) > > > + poll_crash_ipi_and_callback(regs); > > > > Waaait a minute: so if we're getting NMIs broadcasted on every core but > > we're *not* crash dumping, we will run into here too. This can't be > > right. :-\ > > This only does something if crash_ipi_done is set, which means you are killing > the box. But perhaps a comment that states that here would be useful, or maybe > just put in the check here. There's no need to make it depend on SMP, as > raw_spin_trylock() will turn to just ({1}) for UP, and that code wont even be > hit. It seems that poll_crash_ipi_and_callback (now renamed to run_crash_ipi_callback) is referred for UP if CONFIG_DEBUG_SPINLOCK=y, and it causes a build error as below. run_crash_ipi_callback refers crash_ipi_issued and crash_nmi_callback, which are defined only if CONFIG_SMP=y. So we need to defined it separately for SMP and UP. I'll resend this patch later. > Hi Hidehiro, > > [auto build test ERROR on v4.4-rc4] > [also build test ERROR on next-20151209] > [cannot apply to tip/x86/core] > > url: > https://github.com/0day-ci/linux/commits/Hidehiro-Kawai/Fix-race-issues-among-panic-NMI-and-crash_kexec/20151210-095 > 254 > config: x86_64-randconfig-s4-12101030 (attached as .config) > reproduce: > # save the attached .config to linux build tree > make ARCH=x86_64 > > All errors (new ones prefixed by >>): > > arch/x86/built-in.o: In function `do_nmi': > >> (.text+0x7339): undefined reference to `run_crash_ipi_callback' > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?