From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751640AbcBLPwV (ORCPT ); Fri, 12 Feb 2016 10:52:21 -0500 Received: from foss.arm.com ([217.140.101.70]:33854 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751082AbcBLPwT (ORCPT ); Fri, 12 Feb 2016 10:52:19 -0500 Date: Fri, 12 Feb 2016 15:52:22 +0000 From: Will Deacon To: Sebastian Ott Cc: linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, Catalin Marinas , Gerald Schaefer , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, Heiko Carstens , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Paul Mackerras , "Aneesh Kumar K.V" , Benjamin Herrenschmidt , Martin Schwidefsky , "Kirill A. Shutemov" , Andrew Morton , Linus Torvalds , "Kirill A. Shutemov" Subject: Re: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM) Message-ID: <20160212155221.GP25087@arm.com> References: <20160211192223.4b517057@thinkpad> <20160211190942.GA10244@node.shutemov.name> <20160211205702.24f0d17a@thinkpad> <20160212100137.GE25087@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Fri, Feb 12, 2016 at 11:12:34AM +0100, Sebastian Ott wrote: > On Fri, 12 Feb 2016, Will Deacon wrote: > > On Thu, Feb 11, 2016 at 08:57:02PM +0100, Gerald Schaefer wrote: > > > On Thu, 11 Feb 2016 21:09:42 +0200 > > > "Kirill A. Shutemov" wrote: > > > > On Thu, Feb 11, 2016 at 07:22:23PM +0100, Gerald Schaefer wrote: > > > > > Sebastian Ott reported random kernel crashes beginning with v4.5-rc1 and > > > > > he also bisected this to commit 61f5d698 "mm: re-enable THP". Further > > > > > review of the THP rework patches, which cannot be bisected, revealed > > > > > commit fecffad "s390, thp: remove infrastructure for handling splitting PMDs" > > > > > (and also similar commits for other archs). [...] > > Do you have a reliable way to trigger the "random kernel crashes"? We've not > > seen anything reported on arm64, but I don't see why we wouldn't be affected > > by the same bug and it would be good to confirm and validate a fix. > > My testcase was compiling the kernel. Most of the time my test system > didn't survive a single compile run. During bisect I did at least 20 > compile runs to flag a commit as good. I've been building kernels all day with -rc3 on my arm64 box and haven't seen any problems yet.. :/. I'll leave it going over the weekend. Will From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f175.google.com (mail-pf0-f175.google.com [209.85.192.175]) by kanga.kvack.org (Postfix) with ESMTP id 019006B0005 for ; Fri, 12 Feb 2016 10:52:21 -0500 (EST) Received: by mail-pf0-f175.google.com with SMTP id q63so49343151pfb.0 for ; Fri, 12 Feb 2016 07:52:20 -0800 (PST) Received: from foss.arm.com (foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id 66si20675654pfs.142.2016.02.12.07.52.20 for ; Fri, 12 Feb 2016 07:52:20 -0800 (PST) Date: Fri, 12 Feb 2016 15:52:22 +0000 From: Will Deacon Subject: Re: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM) Message-ID: <20160212155221.GP25087@arm.com> References: <20160211192223.4b517057@thinkpad> <20160211190942.GA10244@node.shutemov.name> <20160211205702.24f0d17a@thinkpad> <20160212100137.GE25087@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Sebastian Ott Cc: linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, Catalin Marinas , Gerald Schaefer , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, Heiko Carstens , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Paul Mackerras , "Aneesh Kumar K.V" , Benjamin Herrenschmidt , Martin Schwidefsky , "Kirill A. Shutemov" , Andrew Morton , Linus Torvalds , "Kirill A. Shutemov" On Fri, Feb 12, 2016 at 11:12:34AM +0100, Sebastian Ott wrote: > On Fri, 12 Feb 2016, Will Deacon wrote: > > On Thu, Feb 11, 2016 at 08:57:02PM +0100, Gerald Schaefer wrote: > > > On Thu, 11 Feb 2016 21:09:42 +0200 > > > "Kirill A. Shutemov" wrote: > > > > On Thu, Feb 11, 2016 at 07:22:23PM +0100, Gerald Schaefer wrote: > > > > > Sebastian Ott reported random kernel crashes beginning with v4.5-rc1 and > > > > > he also bisected this to commit 61f5d698 "mm: re-enable THP". Further > > > > > review of the THP rework patches, which cannot be bisected, revealed > > > > > commit fecffad "s390, thp: remove infrastructure for handling splitting PMDs" > > > > > (and also similar commits for other archs). [...] > > Do you have a reliable way to trigger the "random kernel crashes"? We've not > > seen anything reported on arm64, but I don't see why we wouldn't be affected > > by the same bug and it would be good to confirm and validate a fix. > > My testcase was compiling the kernel. Most of the time my test system > didn't survive a single compile run. During bisect I did at least 20 > compile runs to flag a commit as good. I've been building kernels all day with -rc3 on my arm64 box and haven't seen any problems yet.. :/. I'll leave it going over the weekend. Will -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Fri, 12 Feb 2016 15:52:22 +0000 Subject: [BUG] random kernel crashes after THP rework on s390 (maybe also on PowerPC and ARM) In-Reply-To: References: <20160211192223.4b517057@thinkpad> <20160211190942.GA10244@node.shutemov.name> <20160211205702.24f0d17a@thinkpad> <20160212100137.GE25087@arm.com> Message-ID: <20160212155221.GP25087@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Feb 12, 2016 at 11:12:34AM +0100, Sebastian Ott wrote: > On Fri, 12 Feb 2016, Will Deacon wrote: > > On Thu, Feb 11, 2016 at 08:57:02PM +0100, Gerald Schaefer wrote: > > > On Thu, 11 Feb 2016 21:09:42 +0200 > > > "Kirill A. Shutemov" wrote: > > > > On Thu, Feb 11, 2016 at 07:22:23PM +0100, Gerald Schaefer wrote: > > > > > Sebastian Ott reported random kernel crashes beginning with v4.5-rc1 and > > > > > he also bisected this to commit 61f5d698 "mm: re-enable THP". Further > > > > > review of the THP rework patches, which cannot be bisected, revealed > > > > > commit fecffad "s390, thp: remove infrastructure for handling splitting PMDs" > > > > > (and also similar commits for other archs). [...] > > Do you have a reliable way to trigger the "random kernel crashes"? We've not > > seen anything reported on arm64, but I don't see why we wouldn't be affected > > by the same bug and it would be good to confirm and validate a fix. > > My testcase was compiling the kernel. Most of the time my test system > didn't survive a single compile run. During bisect I did at least 20 > compile runs to flag a commit as good. I've been building kernels all day with -rc3 on my arm64 box and haven't seen any problems yet.. :/. I'll leave it going over the weekend. Will