From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DFC84C3F2D7 for ; Thu, 5 Mar 2020 06:24:54 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9ADB0207FD for ; Thu, 5 Mar 2020 06:24:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9ADB0207FD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48Y11w3YkhzDqsh for ; Thu, 5 Mar 2020 17:24:52 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=anshuman.khandual@arm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 48Y10J1NgVzDqh2 for ; Thu, 5 Mar 2020 17:23:25 +1100 (AEDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 17EB71FB; Wed, 4 Mar 2020 22:23:23 -0800 (PST) Received: from [10.163.1.88] (unknown [10.163.1.88]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4D1843F534; Wed, 4 Mar 2020 22:27:09 -0800 (PST) Subject: Re: [PATCH V14] mm/debug: Add tests validating architecture page table helpers To: Christophe Leroy , Qian Cai References: <11F41980-97CF-411F-8120-41287DC1A382@lca.pw> <57a3bc61-bbd5-e251-9621-7bc28f7901a1@arm.com> From: Anshuman Khandual Message-ID: Date: Thu, 5 Mar 2020 11:53:12 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Heiko Carstens , Linux Memory Management List , Paul Mackerras , "H. Peter Anvin" , linux-riscv@lists.infradead.org, Will Deacon , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, the arch/x86 maintainers , Mike Rapoport , Christian Borntraeger , Ingo Molnar , Catalin Marinas , linux-snps-arc@lists.infradead.org, Vasily Gorbik , Borislav Petkov , Paul Walmsley , "Kirill A . Shutemov" , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Vineet Gupta , LKML , Palmer Dabbelt , "Aneesh Kumar K.V" , Andrew Morton , linuxppc-dev Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 03/05/2020 11:13 AM, Christophe Leroy wrote: > > > Le 05/03/2020 à 01:54, Anshuman Khandual a écrit : >> >> >> On 03/04/2020 04:59 PM, Qian Cai wrote: >>> >>> >>>> On Mar 4, 2020, at 1:49 AM, Christophe Leroy wrote: >>>> >>>> AFAIU, you are not taking an interrupt here. You are stuck in the pte_update(), most likely due to nested locks. Try with LOCKDEP ? >>> >>> Not exactly sure what did you mean here, but the kernel has all lockdep enabled and did not flag anything here. >> >> As the patch has been dropped from Linux next (next-20200304) perhaps in >> order to fold back the __pa_symbol() fix [1], so I am planning to respin >> the original patch once more as V15 while adding Qian's signed off by for >> the powerpc part. For now lets enable radix MMU ppc64 along with existing >> ppc32. As PPC_RADIX_MMU depends on PPC_BOOK3S_64, the following change >> should be good enough ? > > I don't think so, even if you have the Radix MMU compiled in, hash MMU is used when Radix is not available or disabled. So until the Hash MMU problem is fixed, you cannot enable it by default. So this implies, that with DEBUG_VM given kernel compiled with Radix MMU will get stuck in soft lock up when forced to use hash MMU in cases where Radix MMU is either not available or is disabled. Hence, we cannot enable that. I will still fold the changes from Qian without enabling ppc64 Radix MMU and respin V15. These new changes dont hurt, build every where and works good on arm64 and x86 platforms. More over we know that they also fix a problem for ppc64 Radix MMU platforms. Hence unless there are some other concerns we should fold them in. > > Christophe >