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=-7.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 5468EC43461 for ; Fri, 4 Sep 2020 06:50:29 +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 02A47206B8 for ; Fri, 4 Sep 2020 06:50:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 02A47206B8 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 bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4BjSwy6K96zDrNf for ; Fri, 4 Sep 2020 16:50:26 +1000 (AEST) 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 4BjSv25ZSfzDqyG for ; Fri, 4 Sep 2020 16:48:45 +1000 (AEST) 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 B589F1045; Thu, 3 Sep 2020 23:48:41 -0700 (PDT) Received: from [10.163.70.23] (unknown [10.163.70.23]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 575CA3F66F; Thu, 3 Sep 2020 23:48:38 -0700 (PDT) Subject: Re: [PATCH v4 00/13] mm/debug_vm_pgtable fixes To: "Aneesh Kumar K.V" , linux-mm@kvack.org, akpm@linux-foundation.org References: <20200902114222.181353-1-aneesh.kumar@linux.ibm.com> From: Anshuman Khandual Message-ID: Date: Fri, 4 Sep 2020 12:18:05 +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: <20200902114222.181353-1-aneesh.kumar@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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: "linux-s390@vger.kernel.org" , Vineet Gupta , linux-riscv , "linux-snps-arc@lists.infradead.org" , linuxppc-dev@lists.ozlabs.org, Gerald Schaefer Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 09/02/2020 05:12 PM, Aneesh Kumar K.V wrote: > This patch series includes fixes for debug_vm_pgtable test code so that > they follow page table updates rules correctly. The first two patches introduce > changes w.r.t ppc64. The patches are included in this series for completeness. We can > merge them via ppc64 tree if required. > > Hugetlb test is disabled on ppc64 because that needs larger change to satisfy > page table update rules. > > These tests are broken w.r.t page table update rules and results in kernel > crash as below. > > [ 21.083519] kernel BUG at arch/powerpc/mm/pgtable.c:304! > cpu 0x0: Vector: 700 (Program Check) at [c000000c6d1e76c0] > pc: c00000000009a5ec: assert_pte_locked+0x14c/0x380 > lr: c0000000005eeeec: pte_update+0x11c/0x190 > sp: c000000c6d1e7950 > msr: 8000000002029033 > current = 0xc000000c6d172c80 > paca = 0xc000000003ba0000 irqmask: 0x03 irq_happened: 0x01 > pid = 1, comm = swapper/0 > kernel BUG at arch/powerpc/mm/pgtable.c:304! > [link register ] c0000000005eeeec pte_update+0x11c/0x190 > [c000000c6d1e7950] 0000000000000001 (unreliable) > [c000000c6d1e79b0] c0000000005eee14 pte_update+0x44/0x190 > [c000000c6d1e7a10] c000000001a2ca9c pte_advanced_tests+0x160/0x3d8 > [c000000c6d1e7ab0] c000000001a2d4fc debug_vm_pgtable+0x7e8/0x1338 > [c000000c6d1e7ba0] c0000000000116ec do_one_initcall+0xac/0x5f0 > [c000000c6d1e7c80] c0000000019e4fac kernel_init_freeable+0x4dc/0x5a4 > [c000000c6d1e7db0] c000000000012474 kernel_init+0x24/0x160 > [c000000c6d1e7e20] c00000000000cbd0 ret_from_kernel_thread+0x5c/0x6c > > With DEBUG_VM disabled > > [ 20.530152] BUG: Kernel NULL pointer dereference on read at 0x00000000 > [ 20.530183] Faulting instruction address: 0xc0000000000df330 > cpu 0x33: Vector: 380 (Data SLB Access) at [c000000c6d19f700] > pc: c0000000000df330: memset+0x68/0x104 > lr: c00000000009f6d8: hash__pmdp_huge_get_and_clear+0xe8/0x1b0 > sp: c000000c6d19f990 > msr: 8000000002009033 > dar: 0 > current = 0xc000000c6d177480 > paca = 0xc00000001ec4f400 irqmask: 0x03 irq_happened: 0x01 > pid = 1, comm = swapper/0 > [link register ] c00000000009f6d8 hash__pmdp_huge_get_and_clear+0xe8/0x1b0 > [c000000c6d19f990] c00000000009f748 hash__pmdp_huge_get_and_clear+0x158/0x1b0 (unreliable) > [c000000c6d19fa10] c0000000019ebf30 pmd_advanced_tests+0x1f0/0x378 > [c000000c6d19fab0] c0000000019ed088 debug_vm_pgtable+0x79c/0x1244 > [c000000c6d19fba0] c0000000000116ec do_one_initcall+0xac/0x5f0 > [c000000c6d19fc80] c0000000019a4fac kernel_init_freeable+0x4dc/0x5a4 > [c000000c6d19fdb0] c000000000012474 kernel_init+0x24/0x160 > [c000000c6d19fe20] c00000000000cbd0 ret_from_kernel_thread+0x5c/0x6c > > Changes from v3: > * Address review feedback > * Move page table depost and withdraw patch after adding pmdlock to avoid bisect failure. This version - Builds on x86, arm64, s390, arc, powerpc and riscv (defconfig with DEBUG_VM_PGTABLE) - Runs on arm64 and x86 without any regression, atleast nothing that I have noticed - Will be great if this could get tested on s390, arc, riscv, ppc32 platforms as well + linux-riscv + linux-snps-arc@lists.infradead.org + linux-s390@vger.kernel.org + Gerald Schaefer + Vineet Gupta There is still an open git bisect issue on arm64 platform which ideally should be fixed. - Anshuman