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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,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 1932BC07E95 for ; Tue, 20 Jul 2021 06:41:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 900F661004 for ; Tue, 20 Jul 2021 06:41:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 900F661004 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 262556B00DA; Tue, 20 Jul 2021 02:41:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 212AC6B00DC; Tue, 20 Jul 2021 02:41:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0DAAC6B00DD; Tue, 20 Jul 2021 02:41:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0023.hostedemail.com [216.40.44.23]) by kanga.kvack.org (Postfix) with ESMTP id D66D96B00DA for ; Tue, 20 Jul 2021 02:41:53 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 51649184E6F4F for ; Tue, 20 Jul 2021 06:41:52 +0000 (UTC) X-FDA: 78382020864.07.7C5D1EE Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf30.hostedemail.com (Postfix) with ESMTP id DBE78E001809 for ; Tue, 20 Jul 2021 06:41:49 +0000 (UTC) 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 E75DD1FB; Mon, 19 Jul 2021 23:41:48 -0700 (PDT) Received: from [10.163.66.175] (unknown [10.163.66.175]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4F1CA3F73D; Mon, 19 Jul 2021 23:41:46 -0700 (PDT) Subject: Re: [PATCH v2 01/12] mm/debug_vm_pgtable: Introduce struct pgtable_debug_args To: Gavin Shan , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, akpm@linux-foundation.org, chuhu@redhat.com, shan.gavin@gmail.com References: <20210719054138.198373-1-gshan@redhat.com> <20210719054138.198373-2-gshan@redhat.com> <8d754894-5c21-1287-82b6-7ac3b064af3d@redhat.com> From: Anshuman Khandual Message-ID: Date: Tue, 20 Jul 2021 12:12:35 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <8d754894-5c21-1287-82b6-7ac3b064af3d@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: DBE78E001809 X-Stat-Signature: ganiqkattuap4ckoco9kfzutei81m35j Authentication-Results: imf30.hostedemail.com; dkim=none; spf=pass (imf30.hostedemail.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com; dmarc=pass (policy=none) header.from=arm.com X-HE-Tag: 1626763309-84865 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 7/19/21 6:31 PM, Gavin Shan wrote: >> +=C2=A0=C2=A0=C2=A0 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 has_transparent_hugepage()= ) { >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 page =3D alloc_pages(GFP_K= ERNEL, HPAGE_PMD_ORDER); >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (page) { >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ar= gs->pmd_pfn =3D page_to_pfn(page); >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ar= gs->pte_pfn =3D args->pmd_pfn; >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 re= turn 0; >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 } >> +=C2=A0=C2=A0=C2=A0 } >> + >=20 > As syzbot reported against v1 series, we could allocate pages larger th= an (1 << (MAX_ORDER - 1)) here. > So __GFP_NOWARN is needed here. I will fix it in v3 series. I could find the following build error reported from lkp on V2. mm/debug_vm_pgtable.c:445:8: warning: variable 'pud' set but not used [-W= unused-but-set-variable] Could you please point to the syzbot reported problem on V1 as you have mentioned above. Are there configs where HPAGE_[PMD|PUD]_ORDER is greater than (MAX_ORDER - 1) ? If yes, how adding __GFP_NOWARN solves the problem ?