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 CA962C433B4 for ; Wed, 12 May 2021 03:53:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 46EC06147D for ; Wed, 12 May 2021 03:53:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 46EC06147D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id ADA0A6B0036; Tue, 11 May 2021 23:53:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A8A2B6B006E; Tue, 11 May 2021 23:53:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9535C6B0070; Tue, 11 May 2021 23:53:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0216.hostedemail.com [216.40.44.216]) by kanga.kvack.org (Postfix) with ESMTP id 77F4B6B0036 for ; Tue, 11 May 2021 23:53:31 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 30824181AF5D8 for ; Wed, 12 May 2021 03:53:31 +0000 (UTC) X-FDA: 78131209422.04.E32DFD5 Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) by imf28.hostedemail.com (Postfix) with ESMTP id 06FBD20001D6 for ; Wed, 12 May 2021 03:53:28 +0000 (UTC) Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4Fg16H2mXQzwSTD; Wed, 12 May 2021 11:50:47 +0800 (CST) Received: from [10.174.177.243] (10.174.177.243) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.498.0; Wed, 12 May 2021 11:53:22 +0800 Subject: Re: [PATCH 3/8] mm/debug: Factor PagePoisoned out of __dump_page To: Matthew Wilcox CC: , , , William Kucharski , Vlastimil Babka , "Anshuman Khandual" References: <20210430145549.2662354-1-willy@infradead.org> <20210430145549.2662354-4-willy@infradead.org> <2baf684e-f35d-5c42-fa11-1e061a12a81f@huawei.com> From: Kefeng Wang Message-ID: <83bcb26b-79ae-d47f-81c0-873e07d43f3b@huawei.com> Date: Wed, 12 May 2021 11:53:22 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.243] X-CFilter-Loop: Reflected X-Rspamd-Queue-Id: 06FBD20001D6 Authentication-Results: imf28.hostedemail.com; dkim=none; spf=pass (imf28.hostedemail.com: domain of wangkefeng.wang@huawei.com designates 45.249.212.191 as permitted sender) smtp.mailfrom=wangkefeng.wang@huawei.com; dmarc=pass (policy=none) header.from=huawei.com X-Rspamd-Server: rspam03 X-Stat-Signature: rtrbejhj3qe98xh98rtcih4i61tptkya Received-SPF: none (huawei.com>: No applicable sender policy available) receiver=imf28; identity=mailfrom; envelope-from=""; helo=szxga05-in.huawei.com; client-ip=45.249.212.191 X-HE-DKIM-Result: none/none X-HE-Tag: 1620791608-443650 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 2021/5/12 11:38, Matthew Wilcox wrote: > On Wed, May 12, 2021 at 11:29:06AM +0800, Kefeng Wang wrote: >>> void dump_page(struct page *page, const char *reason) >>> { >>> - __dump_page(page, reason); >>> + if (PagePoisoned(page)) >>> + pr_warn("page:%p is uninitialized and poisoned", page); >>> + else >>> + __dump_page(page); >> >> Hi Matthew, dump_page_owenr() should be called when !PagePoisoned, right? >> >> >>> + if (reason) >>> + pr_warn("page dumped because: %s\n", reason); >>> dump_page_owner(page); >>> } >>> EXPORT_SYMBOL(dump_page); > > dump_page_owner() is called whether the page is Poisoned or not ... > both before and after this patch. Is there a problem with that? struct page_ext *page_ext = lookup_page_ext(page); unsigned long pfn = page_to_pfn(page); struct mem_section *section = __pfn_to_section(pfn); if (!section->page_ext) If page is Poisoned, I guess the section maybe NULL, so section->page_ext may meet NULL pointer dereference, is it possible? > > . >