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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 B3A64C433B4 for ; Wed, 12 May 2021 03:15:56 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 24F4461942 for ; Wed, 12 May 2021 03:15:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 24F4461942 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9A55E6B0036; Tue, 11 May 2021 23:15:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9574B6B006E; Tue, 11 May 2021 23:15:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 81D7F6B0070; Tue, 11 May 2021 23:15:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0233.hostedemail.com [216.40.44.233]) by kanga.kvack.org (Postfix) with ESMTP id 65F256B0036 for ; Tue, 11 May 2021 23:15:55 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 2BE48B2A3 for ; Wed, 12 May 2021 03:15:55 +0000 (UTC) X-FDA: 78131114670.27.3A00E26 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf01.hostedemail.com (Postfix) with ESMTP id 840DF500152F for ; Wed, 12 May 2021 03:15:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=b3q1cOi5vzb/fYvgXV1ILp6S0UFGe9AtTSyL/tGSRuc=; b=v7uCNGf4pSOH3gT0X6IjJcmOHy JI9VLLn7NG+T1g8+fnu/w62HMsQbejNHTFcV3+ygfzu/NIIUBqe6ZjZTumpwYMqUv3Zd3eyHxz1vF 3oe+WHrz8qHgArXsllzikF9Gjg1WPqob0mFeHjDAg1/M6LpV/5RfuVLYhcDvBYAhRb2C82QP+zart 52ppKfh4FYvku2hRRvDc0HGfffDtqOO5Etg28OxY6naqBhTZ+pstUX4HYY58nfsM5Mykb9tIIKZpm mO+sJqw9s9OuT1rpXJCxAk/m1Q42eqP99HTHNV7vZGlQofAIjIE1wsAsdligDMqc2/WFXyOOhnZTl io6C0rRw==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lgfLB-007taj-9F; Wed, 12 May 2021 03:15:28 +0000 Date: Wed, 12 May 2021 04:15:17 +0100 From: Matthew Wilcox To: Kefeng Wang Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] mm/debug: Check page poisoned firstly in dump_page() Message-ID: References: <20210512031057.13580-1-wangkefeng.wang@huawei.com> <20210512031057.13580-3-wangkefeng.wang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210512031057.13580-3-wangkefeng.wang@huawei.com> Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=v7uCNGf4; dmarc=none; spf=none (imf01.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Stat-Signature: ssr63qibxf9145g3xdwxwrtg7h7hw9zn X-Rspamd-Queue-Id: 840DF500152F X-Rspamd-Server: rspam02 Received-SPF: none (infradead.org>: No applicable sender policy available) receiver=imf01; identity=mailfrom; envelope-from=""; helo=casper.infradead.org; client-ip=90.155.50.34 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620789351-90134 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 Wed, May 12, 2021 at 11:10:57AM +0800, Kefeng Wang wrote: > If page is poisoned, it will crash when we call some page related > functions, so must check whether the page is poisoned or not firstly. https://lore.kernel.org/linux-mm/20210430145549.2662354-4-willy@infradead.org/ > Fixes: 6197ab984b41 ("mm: improve dump_page() for compound pages") > Signed-off-by: Kefeng Wang > --- > mm/debug.c | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) > > diff --git a/mm/debug.c b/mm/debug.c > index 84cdcd0f7bd3..cf84cd9df527 100644 > --- a/mm/debug.c > +++ b/mm/debug.c > @@ -44,20 +44,19 @@ const struct trace_print_flags vmaflag_names[] = { > > static void __dump_page(struct page *page, const char *reason) > { > - struct page *head = compound_head(page); > + struct page *head = NULL; > struct address_space *mapping; > - bool page_poisoned = PagePoisoned(page); > - bool compound = PageCompound(page); > + bool compound; > /* > * Accessing the pageblock without the zone lock. It could change to > * "isolate" again in the meantime, but since we are just dumping the > * state for debugging, it should be fine to accept a bit of > * inaccuracy here due to racing. > */ > - bool page_cma = is_migrate_cma_page(page); > + bool page_cma; > int mapcount; > char *type = ""; > - > + bool page_poisoned = PagePoisoned(page); > /* > * If struct page is poisoned don't access Page*() functions as that > * leads to recursive loop. Page*() check for poisoned pages, and calls > @@ -68,6 +67,10 @@ static void __dump_page(struct page *page, const char *reason) > goto hex_only; > } > > + head = compound_head(page); > + page_poisoned = PagePoisoned(page); > + page_cma = is_migrate_cma_page(page); > + > if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) { > /* > * Corrupt page, so we cannot call page_mapping. Instead, do a > @@ -178,7 +181,7 @@ static void __dump_page(struct page *page, const char *reason) > print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32, > sizeof(unsigned long), page, > sizeof(struct page), false); > - if (head != page) > + if (head && head != page) > print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32, > sizeof(unsigned long), head, > sizeof(struct page), false); > -- > 2.26.2 > >