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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75FC2C433F5 for ; Tue, 26 Apr 2022 12:08:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8E1E76B0073; Tue, 26 Apr 2022 08:08:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 891406B0074; Tue, 26 Apr 2022 08:08:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 759216B0075; Tue, 26 Apr 2022 08:08:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id 63F2B6B0073 for ; Tue, 26 Apr 2022 08:08:18 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 1D38320DE6 for ; Tue, 26 Apr 2022 12:08:18 +0000 (UTC) X-FDA: 79398907476.07.4E4FB6D Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id D997A140045 for ; Tue, 26 Apr 2022 12:08:13 +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=oFju6382BGkZeSCzVjUNRKIZ/1PRe5wDyUSMoe2X2bs=; b=cixsBX/RRpllrTZFRx1hr8Maiv jF26zQymv/PfTCKgTN5mjT82DB8Ld0x3Yp2anTkssEu/bJMNsbpNaQ56kzjKX/dzVoVFowtIvisZm fl5rRr73u46yD7NTvbo/sdJN0pLkGxLdFEFLadtsmrA7b+glmX2Ryh3WM/QzPIeX/6uLV4KF8jsDS LwckdvOcKbqxohtL7SQkd81G91wQhHczN/eEpfCgaYl7K9qQvzt8+j/gXVtSlwDddErTa/DScdztB Dak/2i/zPGSKpjCVgKjE/qjhaZ2YCJuA/CE5Ygdxwa41o4UjMyIYOqT6O3b9aXQw0o6M4NrMqKuYS nvZSyAUw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1njJzE-009c41-AM; Tue, 26 Apr 2022 12:08:08 +0000 Date: Tue, 26 Apr 2022 13:08:08 +0100 From: Matthew Wilcox To: Wan Jiabing Cc: Andrew Morton , Vlastimil Babka , David Howells , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Julia Lawall Subject: Re: [PATCH] mm/filemap: Fix NULL pointer dereference in pagecache_get_page Message-ID: References: <20220426082549.590899-1-wanjiabing@vivo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220426082549.590899-1-wanjiabing@vivo.com> Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="cixsBX/R"; dmarc=none; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: D997A140045 X-Rspam-User: X-Stat-Signature: i17ytsqw96p53s51kr167um754yx5bbd X-HE-Tag: 1650974893-30588 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 Tue, Apr 26, 2022 at 04:25:48PM +0800, Wan Jiabing wrote: > Fix following coccicheck error: > mm/folio-compat.c:128:17-21: ERROR: folio is NULL but dereferenced. > folio = __filemap_get_folio(mapping, index, fgp_flags, gfp); > - if ((fgp_flags & FGP_HEAD) || !folio || xa_is_value(folio)) > + if (!folio) > + return NULL; > + if ((fgp_flags & FGP_HEAD) || xa_is_value(folio)) > return &folio->page; That doesn't dereference the folio. Coccicheck is wrong.