From patchwork Tue Dec 4 13:25:45 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tao Ma X-Patchwork-Id: 203628 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 53CD82C008F for ; Wed, 5 Dec 2012 00:26:00 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753165Ab2LDNZ6 (ORCPT ); Tue, 4 Dec 2012 08:25:58 -0500 Received: from oproxy8-pub.bluehost.com ([69.89.22.20]:47923 "HELO oproxy8-pub.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752423Ab2LDNZ6 (ORCPT ); Tue, 4 Dec 2012 08:25:58 -0500 Received: (qmail 15770 invoked by uid 0); 4 Dec 2012 13:25:58 -0000 Received: from unknown (HELO box585.bluehost.com) (66.147.242.185) by oproxy8.bluehost.com with SMTP; 4 Dec 2012 13:25:58 -0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=tao.ma; s=default; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=TvcisTsY1WN98Ysj3Doq+5/KnmmVSiPvEH3aEBP80CE=; b=pA4jWlqOuAn3uoQwc5aIXNG9SMgf6WKqnJqhIdTXdNL+6Q3/Sc8zc5O6kYcJUaOI94gJpxI35UYXnsaq3irCaG5HN5PeB+b5cfdbt657EHNeIpMQ/KwRwmr6B9175E0m; Received: from [124.65.207.217] (port=60926 helo=tma-laptop1.hz.ali.com) by box585.bluehost.com with esmtpsa (TLSv1:CAMELLIA256-SHA:256) (Exim 4.76) (envelope-from ) id 1TfsVY-0005XX-Ca; Tue, 04 Dec 2012 06:25:57 -0700 From: Tao Ma To: dan.carpenter@oracle.com Cc: tytso@mit.edu, linux-ext4@vger.kernel.org Subject: Re: [ext4:dev 40/60] fs/ext4/inode.c:1953 __ext4_journalled_writepage() error: potential NULL dereference 'page_bufs'. Date: Tue, 4 Dec 2012 21:25:45 +0800 Message-Id: <1354627545-2792-1-git-send-email-tm@tao.ma> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <20121204111011.GD22569@mwanda> References: <20121204111011.GD22569@mwanda> X-Identified-User: {1390:box585.bluehost.com:colyli:tao.ma} {sentby:smtp auth 124.65.207.217 authed with tm@tao.ma} Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Hi Dan, Thanks for the report. Can you check whether this patch works for you? Thanks Tao From: Tao Ma Subject: [PATCH] ext4: Fix a build warning in __ext4_journalled_writepage. smatch complains: fs/ext4/inode.c:1953 __ext4_journalled_writepage() error: potential NULL dereference 'page_bufs'. So add the check for it. Reported-by: Dan Carpenter Signed-off-by: Tao Ma --- fs/ext4/inode.c | 5 ++--- 1 files changed, 2 insertions(+), 3 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index dbc5784..431201b 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1956,7 +1956,7 @@ static int __ext4_journalled_writepage(struct page *page, struct buffer_head *page_bufs = NULL; handle_t *handle = NULL; int ret = 0; - int err; + int err = 0; struct buffer_head *inode_bh = NULL; ClearPageChecked(page); @@ -1987,8 +1987,7 @@ static int __ext4_journalled_writepage(struct page *page, ret = ext4_journal_get_write_access(handle, inode_bh); err = ext4_handle_dirty_metadata(handle, inode, inode_bh); - - } else { + } else if (page_bufs) { ret = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL, do_journal_get_write_access);