From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753720AbbICJ6R (ORCPT ); Thu, 3 Sep 2015 05:58:17 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:41011 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751151AbbICJ6Q (ORCPT ); Thu, 3 Sep 2015 05:58:16 -0400 From: Colin King To: Dave Chinner , xfs@oss.sgi.com Cc: linux-kernel@vger.kernel.org Subject: [PATCH] xfs: fix null pointer dereference when mapping is NULL Date: Thu, 3 Sep 2015 10:57:40 +0100 Message-Id: <1441274260-10120-1-git-send-email-colin.king@canonical.com> X-Mailer: git-send-email 2.5.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King xfs_vm_set_page_dirty checks to see if mapping is NULL however before this unlikely check it already dereferenced mapping when initializing inode. Move the inode initialization after the mapping null check to avoid a potential null pointer dereference. Fixes: 22e757a49cf0 ("xfs: don't dirty buffers beyond EOF") Signed-off-by: Colin Ian King --- fs/xfs/xfs_aops.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index c77499b..d15ae85 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -1935,7 +1935,7 @@ xfs_vm_set_page_dirty( struct page *page) { struct address_space *mapping = page->mapping; - struct inode *inode = mapping->host; + struct inode *inode; loff_t end_offset; loff_t offset; int newly_dirty; @@ -1944,6 +1944,7 @@ xfs_vm_set_page_dirty( if (unlikely(!mapping)) return !TestSetPageDirty(page); + inode = mapping->host; end_offset = i_size_read(inode); offset = page_offset(page); -- 2.5.0