Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750885AbVJSMi7 (ORCPT ); Wed, 19 Oct 2005 08:38:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750886AbVJSMi7 (ORCPT ); Wed, 19 Oct 2005 08:38:59 -0400 Received: from tux06.ltc.ic.unicamp.br ([143.106.24.50]:12426 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id S1750881AbVJSMi6 (ORCPT ); Wed, 19 Oct 2005 08:38:58 -0400 Date: Wed, 19 Oct 2005 10:42:24 -0200 To: Andrew Morton Cc: jesper.juhl@gmail.com, ext2-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, adilger@clusterfs.com, viro@parcelfarce.linux.theplanet.co.uk Subject: Re: [PATCH] Test for sb_getblk return value Message-ID: <20051019124224.GB25893@br.ibm.com> References: <20051017132306.GA30328@br.ibm.com> <9a8748490510170710s3971e0c6u2a95fa2cb6ad2c5a@mail.gmail.com> <200510171356.11639.glommer@br.ibm.com> <20051018163201.79730947.akpm@osdl.org> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="tKW2IUtsqtDRztdT" Content-Disposition: inline In-Reply-To: <20051018163201.79730947.akpm@osdl.org> User-Agent: Mutt/1.5.6+20040907i From: glommer@br.ibm.com (Glauber de Oliveira Costa) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3662 Lines: 110 --tKW2IUtsqtDRztdT Content-Type: text/plain; charset=us-ascii Content-Disposition: inline This patch adds tests for the return value of sb_getblk() in the ext2/3 filesystems. In fs/buffer.c it is stated that the getblk() function never fails. However, it does can return NULL in some situations due to I/O errors, which may lead us to NULL pointer dereferences Signed-off-by: Glauber de Oliveira Costa -- ===================================== Glauber de Oliveira Costa IBM Linux Technology Center - Brazil glommer@br.ibm.com ===================================== --tKW2IUtsqtDRztdT Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="patch_getblk_ext3.v4" diff -Naurp linux-2.6.14-rc2-orig/fs/ext2/inode.c linux-2.6.14-rc2-cleanp/fs/ext2/inode.c --- linux-2.6.14-rc2-orig/fs/ext2/inode.c 2005-10-19 02:04:12.000000000 +0000 +++ linux-2.6.14-rc2-cleanp/fs/ext2/inode.c 2005-10-19 12:07:12.000000000 +0000 @@ -440,6 +440,10 @@ static int ext2_alloc_branch(struct inod * the pointer to new one, then send parent to disk. */ bh = sb_getblk(inode->i_sb, parent); + if (!bh) { + err = -EIO; + break; + } lock_buffer(bh); memset(bh->b_data, 0, blocksize); branch[n].bh = bh; diff -Naurp linux-2.6.14-rc2-orig/fs/ext3/inode.c linux-2.6.14-rc2-cleanp/fs/ext3/inode.c --- linux-2.6.14-rc2-orig/fs/ext3/inode.c 2005-10-19 02:04:12.000000000 +0000 +++ linux-2.6.14-rc2-cleanp/fs/ext3/inode.c 2005-10-19 02:03:22.000000000 +0000 @@ -523,7 +523,6 @@ static int ext3_alloc_branch(handle_t *h if (!nr) break; branch[n].key = cpu_to_le32(nr); - keys = n+1; /* * Get buffer_head for parent block, zero it out @@ -531,6 +530,9 @@ static int ext3_alloc_branch(handle_t *h * parent to disk. */ bh = sb_getblk(inode->i_sb, parent); + if (!bh) + break; + keys = n+1; branch[n].bh = bh; lock_buffer(bh); BUFFER_TRACE(bh, "call get_create_access"); @@ -864,6 +866,10 @@ struct buffer_head *ext3_getblk(handle_t if (!*errp && buffer_mapped(&dummy)) { struct buffer_head *bh; bh = sb_getblk(inode->i_sb, dummy.b_blocknr); + if (!bh) { + *errp = -EIO; + return NULL; + } if (buffer_new(&dummy)) { J_ASSERT(create != 0); J_ASSERT(handle != 0); diff -Naurp linux-2.6.14-rc2-orig/fs/ext3/resize.c linux-2.6.14-rc2-cleanp/fs/ext3/resize.c --- linux-2.6.14-rc2-orig/fs/ext3/resize.c 2005-10-19 02:04:12.000000000 +0000 +++ linux-2.6.14-rc2-cleanp/fs/ext3/resize.c 2005-10-19 01:54:47.000000000 +0000 @@ -118,6 +118,8 @@ static struct buffer_head *bclean(handle int err; bh = sb_getblk(sb, blk); + if (!bh) + return ERR_PTR(-EIO); if ((err = ext3_journal_get_write_access(handle, bh))) { brelse(bh); bh = ERR_PTR(err); @@ -202,6 +204,10 @@ static int setup_new_group_blocks(struct ext3_debug("update backup group %#04lx (+%d)\n", block, bit); gdb = sb_getblk(sb, block); + if (!bh) { + err = -EIO; + goto exit_bh; + } if ((err = ext3_journal_get_write_access(handle, gdb))) { brelse(gdb); goto exit_bh; @@ -643,6 +649,10 @@ static void update_backups(struct super_ break; bh = sb_getblk(sb, group * bpg + blk_off); + if (!bh) { + err = -EIO; + break; + } ext3_debug("update metadata backup %#04lx\n", (unsigned long)bh->b_blocknr); if ((err = ext3_journal_get_write_access(handle, bh))) --tKW2IUtsqtDRztdT-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/