From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933770AbYDQS3x (ORCPT ); Thu, 17 Apr 2008 14:29:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757275AbYDQS3n (ORCPT ); Thu, 17 Apr 2008 14:29:43 -0400 Received: from smtp-out3.tiscali.nl ([195.241.79.178]:51540 "EHLO smtp-out3.tiscali.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757053AbYDQS3m (ORCPT ); Thu, 17 Apr 2008 14:29:42 -0400 Message-ID: <480796FE.2010707@tiscali.nl> Date: Thu, 17 Apr 2008 20:29:18 +0200 From: Roel Kluin <12o3l@tiscali.nl> User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: "Aneesh Kumar K.V" CC: alex@clusterfs.com, sct@redhat.com, akpm@linux-foundation.org, adilger@clusterfs.com, linux-ext4@vger.kernel.org, lkml Subject: [PATCH v2] mballoc: fix hot spins after err_freebuddy and err_freemeta References: <4807762A.9090202@tiscali.nl> <20080417175843.GA7517@skywalker> In-Reply-To: <20080417175843.GA7517@skywalker> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Aneesh Kumar K.V wrote: > The function needs more changes. For ex: > > 2279 if (meta_group_info[j] == NULL) { > 2280 printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n"); > 2281 i--; > 2282 goto err_freebuddy; > 2283 } > > That decrement i--; could result in bad value if i == 0;. Thanks Aneesh, --- Signed-off-by: Roel Kluin <12o3l@tiscali.nl> ext4_mb_init_backend() has a variable i of type ext4_group_t. which is typedefined in include/linux/ext4_fs_i.h:34 to unsigned long. Since unsigned, i >= 0 is always true, so fix hot spins after err_freebuddy and err_freemeta. Also when meta_group_info cannot be allocated prevent a decrement of i when zero. Signed-off-by: Roel Kluin <12o3l@tiscali.nl> --- diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index ef97f19..2c13dca 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2572,8 +2572,13 @@ static int ext4_mb_init_backend(struct super_block *sb) meta_group_info[j] = kzalloc(len, GFP_KERNEL); if (meta_group_info[j] == NULL) { printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n"); - i--; - goto err_freebuddy; + if (i != 0) { + i--; + goto err_freebuddy; + } else { + i = num_meta_group_infos - 1; + goto err_freemeta; + } } desc = ext4_get_group_desc(sb, i, NULL); if (desc == NULL) { @@ -2618,14 +2623,14 @@ static int ext4_mb_init_backend(struct super_block *sb) return 0; err_freebuddy: - while (i >= 0) { + do { kfree(ext4_get_group_info(sb, i)); - i--; - } - i = num_meta_group_infos; + } while (i-- != 0); + i = num_meta_group_infos - 1; err_freemeta: - while (--i >= 0) + do { kfree(sbi->s_group_info[i]); + } while (i-- != 0); iput(sbi->s_buddy_cache); err_freesgi: kfree(sbi->s_group_info);