From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935296AbaICXmF (ORCPT ); Wed, 3 Sep 2014 19:42:05 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45239 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933350AbaICWF6 (ORCPT ); Wed, 3 Sep 2014 18:05:58 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Theodore Tso Subject: [PATCH 3.10 33/55] ext4: fix BUG_ON in mb_free_blocks() Date: Wed, 3 Sep 2014 15:05:23 -0700 Message-Id: <20140903220459.260506935@linuxfoundation.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: <20140903220453.653576908@linuxfoundation.org> References: <20140903220453.653576908@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit c99d1e6e83b06744c75d9f5e491ed495a7086b7b upstream. If we suffer a block allocation failure (for example due to a memory allocation failure), it's possible that we will call ext4_discard_allocated_blocks() before we've actually allocated any blocks. In that case, fe_len and fe_start in ac->ac_f_ex will still be zero, and this will result in mb_free_blocks(inode, e4b, 0, 0) triggering the BUG_ON on mb_free_blocks(): BUG_ON(last >= (sb->s_blocksize << 3)); Fix this by bailing out of ext4_discard_allocated_blocks() if fs_len is zero. Also fix a missing ext4_mb_unload_buddy() call in ext4_discard_allocated_blocks(). Google-Bug-Id: 16844242 Fixes: 86f0afd463215fc3e58020493482faa4ac3a4d69 Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/mballoc.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1396,6 +1396,8 @@ static void mb_free_blocks(struct inode int last = first + count - 1; struct super_block *sb = e4b->bd_sb; + if (WARN_ON(count == 0)) + return; BUG_ON(last >= (sb->s_blocksize << 3)); assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group)); mb_check_buddy(e4b); @@ -3181,6 +3183,8 @@ static void ext4_discard_allocated_block int err; if (pa == NULL) { + if (ac->ac_f_ex.fe_len == 0) + return; err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b); if (err) { /* @@ -3195,6 +3199,7 @@ static void ext4_discard_allocated_block mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start, ac->ac_f_ex.fe_len); ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group); + ext4_mb_unload_buddy(&e4b); return; } if (pa->pa_type == MB_INODE_PA)