From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tao Ma Subject: [PATCH] ext4: Fix a double free in ext4_register_li_request. Date: Mon, 28 Mar 2011 15:37:37 +0800 Message-ID: <1301297857-3839-1-git-send-email-tm@tao.ma> Cc: stable@kernel.org To: linux-ext4@vger.kernel.org Return-path: Received: from cpoproxy1-pub.bluehost.com ([69.89.21.11]:41763 "HELO outbound-mail-01.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750776Ab1C1Hhv (ORCPT ); Mon, 28 Mar 2011 03:37:51 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Tao Ma In ext4_register_li_request, we malloc a ext4_li_request and inserts it into ext4_li_info->li_request_list. In case of any error later, we free it in the end. But if we have some error in ext4_run_lazyinit_thread, the whole li_request_list will be dropped and freed in it. So we will double free this ext4_li_request. This patch just sets elr to NULL after it is inserted to the list so that the latter kfree won't double free it. Cc: stable@kernel.org Signed-off-by: Tao Ma --- fs/ext4/super.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 22546ad..2d1378f 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2975,6 +2975,12 @@ static int ext4_register_li_request(struct super_block *sb, mutex_unlock(&ext4_li_info->li_list_mtx); sbi->s_li_request = elr; + /* + * set elr to NULL here since it has been inserted to + * the request_list and the removal and free of it is + * handled by ext4_clear_request_list from now on. + */ + elr = NULL; if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) { ret = ext4_run_lazyinit_thread(); -- 1.7.4