From: Tao Ma Date: Mon, 4 Apr 2011 20:00:49 +0000 (-0400) Subject: ext4: fix a double free in ext4_register_li_request X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=46e4690bbd9a4f8d9e7c4f34e34b48f703ad47e0;p=linux-beck.git ext4: fix a double free in ext4_register_li_request 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. Signed-off-by: Tao Ma Reviewed-by: Lukas Czerner Signed-off-by: "Theodore Ts'o" Cc: stable@kernel.org --- diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 35ff9fef68bd..35bd0206bbb3 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();