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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 <boyu.mt@taobao.com>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
This commit is contained in:
Tao Ma 2011-04-04 16:00:49 -04:00 committed by Theodore Ts'o
parent 5b41395fcc
commit 46e4690bbd
1 changed files with 6 additions and 0 deletions
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6
fs/ext4/super.c
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@ -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();