On Mon, 28 Mar 2011, Tao Ma wrote:
> From: Tao Ma <boyu.mt@xxxxxxxxxx>
>
> 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@xxxxxxxxxx
> Signed-off-by: Tao Ma <boyu.mt@xxxxxxxxxx>
> ---
> 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();
>
Good catch. Thanks, the patch looks good.
-Lukas
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