Re: [PATCH 3/4] xfs: fix double free in xlog_recover_commit_trans

Brian Foster
2014-08-26T12:42:36Z

On Tue, Aug 26, 2014 at 11:21:40AM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> When an error occurs during buffer submission in
> xlog_recover_commit_trans(), we free the trans structure twice. Fix
> it by only freeing the structure in the caller regardless of the
> success or failure of the function.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
> fs/xfs/xfs_log_recover.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
> index 460cf98..23895d5 100644
> --- a/fs/xfs/xfs_log_recover.c
> +++ b/fs/xfs/xfs_log_recover.c
> @@ -3524,8 +3524,6 @@ out:
> if (!list_empty(&done_list))
> list_splice_init(&done_list, &trans->r_itemq);
>
> - xlog_recover_free_trans(trans);
> -
> error2 = xfs_buf_delwri_submit(&buffer_list);
> return error ? error : error2;
> }
> @@ -3571,6 +3569,11 @@ xlog_recovery_process_ophdr(
> if (flags & XLOG_WAS_CONT_TRANS)
> flags &= ~XLOG_CONTINUE_TRANS;
>
> + /*
> + * Callees must not free the trans structure. We own it, so we'll decide
> + * if we need to free it or not based on the operation being done and
> + * it's result.

its

> + */
> switch (flags) {
> /* expected flag values */
> case 0:
> @@ -3582,7 +3585,8 @@ xlog_recovery_process_ophdr(
> break;
> case XLOG_COMMIT_TRANS:
> error = xlog_recover_commit_trans(log, trans, pass);
> - break;
> + xlog_recover_free_trans(trans);
> + return error;
>
> /* unexpected flag values */
> case XLOG_UNMOUNT_TRANS:
> --
> 2.0.0
>
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