Re: [PATCH 1/2] xfs: fix memory leak in xfs_dir2_node_removename

Dave Chinner
2013-10-02T20:32:51Z

On Wed, Oct 02, 2013 at 07:51:11AM -0500, Mark Tinguely wrote:
> Fix the leak of kernel memory in xfs_dir2_node_removename()
> when xfs_dir2_leafn_remove() returns an error code.
>
> Found by Coverity in userspace same patch applies there also.
>
> Signed-off-by: Mark Tinguely <tinguely@sgi.com>
> ---
> v2 corrected bad return code as pointed out by Roger Willcocks.
>
> fs/xfs/xfs_dir2_node.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> Index: b/fs/xfs/xfs_dir2_node.c
> ===================================================================
> --- a/fs/xfs/xfs_dir2_node.c
> +++ b/fs/xfs/xfs_dir2_node.c
> @@ -2105,12 +2105,12 @@ xfs_dir2_node_lookup(
> */
> int /* error */
> xfs_dir2_node_removename(
> - xfs_da_args_t *args) /* operation arguments */
> + struct xfs_da_args *args) /* operation arguments */
> {
> - xfs_da_state_blk_t *blk; /* leaf block */
> + struct xfs_da_state_blk *blk; /* leaf block */
> int error; /* error return value */
> int rval; /* operation return value */
> - xfs_da_state_t *state; /* btree cursor */
> + struct xfs_da_state *state; /* btree cursor */
>
> trace_xfs_dir2_node_removename(args);
>
> @@ -2132,9 +2132,10 @@ xfs_dir2_node_removename(
> * Didn't find it, upper layer screwed up.
> */
> if (rval != EEXIST) {
> - xfs_da_state_free(state);
> - return rval;
> + error = rval;
> + goto done;

Can you make this something like "out_free"? We tend to name jump
labels according to the action that needs to be taken, like
"out_unlock", "error_trans_cancel", etc...

Also, this code is now "funky" in how it handles rval. it will do
this:

/*
* Look up the entry we're deleting, set up the cursor.
*/
error = xfs_da3_node_lookup_int(state, &rval);
if (error)
rval = error;
/*
* Didn't find it, upper layer screwed up.
*/
if (rval != EEXIST) {
error = rval;
goto out_free;
}

That's kind funky with the reassignment of rval if there's an error.
Better would be:

/* Look up the entry we're deleting, set up the cursor. */
error = xfs_da3_node_lookup_int(state, &rval);
if (error)
goto out_free;

/* Didn't find it, upper layer screwed up. */
if (rval != EEXIST) {
error = rval;
goto out_free;
}

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com