Re: [RFC v2 2/5] vfio-ccw: Fix memory leak and don't call cp_free in cp_init

Cornelia Huck
2019-07-09T10:06:56Z

On Mon, 8 Jul 2019 16:10:35 -0400
Farhan Ali <alifm@linux.ibm.com> wrote:

> We don't set cp->initialized to true so calling cp_free
> will just return and not do anything.
>
> Also fix a memory leak where we fail to free a ccwchain
> on an error.
>
> Fixes: 812271b910 ("s390/cio: Squash cp_free() and cp_unpin_free()")
> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
> ---
> drivers/s390/cio/vfio_ccw_cp.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)

(...)

> @@ -642,8 +647,6 @@ int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb)
>
> /* Build a ccwchain for the first CCW segment */
> ret = ccwchain_handle_ccw(orb->cmd.cpa, cp);
> - if (ret)
> - cp_free(cp);

Now that I look again: it's a bit odd that we set the bit in all cases,
even if we have an error. We could move that into the !ret branch that
sets ->initialized; but it does not really hurt.

>
> /* It is safe to force: if it was not set but idals used
> * ccwchain_calc_length would have returned an error.

The rest of the patch looks good to me.