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

Cornelia Huck
2019-07-09T14:19:01Z

On Tue, 9 Jul 2019 10:07:57 -0400
Farhan Ali <alifm@linux.ibm.com> wrote:

> On 07/09/2019 06:06 AM, Cornelia Huck wrote:
> > 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.
>
> By setting the bit, I am assuming you meant cmd.c64?
>
> Yes, it doesn't harm anything but for better code readability you have a
> good point. I will move it into !ret branch in the first patch since I
> think it would be more appropriate there, no?

Yes to all of that :)

>
> >
> >>
> >> /* 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.
> >
> >
>