Re: [PATCH 4.19 03/79] RDMA/restrack: Release task struct which was hold by CM_ID object

Greg Kroah-Hartman
2019-09-22T08:30:09Z

On Sat, Sep 21, 2019 at 10:22:10PM +0200, Pavel Machek wrote:
> Hi!
>
> > commit ed7a01fd3fd77f40b4ef2562b966a5decd8928d2 upstream.
> >
> > Tracking CM_ID resource is performed in two stages: creation of cm_id
> > and connecting it to the cma_dev. It is needed because rdma-cm protocol
> > exports two separate user-visible calls rdma_create_id and
> > rdma_accept.
> ...
>
> Mainline says this needs additional fix, fe9bc1644918aa1d, see below.
>
> > --- a/drivers/infiniband/core/restrack.c
> > +++ b/drivers/infiniband/core/restrack.c
> > @@ -209,7 +209,7 @@ void rdma_restrack_del(struct rdma_restr
> > struct ib_device *dev;
> >
> > if (!res->valid)
> > - return;
> > + goto out;
> >
> > dev = res_to_dev(res);
> > if (!dev)
> # return;
>
> This test does return, does it need to go through 'goto out', too? (I
> see it should not happen, but...)
>
> > @@ -222,8 +222,10 @@ void rdma_restrack_del(struct rdma_restr
> > down_write(&dev->res.rwsem);
> > hash_del(&res->node);
> > res->valid = false;
> > + up_write(&dev->res.rwsem);
> > +
> > +out:
> > if (res->task)
> > put_task_struct(res->task);
> > - up_write(&dev->res.rwsem);
> > }
>
> Mainline says res->task = NULL is needed there, see fe9bc1644918aa1d.

Good catch, now queued up, thanks!

greg k-h