On Thu, 2016-08-25 at 21:26 +0800, Wei Yongjun wrote:
> On 08/25/2016 12:39 AM, Eric Dumazet wrote:
> > From: Eric Dumazet <eduma...@google.com>
> >
> > Should qdisc_alloc() fail, we must release the module refcount
> > we got right before.
> >
> > Fixes: 6da7c8fcbcbd ("qdisc: allow setting default queuing discipline")
> > Signed-off-by: Eric Dumazet <eduma...@google.com>
> > ---
> > net/sched/sch_generic.c | 9 +++++----
> > 1 file changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
> > index e95b67cd5718..657c13362b19 100644
> > --- a/net/sched/sch_generic.c
> > +++ b/net/sched/sch_generic.c
> > @@ -643,18 +643,19 @@ struct Qdisc *qdisc_create_dflt(struct netdev_queue
> > *dev_queue,
> > struct Qdisc *sch;
> >
> > if (!try_module_get(ops->owner))
> > - goto errout;
> > + return NULL;
> >
> > sch = qdisc_alloc(dev_queue, ops);
> > - if (IS_ERR(sch))
> > - goto errout;
> > + if (IS_ERR(sch)) {
> > + module_put(ops->owner);
> > + return NULL;
> > + }
> > sch->parent = parentid;
> >
> > if (!ops->init || ops->init(sch, NULL) == 0)
> > return sch;
> >
> > qdisc_destroy(sch);
>
> ops->init() failed, missing module_put() here.
qdisc_destroy() is doing this for us, we do not want to have a double
module_put()
