Re: Leaked net-device reference in eql.c

[Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>]

On 8/27/05, Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> wrote:
> On 8/27/05, Ben Greear <greearb@candelatech.com> wrote:
> > Patrick McHardy wrote:
> > > Ben Greear wrote:
> > >
> > >> I think the eql_s_slave_cfg method in eql.c leaks
> > >> the reference to slave_dev.  Am I missing something?
> > >
> > >
> > > No, it should also put the device, as in eql_g_slave_cfg.
> >
> > Ok, I'm making a patch...will add this to it.
> >
> > How about this one.  It seems like it does a dev_put when it shouldn't
> > (if some of the if's fail, the dev_get never happened):
> >
> > net/sched/sch_generic.c
> >
> > static void dev_watchdog(unsigned long arg)
> > {
> >         struct net_device *dev = (struct net_device *)arg;
> >
> >         spin_lock(&dev->xmit_lock);
> >         if (dev->qdisc != &noop_qdisc) {
> >                 if (netif_device_present(dev) &&
> >                     netif_running(dev) &&
> >                     netif_carrier_ok(dev)) {
> >                         if (netif_queue_stopped(dev) &&
> >                             (jiffies - dev->trans_start) > dev->watchdog_timeo) {
> >                                 printk(KERN_INFO "NETDEV WATCHDOG: %s: transmit timed out\n", dev->name);
> >                                 dev->tx_timeout(dev);
> >                         }
> >                         if (!mod_timer(&dev->watchdog_timer, jiffies + dev->watchdog_timeo))
> >                                 dev_hold(dev);
> >                 }
> >         }
> >         spin_unlock(&dev->xmit_lock);
> >
> >         dev_put(dev);
> > }
> 
> Doesn't look like its a problem, its the classical case where when you
> associate some data structure to a timer you grab a refcount, when the
> timer expires you drop the refcount, and as the code above shows when
> mod_timer is succesfully called it grabs a reference, so the reference
> being dropped above is from the previous timer firing, now its just a matter
> if looking for the first mod_timer, that must be at some other place in
> sched_generic.c, lemme see...

Yup, look at __netdev_watchdog_up :-)

- Arnaldo