On Mon, 2010-11-22 at 14:52 +0200, Luciano Coelho wrote:
> On Thu, 2010-11-18 at 15:19 +0200, juuso.oikarinen@xxxxxxxxx wrote:
> > From: Juuso Oikarinen <juuso.oikarinen@xxxxxxxxx>
> >
> > It is possible that the op_remove_interface function is invoked exactly at
> > the same time has hw recovery is started. In this case it is possible for the
> > interface to be already removed in the op_remove_interface call, which
> > currently leads to a kernel warning and a subsequent kernel crash.
> >
> > Fix this by ignoring the op_remove_interface call if the interface is already
> > down at that point.
> >
> > Signed-off-by: Juuso Oikarinen <juuso.oikarinen@xxxxxxxxx>
> > ---
>
> [...]
>
> > diff --git a/drivers/net/wireless/wl12xx/main.c b/drivers/net/wireless/wl12xx/main.c
> > index 31f0e2f..11b0477 100644
> > --- a/drivers/net/wireless/wl12xx/main.c
> > +++ b/drivers/net/wireless/wl12xx/main.c
> > @@ -1157,10 +1157,16 @@ static void wl1271_op_remove_interface(struct ieee80211_hw *hw,
> > struct wl1271 *wl = hw->priv;
> >
> > mutex_lock(&wl->mutex);
> > - WARN_ON(wl->vif != vif);
> > - __wl1271_op_remove_interface(wl);
> > - mutex_unlock(&wl->mutex);
> > + /*
> > + * wl->vif can be null here if someone shuts down the interface
> > + * just when hardware recovery has been started.
> > + */
> > + if (wl->vif) {
> > + WARN_ON(wl->vif != vif);
> > + __wl1271_op_remove_interface(wl);
> > + }
>
> Should you still remove the interface if the vif you received is wrong?
> Surely, something is totally wrong if you get a different vif, but maybe
> removing the interface here will just confuse things even more?
Dunno if it would be better to remove or leave unremoved - probably does
not matter. If the vif is wrong, there is some serious bug somewhere,
and probably the result is serious instability anyway.
The WARN_ON is there just to validate the assumption the driver makes
about the vif, and this function call. If there is a bug somewhere, or
the assumption somehow changes, the warning will be a clear indication
of it.
-Juuso
>
> > + mutex_unlock(&wl->mutex);
> > cancel_work_sync(&wl->recovery_work);
> > }
> >
>
>
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