[PATCH] wifi: mt76: mt7996: prevent uninit return in mt7996_mac_sta_add_links

[Lorenzo Bianconi]

> On Thu, Mar 20, 2025 at 08:19:14PM +0000, Qasim Ijaz wrote:
> > If link_conf_dereference_protected() or mt7996_vif_link() 
> > or link_sta_dereference_protected() fail the code jumps to
> > the error_unlink label and returns ret which is uninitialised.
> > 
> > Fix this by setting err before jumping to error_unlink.
> > 
> > Fixes: c7e4fc362443 ("wifi: mt76: mt7996: Update mt7996_mcu_add_sta to MLO support")
> > Fixes: dd82a9e02c05 ("wifi: mt76: mt7996: Rely on mt7996_sta_link in sta_add/sta_remove callbacks")
> > Signed-off-by: Qasim Ijaz <qasdev00 at gmail.com>
> > ---
> >  drivers/net/wireless/mediatek/mt76/mt7996/main.c | 12 +++++++++---
> >  1 file changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > index 91c64e3a0860..78f7f1fc867e 100644
> > --- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > +++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
> > @@ -998,16 +998,22 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
> >  			continue;
> 
> What about if the list is empty or we hit this continue on every link?

we will return 0 and I guess that's fine, agree?

Regards,
Lorenzo

> 
> regards,
> dan carpenter
> 
> >  
> >  		link_conf = link_conf_dereference_protected(vif, link_id);
> > -		if (!link_conf)
> > +		if (!link_conf) {
> > +			err = -EINVAL;
> >  			goto error_unlink;
> > +		}
> >  
> >  		link = mt7996_vif_link(dev, vif, link_id);
> > -		if (!link)
> > +		if (!link) {
> > +			err = -EINVAL;
> >  			goto error_unlink;
> > +		}
> >  
> >  		link_sta = link_sta_dereference_protected(sta, link_id);
> > -		if (!link_sta)
> > +		if (!link_sta) {
> > +			err = -EINVAL
> >  			goto error_unlink;
> > +		}
> >  
> >  		err = mt7996_mac_sta_init_link(dev, link_conf, link_sta, link,
> >  					       link_id);
> > -- 
> > 2.39.5
> > 
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