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

[Dan Carpenter]

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@xxxxxxxxx>
> ---
>  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?

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
>