If there is no rtwsta_link found in rtw89_core_send_nullfunc(), allocated
skb is leaked.  Free it on the error handling path.

Found by Linux Verification Center (linuxtesting.org).

Fixes: a8ba4acab7db ("wifi: rtw89: send nullfunc based on the given link")
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
---
 drivers/net/wireless/realtek/rtw89/core.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw89/core.c b/drivers/net/wireless/realtek/rtw89/core.c
index 28bbc898b95e..e498c08151d5 100644
--- a/drivers/net/wireless/realtek/rtw89/core.c
+++ b/drivers/net/wireless/realtek/rtw89/core.c
@@ -3454,14 +3454,14 @@ int rtw89_core_send_nullfunc(struct rtw89_dev *rtwdev, struct rtw89_vif_link *rt
 	sta = ieee80211_find_sta(vif, vif->cfg.ap_addr);
 	if (!sta) {
 		ret = -EINVAL;
-		goto out;
+		goto out_unlock;
 	}
 	rtwsta = sta_to_rtwsta(sta);
 
 	skb = ieee80211_nullfunc_get(rtwdev->hw, vif, link_id, qos);
 	if (!skb) {
 		ret = -ENOMEM;
-		goto out;
+		goto out_unlock;
 	}
 
 	hdr = (struct ieee80211_hdr *)skb->data;
@@ -3471,22 +3471,23 @@ int rtw89_core_send_nullfunc(struct rtw89_dev *rtwdev, struct rtw89_vif_link *rt
 	rtwsta_link = rtwsta->links[rtwvif_link->link_id];
 	if (unlikely(!rtwsta_link)) {
 		ret = -ENOLINK;
-		goto out;
+		goto out_free_skb;
 	}
 
 	ret = rtw89_core_tx_write_link(rtwdev, rtwvif_link, rtwsta_link, skb, &qsel, true,
 				       wait);
 	if (ret) {
 		rtw89_warn(rtwdev, "nullfunc transmit failed: %d\n", ret);
-		dev_kfree_skb_any(skb);
-		goto out;
+		goto out_free_skb;
 	}
 
 	rcu_read_unlock();
 
 	return rtw89_core_tx_kick_off_and_wait(rtwdev, skb, qsel,
 					       timeout);
-out:
+out_free_skb:
+	dev_kfree_skb_any(skb);
+out_unlock:
 	rcu_read_unlock();
 	kfree(wait);
 
-- 
2.50.1

Fedor Pchelkin <pchelkin@ispras.ru> wrote:
> If there is no rtwsta_link found in rtw89_core_send_nullfunc(), allocated skb is leaked.  Free
> it on the error handling path.
> 
> Found by Linux Verification Center (linuxtesting.org).
> 
> Fixes: a8ba4acab7db ("wifi: rtw89: send nullfunc based on the given link")
> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
> ---
>  drivers/net/wireless/realtek/rtw89/core.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtw89/core.c
> b/drivers/net/wireless/realtek/rtw89/core.c
> index 28bbc898b95e..e498c08151d5 100644
> --- a/drivers/net/wireless/realtek/rtw89/core.c
> +++ b/drivers/net/wireless/realtek/rtw89/core.c
> @@ -3454,14 +3454,14 @@ int rtw89_core_send_nullfunc(struct rtw89_dev *rtwdev, struct
> rtw89_vif_link *rt
>         sta = ieee80211_find_sta(vif, vif->cfg.ap_addr);
>         if (!sta) {
>                 ret = -EINVAL;
> -               goto out;
> +               goto out_unlock;
>         }
>         rtwsta = sta_to_rtwsta(sta);
> 
>         skb = ieee80211_nullfunc_get(rtwdev->hw, vif, link_id, qos);
>         if (!skb) {
>                 ret = -ENOMEM;
> -               goto out;
> +               goto out_unlock;
>         }
> 
>         hdr = (struct ieee80211_hdr *)skb->data; @@ -3471,22 +3471,23 @@ int
> rtw89_core_send_nullfunc(struct rtw89_dev *rtwdev, struct rtw89_vif_link *rt
>         rtwsta_link = rtwsta->links[rtwvif_link->link_id];
>         if (unlikely(!rtwsta_link)) {
>                 ret = -ENOLINK;
> -               goto out;
> +               goto out_free_skb;
>         }

How about just adding dev_kfree_skb_any(skb) here ?

> 
>         ret = rtw89_core_tx_write_link(rtwdev, rtwvif_link, rtwsta_link, skb, &qsel, true,
>                                        wait);
>         if (ret) {
>                 rtw89_warn(rtwdev, "nullfunc transmit failed: %d\n", ret);
> -               dev_kfree_skb_any(skb);
> -               goto out;
> +               goto out_free_skb;
>         }
> 
>         rcu_read_unlock();
> 
>         return rtw89_core_tx_kick_off_and_wait(rtwdev, skb, qsel,
>                                                timeout);
> -out:
> +out_free_skb:
> +       dev_kfree_skb_any(skb);
> +out_unlock:
>         rcu_read_unlock();
>         kfree(wait);
> 
> --
> 2.50.1
>