[PATCH] mt76: mt7925: main.c: Avoid possible NULL Pointer Dereference in mt7925_change_vif_links()

[Gax-c]

'mconf = devm_kzalloc()' and 'mlink = devm_kzalloc()' may return NULL.
NULL Pointer Dereference may be triggered in the statement 'mconf->link_id = link_id;' below.
Add a null check for the returned pointer.

Fixes: 69acd6d910b0 ("wifi: mt76: mt7925: add mt7925_change_vif_links")
Signed-off-by: Zichen Xie <zichenxie0106 at gmail.com>
Reported-by: Zichen Xie <zichenxie0106 at gmail.com>
Reported-by: Zijie Zhao <zzjas98 at gmail.com>
Reported-by: Chenyuan Yang <chenyuan0y at gmail.com>
---
 drivers/net/wireless/mediatek/mt76/mt7925/main.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/main.c b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
index 791c8b00e112..ea635169497f 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
@@ -1948,6 +1948,12 @@ mt7925_change_vif_links(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 					     GFP_KERNEL);
 		}
 
+		if (!mconf || !mlink) {
+			err = -ENOMEM;
+			goto free;
+		}
+
+
 		mconfs[link_id] = mconf;
 		mlinks[link_id] = mlink;
 		mconf->link_id = link_id;
-- 
2.25.1