[PATCH 5.16 0312/1039] mt76: mt7921: fix possible NULL pointer dereference in mt7921_mac_write_txwi

[Greg Kroah-Hartman]

From: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>

[ Upstream commit ec2ebc1c5a5ce49538fa78108c53eaf722eee908 ]

Fix a possible NULL pointer deference issue in mt7921_mac_write_txwi
routine if vif is NULL.

Fixes: 33920b2bf0483 ("mt76: add support for setting mcast rate")
Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/wireless/mediatek/mt76/mt7921/mac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index db3302b1576a0..321d9f1d3f865 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -903,7 +903,7 @@ void mt7921_mac_write_txwi(struct mt7921_dev *dev, __le32 *txwi,
 		mt7921_mac_write_txwi_80211(dev, txwi, skb, key);
 
 	if (txwi[2] & cpu_to_le32(MT_TXD2_FIX_RATE)) {
-		int rateidx = ffs(vif->bss_conf.basic_rates) - 1;
+		int rateidx = vif ? ffs(vif->bss_conf.basic_rates) - 1 : 0;
 		u16 rate, mode;
 
 		/* hardware won't add HTC for mgmt/ctrl frame */
-- 
2.34.1