nl80211: fix locking in nl80211_set_tx_bitrate_mask()

This accesses the wdev's chandef etc., so cannot safely
be used without holding the lock.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20220506102136.06b7205419e6.I2a87c05fbd8bc5e565e84d190d4cfd2e92695a90@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -11666,18 +11666,23 @@ static int nl80211_set_tx_bitrate_mask(struct sk_buff *skb,
 	struct cfg80211_bitrate_mask mask;
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
 	struct net_device *dev = info->user_ptr[1];
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	int err;
 
 	if (!rdev->ops->set_bitrate_mask)
 		return -EOPNOTSUPP;
 
+	wdev_lock(wdev);
 	err = nl80211_parse_tx_bitrate_mask(info, info->attrs,
 					    NL80211_ATTR_TX_RATES, &mask,
 					    dev, true);
 	if (err)
-		return err;
+		goto out;
 
-	return rdev_set_bitrate_mask(rdev, dev, NULL, &mask);
+	err = rdev_set_bitrate_mask(rdev, dev, NULL, &mask);
+out:
+	wdev_unlock(wdev);
+	return err;
 }
 
 static int nl80211_register_mgmt(struct sk_buff *skb, struct genl_info *info)