diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index e510a33fec76..1b7eed252fe9 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -3099,22 +3099,32 @@ static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
 				   ht_cfreq, ht_oper->primary_chan,
 				   cbss->channel->band);
 			ht_oper = NULL;
+		} else {
+			channel_type = NL80211_CHAN_HT20;
 		}
 	}
 
-	if (ht_oper) {
-		channel_type = NL80211_CHAN_HT20;
+	if (ht_oper && sband->ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) {
+		/*
+		 * cfg80211 already verified that the channel itself can
+		 * be used, but it didn't check that we can do the right
+		 * HT type, so do that here as well. If HT40 isn't allowed
+		 * on this channel, disable 40 MHz operation.
+		 */
 
-		if (sband->ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) {
-			switch (ht_oper->ht_param &
-					IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
-			case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
+		switch (ht_oper->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
+		case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
+			if (cbss->channel->flags & IEEE80211_CHAN_NO_HT40PLUS)
+				ifmgd->flags |= IEEE80211_STA_DISABLE_40MHZ;
+			else
 				channel_type = NL80211_CHAN_HT40PLUS;
-				break;
-			case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
+			break;
+		case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
+			if (cbss->channel->flags & IEEE80211_CHAN_NO_HT40MINUS)
+				ifmgd->flags |= IEEE80211_STA_DISABLE_40MHZ;
+			else
 				channel_type = NL80211_CHAN_HT40MINUS;
-				break;
-			}
+			break;
 		}
 	}