2 files changed, 31 insertions, 0 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index ce7cb1b5d453..d98fac54577b 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2110,6 +2110,17 @@ rate_lowest_index(struct ieee80211_supported_band *sband,
         return 0;
 }
 
+static inline
+bool rate_usable_index_exists(struct ieee80211_supported_band *sband,
+                              struct ieee80211_sta *sta)
+{
+        unsigned int i;
+
+        for (i = 0; i < sband->n_bitrates; i++)
+                if (rate_supported(sta, sband->band, i))
+                        return true;
+        return false;
+}
 
 int ieee80211_rate_control_register(struct rate_control_ops *ops);
 void ieee80211_rate_control_unregister(struct rate_control_ops *ops);
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 60ae086995b1..f3efd4f16e91 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -512,6 +512,7 @@ ieee80211_tx_h_rate_ctrl(struct ieee80211_tx_data *tx)
         int i, len;
         bool inval = false, rts = false, short_preamble = false;
         struct ieee80211_tx_rate_control txrc;
+        u32 sta_flags;
 
         memset(&txrc, 0, sizeof(txrc));
 
@@ -544,7 +545,26 @@ ieee80211_tx_h_rate_ctrl(struct ieee80211_tx_data *tx)
              (tx->sta && test_sta_flags(tx->sta, WLAN_STA_SHORT_PREAMBLE))))
                 txrc.short_preamble = short_preamble = true;
 
+        sta_flags = tx->sta ? get_sta_flags(tx->sta) : 0;
+
+        /*
+         * Lets not bother rate control if we're associated and cannot
+         * talk to the sta. This should not happen.
+         */
+        if (WARN((tx->local->sw_scanning) &&
+                 (sta_flags & WLAN_STA_ASSOC) &&
+                 !rate_usable_index_exists(sband, &tx->sta->sta),
+                 "%s: Dropped data frame as no usable bitrate found while "
+                 "scanning and associated. Target station: "
+                 "%pM on %d GHz band\n",
+                 tx->dev->name, hdr->addr1,
+                 tx->channel->band ? 5 : 2))
+                return TX_DROP;
 
+        /*
+         * If we're associated with the sta at this point we know we can at
+         * least send the frame at the lowest bit rate.
+         */
         rate_control_get_rate(tx->sdata, tx->sta, &txrc);
 
         if (unlikely(info->control.rates[0].idx < 0))