A handful of fixes:

* a use-after-free fix in rfkill
  * a memory leak fix in the mac80211 TX status path
  * some rate scaling fixes
  * a fix for the often-reported (by syzbot) sleeping
    in atomic issue with mac80211's station removal
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Merge tag 'mac80211-for-net-2020-11-13' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211

Johannes Berg says:

====================
A handful of fixes:
 * a use-after-free fix in rfkill
 * a memory leak fix in the mac80211 TX status path
 * some rate scaling fixes
 * a fix for the often-reported (by syzbot) sleeping
   in atomic issue with mac80211's station removal

* tag 'mac80211-for-net-2020-11-13' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211:
  mac80211: free sta in sta_info_insert_finish() on errors
  mac80211: minstrel: fix tx status processing corner case
  mac80211: minstrel: remove deferred sampling code
  mac80211: fix memory leak on filtered powersave frames
  rfkill: Fix use-after-free in rfkill_resume()
====================

Link: https://lore.kernel.org/r/20201113093421.24025-1-johannes@sipsolutions.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/mac80211/rc80211_minstrel.c

@@ -274,7 +274,7 @@ minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
 	success = !!(info->flags & IEEE80211_TX_STAT_ACK);
 
 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
-		if (ar[i].idx < 0)
+		if (ar[i].idx < 0 || !ar[i].count)
 			break;
 
 		ndx = rix_to_ndx(mi, ar[i].idx);
@@ -287,12 +287,6 @@ minstrel_tx_status(void *priv, struct ieee80211_supported_band *sband,
 			mi->r[ndx].stats.success += success;
 	}
 
-	if ((info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) && (i >= 0))
-		mi->sample_packets++;
-
-	if (mi->sample_deferred > 0)
-		mi->sample_deferred--;
-
 	if (time_after(jiffies, mi->last_stats_update +
 				mp->update_interval / (mp->new_avg ? 2 : 1)))
 		minstrel_update_stats(mp, mi);
@@ -367,7 +361,7 @@ minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
 		return;
 
 	delta = (mi->total_packets * sampling_ratio / 100) -
-			(mi->sample_packets + mi->sample_deferred / 2);
+			mi->sample_packets;
 
 	/* delta < 0: no sampling required */
 	prev_sample = mi->prev_sample;
@@ -376,7 +370,6 @@ minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
 		return;
 
 	if (mi->total_packets >= 10000) {
-		mi->sample_deferred = 0;
 		mi->sample_packets = 0;
 		mi->total_packets = 0;
 	} else if (delta > mi->n_rates * 2) {
@@ -401,19 +394,8 @@ minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
 	 * rate sampling method should be used.
 	 * Respect such rates that are not sampled for 20 interations.
 	 */
-	if (mrr_capable &&
-	    msr->perfect_tx_time > mr->perfect_tx_time &&
-	    msr->stats.sample_skipped < 20) {
-		/* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
-		 * packets that have the sampling rate deferred to the
-		 * second MRR stage. Increase the sample counter only
-		 * if the deferred sample rate was actually used.
-		 * Use the sample_deferred counter to make sure that
-		 * the sampling is not done in large bursts */
-		info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
-		rate++;
-		mi->sample_deferred++;
-	} else {
+	if (msr->perfect_tx_time < mr->perfect_tx_time ||
+	    msr->stats.sample_skipped >= 20) {
 		if (!msr->sample_limit)
 			return;
 
@@ -433,6 +415,7 @@ minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
 
 	rate->idx = mi->r[ndx].rix;
 	rate->count = minstrel_get_retry_count(&mi->r[ndx], info);
+	info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
 }
 
 

net/mac80211/rc80211_minstrel.h

@@ -126,7 +126,6 @@ struct minstrel_sta_info {
 	u8 max_prob_rate;
 	unsigned int total_packets;
 	unsigned int sample_packets;
-	int sample_deferred;
 
 	unsigned int sample_row;
 	unsigned int sample_column;

net/mac80211/sta_info.c

@@ -705,7 +705,7 @@ static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU)
  out_drop_sta:
 	local->num_sta--;
 	synchronize_net();
-	__cleanup_single_sta(sta);
+	cleanup_single_sta(sta);
  out_err:
 	mutex_unlock(&local->sta_mtx);
 	kfree(sinfo);
@@ -724,19 +724,13 @@ int sta_info_insert_rcu(struct sta_info *sta) __acquires(RCU)
 
 	err = sta_info_insert_check(sta);
 	if (err) {
+		sta_info_free(local, sta);
 		mutex_unlock(&local->sta_mtx);
 		rcu_read_lock();
-		goto out_free;
+		return err;
 	}
 
-	err = sta_info_insert_finish(sta);
-	if (err)
-		goto out_free;
-
-	return 0;
- out_free:
-	sta_info_free(local, sta);
-	return err;
+	return sta_info_insert_finish(sta);
 }
 
 int sta_info_insert(struct sta_info *sta)

net/mac80211/status.c

@@ -49,7 +49,8 @@ static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
 	int ac;
 
 	if (info->flags & (IEEE80211_TX_CTL_NO_PS_BUFFER |
-			   IEEE80211_TX_CTL_AMPDU)) {
+			   IEEE80211_TX_CTL_AMPDU |
+			   IEEE80211_TX_CTL_HW_80211_ENCAP)) {
 		ieee80211_free_txskb(&local->hw, skb);
 		return;
 	}
@@ -915,15 +916,6 @@ static void __ieee80211_tx_status(struct ieee80211_hw *hw,
 			ieee80211_mpsp_trigger_process(
 				ieee80211_get_qos_ctl(hdr), sta, true, acked);
 
-		if (!acked && test_sta_flag(sta, WLAN_STA_PS_STA)) {
-			/*
-			 * The STA is in power save mode, so assume
-			 * that this TX packet failed because of that.
-			 */
-			ieee80211_handle_filtered_frame(local, sta, skb);
-			return;
-		}
-
 		if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL) &&
 		    (ieee80211_is_data(hdr->frame_control)) &&
 		    (rates_idx != -1))
@@ -1150,6 +1142,12 @@ void ieee80211_tx_status_ext(struct ieee80211_hw *hw,
 							    -info->status.ack_signal);
 				}
 			} else if (test_sta_flag(sta, WLAN_STA_PS_STA)) {
+				/*
+				 * The STA is in power save mode, so assume
+				 * that this TX packet failed because of that.
+				 */
+				if (skb)
+					ieee80211_handle_filtered_frame(local, sta, skb);
 				return;
 			} else if (noack_success) {
 				/* nothing to do here, do not account as lost */

net/rfkill/core.c

@@ -876,6 +876,9 @@ static int rfkill_resume(struct device *dev)
 
 	rfkill->suspended = false;
 
+	if (!rfkill->registered)
+		return 0;
+
 	if (!rfkill->persistent) {
 		cur = !!(rfkill->state & RFKILL_BLOCK_SW);
 		rfkill_set_block(rfkill, cur);