4 files changed, 22 insertions, 13 deletions

diff --git a/drivers/net/wireless/ath/ath6kl/cfg80211.c b/drivers/net/wireless/ath/ath6kl/cfg80211.c
index 36dc61da8336..fd4c89df67e1 100644
--- a/drivers/net/wireless/ath/ath6kl/cfg80211.c
+++ b/drivers/net/wireless/ath/ath6kl/cfg80211.c
@@ -1109,7 +1109,9 @@ void ath6kl_cfg80211_ch_switch_notify(struct ath6kl_vif *vif, int freq,
                                 (mode == WMI_11G_HT20) ?
                                         NL80211_CHAN_HT20 : NL80211_CHAN_NO_HT);
 
+        mutex_lock(&vif->wdev.mtx);
         cfg80211_ch_switch_notify(vif->ndev, &chandef);
+        mutex_unlock(&vif->wdev.mtx);
 }
 
 static int ath6kl_cfg80211_add_key(struct wiphy *wiphy, struct net_device *ndev,
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 6c2bc329a900..e9abc7b536cd 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4286,7 +4286,8 @@ bool cfg80211_reg_can_beacon(struct wiphy *wiphy,
  * @dev: the device which switched channels
  * @chandef: the new channel definition
  *
- * Acquires wdev_lock, so must only be called from sleepable driver context!
+ * Caller must acquire wdev_lock, therefore must only be called from sleepable
+ * driver context!
  */
 void cfg80211_ch_switch_notify(struct net_device *dev,
                                struct cfg80211_chan_def *chandef);
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 4a5c21ed64d1..1d446ac97ab5 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2988,13 +2988,18 @@ void ieee80211_csa_finalize_work(struct work_struct *work)
         struct ieee80211_local *local = sdata->local;
         int err, changed = 0;
 
+        sdata_lock(sdata);
+        /* AP might have been stopped while waiting for the lock. */
+        if (!sdata->vif.csa_active)
+                goto unlock;
+
         if (!ieee80211_sdata_running(sdata))
-                return;
+                goto unlock;
 
         sdata->radar_required = sdata->csa_radar_required;
         err = ieee80211_vif_change_channel(sdata, &changed);
         if (WARN_ON(err < 0))
-                return;
+                goto unlock;
 
         if (!local->use_chanctx) {
                 local->_oper_chandef = sdata->csa_chandef;
@@ -3003,11 +3008,13 @@ void ieee80211_csa_finalize_work(struct work_struct *work)
 
         ieee80211_bss_info_change_notify(sdata, changed);
 
+        sdata->vif.csa_active = false;
         switch (sdata->vif.type) {
         case NL80211_IFTYPE_AP:
                 err = ieee80211_assign_beacon(sdata, sdata->u.ap.next_beacon);
                 if (err < 0)
-                        return;
+                        goto unlock;
+
                 changed |= err;
                 kfree(sdata->u.ap.next_beacon);
                 sdata->u.ap.next_beacon = NULL;
@@ -3021,20 +3028,22 @@ void ieee80211_csa_finalize_work(struct work_struct *work)
         case NL80211_IFTYPE_MESH_POINT:
                 err = ieee80211_mesh_finish_csa(sdata);
                 if (err < 0)
-                        return;
+                        goto unlock;
                 break;
 #endif
         default:
                 WARN_ON(1);
-                return;
+                goto unlock;
         }
-        sdata->vif.csa_active = false;
 
         ieee80211_wake_queues_by_reason(&sdata->local->hw,
                                         IEEE80211_MAX_QUEUE_MAP,
                                         IEEE80211_QUEUE_STOP_REASON_CSA);
 
         cfg80211_ch_switch_notify(sdata->dev, &sdata->csa_chandef);
+
+unlock:
+        sdata_unlock(sdata);
 }
 
 static int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 398756c226c3..95882a788b5b 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -10821,21 +10821,18 @@ void cfg80211_ch_switch_notify(struct net_device *dev,
         struct wiphy *wiphy = wdev->wiphy;
         struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
 
-        trace_cfg80211_ch_switch_notify(dev, chandef);
+        ASSERT_WDEV_LOCK(wdev);
 
-        wdev_lock(wdev);
+        trace_cfg80211_ch_switch_notify(dev, chandef);
 
         if (WARN_ON(wdev->iftype != NL80211_IFTYPE_AP &&
                     wdev->iftype != NL80211_IFTYPE_P2P_GO &&
                     wdev->iftype != NL80211_IFTYPE_ADHOC &&
                     wdev->iftype != NL80211_IFTYPE_MESH_POINT))
-                goto out;
+                return;
 
         wdev->channel = chandef->chan;
         nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL);
-out:
-        wdev_unlock(wdev);
-        return;
 }
 EXPORT_SYMBOL(cfg80211_ch_switch_notify);