cfg80211: fix potential management registrations deadlock

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index b58ad1a3f695..fc7e8807838d 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -5075,7 +5075,8 @@  struct cfg80211_cqm_config;
  *	by cfg80211 on change_interface
  * @mgmt_registrations: list of registrations for management frames
  * @mgmt_registrations_lock: lock for the list
- * @mgmt_registrations_update_wk: update work to defer from atomic context
+ * @mgmt_registrations_need_update: mgmt registrations were updated,
+ *	need to propagate the update to the driver
  * @mtx: mutex used to lock data in this struct, may be used by drivers
  *	and some API functions require it held
  * @beacon_interval: beacon interval used on this device for transmitting
@@ -5121,7 +5122,7 @@  struct wireless_dev {
 
 	struct list_head mgmt_registrations;
 	spinlock_t mgmt_registrations_lock;
-	struct work_struct mgmt_registrations_update_wk;
+	u8 mgmt_registrations_need_update:1;
 
 	struct mutex mtx;
 
diff --git a/net/wireless/core.c b/net/wireless/core.c
index f0226ae9561c..c623d9bf5096 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -497,6 +497,8 @@  struct wiphy *wiphy_new_nm(const struct cfg80211_ops *ops, int sizeof_priv,
 	INIT_WORK(&rdev->propagate_radar_detect_wk,
 		  cfg80211_propagate_radar_detect_wk);
 	INIT_WORK(&rdev->propagate_cac_done_wk, cfg80211_propagate_cac_done_wk);
+	INIT_WORK(&rdev->mgmt_registrations_update_wk,
+		  cfg80211_mgmt_registrations_update_wk);
 
 #ifdef CONFIG_CFG80211_DEFAULT_PS
 	rdev->wiphy.flags |= WIPHY_FLAG_PS_ON_BY_DEFAULT;
@@ -1047,6 +1049,7 @@  void wiphy_unregister(struct wiphy *wiphy)
 	flush_work(&rdev->sched_scan_stop_wk);
 	flush_work(&rdev->propagate_radar_detect_wk);
 	flush_work(&rdev->propagate_cac_done_wk);
+	flush_work(&rdev->mgmt_registrations_update_wk);
 
 #ifdef CONFIG_PM
 	if (rdev->wiphy.wowlan_config && rdev->ops->set_wakeup)
@@ -1108,7 +1111,6 @@  static void __cfg80211_unregister_wdev(struct wireless_dev *wdev, bool sync)
 	rdev->devlist_generation++;
 
 	cfg80211_mlme_purge_registrations(wdev);
-	flush_work(&wdev->mgmt_registrations_update_wk);
 
 	switch (wdev->iftype) {
 	case NL80211_IFTYPE_P2P_DEVICE:
@@ -1253,8 +1255,6 @@  void cfg80211_init_wdev(struct cfg80211_registered_device *rdev,
 	spin_lock_init(&wdev->event_lock);
 	INIT_LIST_HEAD(&wdev->mgmt_registrations);
 	spin_lock_init(&wdev->mgmt_registrations_lock);
-	INIT_WORK(&wdev->mgmt_registrations_update_wk,
-		  cfg80211_mgmt_registrations_update_wk);
 	INIT_LIST_HEAD(&wdev->pmsr_list);
 	spin_lock_init(&wdev->pmsr_lock);
 	INIT_WORK(&wdev->pmsr_free_wk, cfg80211_pmsr_free_wk);
diff --git a/net/wireless/core.h b/net/wireless/core.h
index e0e5b3ee9699..67b0389fca4d 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -99,6 +99,8 @@  struct cfg80211_registered_device {
 	struct cfg80211_chan_def cac_done_chandef;
 	struct work_struct propagate_cac_done_wk;
 
+	struct work_struct mgmt_registrations_update_wk;
+
 	/* must be last because of the way we do wiphy_priv(),
 	 * and it should at least be aligned to NETDEV_ALIGN */
 	struct wiphy wiphy __aligned(NETDEV_ALIGN);
diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
index 189334314cba..a6c61a2e6569 100644
--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -440,9 +440,15 @@  static void cfg80211_mgmt_registrations_update(struct wireless_dev *wdev)
 
 	ASSERT_RTNL();
 
+	spin_lock_bh(&wdev->mgmt_registrations_lock);
+	if (!wdev->mgmt_registrations_need_update) {
+		spin_unlock_bh(&wdev->mgmt_registrations_lock);
+		return;
+	}
+
 	rcu_read_lock();
 	list_for_each_entry_rcu(tmp, &rdev->wiphy.wdev_list, list) {
-		list_for_each_entry_rcu(reg, &tmp->mgmt_registrations, list) {
+		list_for_each_entry(reg, &tmp->mgmt_registrations, list) {
 			u32 mask = BIT(le16_to_cpu(reg->frame_type) >> 4);
 			u32 mcast_mask = 0;
 
@@ -460,16 +466,23 @@  static void cfg80211_mgmt_registrations_update(struct wireless_dev *wdev)
 	}
 	rcu_read_unlock();
 
+	wdev->mgmt_registrations_need_update = 0;
+	spin_unlock_bh(&wdev->mgmt_registrations_lock);
+
 	rdev_update_mgmt_frame_registrations(rdev, wdev, &upd);
 }
 
 void cfg80211_mgmt_registrations_update_wk(struct work_struct *wk)
 {
-	struct wireless_dev *wdev = container_of(wk, struct wireless_dev,
-						 mgmt_registrations_update_wk);
+	struct cfg80211_registered_device *rdev;
+	struct wireless_dev *wdev;
+
+	rdev = container_of(wk, struct cfg80211_registered_device,
+			    mgmt_registrations_update_wk);
 
 	rtnl_lock();
-	cfg80211_mgmt_registrations_update(wdev);
+	list_for_each_entry(wdev, &rdev->wiphy.wdev_list, list)
+		cfg80211_mgmt_registrations_update(wdev);
 	rtnl_unlock();
 }
 
@@ -557,6 +570,7 @@  int cfg80211_mlme_register_mgmt(struct wireless_dev *wdev, u32 snd_portid,
 		nreg->multicast_rx = multicast_rx;
 		list_add(&nreg->list, &wdev->mgmt_registrations);
 	}
+	wdev->mgmt_registrations_need_update = 1;
 	spin_unlock_bh(&wdev->mgmt_registrations_lock);
 
 	cfg80211_mgmt_registrations_update(wdev);
@@ -585,7 +599,8 @@  void cfg80211_mlme_unregister_socket(struct wireless_dev *wdev, u32 nlportid)
 		list_del(&reg->list);
 		kfree(reg);
 
-		schedule_work(&wdev->mgmt_registrations_update_wk);
+		wdev->mgmt_registrations_need_update = 1;
+		schedule_work(&rdev->mgmt_registrations_update_wk);
 	}
 
 	spin_unlock_bh(&wdev->mgmt_registrations_lock);
@@ -608,6 +623,7 @@  void cfg80211_mlme_purge_registrations(struct wireless_dev *wdev)
 		list_del(&reg->list);
 		kfree(reg);
 	}
+	wdev->mgmt_registrations_need_update = 1;
 	spin_unlock_bh(&wdev->mgmt_registrations_lock);
 
 	cfg80211_mgmt_registrations_update(wdev);