1 files changed, 23 insertions, 6 deletions

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 7e1e87257647..bfdaf5c82f9d 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -351,7 +351,7 @@ int sta_info_insert(struct sta_info *sta)
 	 * NOTE: due to auto-freeing semantics this may only be done
 	 *       if the insertion is successful!
 	 */
-	queue_work(local->hw.workqueue, &local->sta_debugfs_add);
+	schedule_work(&local->sta_debugfs_add);
 #endif
 
 	if (ieee80211_vif_is_mesh(&sdata->vif))
@@ -476,16 +476,23 @@ void __sta_info_unlink(struct sta_info **sta)
 	 *
 	 * The rules are not trivial, but not too complex either:
 	 *  (1) pin_status is only modified under the sta_lock
-	 *  (2) sta_info_debugfs_add_work() will set the status
+	 *  (2) STAs may only be pinned under the RTNL so that
+	 *	sta_info_flush() is guaranteed to actually destroy
+	 *	all STAs that are active for a given interface, this
+	 *	is required for correctness because otherwise we
+	 *	could notify a driver that an interface is going
+	 *	away and only after that (!) notify it about a STA
+	 *	on that interface going away.
+	 *  (3) sta_info_debugfs_add_work() will set the status
 	 *	to PINNED when it found an item that needs a new
 	 *	debugfs directory created. In that case, that item
 	 *	must not be freed although all *RCU* users are done
 	 *	with it. Hence, we tell the caller of _unlink()
 	 *	that the item is already gone (as can happen when
 	 *	two tasks try to unlink/destroy at the same time)
-	 *  (3) We set the pin_status to DESTROY here when we
+	 *  (4) We set the pin_status to DESTROY here when we
 	 *	find such an item.
-	 *  (4) sta_info_debugfs_add_work() will reset the pin_status
+	 *  (5) sta_info_debugfs_add_work() will reset the pin_status
 	 *	from PINNED to NORMAL when it is done with the item,
 	 *	but will check for DESTROY before resetting it in
 	 *	which case it will free the item.
@@ -617,6 +624,8 @@ static void sta_info_debugfs_add_work(struct work_struct *work)
 	struct sta_info *sta, *tmp;
 	unsigned long flags;
 
+	/* We need to keep the RTNL across the whole pinned status. */
+	rtnl_lock();
 	while (1) {
 		sta = NULL;
 
@@ -637,10 +646,9 @@ static void sta_info_debugfs_add_work(struct work_struct *work)
 		rate_control_add_sta_debugfs(sta);
 
 		sta = __sta_info_unpin(sta);
-		rtnl_lock();
 		sta_info_destroy(sta);
-		rtnl_unlock();
 	}
+	rtnl_unlock();
 }
 #endif
 
@@ -700,6 +708,15 @@ void sta_info_stop(struct ieee80211_local *local)
 {
 	del_timer(&local->sta_cleanup);
 	cancel_work_sync(&local->sta_flush_work);
+#ifdef CONFIG_MAC80211_DEBUGFS
+	/*
+	 * Make sure the debugfs adding work isn't pending after this
+	 * because we're about to be destroyed. It doesn't matter
+	 * whether it ran or not since we're going to flush all STAs
+	 * anyway.
+	 */
+	cancel_work_sync(&local->sta_debugfs_add);
+#endif
 
 	rtnl_lock();
 	sta_info_flush(local, NULL);