From 9d3f7e38fda89bfaab58f8407edbdab7aeab1215 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes@sipsolutions.net>
Date: Tue, 7 Oct 2008 12:04:29 +0200
Subject: [PATCH] --- yaml --- r: 115020 b: refs/heads/master c:
 63044e9f54b6bac50d2380bf4d14f63e9e7de72b h: refs/heads/master v: v3

---
 [refs]                           |  2 +-
 trunk/net/mac80211/debugfs_sta.c | 11 +++++++++++
 trunk/net/mac80211/sta_info.c    |  7 ++++++-
 trunk/net/mac80211/sta_info.h    |  1 +
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index d53164433eed..4928158c511b 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 45527c2c4f698f8927239cfdec9f515cafed5f10
+refs/heads/master: 63044e9f54b6bac50d2380bf4d14f63e9e7de72b
diff --git a/trunk/net/mac80211/debugfs_sta.c b/trunk/net/mac80211/debugfs_sta.c
index b9902e425f09..189d0bafa91a 100644
--- a/trunk/net/mac80211/debugfs_sta.c
+++ b/trunk/net/mac80211/debugfs_sta.c
@@ -249,11 +249,22 @@ void ieee80211_sta_debugfs_add(struct sta_info *sta)
 	DECLARE_MAC_BUF(mbuf);
 	u8 *mac;
 
+	sta->debugfs.add_has_run = true;
+
 	if (!stations_dir)
 		return;
 
 	mac = print_mac(mbuf, sta->sta.addr);
 
+	/*
+	 * This might fail due to a race condition:
+	 * When mac80211 unlinks a station, the debugfs entries
+	 * remain, but it is already possible to link a new
+	 * station with the same address which triggers adding
+	 * it to debugfs; therefore, if the old station isn't
+	 * destroyed quickly enough the old station's debugfs
+	 * dir might still be around.
+	 */
 	sta->debugfs.dir = debugfs_create_dir(mac, stations_dir);
 	if (!sta->debugfs.dir)
 		return;
diff --git a/trunk/net/mac80211/sta_info.c b/trunk/net/mac80211/sta_info.c
index 9b72d15bc8dc..7fef8ea1f5ec 100644
--- a/trunk/net/mac80211/sta_info.c
+++ b/trunk/net/mac80211/sta_info.c
@@ -635,7 +635,12 @@ static void sta_info_debugfs_add_work(struct work_struct *work)
 
 		spin_lock_irqsave(&local->sta_lock, flags);
 		list_for_each_entry(tmp, &local->sta_list, list) {
-			if (!tmp->debugfs.dir) {
+			/*
+			 * debugfs.add_has_run will be set by
+			 * ieee80211_sta_debugfs_add regardless
+			 * of what else it does.
+			 */
+			if (!tmp->debugfs.add_has_run) {
 				sta = tmp;
 				__sta_info_pin(sta);
 				break;
diff --git a/trunk/net/mac80211/sta_info.h b/trunk/net/mac80211/sta_info.h
index a6b51862a89d..168a39a298bd 100644
--- a/trunk/net/mac80211/sta_info.h
+++ b/trunk/net/mac80211/sta_info.h
@@ -300,6 +300,7 @@ struct sta_info {
 		struct dentry *inactive_ms;
 		struct dentry *last_seq_ctrl;
 		struct dentry *agg_status;
+		bool add_has_run;
 	} debugfs;
 #endif