From f3209bea110cade12e2b133da8b8499689cb0e2e Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Wed, 8 Jun 2011 13:27:29 +0200
Subject: [PATCH] mac80211: fix IBSS teardown race
Ignacy reports that sometimes after leaving an IBSS
joining a new one didn't work because there still
were stations on the list. He fixed it by flushing
stations when attempting to join a new IBSS, but
this shouldn't be happening in the first case. When
I looked into it I saw a race condition in teardown
that could cause stations to be added after flush,
and thus cause this situation. Ignacy confirms that
after applying my patch he hasn't seen this happen
again.
Reported-by: Ignacy Gawedzki <i@lri.fr>
Debugged-by: Ignacy Gawedzki <i@lri.fr>
Tested-by: Ignacy Gawedzki <i@lri.fr>
Cc: stable@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
---
net/mac80211/ibss.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index 421eaa6b0c2b..56c24cabf26d 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -965,6 +965,10 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
mutex_lock(&sdata->u.ibss.mtx);
+ sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
+ memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
+ sdata->u.ibss.ssid_len = 0;
+
active_ibss = ieee80211_sta_active_ibss(sdata);
if (!active_ibss && !is_zero_ether_addr(ifibss->bssid)) {
@@ -999,8 +1003,6 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
kfree_skb(skb);
skb_queue_purge(&sdata->skb_queue);
- memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
- sdata->u.ibss.ssid_len = 0;
del_timer_sync(&sdata->u.ibss.timer);
--
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