Commit f3209bea authored Jun 08, 2011 by Johannes Berg Committed by John W. Linville Jun 08, 2011

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>

parent 43e4e0b9

net/mac80211/ibss.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -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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