From: Johannes Berg Date: Wed, 8 Jun 2011 11:27:29 +0000 (+0200) Subject: mac80211: fix IBSS teardown race X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f3209bea110cade12e2b133da8b8499689cb0e2e;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git 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 Debugged-by: Ignacy Gawedzki Tested-by: Ignacy Gawedzki Cc: stable@kernel.org Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- 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);