From ae2e9fba85f69e0b53b1ef15e3011ce09ac1b9f2 Mon Sep 17 00:00:00 2001 From: Arik Nemtsov Date: Sun, 1 Mar 2015 09:10:09 +0200 Subject: [PATCH] mac80211: allow TDLS setup code to take wdev lock TDLS off-channel can be allowed in channels marked with GO_CONCURRENT, provided the device is connected to an AP on the same UNII. When relaxing the NO-IR requirements for TDLS, we might hit flows in cfg80211_reg_can_beacon that acquire the wdev lock. Take some measures to allow this during TDLS setup. Acquire the RCU read lock later in the flow that invokes cfg80211_reg_can_beacon. Avoid taking local->mtx when preparing the setup packet to avoid circular deadlocks with mac80211 code that is invoked with wdev-mtx held. Signed-off-by: Arik Nemtsov Signed-off-by: Emmanuel Grumbach Signed-off-by: Johannes Berg --- net/mac80211/tdls.c | 41 ++++++++++++++++++++++++----------------- 1 file changed, 24 insertions(+), 17 deletions(-) diff --git a/net/mac80211/tdls.c b/net/mac80211/tdls.c index 5bcd542e4933..bc7e4049896f 100644 --- a/net/mac80211/tdls.c +++ b/net/mac80211/tdls.c @@ -287,17 +287,6 @@ ieee80211_tdls_add_setup_start_ies(struct ieee80211_sub_if_data *sdata, size_t offset = 0, noffset; u8 *pos; - rcu_read_lock(); - - /* we should have the peer STA if we're already responding */ - if (action_code == WLAN_TDLS_SETUP_RESPONSE) { - sta = sta_info_get(sdata, peer); - if (WARN_ON_ONCE(!sta)) { - rcu_read_unlock(); - return; - } - } - ieee80211_add_srates_ie(sdata, skb, false, band); ieee80211_add_ext_srates_ie(sdata, skb, false, band); ieee80211_tdls_add_supp_channels(sdata, skb); @@ -350,6 +339,17 @@ ieee80211_tdls_add_setup_start_ies(struct ieee80211_sub_if_data *sdata, offset = noffset; } + rcu_read_lock(); + + /* we should have the peer STA if we're already responding */ + if (action_code == WLAN_TDLS_SETUP_RESPONSE) { + sta = sta_info_get(sdata, peer); + if (WARN_ON_ONCE(!sta)) { + rcu_read_unlock(); + return; + } + } + /* * with TDLS we can switch channels, and HT-caps are not necessarily * the same on all bands. The specification limits the setup to a @@ -983,7 +983,7 @@ ieee80211_tdls_mgmt_setup(struct wiphy *wiphy, struct net_device *dev, if (!is_zero_ether_addr(sdata->u.mgd.tdls_peer) && !ether_addr_equal(sdata->u.mgd.tdls_peer, peer)) { ret = -EBUSY; - goto exit; + goto out_unlock; } /* @@ -998,27 +998,34 @@ ieee80211_tdls_mgmt_setup(struct wiphy *wiphy, struct net_device *dev, if (!sta_info_get(sdata, peer)) { rcu_read_unlock(); ret = -ENOLINK; - goto exit; + goto out_unlock; } rcu_read_unlock(); } ieee80211_flush_queues(local, sdata, false); + memcpy(sdata->u.mgd.tdls_peer, peer, ETH_ALEN); + mutex_unlock(&local->mtx); + /* we cannot take the mutex while preparing the setup packet */ ret = ieee80211_tdls_prep_mgmt_packet(wiphy, dev, peer, action_code, dialog_token, status_code, peer_capability, initiator, extra_ies, extra_ies_len, 0, NULL); - if (ret < 0) - goto exit; + if (ret < 0) { + mutex_lock(&local->mtx); + eth_zero_addr(sdata->u.mgd.tdls_peer); + mutex_unlock(&local->mtx); + return ret; + } - memcpy(sdata->u.mgd.tdls_peer, peer, ETH_ALEN); ieee80211_queue_delayed_work(&sdata->local->hw, &sdata->u.mgd.tdls_peer_del_work, TDLS_PEER_SETUP_TIMEOUT); + return 0; -exit: +out_unlock: mutex_unlock(&local->mtx); return ret; } -- 2.20.1