Commit ae2e9fba authored by Arik Nemtsov's avatar Arik Nemtsov Committed by Johannes Berg
Browse files

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: default avatarArik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: default avatarEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 23e37098

net/mac80211/tdls.c

+24 −17
Original line number Diff line number Diff line
@@ -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;

}

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