From 3d06535693a3d4e9eed1a2c0a86c32ad9d5f5d4c Mon Sep 17 00:00:00 2001 From: =?utf8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Tue, 27 Feb 2018 19:09:44 +0200 Subject: [PATCH] ath9k: Protect queue draining by rcu_read_lock() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 182b1917109892ab9f26d66bfdcbc4ba6f0a0a65 upstream. When ath9k was switched over to use the mac80211 intermediate queues, node cleanup now drains the mac80211 queues. However, this call path is not protected by rcu_read_lock() as it was previously entirely internal to the driver which uses its own locking. This leads to a possible rcu_dereference() without holding rcu_read_lock(); but only if a station is cleaned up while having packets queued on the TXQ. Fix this by adding the rcu_read_lock() to the caller in ath9k. Fixes: 50f08edf9809 ("ath9k: Switch to using mac80211 intermediate software queues.") Cc: stable@vger.kernel.org Reported-by: Ben Greear Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Kalle Valo Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/ath/ath9k/xmit.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c index 396bf05c6bf6..d8b041f48ca8 100644 --- a/drivers/net/wireless/ath/ath9k/xmit.c +++ b/drivers/net/wireless/ath/ath9k/xmit.c @@ -2892,6 +2892,8 @@ void ath_tx_node_cleanup(struct ath_softc *sc, struct ath_node *an) struct ath_txq *txq; int tidno; + rcu_read_lock(); + for (tidno = 0; tidno < IEEE80211_NUM_TIDS; tidno++) { tid = ath_node_to_tid(an, tidno); txq = tid->txq; @@ -2909,6 +2911,8 @@ void ath_tx_node_cleanup(struct ath_softc *sc, struct ath_node *an) if (!an->sta) break; /* just one multicast ath_atx_tid */ } + + rcu_read_unlock(); } #ifdef CONFIG_ATH9K_TX99 -- 2.20.1