Return-path: Received: from mail.toke.dk ([52.28.52.200]:47147 "EHLO mail.toke.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751671AbeBBKhz (ORCPT ); Fri, 2 Feb 2018 05:37:55 -0500 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= To: linux-wireless@vger.kernel.org Cc: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , stable@vger.kernel.org Subject: [PATCH] ath9k: Protect queue draining by rcu_read_lock() Date: Fri, 2 Feb 2018 11:36:45 +0100 Message-Id: <20180202103645.12215-1-toke@toke.dk> (sfid-20180202_113759_661422_E25FFE92) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: 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 --- 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 -- 2.16.0