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ath9k: Protect queue draining by rcu_read_lock() 

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: 50f08edf98 ("ath9k: Switch to using mac80211 intermediate software queues.")
Cc: stable@vger.kernel.org
Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
This commit is contained in:
Toke Høiland-Jørgensen 2018-02-27 19:09:44 +02:00 committed by Kalle Valo
parent 38a1390e02
commit 182b191710
1 changed files with 4 additions and 0 deletions
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4
drivers/net/wireless/ath/ath9k/xmit.c
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@ -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