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From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
Date: Fri, 2 Feb 2018 11:36:45 +0100
Subject: [PATCH] ath9k: Protect queue draining by rcu_read_lock()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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 <greearb@candelatech.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
---
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -2915,6 +2915,8 @@ void ath_tx_node_cleanup(struct ath_soft
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;
@@ -2932,6 +2934,8 @@ void ath_tx_node_cleanup(struct ath_soft
if (!an->sta)
break; /* just one multicast ath_atx_tid */
}
+
+ rcu_read_unlock();
}
#ifdef CPTCFG_ATH9K_TX99
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