releases/3.7.6/ath9k-disable-the-tasklet-before-taking-the-pcu-lock.patch

From 4668cce527acb3bd048c5e6c99b157a14b214671 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Mon, 14 Jan 2013 16:56:46 +0100
Subject: ath9k: disable the tasklet before taking the PCU lock

From: Felix Fietkau <nbd@openwrt.org>

commit 4668cce527acb3bd048c5e6c99b157a14b214671 upstream.

Fixes a reported CPU soft lockup where the tasklet tries to acquire the
lock and blocks while ath_prepare_reset (holding the lock) waits for it
to complete.

Reported-by: Robert Shade <robert.shade@gmail.com>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/wireless/ath/ath9k/main.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -195,16 +195,12 @@ static bool ath_prepare_reset(struct ath
 	ath9k_debug_samp_bb_mac(sc);
 	ath9k_hw_disable_interrupts(ah);
 
-	tasklet_disable(&sc->intr_tq);
-
 	if (!ath_stoprecv(sc))
 		ret = false;
 
 	if (!ath_drain_all_txq(sc, retry_tx))
 		ret = false;
 
-	tasklet_enable(&sc->intr_tq);
-
 	return ret;
 }
 
@@ -261,6 +257,7 @@ static int ath_reset_internal(struct ath
 
 	__ath_cancel_work(sc);
 
+	tasklet_disable(&sc->intr_tq);
 	spin_lock_bh(&sc->sc_pcu_lock);
 
 	if (!(sc->hw->conf.flags & IEEE80211_CONF_OFFCHANNEL)) {
@@ -291,6 +288,8 @@ static int ath_reset_internal(struct ath
 
 out:
 	spin_unlock_bh(&sc->sc_pcu_lock);
+	tasklet_enable(&sc->intr_tq);
+
 	return r;
 }