ath9k_htc: fix race conditions when stop device

We do not kill any scheduled tasklets when stopping device, that may
cause usage of resources after free. Disable interrupts, kill tasklets
and then works in correct order.

Cc: stable@kernel.org
Tested-by: Sujith <m.sujith@gmail.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 15 insertions, 9 deletions

diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_init.c b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
index 38433f9bfe59..0352f0994caa 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_init.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
@@ -142,9 +142,6 @@ static void ath9k_deinit_priv(struct ath9k_htc_priv *priv)
 {
         ath9k_htc_exit_debug(priv->ah);
         ath9k_hw_deinit(priv->ah);
-        tasklet_kill(&priv->swba_tasklet);
-        tasklet_kill(&priv->rx_tasklet);
-        tasklet_kill(&priv->tx_tasklet);
         kfree(priv->ah);
         priv->ah = NULL;
 }
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_main.c b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
index f4d576bc3ccd..6bb59958f71e 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_main.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
@@ -1025,12 +1025,6 @@ static void ath9k_htc_stop(struct ieee80211_hw *hw)
         int ret = 0;
         u8 cmd_rsp;
 
-        /* Cancel all the running timers/work .. */
-        cancel_work_sync(&priv->fatal_work);
-        cancel_work_sync(&priv->ps_work);
-        cancel_delayed_work_sync(&priv->ath9k_led_blink_work);
-        ath9k_led_stop_brightness(priv);
-
         mutex_lock(&priv->mutex);
 
         if (priv->op_flags & OP_INVALID) {
@@ -1044,8 +1038,23 @@ static void ath9k_htc_stop(struct ieee80211_hw *hw)
         WMI_CMD(WMI_DISABLE_INTR_CMDID);
         WMI_CMD(WMI_DRAIN_TXQ_ALL_CMDID);
         WMI_CMD(WMI_STOP_RECV_CMDID);
+
+        tasklet_kill(&priv->swba_tasklet);
+        tasklet_kill(&priv->rx_tasklet);
+        tasklet_kill(&priv->tx_tasklet);
+
         skb_queue_purge(&priv->tx_queue);
 
+        mutex_unlock(&priv->mutex);
+
+        /* Cancel all the running timers/work .. */
+        cancel_work_sync(&priv->fatal_work);
+        cancel_work_sync(&priv->ps_work);
+        cancel_delayed_work_sync(&priv->ath9k_led_blink_work);
+        ath9k_led_stop_brightness(priv);
+
+        mutex_lock(&priv->mutex);
+
         /* Remove monitor interface here */
         if (ah->opmode == NL80211_IFTYPE_MONITOR) {
                 if (ath9k_htc_remove_monitor_interface(priv))