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authorDaniel Drake <dsd@laptop.org>2013-06-11 15:40:20 -0400
committerJohn W. Linville <linville@tuxdriver.com>2013-06-13 13:05:40 -0400
commitea05fea9042620ac3b8ab9a3e5e4d2ed80c89244 (patch)
treea5f6856405fb195854847a660c50d51bbcacaf1f /drivers/bluetooth/btmrvl_main.c
parent59f45d576a0715026d1919ab8a12047616204656 (diff)
downloadlinux-ea05fea9042620ac3b8ab9a3e5e4d2ed80c89244.tar.gz
Bluetooth: btmrvl: fix thread stopping race
There is currently a race condition in the btmrvl_remove_card() which
is causing hangs on suspend for OLPC. When the race occurs,
kthread_stop() never returns.

The problem is that btmrvl_service_main_thread() calls kthread_should_stop()
and then does a fair number of things before restarting the loop and
sleeping.

If the thread gets stopped after kthread_should_stop() is checked, but
before the sleep happens, the thread will go to sleep and won't necessarily
be woken up.

Move the kthread_should_stop() check into a race-free place.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'drivers/bluetooth/btmrvl_main.c')
-rw-r--r--drivers/bluetooth/btmrvl_main.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/bluetooth/btmrvl_main.c b/drivers/bluetooth/btmrvl_main.c
index 3a4343b3bd6d..9a9f51875df5 100644
--- a/drivers/bluetooth/btmrvl_main.c
+++ b/drivers/bluetooth/btmrvl_main.c
@@ -498,6 +498,10 @@ static int btmrvl_service_main_thread(void *data)
 		add_wait_queue(&thread->wait_q, &wait);
 
 		set_current_state(TASK_INTERRUPTIBLE);
+		if (kthread_should_stop()) {
+			BT_DBG("main_thread: break from main thread");
+			break;
+		}
 
 		if (adapter->wakeup_tries ||
 				((!adapter->int_count) &&
@@ -513,11 +517,6 @@ static int btmrvl_service_main_thread(void *data)
 
 		BT_DBG("main_thread woke up");
 
-		if (kthread_should_stop()) {
-			BT_DBG("main_thread: break from main thread");
-			break;
-		}
-
 		spin_lock_irqsave(&priv->driver_lock, flags);
 		if (adapter->int_count) {
 			adapter->int_count = 0;