From: Daniel Drake Date: Tue, 11 Jun 2013 19:40:20 +0000 (-0400) Subject: Bluetooth: btmrvl: fix thread stopping race X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=ea05fea9042620ac3b8ab9a3e5e4d2ed80c89244;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git 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 Signed-off-by: Gustavo Padovan Signed-off-by: John W. Linville --- 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;