From ea05fea9042620ac3b8ab9a3e5e4d2ed80c89244 Mon Sep 17 00:00:00 2001
From: Daniel Drake <dsd@laptop.org>
Date: Tue, 11 Jun 2013 15:40:20 -0400
Subject: 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>
---
drivers/bluetooth/btmrvl_main.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
(limited to 'drivers/bluetooth')
diff --git a/drivers/bluetooth/btmrvl_main.c b/drivers/bluetooth/btmrvl_main.c
index 3a4343b3bd6..9a9f51875df 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;
--
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