From 7bb59df83b190817f56c4e2fec3078d99d906ad4 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Thu, 30 Jun 2011 13:53:53 -0400 Subject: Bluetooth: Fix hidp disconnect deadlocks and lost wakeup Partial revert of commit aabf6f89. When the hidp session thread was converted from kernel_thread to kthread, the atomic/wakeups were replaced with kthread_stop. kthread_stop has blocking semantics which are inappropriate for the hidp session kthread. In addition, the kthread signals itself to terminate in hidp_process_hid_control() - it cannot do this with kthread_stop(). Lastly, a wakeup can be lost if the wakeup happens between checking for the loop exit condition and setting the current state to TASK_INTERRUPTIBLE. (Without appropriate synchronization mechanisms, the task state should not be changed between the condition test and the yield - via schedule() - as this creates a race between the wakeup and resetting the state back to interruptible.) Signed-off-by: Peter Hurley Signed-off-by: Gustavo F. Padovan --- net/bluetooth/hidp/hidp.h | 1 + 1 file changed, 1 insertion(+) (limited to 'net/bluetooth/hidp/hidp.h') diff --git a/net/bluetooth/hidp/hidp.h b/net/bluetooth/hidp/hidp.h index 19e95004b28..af1bcc823f2 100644 --- a/net/bluetooth/hidp/hidp.h +++ b/net/bluetooth/hidp/hidp.h @@ -142,6 +142,7 @@ struct hidp_session { uint ctrl_mtu; uint intr_mtu; + atomic_t terminate; struct task_struct *task; unsigned char keys[8]; -- cgit v1.2.3-70-g09d2