Return-Path: From: Peter Hurley To: linux-bluetooth CC: Jaikumar Ganesh Date: Fri, 5 Aug 2011 10:41:35 -0400 Subject: [PATCH v2] Bluetooth: bnep: Fix deadlock in session deletion Message-ID: <1312555295.2172.2.camel@THOR> Content-Type: text/plain; charset=US-ASCII MIME-Version: 1.0 Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Commit f4d7cd4a4c introduced the usage of kthread API. kthread_stop is a blocking function which returns only when the thread exits. In this case, the thread can't exit because it's waiting for the write lock, which is being held by bnep_del_connection() which is waiting for the thread to exit -- deadlock. Use atomic_t/wake_up_process instead to signal to the thread to exit. Signed-off-by: Jaikumar Ganesh Signed-off-by: Peter Hurley --- net/bluetooth/bnep/bnep.h | 1 + net/bluetooth/bnep/core.c | 9 +++++---- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/net/bluetooth/bnep/bnep.h b/net/bluetooth/bnep/bnep.h index 8e6c061..e7ee531 100644 --- a/net/bluetooth/bnep/bnep.h +++ b/net/bluetooth/bnep/bnep.h @@ -155,6 +155,7 @@ struct bnep_session { unsigned int role; unsigned long state; unsigned long flags; + atomic_t terminate; struct task_struct *task; struct ethhdr eh; diff --git a/net/bluetooth/bnep/core.c b/net/bluetooth/bnep/core.c index 7e8ff3c..d9edfe8 100644 --- a/net/bluetooth/bnep/core.c +++ b/net/bluetooth/bnep/core.c @@ -487,7 +487,7 @@ static int bnep_session(void *arg) while (1) { set_current_state(TASK_INTERRUPTIBLE); - if (kthread_should_stop()) + if (atomic_read(&s->terminate)) break; /* RX */ while ((skb = skb_dequeue(&sk->sk_receive_queue))) { @@ -642,9 +642,10 @@ int bnep_del_connection(struct bnep_conndel_req *req) down_read(&bnep_session_sem); s = __bnep_get_session(req->dst); - if (s) - kthread_stop(s->task); - else + if (s) { + atomic_inc(&s->terminate); + wake_up_process(s->task); + } else err = -ENOENT; up_read(&bnep_session_sem); -- 1.7.4.1