From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeffy Chen Subject: [PATCH 3/3] Bluetooth: hidp: fix possible might sleep error in hidp_session_thread Date: Tue, 24 Jan 2017 12:07:51 +0800 Message-ID: <1485230871-22828-3-git-send-email-jeffy.chen@rock-chips.com> References: <1485230871-22828-1-git-send-email-jeffy.chen@rock-chips.com> Cc: Brian Norris , Douglas Anderson , Johan Hedberg , Peter Hurley , Jeffy Chen , Johan Hedberg , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "David S. Miller" , Marcel Holtmann , Gustavo Padovan To: linux-bluetooth@vger.kernel.org Return-path: Received: from regular1.263xmail.com ([211.150.99.132]:51582 "EHLO regular1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750709AbdAXEJf (ORCPT ); Mon, 23 Jan 2017 23:09:35 -0500 In-Reply-To: <1485230871-22828-1-git-send-email-jeffy.chen@rock-chips.com> Sender: netdev-owner@vger.kernel.org List-ID: It looks like hidp_session_thread has same pattern as the issue reported in old rfcomm: while (1) { set_current_state(TASK_INTERRUPTIBLE); if (condition) break; // may call might_sleep here schedule(); } __set_current_state(TASK_RUNNING); Which fixed at: dfb2fae Bluetooth: Fix nested sleeps So let's fix it at the same way, also follow the suggestion of: https://lwn.net/Articles/628628/ Signed-off-by: Jeffy Chen --- net/bluetooth/hidp/core.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c index 0bec458..43d6e6a 100644 --- a/net/bluetooth/hidp/core.c +++ b/net/bluetooth/hidp/core.c @@ -36,6 +36,7 @@ #define VERSION "1.2" static DECLARE_RWSEM(hidp_session_sem); +static DECLARE_WAIT_QUEUE_HEAD(hidp_session_wq); static LIST_HEAD(hidp_session_list); static unsigned char hidp_keycode[256] = { @@ -1068,12 +1069,15 @@ static int hidp_session_start_sync(struct hidp_session *session) * Wake up session thread and notify it to stop. This is asynchronous and * returns immediately. Call this whenever a runtime error occurs and you want * the session to stop. - * Note: wake_up_process() performs any necessary memory-barriers for us. */ static void hidp_session_terminate(struct hidp_session *session) { atomic_inc(&session->terminate); - wake_up_process(session->task); + + /* Ensure session->terminate is updated */ + smp_mb__after_atomic(); + + wake_up_interruptible(&hidp_session_wq); } /* @@ -1180,7 +1184,9 @@ static void hidp_session_run(struct hidp_session *session) struct sock *ctrl_sk = session->ctrl_sock->sk; struct sock *intr_sk = session->intr_sock->sk; struct sk_buff *skb; + DEFINE_WAIT_FUNC(wait, woken_wake_function); + add_wait_queue(&hidp_session_wq, &wait); for (;;) { /* * This thread can be woken up two ways: @@ -1188,12 +1194,10 @@ static void hidp_session_run(struct hidp_session *session) * session->terminate flag and wakes this thread up. * - Via modifying the socket state of ctrl/intr_sock. This * thread is woken up by ->sk_state_changed(). - * - * Note: set_current_state() performs any necessary - * memory-barriers for us. */ - set_current_state(TASK_INTERRUPTIBLE); + /* Ensure session->terminate is updated */ + smp_mb__before_atomic(); if (atomic_read(&session->terminate)) break; @@ -1227,11 +1231,14 @@ static void hidp_session_run(struct hidp_session *session) hidp_process_transmit(session, &session->ctrl_transmit, session->ctrl_sock); - schedule(); + wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); } + remove_wait_queue(&hidp_session_wq, &wait); atomic_inc(&session->terminate); - set_current_state(TASK_RUNNING); + + /* Ensure session->terminate is updated */ + smp_mb__after_atomic(); } /* -- 2.1.4