From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754241AbdH1IPJ (ORCPT ); Mon, 28 Aug 2017 04:15:09 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:34950 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754224AbdH1IPG (ORCPT ); Mon, 28 Aug 2017 04:15:06 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jeffy Chen , Brian Norris , AL Yu-Chen Cho , Marcel Holtmann , Jiri Slaby Subject: [PATCH 4.4 37/53] Bluetooth: bnep: fix possible might sleep error in bnep_session Date: Mon, 28 Aug 2017 10:05:42 +0200 Message-Id: <20170828080519.316731713@linuxfoundation.org> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20170828080517.599193891@linuxfoundation.org> References: <20170828080517.599193891@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeffy Chen commit 25717382c1dd0ddced2059053e3ca5088665f7a5 upstream. It looks like bnep_session 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 Reviewed-by: Brian Norris Reviewed-by: AL Yu-Chen Cho Signed-off-by: Marcel Holtmann Cc: Jiri Slaby Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/bnep/core.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) --- a/net/bluetooth/bnep/core.c +++ b/net/bluetooth/bnep/core.c @@ -484,16 +484,16 @@ static int bnep_session(void *arg) struct net_device *dev = s->dev; struct sock *sk = s->sock->sk; struct sk_buff *skb; - wait_queue_t wait; + DEFINE_WAIT_FUNC(wait, woken_wake_function); BT_DBG(""); set_user_nice(current, -15); - init_waitqueue_entry(&wait, current); add_wait_queue(sk_sleep(sk), &wait); while (1) { - set_current_state(TASK_INTERRUPTIBLE); + /* Ensure session->terminate is updated */ + smp_mb__before_atomic(); if (atomic_read(&s->terminate)) break; @@ -515,9 +515,8 @@ static int bnep_session(void *arg) break; netif_wake_queue(dev); - schedule(); + wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); } - __set_current_state(TASK_RUNNING); remove_wait_queue(sk_sleep(sk), &wait); /* Cleanup session */ @@ -663,7 +662,7 @@ int bnep_del_connection(struct bnep_conn s = __bnep_get_session(req->dst); if (s) { atomic_inc(&s->terminate); - wake_up_process(s->task); + wake_up_interruptible(sk_sleep(s->sock->sk)); } else err = -ENOENT;