Return-Path: From: Jeffy Chen To: linux-bluetooth@vger.kernel.org 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 Subject: [PATCH v4 1/3] Bluetooth: bnep: fix possible might sleep error in bnep_session Date: Tue, 14 Feb 2017 08:55:23 +0800 Message-Id: <1487033725-7208-1-git-send-email-jeffy.chen@rock-chips.com> List-ID: 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 --- Changes in v3: Add brian's Reviewed-by. Changes in v2: Remove unnecessary memory barrier before wake_up_* functions. net/bluetooth/bnep/core.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/net/bluetooth/bnep/core.c b/net/bluetooth/bnep/core.c index fbf251f..4d6b94d 100644 --- 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 */ @@ -666,7 +665,7 @@ int bnep_del_connection(struct bnep_conndel_req *req) 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; -- 2.1.4