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Groups > linux.kernel > #1675456 > unrolled thread

[RESEND PATCH v4 1/3] Bluetooth: bnep: fix possible might sleep error in bnep_session

Started byJeffy Chen <jeffy.chen@rock-chips.com>
First post2017-06-27 11:40 +0200
Last post2017-06-27 19:40 +0200
Articles 3 — 2 participants

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  [RESEND PATCH v4 1/3] Bluetooth: bnep: fix possible might sleep error in bnep_session Jeffy Chen <jeffy.chen@rock-chips.com> - 2017-06-27 11:40 +0200
    [RESEND PATCH v4 2/3] Bluetooth: cmtp: fix possible might sleep error in cmtp_session Jeffy Chen <jeffy.chen@rock-chips.com> - 2017-06-27 11:40 +0200
    Re: [RESEND PATCH v4 1/3] Bluetooth: bnep: fix possible might sleep  error in bnep_session Marcel Holtmann <marcel@holtmann.org> - 2017-06-27 19:40 +0200

#1675456 — [RESEND PATCH v4 1/3] Bluetooth: bnep: fix possible might sleep error in bnep_session

FromJeffy Chen <jeffy.chen@rock-chips.com>
Date2017-06-27 11:40 +0200
Subject[RESEND PATCH v4 1/3] Bluetooth: bnep: fix possible might sleep error in bnep_session
Message-ID<tWV8t-6Z7-15@gated-at.bofh.it>
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 <jeffy.chen@rock-chips.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: AL Yu-Chen Cho <acho@suse.com>
---

Changes in v4: None
Changes in v2: None

 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

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#1675458 — [RESEND PATCH v4 2/3] Bluetooth: cmtp: fix possible might sleep error in cmtp_session

FromJeffy Chen <jeffy.chen@rock-chips.com>
Date2017-06-27 11:40 +0200
Subject[RESEND PATCH v4 2/3] Bluetooth: cmtp: fix possible might sleep error in cmtp_session
Message-ID<tWV8u-6Z7-29@gated-at.bofh.it>
In reply to#1675456
It looks like cmtp_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 <jeffy.chen@rock-chips.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: AL Yu-Chen Cho <acho@suse.com>

---

Changes in v4: None
Changes in v2:
Remove unnecessary memory barrier before wake_up_* functions.

 net/bluetooth/cmtp/core.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/net/bluetooth/cmtp/core.c b/net/bluetooth/cmtp/core.c
index 9e59b66..1152ce3 100644
--- a/net/bluetooth/cmtp/core.c
+++ b/net/bluetooth/cmtp/core.c
@@ -280,16 +280,16 @@ static int cmtp_session(void *arg)
 	struct cmtp_session *session = arg;
 	struct sock *sk = session->sock->sk;
 	struct sk_buff *skb;
-	wait_queue_t wait;
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 
 	BT_DBG("session %p", session);
 
 	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(&session->terminate))
 			break;
@@ -306,9 +306,8 @@ static int cmtp_session(void *arg)
 
 		cmtp_process_transmit(session);
 
-		schedule();
+		wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
 	}
-	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(sk_sleep(sk), &wait);
 
 	down_write(&cmtp_session_sem);
@@ -393,7 +392,7 @@ int cmtp_add_connection(struct cmtp_connadd_req *req, struct socket *sock)
 		err = cmtp_attach_device(session);
 		if (err < 0) {
 			atomic_inc(&session->terminate);
-			wake_up_process(session->task);
+			wake_up_interruptible(sk_sleep(session->sock->sk));
 			up_write(&cmtp_session_sem);
 			return err;
 		}
@@ -431,7 +430,11 @@ int cmtp_del_connection(struct cmtp_conndel_req *req)
 
 		/* Stop session thread */
 		atomic_inc(&session->terminate);
-		wake_up_process(session->task);
+
+		/* Ensure session->terminate is updated */
+		smp_mb__after_atomic();
+
+		wake_up_interruptible(sk_sleep(session->sock->sk));
 	} else
 		err = -ENOENT;
 
-- 
2.1.4

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#1676022 — Re: [RESEND PATCH v4 1/3] Bluetooth: bnep: fix possible might sleep error in bnep_session

FromMarcel Holtmann <marcel@holtmann.org>
Date2017-06-27 19:40 +0200
SubjectRe: [RESEND PATCH v4 1/3] Bluetooth: bnep: fix possible might sleep error in bnep_session
Message-ID<tX2CZ-3Ko-7@gated-at.bofh.it>
In reply to#1675456
Hi Jeffy,

> 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 <jeffy.chen@rock-chips.com>
> Reviewed-by: Brian Norris <briannorris@chromium.org>
> Reviewed-by: AL Yu-Chen Cho <acho@suse.com>
> ---
> 
> Changes in v4: None
> Changes in v2: None
> 
> net/bluetooth/bnep/core.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)

all 3 patches have been applied to bluetooth-next tree.

Regards

Marcel

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