[PATCH 4.4 36/53] Bluetooth: cmtp: fix possible might sleep error in cmtp_session
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2017-08-28 08:32:26
Also in:
lkml
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jeffy Chen <redacted>
commit f06d977309d09253c744e54e75c5295ecc52b7b4 upstream.
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 <redacted>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: AL Yu-Chen Cho <redacted>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: Jiri Slaby <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/bluetooth/cmtp/core.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
--- a/net/bluetooth/cmtp/core.c
+++ b/net/bluetooth/cmtp/core.c@@ -281,16 +281,16 @@ 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;
@@ -307,9 +307,8 @@ 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);
@@ -394,7 +393,7 @@ int cmtp_add_connection(struct cmtp_conn 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; }
@@ -432,7 +431,11 @@ int cmtp_del_connection(struct cmtp_conn /* 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;