2011-07-24 04:10:41

by Peter Hurley

Subject: [PATCH 2/7] Bluetooth: rfcomm: Fix lost wakeups waiting to accept socket

Fix race conditions which can cause lost wakeups (or missed
signals) while waiting to accept an rfcomm socket connection.

Signed-off-by: Peter Hurley <[email protected]>
---
net/bluetooth/rfcomm/sock.c | 28 ++++++++++++++--------------
1 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 1b10727..bda7402 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -485,11 +485,6 @@ static int rfcomm_sock_accept(struct socket *sock, struct socket *newsock, int f

lock_sock(sk);

- if (sk->sk_state != BT_LISTEN) {
- err = -EBADFD;
- goto done;
- }
-
if (sk->sk_type != SOCK_STREAM) {
err = -EINVAL;
goto done;
@@ -501,19 +496,20 @@ static int rfcomm_sock_accept(struct socket *sock, struct socket *newsock, int f

/* Wait for an incoming connection. (wake-one). */
add_wait_queue_exclusive(sk_sleep(sk), &wait);
- while (!(nsk = bt_accept_dequeue(sk, newsock))) {
+ while (1) {
set_current_state(TASK_INTERRUPTIBLE);
- if (!timeo) {
- err = -EAGAIN;
+
+ if (sk->sk_state != BT_LISTEN) {
+ err = -EBADFD;
break;
}

- release_sock(sk);
- timeo = schedule_timeout(timeo);
- lock_sock(sk);
+ nsk = bt_accept_dequeue(sk, newsock);
+ if (nsk)
+ break;

- if (sk->sk_state != BT_LISTEN) {
- err = -EBADFD;
+ if (!timeo) {
+ err = -EAGAIN;
break;
}

@@ -521,8 +517,12 @@ static int rfcomm_sock_accept(struct socket *sock, struct socket *newsock, int f
err = sock_intr_errno(timeo);
break;
}
+
+ release_sock(sk);
+ timeo = schedule_timeout(timeo);
+ lock_sock(sk);
}
- set_current_state(TASK_RUNNING);
+ __set_current_state(TASK_RUNNING);
remove_wait_queue(sk_sleep(sk), &wait);

if (err)
--
1.7.4.1