[ 111/123] Revert "Bluetooth: Fix possible deadlock in SCO code"

Greg Kroah-Hartman
2013-01-09T20:50:27Z

From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

commit 0b27a4b97cb1874503c78453c0903df53c0c86b2 upstream.

This reverts commit 269c4845d5b3627b95b1934107251bacbe99bb68.

The commit was causing dead locks and NULL dereferences in the sco code:

[28084.104013] BUG: soft lockup - CPU#0 stuck for 22s! [kworker/u:0H:7]
[28084.104021] Modules linked in: btusb bluetooth <snip [last unloaded:
bluetooth]
...
[28084.104021] [<c160246d>] _raw_spin_lock+0xd/0x10
[28084.104021] [<f920e708>] sco_conn_del+0x58/0x1b0 [bluetooth]
[28084.104021] [<f920f1a9>] sco_connect_cfm+0xb9/0x2b0 [bluetooth]
[28084.104021] [<f91ef289>]
hci_sync_conn_complete_evt.isra.94+0x1c9/0x260 [bluetooth]
[28084.104021] [<f91f1a8d>] hci_event_packet+0x74d/0x2b40 [bluetooth]
[28084.104021] [<c1501abd>] ? __kfree_skb+0x3d/0x90
[28084.104021] [<c1501b46>] ? kfree_skb+0x36/0x90
[28084.104021] [<f91fcb4e>] ? hci_send_to_monitor+0x10e/0x190 [bluetooth]
[28084.104021] [<f91fcb4e>] ? hci_send_to_monitor+0x10e/0x190 [bluetooth]

Reported-by: Chan-yeol Park <chanyeol.park@gmail.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/bluetooth/sco.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -131,15 +131,6 @@ static int sco_conn_del(struct hci_conn
sco_sock_clear_timer(sk);
sco_chan_del(sk, err);
bh_unlock_sock(sk);
-
- sco_conn_lock(conn);
- conn->sk = NULL;
- sco_pi(sk)->conn = NULL;
- sco_conn_unlock(conn);
-
- if (conn->hcon)
- hci_conn_put(conn->hcon);
-
sco_sock_kill(sk);
}

@@ -830,6 +821,16 @@ static void sco_chan_del(struct sock *sk

BT_DBG("sk %p, conn %p, err %d", sk, conn, err);

+ if (conn) {
+ sco_conn_lock(conn);
+ conn->sk = NULL;
+ sco_pi(sk)->conn = NULL;
+ sco_conn_unlock(conn);
+
+ if (conn->hcon)
+ hci_conn_put(conn->hcon);
+ }
+
sk->sk_state = BT_CLOSED;
sk->sk_err = err;
sk->sk_state_change(sk);