[ 72/80] Bluetooth: Add missing lock nesting notation

Greg Kroah-Hartman
2013-01-09T20:58:19Z

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

commit dc2a0e20fbc85a71c63aa4330b496fda33f6bf80 upstream.

This patch fixes the following report, it happens when accepting rfcomm
connections:

[ 228.165378] =============================================
[ 228.165378] [ INFO: possible recursive locking detected ]
[ 228.165378] 3.7.0-rc1-00536-gc1d5dc4 #120 Tainted: G W
[ 228.165378] ---------------------------------------------
[ 228.165378] bluetoothd/1341 is trying to acquire lock:
[ 228.165378] (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+...}, at:
[<ffffffffa0000aa0>] bt_accept_dequeue+0xa0/0x180 [bluetooth]
[ 228.165378]
[ 228.165378] but task is already holding lock:
[ 228.165378] (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+...}, at:
[<ffffffffa0205118>] rfcomm_sock_accept+0x58/0x2d0 [rfcomm]
[ 228.165378]
[ 228.165378] other info that might help us debug this:
[ 228.165378] Possible unsafe locking scenario:
[ 228.165378]
[ 228.165378] CPU0
[ 228.165378] ----
[ 228.165378] lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM);
[ 228.165378] lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM);
[ 228.165378]
[ 228.165378] *** DEADLOCK ***
[ 228.165378]
[ 228.165378] May be due to missing lock nesting notation

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/bluetooth/rfcomm/sock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -485,7 +485,7 @@ static int rfcomm_sock_accept(struct soc
long timeo;
int err = 0;

- lock_sock(sk);
+ lock_sock_nested(sk, SINGLE_DEPTH_NESTING);

if (sk->sk_type != SOCK_STREAM) {
err = -EINVAL;
@@ -522,7 +522,7 @@ static int rfcomm_sock_accept(struct soc

release_sock(sk);
timeo = schedule_timeout(timeo);
- lock_sock(sk);
+ lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
}
__set_current_state(TASK_RUNNING);
remove_wait_queue(sk_sleep(sk), &wait);