Bluetooth: Hold socket in defer callback in L2CAP socket

In both places that we use the defer callback the socket lock is held for
a indirect sk access inside __l2cap_change_state() and chan->ops->defer(),
all the rest of the code between lock_sock() and release_sock() is
already protected by the channel lock and won't be affected by this
change.

We now use l2cap_change_state(), the locked version of the change state
function, and the defer callback does the locking itself now. This does
not affect other uses of the defer callback.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index a0b31db1246e..e55999228c8a 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1195,11 +1195,15 @@ static void l2cap_sock_ready_cb(struct l2cap_chan *chan)
 
 static void l2cap_sock_defer_cb(struct l2cap_chan *chan)
 {
-	struct sock *sk = chan->data;
-	struct sock *parent = bt_sk(sk)->parent;
+	struct sock *parent, *sk = chan->data;
+
+	lock_sock(sk);
 
+	parent = bt_sk(sk)->parent;
 	if (parent)
 		parent->sk_data_ready(parent, 0);
+
+	release_sock(sk);
 }
 
 static void l2cap_sock_resume_cb(struct l2cap_chan *chan)