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From:   Coiby Xu <coiby.xu@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Cc:     linux-kernel-mentees@lists.linuxfoundation.org,
        syzkaller-bugs@googlegroups.com,
        syzbot+305a91e025a73e4fd6ce@syzkaller.appspotmail.com,
        Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        netdev@vger.kernel.org (open list:NETWORKING [GENERAL]),
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] Bluetooth: Delete both L2CAP connction and HCI channel when completing destroying logical link in AMP
Date:   Fri,  7 Aug 2020 21:59:17 +0800
Message-Id: <20200807135918.1177869-1-coiby.xu@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

When destroying a logical link (HCI_EV_DISCONN_LOGICAL_LINK_COMPLETE) in
AMP, L2CAP connection (struct l2cap_conn) should be deleted together with
HCI channel (struct hci_chan). Otherwise HCI channel will be deleted twice
when unregistering a HCI device.

`static void l2cap_conn_del(struct hci_conn *hcon, int err)` could
achieve this purpose. Make it a public function.

Reported-and-tested-by: syzbot+305a91e025a73e4fd6ce@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=305a91e025a73e4fd6ce
Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
---
 include/net/bluetooth/l2cap.h | 1 +
 net/bluetooth/amp.c           | 2 +-
 net/bluetooth/l2cap_core.c    | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 8f1e6a7a2df8..8508a433d6ac 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -988,6 +988,7 @@ void __l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan);
 typedef void (*l2cap_chan_func_t)(struct l2cap_chan *chan, void *data);
 void l2cap_chan_list(struct l2cap_conn *conn, l2cap_chan_func_t func,
 		     void *data);
+void l2cap_conn_del(struct hci_conn *hcon, int err);
 void l2cap_chan_del(struct l2cap_chan *chan, int err);
 void l2cap_send_conn_req(struct l2cap_chan *chan);
 void l2cap_move_start(struct l2cap_chan *chan);
diff --git a/net/bluetooth/amp.c b/net/bluetooth/amp.c
index 9c711f0dfae3..cee02f009cef 100644
--- a/net/bluetooth/amp.c
+++ b/net/bluetooth/amp.c
@@ -584,5 +584,5 @@ void amp_destroy_logical_link(struct hci_chan *hchan, u8 reason)
 {
 	BT_DBG("hchan %p", hchan);

-	hci_chan_del(hchan);
+	l2cap_conn_del(hchan->conn, bt_to_errno(reason));
 }
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index fe913a5c754a..38f60fb9b515 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1851,7 +1851,7 @@ static void l2cap_unregister_all_users(struct l2cap_conn *conn)
 	}
 }

-static void l2cap_conn_del(struct hci_conn *hcon, int err)
+void l2cap_conn_del(struct hci_conn *hcon, int err)
 {
 	struct l2cap_conn *conn = hcon->l2cap_data;
 	struct l2cap_chan *chan, *l;
--
2.27.0