Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in l2cap_connect (2)

[Edward Adam Davis]

after release conn, we need to cancle rx_work

#syz test

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index f25a21f532aa..4f7b45bb863f 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -3776,18 +3776,19 @@ static void hci_acldata_packet(struct hci_dev *hdev, struct sk_buff *skb)
 
 	hci_dev_lock(hdev);
 	conn = hci_conn_hash_lookup_handle(hdev, handle);
-	hci_dev_unlock(hdev);
 
 	if (conn) {
 		hci_conn_enter_active_mode(conn, BT_POWER_FORCE_ACTIVE_OFF);
 
 		/* Send to upper protocol */
 		l2cap_recv_acldata(conn, skb, flags);
+		hci_dev_unlock(hdev);
 		return;
 	} else {
 		bt_dev_err(hdev, "ACL packet for unknown connection handle %d",
 			   handle);
 	}
+	hci_dev_unlock(hdev);
 
 	kfree_skb(skb);
 }