Bluetooth: Fix failure to release lock in read_index_list()

If alloc_skb() fails in read_index_list() we'll return -ENOMEM without
releasing 'hci_dev_list_lock'.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

net/bluetooth/mgmt.c

@@ -111,8 +111,10 @@ static int read_index_list(struct sock *sk)
 
 	body_len = sizeof(*ev) + sizeof(*rp) + (2 * count);
 	skb = alloc_skb(sizeof(*hdr) + body_len, GFP_ATOMIC);
-	if (!skb)
+	if (!skb) {
+		read_unlock(&hci_dev_list_lock);
 		return -ENOMEM;
+	}
 
 	hdr = (void *) skb_put(skb, sizeof(*hdr));
 	hdr->opcode = cpu_to_le16(MGMT_EV_CMD_COMPLETE);