Bluetooth: hci_uart: fix race during initialization

[ Upstream commit 366ceff495f902182d42b6f41525c2474caf3f9a ]

'hci_register_dev()' calls power up function, which is executed by
kworker - 'hci_power_on()'. This function does access to bluetooth chip
using callbacks from 'hci_ldisc.c', for example 'hci_uart_send_frame()'.
Now 'hci_uart_send_frame()' checks 'HCI_UART_PROTO_READY' bit set, and
if not - it fails. Problem is that 'HCI_UART_PROTO_READY' is set after
'hci_register_dev()', and there is tiny chance that 'hci_power_on()' will
be executed before setting this bit. In that case HCI init logic fails.

Patch moves setting of 'HCI_UART_PROTO_READY' before calling function
'hci_uart_register_dev()'.

Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index 17a2f158a0dfab2b7832819cfe01f1d004508dc0..b67023d69e03ddb1eeb3439ce442289439a534b2 100644 (file)
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -704,12 +704,13 @@ static int hci_uart_set_proto(struct hci_uart *hu, int id)
 
        hu->proto = p;
 
+       set_bit(HCI_UART_PROTO_READY, &hu->flags);
+
        err = hci_uart_register_dev(hu);
        if (err) {
                return err;
        }
 
-       set_bit(HCI_UART_PROTO_READY, &hu->flags);
        return 0;
 }