[PATCH AUTOSEL 5.10 15/15] Bluetooth: hci_uart: fix race during initialization

Sasha Levin
2025-04-03T19:10:35Z

From: Arseniy Krasnov <avkrasnov@salutedevices.com>

[ 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>
---
drivers/bluetooth/hci_ldisc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index e7d78937f7d6b..8ca0ac3a440c9 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -706,12 +706,13 @@ 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;
}

--
2.39.5