On 19.12.2024 22:18, Luiz Augusto von Dentz wrote:
> Hi Arseniy,
>
> On Tue, Dec 17, 2024 at 3:12 AM Arseniy Krasnov
> <avkrasnov@xxxxxxxxxxxxxxxxx> wrote:
>>
>> '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@xxxxxxxxxxxxxxxxx>
>> ---
>> Changelog v1->v2:
>> * Move 'set_bit()' before 'hci_uart_register_dev()' instead of
>> adding new bit 'HCI_UART_PROTO_INIT'.
>
> What drivers/controllers this was tested with? I want to make sure
> this doesn't cause regressions to other drivers if there are perhaps
> some drivers assuming HCI_UART_PROTO_READY was set in a certain order.
Hi,
I tested this on:
CONFIG_BT=y
CONFIG_BT_HCIUART=y
CONFIG_BT_HCIUART_H4=y
Yes, my v1 patchset with extra INIT bit was targeted to keep
original behaviour - e.g. PROTO_READY bit usage still the same,
just adding extra bit to handle this specific case.
Thanks
>
>> 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 30192bb083549..07b9aa09bbe2e 100644
>> --- 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;
>> }
>>
>> --
>> 2.30.1
>
>
>
