Re: [PATCH] Bluetooth: hci_ldisc: Fix another race when closing the tty.

[Marcel Holtmann]

Hi Ronald,

> The following race condition still existed:
> 
>         P1                                P2
>  cancel_work_sync()
>                                     hci_uart_tx_wakeup()
>                                     hci_uart_write_work()
>                                     hci_uart_dequeue()
>  clear_bit(HCI_UART_PROTO_READY)
>  hci_unregister_dev(hdev)
>  hci_free_dev(hdev)
>  hu->proto->close(hu)
>  kfree(hu)
>                                     access to hdev and hu
> 
> Cancelling the work after clearing the HCI_UART_PROTO_READY bit avoids
> this as any hci_uart_tx_wakeup() issued after the flag is cleared will
> detect that and not schedule further work.
> 
> Signed-off-by: Ronald TschalÃr <ronald@xxxxxxxxxxxxx>
> Cc: Dean Jenkins <Dean_Jenkins@xxxxxxxxxx>
> Cc: Lukas Wunner <lukas@xxxxxxxxx>
> Cc: Marcel Holtmann <marcel@xxxxxxxxxxxx>
> Cc: Gustavo Padovan <gustavo@xxxxxxxxxxx>
> Cc: Johan Hedberg <johan.hedberg@xxxxxxxxx>
> ---
> drivers/bluetooth/hci_ldisc.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel