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

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Message-ID: <20171026065202.GA6487@wunner.de>
Date:   Thu, 26 Oct 2017 08:52:02 +0200
From:   Lukas Wunner <lukas@...ner.de>
To:     =?UTF-8?q?Ronald=20Tschal=C3=A4r?= 
        <ronald@...ovation.ch>
Cc:     Marcel Holtmann <marcel@...tmann.org>,
        Gustavo Padovan <gustavo@...ovan.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Dean Jenkins <Dean_Jenkins@...tor.com>,
        linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Bluetooth: hci_ldisc: Fix another race when closing the
 tty.

On Wed, Oct 25, 2017 at 10:15:19PM -0700, =?UTF-8?q?Ronald=20Tschal=C3=A4r?= wrote:
> --- a/drivers/bluetooth/hci_ldisc.c
> +++ b/drivers/bluetooth/hci_ldisc.c
> @@ -523,13 +523,13 @@ static void hci_uart_tty_close(struct tty_struct *tty)
>  	if (hdev)
>  		hci_uart_close(hdev);
>  
> -	cancel_work_sync(&hu->write_work);
> -
>  	if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
>  		percpu_down_write(&hu->proto_lock);
>  		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
>  		percpu_up_write(&hu->proto_lock);
>  
> +		cancel_work_sync(&hu->write_work);
> +

Now the work is only cancelled if HCI_UART_PROTO_READY is set,
but that seems fine, so

Reviewed-by: Lukas Wunner <lukas@...ner.de>

It should be noted that this patch only applies cleanly if Ronald's
other patch is applied before.