linux-kernel - Re: [PATCH 1/2] Bluetooth: fix debugfs registration

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Message-ID: <CABBYNZLBQjWVb=z8mffi4RmeKS-+RDLV+XF8bR2MiJ-ZOaFVHA@mail.gmail.com>
Date:   Tue, 2 May 2023 16:37:51 -0700
From:   Luiz Augusto von Dentz <luiz.dentz@...il.com>
To:     Johan Hovold <johan+linaro@...nel.org>
Cc:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH 1/2] Bluetooth: fix debugfs registration

Hi Johan,

On Mon, Apr 24, 2023 at 5:50 AM Johan Hovold <johan+linaro@...nel.org> wrote:
>
> Since commit ec6cef9cd98d ("Bluetooth: Fix SMP channel registration for
> unconfigured controllers") the debugfs interface for unconfigured
> controllers will be created when the controller is configured.
>
> There is however currently nothing preventing a controller from being
> configured multiple time (e.g. setting the device address using btmgmt)
> which results in failed attempts to register the already registered
> debugfs entries:
>
>         debugfs: File 'features' in directory 'hci0' already present!
>         debugfs: File 'manufacturer' in directory 'hci0' already present!
>         debugfs: File 'hci_version' in directory 'hci0' already present!
>         ...
>         debugfs: File 'quirk_simultaneous_discovery' in directory 'hci0' already present!
>
> Add a controller flag to avoid trying to register the debugfs interface
> more than once.
>
> Fixes: ec6cef9cd98d ("Bluetooth: Fix SMP channel registration for unconfigured controllers")
> Cc: stable@...r.kernel.org      # 4.0
> Signed-off-by: Johan Hovold <johan+linaro@...nel.org>
> ---
>  include/net/bluetooth/hci.h | 1 +
>  net/bluetooth/hci_sync.c    | 3 +++
>  2 files changed, 4 insertions(+)
>
> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
> index 400f8a7d0c3f..b8bca65bcd79 100644
> --- a/include/net/bluetooth/hci.h
> +++ b/include/net/bluetooth/hci.h
> @@ -335,6 +335,7 @@ enum {
>  enum {
>         HCI_SETUP,
>         HCI_CONFIG,
> +       HCI_DEBUGFS_CREATED,
>         HCI_AUTO_OFF,
>         HCI_RFKILLED,
>         HCI_MGMT,
> diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
> index 632be1267288..a8785126df75 100644
> --- a/net/bluetooth/hci_sync.c
> +++ b/net/bluetooth/hci_sync.c
> @@ -4501,6 +4501,9 @@ static int hci_init_sync(struct hci_dev *hdev)
>             !hci_dev_test_flag(hdev, HCI_CONFIG))
>                 return 0;
>
> +       if (hci_dev_test_and_set_flag(hdev, HCI_DEBUGFS_CREATED))
> +               return 0;

Can't we just use HCI_SETUP like we do with in create_basic:

    if (hci_dev_test_flag(hdev, HCI_SETUP))
        hci_debugfs_create_basic(hdev);

Actually we might as well move these checks directly inside the
hci_debugfs function to make sure these only take effect during the
setup/first init.

>         hci_debugfs_create_common(hdev);
>
>         if (lmp_bredr_capable(hdev))
> --
> 2.39.2
>


-- 
Luiz Augusto von Dentz