[PATCH 0/2] Bluetooth: fix debugfs registration

[PATCH 0/2] Bluetooth: fix debugfs registration

[Johan Hovold]

The HCI controller debugfs interface is created during setup or when a
controller is configured, but there is nothing preventing a controller
from being configured multiple times (e.g. by setting the device
address), which results in a host of errors in the logs:

	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!

The Qualcomm driver suffers from a related problem for controllers with
non-persistent setup.

Johan


Johan Hovold (2):
  Bluetooth: fix debugfs registration
  Bluetooth: hci_qca: fix debugfs registration

 drivers/bluetooth/hci_qca.c | 6 +++++-
 include/net/bluetooth/hci.h | 1 +
 net/bluetooth/hci_sync.c    | 3 +++
 3 files changed, 9 insertions(+), 1 deletion(-)

-- 
2.39.2

[PATCH 1/2] Bluetooth: fix debugfs registration

[Johan Hovold]

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@vger.kernel.org      # 4.0
Signed-off-by: Johan Hovold <johan+linaro@kernel.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;
+
 	hci_debugfs_create_common(hdev);
 
 	if (lmp_bredr_capable(hdev))
-- 
2.39.2

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

[Luiz Augusto von Dentz]

Hi Johan,

On Mon, Apr 24, 2023 at 5:50 AM Johan Hovold <johan+linaro@kernel.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@vger.kernel.org      # 4.0
> Signed-off-by: Johan Hovold <johan+linaro@kernel.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

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

[Johan Hovold]

On Tue, May 02, 2023 at 04:37:51PM -0700, Luiz Augusto von Dentz wrote:
> Hi Johan,
> 
> On Mon, Apr 24, 2023 at 5:50 AM Johan Hovold <johan+linaro@kernel.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@vger.kernel.org      # 4.0
> > Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> > ---

> > 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.

The problem is that commit ec6cef9cd98d ("Bluetooth: Fix SMP channel
registration for unconfigured controllers") started deferring creation
of most parts of the debugfs interface until the controller is
configured (e.g. as some information is not available until then).

Moving everything back to setup-time would effectively revert that.

Perhaps the interface can be changed in some way so that everything is
again registered at setup-time (e.g. with placeholder values instead of
conditionally created attributes), but that would at least not be
something that we could backport.

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

Johan

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

[Luiz Augusto von Dentz]

Hi Johan,

On Wed, May 3, 2023 at 12:04 AM Johan Hovold <johan@kernel.org> wrote:
>
> On Tue, May 02, 2023 at 04:37:51PM -0700, Luiz Augusto von Dentz wrote:
> > Hi Johan,
> >
> > On Mon, Apr 24, 2023 at 5:50 AM Johan Hovold <johan+linaro@kernel.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@vger.kernel.org      # 4.0
> > > Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> > > ---
>
> > > 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.
>
> The problem is that commit ec6cef9cd98d ("Bluetooth: Fix SMP channel
> registration for unconfigured controllers") started deferring creation
> of most parts of the debugfs interface until the controller is
> configured (e.g. as some information is not available until then).
>
> Moving everything back to setup-time would effectively revert that.

Not moving back but just doing something like:

diff --git a/net/bluetooth/hci_debugfs.c b/net/bluetooth/hci_debugfs.c
index ec0df2f9188e..a6e94c29fc5a 100644
--- a/net/bluetooth/hci_debugfs.c
+++ b/net/bluetooth/hci_debugfs.c
@@ -310,6 +310,9 @@ DEFINE_INFO_ATTRIBUTE(firmware_info, fw_info);

 void hci_debugfs_create_common(struct hci_dev *hdev)
 {
+       if (!hci_dev_test_flag(hdev, HCI_SETUP))
+               return;
+
        debugfs_create_file("features", 0444, hdev->debugfs, hdev,
                            &features_fops);
        debugfs_create_u16("manufacturer", 0444, hdev->debugfs,

> Perhaps the interface can be changed in some way so that everything is
> again registered at setup-time (e.g. with placeholder values instead of
> conditionally created attributes), but that would at least not be
> something that we could backport.
>
> > >         hci_debugfs_create_common(hdev);
> > >
> > >         if (lmp_bredr_capable(hdev))
>
> Johan



-- 
Luiz Augusto von Dentz

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

[Johan Hovold]

On Wed, May 03, 2023 at 10:34:06AM -0700, Luiz Augusto von Dentz wrote:
> Hi Johan,
> 
> On Wed, May 3, 2023 at 12:04 AM Johan Hovold <johan@kernel.org> wrote:
> >
> > On Tue, May 02, 2023 at 04:37:51PM -0700, Luiz Augusto von Dentz wrote:
> > > Hi Johan,
> > >
> > > On Mon, Apr 24, 2023 at 5:50 AM Johan Hovold <johan+linaro@kernel.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@vger.kernel.org      # 4.0
> > > > Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> > > > ---
> >
> > > > 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.
> >
> > The problem is that commit ec6cef9cd98d ("Bluetooth: Fix SMP channel
> > registration for unconfigured controllers") started deferring creation
> > of most parts of the debugfs interface until the controller is
> > configured (e.g. as some information is not available until then).
> >
> > Moving everything back to setup-time would effectively revert that.
> 
> Not moving back but just doing something like:
> 
> diff --git a/net/bluetooth/hci_debugfs.c b/net/bluetooth/hci_debugfs.c
> index ec0df2f9188e..a6e94c29fc5a 100644
> --- a/net/bluetooth/hci_debugfs.c
> +++ b/net/bluetooth/hci_debugfs.c
> @@ -310,6 +310,9 @@ DEFINE_INFO_ATTRIBUTE(firmware_info, fw_info);
> 
>  void hci_debugfs_create_common(struct hci_dev *hdev)
>  {
> +       if (!hci_dev_test_flag(hdev, HCI_SETUP))
> +               return;
> +
>         debugfs_create_file("features", 0444, hdev->debugfs, hdev,
>                             &features_fops);
>         debugfs_create_u16("manufacturer", 0444, hdev->debugfs,
> 

What I tried to explain above is that doing this would always create
the attributes as setup-time rather than at config-time, which
effectively reverts commit ec6cef9cd98d ("Bluetooth: Fix SMP channel
registration for unconfigured controllers"). And doing so looks like it
would amount to a regression.

Johan

[PATCH 2/2] Bluetooth: hci_qca: fix debugfs registration

[Johan Hovold]

Since commit 3e4be65eb82c ("Bluetooth: hci_qca: Add poweroff support
during hci down for wcn3990"), the setup callback which registers the
debugfs interface can be called multiple times.

This specifically leads to the following error when powering on the
controller:

	debugfs: Directory 'ibs' with parent 'hci0' already present!

Add a driver flag to avoid trying to register the debugfs interface more
than once.

Fixes: 3e4be65eb82c ("Bluetooth: hci_qca: Add poweroff support during hci down for wcn3990")
Cc: stable@vger.kernel.org	# 4.20
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/bluetooth/hci_qca.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index 38ff962662ff..db020c04b3e8 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -78,7 +78,8 @@ enum qca_flags {
 	QCA_HW_ERROR_EVENT,
 	QCA_SSR_TRIGGERED,
 	QCA_BT_OFF,
-	QCA_ROM_FW
+	QCA_ROM_FW,
+	QCA_DEBUGFS_CREATED,
 };
 
 enum qca_capabilities {
@@ -635,6 +636,9 @@ static void qca_debugfs_init(struct hci_dev *hdev)
 	if (!hdev->debugfs)
 		return;
 
+	if (test_and_set_bit(QCA_DEBUGFS_CREATED, &qca->flags))
+		return;
+
 	ibs_dir = debugfs_create_dir("ibs", hdev->debugfs);
 
 	/* read only */
-- 
2.39.2

Re: [PATCH 0/2] Bluetooth: fix debugfs registration

[Johan Hovold]

On Mon, Apr 24, 2023 at 02:48:50PM +0200, Johan Hovold wrote:
> The HCI controller debugfs interface is created during setup or when a
> controller is configured, but there is nothing preventing a controller
> from being configured multiple times (e.g. by setting the device
> address), which results in a host of errors in the logs:
> 
> 	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!
> 
> The Qualcomm driver suffers from a related problem for controllers with
> non-persistent setup.
>
> 
> Johan Hovold (2):
>   Bluetooth: fix debugfs registration
>   Bluetooth: hci_qca: fix debugfs registration
> 
>  drivers/bluetooth/hci_qca.c | 6 +++++-
>  include/net/bluetooth/hci.h | 1 +
>  net/bluetooth/hci_sync.c    | 3 +++
>  3 files changed, 9 insertions(+), 1 deletion(-)

Are there any more comments to this series or can we can get this merged
for 6.5?

I hope this is not blocked on the bogus checkpatch warning the robot
posted?

Johan