From: Tzung-Bi Shih <tzungbi@kernel.org>
To: Bartosz Golaszewski <brgl@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>, Shuah Khan <shuah@kernel.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Jason Gunthorpe <jgg@nvidia.com>, Johan Hovold <johan@kernel.org>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
chrome-platform@lists.linux.dev,
Dan Williams <dan.j.williams@intel.com>,
linux-gpio@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Danilo Krummrich <dakr@kernel.org>,
Bartosz Golaszewski <brgl@bgdev.pl>,
Linus Walleij <linusw@kernel.org>
Subject: Re: [PATCH v2 07/11] gpio: Add revocable provider handle for struct gpio_chip
Date: Thu, 5 Feb 2026 08:52:06 +0000 [thread overview]
Message-ID: <aYRaNu-ZistKBPN-@google.com> (raw)
In-Reply-To: <CAMRc=MdYeoMxNFYeX_9S-M286aUjnsxLyy9_apmfPR4NeqVouw@mail.gmail.com>
On Wed, Feb 04, 2026 at 07:58:44AM -0500, Bartosz Golaszewski wrote:
> On Tue, 3 Feb 2026 07:10:54 +0100, Tzung-Bi Shih <tzungbi@kernel.org> said:
> > diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
> > index 3abb90385829..cd136d5b52e9 100644
> > --- a/drivers/gpio/gpiolib.h
> > +++ b/drivers/gpio/gpiolib.h
> > @@ -52,6 +52,7 @@
> > * @device_notifier: used to notify character device wait queues about the GPIO
> > * device being unregistered
> > * @srcu: protects the pointer to the underlying GPIO chip
> > + * @chip_rp: revocable provider handle for the corresponding struct gpio_chip.
> > * @pin_ranges: range of pins served by the GPIO driver
> > *
> > * This state container holds most of the runtime variable data
> > @@ -79,6 +80,7 @@ struct gpio_device {
> > struct workqueue_struct *line_state_wq;
> > struct blocking_notifier_head device_notifier;
> > struct srcu_struct srcu;
> > + struct revocable_provider __rcu *chip_rp;
> >
>
> Why __rcu? This doesn't live in a different address space, only the internal
> resource it protects does. If anything - this could be __attribute__((noderef))
> but even that is questionable as this is an opaque structure.
For fixing a race on the pointer itself. See also [1].
[1] https://lore.kernel.org/all/20260129143733.45618-2-tzungbi@kernel.org
next prev parent reply other threads:[~2026-02-05 8:52 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-03 6:10 [PATCH v2 00/11] gpio: Adopt revocable mechanism for UAF prevention Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 01/11] gpio: Access `gpio_bus_type` in gpiochip_setup_dev() Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 02/11] gpio: Remove redundant check for struct gpio_chip Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 03/11] gpio: sysfs: " Tzung-Bi Shih
2026-02-04 10:33 ` Bartosz Golaszewski
2026-02-05 8:51 ` Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 04/11] gpio: Ensure struct gpio_chip for gpiochip_setup_dev() Tzung-Bi Shih
2026-02-04 10:36 ` Bartosz Golaszewski
2026-02-05 8:51 ` Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 05/11] gpio: cdev: Don't check struct gpio_chip in gpio_chrdev_open() Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 06/11] selftests: gpio: Add gpio-cdev-uaf tests Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 07/11] gpio: Add revocable provider handle for struct gpio_chip Tzung-Bi Shih
2026-02-04 12:58 ` Bartosz Golaszewski
2026-02-05 8:52 ` Tzung-Bi Shih [this message]
2026-02-05 16:57 ` Bartosz Golaszewski
2026-02-06 9:13 ` Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 08/11] gpio: cdev: Leverage revocable for accessing " Tzung-Bi Shih
2026-02-03 9:51 ` Tzung-Bi Shih
2026-02-04 13:02 ` Bartosz Golaszewski
2026-02-03 6:10 ` [PATCH v2 09/11] gpio: Remove gpio_chip_guard by using revocable Tzung-Bi Shih
2026-02-04 13:05 ` Bartosz Golaszewski
2026-02-03 6:10 ` [PATCH v2 10/11] gpio: Leverage revocable for accessing struct gpio_chip Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 11/11] gpio: Remove unused `chip` and `srcu` in struct gpio_device Tzung-Bi Shih
2026-02-03 11:15 ` [PATCH v2 00/11] gpio: Adopt revocable mechanism for UAF prevention Bartosz Golaszewski
2026-02-03 16:53 ` Bartosz Golaszewski
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