From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Kent Gibson <warthog618@gmail.com>,
Linus Walleij <linus.walleij@linaro.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Nick Hainke <vincent@systemli.org>
Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Subject: [PATCH v7 0/2] gpiolib: don't allow user-space to crash the kernel with hot-unplugs
Date: Fri, 2 Dec 2022 16:04:42 +0100 [thread overview]
Message-ID: <20221202150444.244313-1-brgl@bgdev.pl> (raw)
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
I need to respin this series after Nick Hainke reported a build failure when
the v1 uAPI for character device is disabled. I also noticed that we need to
lower the semaphore when opening the character device file as well.
v6 -> v7:
- fix a build issue with CDEV_V1 code disabled (giving credit to Nick Hainke)
- protect the gdev->chip also in gpio_chrdev_open()
v5 -> v6:
- signal an error in poll callbacks instead of returning 0 which would make
the user-space assume a timeout occurred (which could lead to user-space
spinning a timeout loop forever)
v4 -> v5:
- try to acquire the semaphore for reading and bail out of syscall callbacks
immediately in case of lock contention
v3 -> v4:
- use function typedefs to make code cleaner
- add a blank line after down_write()
v2 -> v3:
- drop the helper variable in patch 1/2 as we won't be using it in 2/2
- refactor patch 2/2 to use locking wrappers around the syscall callbacks
v1 -> v2:
- add missing gdev->chip checks in patch 1/2
- add a second patch that protects the structures that can be accessed
by user-space calls against concurrent removal
Bartosz Golaszewski (2):
gpiolib: cdev: fix NULL-pointer dereferences
gpiolib: protect the GPIO device against being dropped while in use by
user-space
drivers/gpio/gpiolib-cdev.c | 207 +++++++++++++++++++++++++++++++-----
drivers/gpio/gpiolib.c | 4 +
drivers/gpio/gpiolib.h | 5 +
3 files changed, 191 insertions(+), 25 deletions(-)
--
2.37.2
next reply other threads:[~2022-12-02 15:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-02 15:04 Bartosz Golaszewski [this message]
2022-12-02 15:04 ` [PATCH v7 1/2] gpiolib: cdev: fix NULL-pointer dereferences Bartosz Golaszewski
2022-12-02 15:04 ` [PATCH v7 2/2] gpiolib: protect the GPIO device against being dropped while in use by user-space Bartosz Golaszewski
2022-12-02 15:44 ` Andy Shevchenko
2022-12-02 15:47 ` Bartosz Golaszewski
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