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Message-Id: <20221201083335.819190-1-brgl@bgdev.pl>
Date: Thu, 1 Dec 2022 09:33:33 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Kent Gibson <warthog618@...il.com>,
Linus Walleij <linus.walleij@...aro.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH v5 0/2] gpiolib: don't allow user-space to crash the kernel with hot-unplugs
From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
This is (hopefully) the final iteration of the changes that aim at fixing
the situation in which the user-space can provoke a NULL-pointer derefence
in the kernel when a GPIO device that's in use by user-space is removed.
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 | 193 ++++++++++++++++++++++++++++++++----
drivers/gpio/gpiolib.c | 4 +
drivers/gpio/gpiolib.h | 5 +
3 files changed, 180 insertions(+), 22 deletions(-)
--
2.37.2
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