Messages in this thread | | | From | Bartosz Golaszewski <> | Subject | [PATCH v8 0/2] gpiolib: don't allow user-space to crash the kernel with hot-unplugs | Date | Mon, 5 Dec 2022 13:39:01 +0100 |
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From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Linus Torvalds pointed out that using trylock here is wrong. This iteration drops it in favor of unconditional locks but keeps all the fixes that came later.
I will also not send it for this release but make it part of the updates PR for v6.2 to give it some time in next.
v7 -> v8: - don't use down_read_trylock(), just go straight for a full lock
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 | 204 +++++++++++++++++++++++++++++++----- drivers/gpio/gpiolib.c | 4 + drivers/gpio/gpiolib.h | 5 + 3 files changed, 188 insertions(+), 25 deletions(-)
-- 2.37.2
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