| Message ID | 20221205123903.159838-1-brgl@bgdev.pl |
|---|---|
| Headers | show |
| Series | gpiolib: don't allow user-space to crash the kernel with hot-unplugs | expand |
On Mon, Dec 5, 2022 at 1:39 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote: > > 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 > Reapplied again to get it back into next for testing. Bart
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(-)