On Thu, 14 Dec 2023, George Stark wrote: > This patch series fixes the problem of devm_led_classdev_register misusing. > > The basic problem is described in [1]. Shortly when devm_led_classdev_register() > is used then led_classdev_unregister() called after driver's remove() callback. > led_classdev_unregister() calls driver's brightness_set callback and that callback > may use resources which were destroyed already in driver's remove(). > > After discussion with maintainers [2] [3] we decided: > 1) don't touch led subsytem core code and don't remove led_set_brightness() from it > but fix drivers > 2) don't use devm_led_classdev_unregister > > So the solution is to use devm wrappers for all resources > driver's brightness_set() depends on. And introduce dedicated devm wrapper > for mutex as it's often used resource. > > [1] https://lore.kernel.org/lkml/8704539b-ed3b-44e6-aa82-586e2f895e2b@xxxxxxxxxxxxxxxxx/T/ > [2] https://lore.kernel.org/lkml/8704539b-ed3b-44e6-aa82-586e2f895e2b@xxxxxxxxxxxxxxxxx/T/#mc132b9b350fa51931b4fcfe14705d9f06e91421f > [3] https://lore.kernel.org/lkml/8704539b-ed3b-44e6-aa82-586e2f895e2b@xxxxxxxxxxxxxxxxx/T/#mdbf572a85c33f869a553caf986b6228bb65c8383 > > Changelog: > v1->v2: > revise patch series completely > > v2->v3: > locking: add define if mutex_destroy() is not an empty function > new patch, discussed here [8] > > devm-helpers: introduce devm_mutex_init > previous version [4] > - revise code based on mutex_destroy define > - update commit message > - update devm_mutex_init()'s description > > leds: aw2013: unlock mutex before destroying it > previous version [5] > - make this patch first in the series > - add tags Fixes and RvB by Andy > > leds: aw2013: use devm API to cleanup module's resources > previous version [6] > - make aw2013_chip_disable_action()'s body oneline > - don't shadow devm_mutex_init() return code > > leds: aw200xx: use devm API to cleanup module's resources > previous version [7] > - make aw200xx_*_action()'s bodies oneline > - don't shadow devm_mutex_init() return code > > leds: lm3532: use devm API to cleanup module's resources > leds: nic78bx: use devm API to cleanup module's resources > leds: mlxreg: use devm_mutex_init for mutex initializtion > leds: an30259a: use devm_mutext_init for mutext initialization > leds: powernv: add LED_RETAIN_AT_SHUTDOWN flag for leds > - those pathes were planned but not sent in the series #2 due to mail server > problem on my side. I revised them according to the comments. > > v3->v4: > locking: introduce devm_mutex_init > new patch > - move devm_mutex_init implementation completely from devm-helpers.h to mutex.h > > locking: add define if mutex_destroy() is not an empty function > drop the patch [9] > > devm-helpers: introduce devm_mutex_init > drop the patch [10] > > leds: aw2013: use devm API to cleanup module's resources > - add tag Tested-by: Nikita Travkin <nikita@xxxxxxx> > > [4] https://lore.kernel.org/lkml/20231204180603.470421-1-gnstark@xxxxxxxxxxxxxxxxx/T/#mf500af0eda2a9ffc95594607dbe4cb64f2e3c9a8 > [5] https://lore.kernel.org/lkml/20231204180603.470421-1-gnstark@xxxxxxxxxxxxxxxxx/T/#mc92df4fb4f7d4187fb01cc1144acfa5fb5230dd2 > [6] https://lore.kernel.org/lkml/20231204180603.470421-1-gnstark@xxxxxxxxxxxxxxxxx/T/#m300df89710c43cc2ab598baa16c68dd0a0d7d681 > [7] https://lore.kernel.org/lkml/20231204180603.470421-1-gnstark@xxxxxxxxxxxxxxxxx/T/#m8e5c65e0c6b137c91fa00bb9320ad581164d1d0b > [8] https://lore.kernel.org/lkml/377e4437-7051-4d88-ae68-1460bcd692e1@xxxxxxxxxx/T/#m5f84a4a2f387d49678783e652b9e658e02c27450 > [9] https://lore.kernel.org/lkml/20231213223020.2713164-1-gnstark@xxxxxxxxxxxxxxxxx/T/#m19ad1fc04c560012c1e27418e3156d0c9306dd84 > [10] https://lore.kernel.org/lkml/20231213223020.2713164-1-gnstark@xxxxxxxxxxxxxxxxx/T/#m63126025f5d1bdcef69bcad50f2e58274d42e2d7 > > George Stark (10): > leds: aw2013: unlock mutex before destroying it > locking: introduce devm_mutex_init > leds: aw2013: use devm API to cleanup module's resources > leds: aw200xx: use devm API to cleanup module's resources > leds: lp3952: use devm API to cleanup module's resources > leds: lm3532: use devm API to cleanup module's resources > leds: nic78bx: use devm API to cleanup module's resources > leds: mlxreg: use devm_mutex_init for mutex initializtion > leds: an30259a: use devm_mutext_init for mutext initialization > leds: powernv: use LED_RETAIN_AT_SHUTDOWN flag for leds > > drivers/leds/leds-an30259a.c | 15 +++++---------- > drivers/leds/leds-aw200xx.c | 33 ++++++++++++++++++++++----------- > drivers/leds/leds-aw2013.c | 27 +++++++++++++++------------ > drivers/leds/leds-lm3532.c | 30 ++++++++++++++++++------------ > drivers/leds/leds-lp3952.c | 21 +++++++++++---------- > drivers/leds/leds-mlxreg.c | 17 ++++++----------- > drivers/leds/leds-nic78bx.c | 25 +++++++++++++------------ > drivers/leds/leds-powernv.c | 23 ++++++++--------------- FYI: I'll conduct my review once the locking side is settled. > include/linux/mutex.h | 23 +++++++++++++++++++++++ > kernel/locking/mutex-debug.c | 22 ++++++++++++++++++++++ > 10 files changed, 143 insertions(+), 93 deletions(-) > > -- > 2.25.1 > > -- Lee Jones [李琼斯]
