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 ++++++++--------------- include/linux/mutex.h | 23 +++++++++++++++++++++++ kernel/locking/mutex-debug.c | 22 ++++++++++++++++++++++ 10 files changed, 143 insertions(+), 93 deletions(-) -- 2.25.1
