[PATCH v8 0/8] devm_led_classdev_register() usage problem
From: George Stark
Date: Thu Apr 11 2024 - 13:40:48 EST
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 subsystem 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 one line
- 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 one line
- 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 initialization
leds: an30259a: use devm_mutext_init for mutext initialization
leds: powernv: add LED_RETAIN_AT_SHUTDOWN flag for leds
- those patches 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>
v4->v5:
leds: aw2013: unlock mutex before destroying it
merged separately and removed from the series
locking/mutex: move mutex_destroy() definition lower
introduce optional refactoring patch
locking/mutex: introduce devm_mutex_init
leave only one devm_mutex_init definition
add tag Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
leds* patches
remove #include <linux/devm-helpers.h> due to devm_mutex_init() in mutex.h now
v5->v6:
locking/mutex: move mutex_destroy() definition lower [11]
drop the patch due to devm_mutex_init block is big enough to be declared standalone.
locking/mutex: introduce devm_mutex_init
redesign devm_mutex_init function to macro to keep lockdep feature working
use typeof to redeclare mutex var in macro body (thanks to checkpatch)
previous version [12]
v6->v7:
locking/mutex: introduce devm_mutex_init
fix comment at __devm_mutex_init
move #include <linux/device.h> upper
commit message: change devm_mutex_init -> devm_mutex_init(), add point in the end
fix and move up tag Suggested-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
add tags (in the order received):
Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Reviewed-by: Marek Behún <kabel@xxxxxxxxxx>
Acked-by: Waiman Long <longman@xxxxxxxxxx>
leds: powernv: use LED_RETAIN_AT_SHUTDOWN flag for leds
remove the patch from this series to send it separately
leds: mlxreg: use devm_mutex_init() for mutex initialization
leds: an30259a: use devm_mutex_init() for mutex initialization
commit message: change devm_mutex_init -> devm_mutex_init()
add tag Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
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
add tag Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
v7->v8:
locking/mutex: introduce devm_mutex_init()
add EXPORT_SYMBOL_GPL(__devm_mutex_init) to mutex-debug.c
next changes were asked by Andy in [13]
leds: lp3952: use devm API to cleanup module's resources
drop type casting in gpio_set_low_action()
leds: lm3532: use devm API to cleanup module's resources
drop type casting in gpio_set_low_action()
leds: nic78bx: use devm API to cleanup module's resources
drop type casting in lock_led_reg_action()
[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/#m63126025f5d1bdcef69bcad50f2e58274d42e2d
[11] https://lore.kernel.org/lkml/20240307024034.1548605-2-gnstark@xxxxxxxxxxxxxxxxx/
[12] https://lore.kernel.org/lkml/20240307024034.1548605-3-gnstark@xxxxxxxxxxxxxxxxx/
[13] https://lore.kernel.org/lkml/CAHp75VeNijg6sXyW_frwD4siJ-LWBLBfVCmMDug8jYAVVg9Bmw@xxxxxxxxxxxxxx/
George Stark (8):
locking/mutex: 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 initialization
leds: an30259a: use devm_mutex_init() for mutex initialization
drivers/leds/leds-an30259a.c | 14 ++++----------
drivers/leds/leds-aw200xx.c | 32 +++++++++++++++++++++-----------
drivers/leds/leds-aw2013.c | 25 +++++++++++++------------
drivers/leds/leds-lm3532.c | 29 +++++++++++++++++------------
drivers/leds/leds-lp3952.c | 21 +++++++++++----------
drivers/leds/leds-mlxreg.c | 14 +++++---------
drivers/leds/leds-nic78bx.c | 23 +++++++++++++----------
include/linux/mutex.h | 27 +++++++++++++++++++++++++++
kernel/locking/mutex-debug.c | 12 ++++++++++++
9 files changed, 123 insertions(+), 74 deletions(-)
--
2.25.1