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Message-ID: <20240307024034.1548605-1-gnstark@salutedevices.com>
Date: Thu, 7 Mar 2024 05:40:24 +0300
From: George Stark <gnstark@...utedevices.com>
To: <andy.shevchenko@...il.com>, <pavel@....cz>, <lee@...nel.org>,
<vadimp@...dia.com>, <mpe@...erman.id.au>, <npiggin@...il.com>,
<christophe.leroy@...roup.eu>, <hdegoede@...hat.com>,
<mazziesaccount@...il.com>, <peterz@...radead.org>, <mingo@...hat.com>,
<will@...nel.org>, <longman@...hat.com>, <boqun.feng@...il.com>,
<nikitos.tr@...il.com>, <kabel@...nel.org>
CC: <linux-leds@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linuxppc-dev@...ts.ozlabs.org>, <kernel@...utedevices.com>, George Stark
<gnstark@...utedevices.com>
Subject: [PATCH v5 00/10] devm_led_classdev_register() usage problem
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@salutedevices.com/T/
[2] https://lore.kernel.org/lkml/8704539b-ed3b-44e6-aa82-586e2f895e2b@salutedevices.com/T/#mc132b9b350fa51931b4fcfe14705d9f06e91421f
[3] https://lore.kernel.org/lkml/8704539b-ed3b-44e6-aa82-586e2f895e2b@salutedevices.com/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@...n.ru>
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@...roup.eu>
leds* patches
remove #include <linux/devm-helpers.h> due to devm_mutext_init in mutex.h now
[4] https://lore.kernel.org/lkml/20231204180603.470421-1-gnstark@salutedevices.com/T/#mf500af0eda2a9ffc95594607dbe4cb64f2e3c9a8
[5] https://lore.kernel.org/lkml/20231204180603.470421-1-gnstark@salutedevices.com/T/#mc92df4fb4f7d4187fb01cc1144acfa5fb5230dd2
[6] https://lore.kernel.org/lkml/20231204180603.470421-1-gnstark@salutedevices.com/T/#m300df89710c43cc2ab598baa16c68dd0a0d7d681
[7] https://lore.kernel.org/lkml/20231204180603.470421-1-gnstark@salutedevices.com/T/#m8e5c65e0c6b137c91fa00bb9320ad581164d1d0b
[8] https://lore.kernel.org/lkml/377e4437-7051-4d88-ae68-1460bcd692e1@redhat.com/T/#m5f84a4a2f387d49678783e652b9e658e02c27450
[9] https://lore.kernel.org/lkml/20231213223020.2713164-1-gnstark@salutedevices.com/T/#m19ad1fc04c560012c1e27418e3156d0c9306dd84
[10] https://lore.kernel.org/lkml/20231213223020.2713164-1-gnstark@salutedevices.com/T/#m63126025f5d1bdcef69bcad50f2e58274d42e2d
George Stark (10):
locking/mutex: move mutex_destroy() definition lower
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 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 | 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 +++++++++++++----------
drivers/leds/leds-powernv.c | 23 ++++++++---------------
include/linux/mutex.h | 27 +++++++++++++++++++++++----
kernel/locking/mutex-debug.c | 22 ++++++++++++++++++++++
10 files changed, 137 insertions(+), 93 deletions(-)
--
2.25.1
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