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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Thu, 23 Jan 2014 14:45:59 +0100
Subject: [PATCH] leds: trigger: Disable CPU trigger on PREEMPT_RT
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.15/older/patches-5.15.3-rt21.tar.xz
The CPU trigger is invoked on ARM from CPU-idle. That trigger later
invokes led_trigger_event() which may invoke the callback of the actual driver.
That driver can acquire a spinlock_t which is okay on kernel without
PREEMPT_RT. On PREEMPT_RT enabled kernel this lock is turned into a sleeping
lock and must not be acquired with disabled interrupts.
Disable the CPU trigger on PREEMPT_RT.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20210924111501.m57cwwn7ahiyxxdd@linutronix.de
---
drivers/leds/trigger/Kconfig | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -64,6 +64,7 @@ config LEDS_TRIGGER_BACKLIGHT
config LEDS_TRIGGER_CPU
bool "LED CPU Trigger"
+ depends on !PREEMPT_RT
help
This allows LEDs to be controlled by active CPUs. This shows
the active CPUs across an array of LEDs so you can see which
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