leds: trigger: Disable CPU trigger on PREEMPT_RT

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 a 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 <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Pavel Machek <[email protected]>

diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index 1f1d572880859c3dd9cad472ca3071af6e331439..dc6816d36d069042676e40297254422b8fbd27c2 100644 (file)
--- 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