Commit 58c644ba authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

sched/idle: Fix arch_cpu_idle() vs tracing 



We call arch_cpu_idle() with RCU disabled, but then use
local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.

Switch all arch_cpu_idle() implementations to use
raw_local_irq_{en,dis}able() and carefully manage the
lockdep,rcu,tracing state like we do in entry.

(XXX: we really should change arch_cpu_idle() to not return with
interrupts enabled)

Reported-by: default avatarSven Schnelle <svens@linux.ibm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org
parent 43be4388

arch/alpha/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ EXPORT_SYMBOL(pm_power_off); 
void arch_cpu_idle(void)

{

	wtint(0);

	local_irq_enable();

	raw_local_irq_enable();

}



void arch_cpu_idle_dead(void)

arch/arm/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -71,7 +71,7 @@ void arch_cpu_idle(void) 
		arm_pm_idle();

	else

		cpu_do_idle();

	local_irq_enable();

	raw_local_irq_enable();

}



void arch_cpu_idle_prepare(void)

arch/arm64/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -126,7 +126,7 @@ void arch_cpu_idle(void) 
	 * tricks

	 */

	cpu_do_idle();

	local_irq_enable();

	raw_local_irq_enable();

}



#ifdef CONFIG_HOTPLUG_CPU

arch/csky/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -102,6 +102,6 @@ void arch_cpu_idle(void) 
#ifdef CONFIG_CPU_PM_STOP

	asm volatile("stop\n");

#endif

	local_irq_enable();

	raw_local_irq_enable();

}

#endif

arch/h8300/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ asmlinkage void ret_from_kernel_thread(void); 
 */

void arch_cpu_idle(void)

{

	local_irq_enable();

	raw_local_irq_enable();

	__asm__("sleep");

}

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