Commit 300d3739 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

Revert "NMI watchdog: fix for lockup detector breakage on resume" 



Revert commit 45226e94 (NMI watchdog: fix for lockup detector breakage
on resume) which breaks resume from system suspend on my SH7372
Mackerel board (by causing a NULL pointer dereference to happen) and
is generally wrong, because it abuses the CPU hotplug functionality
in a shamelessly blatant way.

The original issue should be addressed through appropriate syscore
resume callback instead.

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 77254950

include/linux/sched.h

+0 −8
Original line number Diff line number Diff line
@@ -334,14 +334,6 @@ static inline void lockup_detector_init(void) 
}

#endif



#if defined(CONFIG_LOCKUP_DETECTOR) && defined(CONFIG_SUSPEND)

void lockup_detector_bootcpu_resume(void);

#else

static inline void lockup_detector_bootcpu_resume(void)

{

}

#endif



#ifdef CONFIG_DETECT_HUNG_TASK

extern unsigned int  sysctl_hung_task_panic;

extern unsigned long sysctl_hung_task_check_count;

kernel/power/suspend.c

+0 −3
Original line number Diff line number Diff line
@@ -178,9 +178,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) 
	arch_suspend_enable_irqs();

	BUG_ON(irqs_disabled());



	/* Kick the lockup detector */

	lockup_detector_bootcpu_resume();



 Enable_cpus:

	enable_nonboot_cpus();

kernel/watchdog.c

+2 −19
Original line number Diff line number Diff line
@@ -575,7 +575,7 @@ out: 
/*

 * Create/destroy watchdog threads as CPUs come and go:

 */

static int

static int __cpuinit

cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)

{

	int hotcpu = (unsigned long)hcpu;
@@ -610,27 +610,10 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) 
	return NOTIFY_OK;

}



static struct notifier_block cpu_nfb = {

static struct notifier_block __cpuinitdata cpu_nfb = {

	.notifier_call = cpu_callback

};



#ifdef CONFIG_SUSPEND

/*

 * On exit from suspend we force an offline->online transition on the boot CPU

 * so that the PMU state that was lost while in suspended state gets set up

 * properly for the boot CPU.  This information is required for restarting the

 * NMI watchdog.

 */

void lockup_detector_bootcpu_resume(void)

{

	void *cpu = (void *)(long)smp_processor_id();



	cpu_callback(&cpu_nfb, CPU_DEAD_FROZEN, cpu);

	cpu_callback(&cpu_nfb, CPU_UP_PREPARE_FROZEN, cpu);

	cpu_callback(&cpu_nfb, CPU_ONLINE_FROZEN, cpu);

}

#endif



void __init lockup_detector_init(void)

{

	void *cpu = (void *)(long)smp_processor_id();

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