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

Revert commit 45226e9 (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: Rafael J. Wysocki <rjw@sisk.pl>
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1 parent 7725495 commit 300d3739e873d50d4c6e3656f89007a217fb1d29 @rjwysocki rjwysocki committed Aug 7, 2012
Showing with 2 additions and 30 deletions.
  1. +0 −8 include/linux/sched.h
  2. +0 −3 kernel/power/suspend.c
  3. +2 −19 kernel/watchdog.c
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@@ -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;
View
@@ -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();
View
@@ -575,7 +575,7 @@ int proc_dowatchdog(struct ctl_table *table, int write,
/*
* 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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