/*
* Detect Soft Lockups
*
- * started by Ingo Molnar, Copyright (C) 2005, 2006 Red Hat, Inc.
+ * started by Ingo Molnar, (C) 2005, Red Hat
*
* this code detects soft lockups: incidents in where on a CPU
* the kernel does not reschedule for 10 seconds or more.
*/
+
#include <linux/mm.h>
#include <linux/cpu.h>
#include <linux/init.h>
static DEFINE_SPINLOCK(print_lock);
-static DEFINE_PER_CPU(unsigned long, touch_timestamp);
-static DEFINE_PER_CPU(unsigned long, print_timestamp);
+static DEFINE_PER_CPU(unsigned long, timestamp) = 0;
+static DEFINE_PER_CPU(unsigned long, print_timestamp) = 0;
static DEFINE_PER_CPU(struct task_struct *, watchdog_task);
static int did_panic = 0;
-
-static int
-softlock_panic(struct notifier_block *this, unsigned long event, void *ptr)
+static int softlock_panic(struct notifier_block *this, unsigned long event,
+ void *ptr)
{
did_panic = 1;
void touch_softlockup_watchdog(void)
{
- __raw_get_cpu_var(touch_timestamp) = jiffies;
+ per_cpu(timestamp, raw_smp_processor_id()) = jiffies;
}
EXPORT_SYMBOL(touch_softlockup_watchdog);
* This callback runs from the timer interrupt, and checks
* whether the watchdog thread has hung or not:
*/
-void softlockup_tick(void)
+void softlockup_tick(struct pt_regs *regs)
{
int this_cpu = smp_processor_id();
- unsigned long touch_timestamp = per_cpu(touch_timestamp, this_cpu);
+ unsigned long timestamp = per_cpu(timestamp, this_cpu);
- /* prevent double reports: */
- if (per_cpu(print_timestamp, this_cpu) == touch_timestamp ||
- did_panic ||
- !per_cpu(watchdog_task, this_cpu))
+ if (per_cpu(print_timestamp, this_cpu) == timestamp)
return;
- /* do not print during early bootup: */
- if (unlikely(system_state != SYSTEM_RUNNING)) {
- touch_softlockup_watchdog();
+ /* Do not cause a second panic when there already was one */
+ if (did_panic)
return;
- }
- /* Wake up the high-prio watchdog task every second: */
- if (time_after(jiffies, touch_timestamp + HZ))
- wake_up_process(per_cpu(watchdog_task, this_cpu));
-
- /* Warn about unreasonable 10+ seconds delays: */
- if (time_after(jiffies, touch_timestamp + 10*HZ)) {
- per_cpu(print_timestamp, this_cpu) = touch_timestamp;
+ if (time_after(jiffies, timestamp + 10*HZ)) {
+ per_cpu(print_timestamp, this_cpu) = timestamp;
spin_lock(&print_lock);
printk(KERN_ERR "BUG: soft lockup detected on CPU#%d!\n",
this_cpu);
- dump_stack();
+ show_regs(regs);
spin_unlock(&print_lock);
}
}
sched_setscheduler(current, SCHED_FIFO, ¶m);
current->flags |= PF_NOFREEZE;
+ set_current_state(TASK_INTERRUPTIBLE);
+
/*
- * Run briefly once per second to reset the softlockup timestamp.
- * If this gets delayed for more than 10 seconds then the
- * debug-printout triggers in softlockup_tick().
+ * Run briefly once per second - if this gets delayed for
+ * more than 10 seconds then the debug-printout triggers
+ * in softlockup_tick():
*/
while (!kthread_should_stop()) {
- set_current_state(TASK_INTERRUPTIBLE);
+ msleep_interruptible(1000);
touch_softlockup_watchdog();
- schedule();
}
+ __set_current_state(TASK_RUNNING);
return 0;
}
/*
* Create/destroy watchdog threads as CPUs come and go:
*/
-static int __cpuinit
+static int __devinit
cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
{
int hotcpu = (unsigned long)hcpu;
printk("watchdog for %i failed\n", hotcpu);
return NOTIFY_BAD;
}
- per_cpu(touch_timestamp, hotcpu) = jiffies;
per_cpu(watchdog_task, hotcpu) = p;
kthread_bind(p, hotcpu);
break;
case CPU_ONLINE:
+
wake_up_process(per_cpu(watchdog_task, hotcpu));
break;
#ifdef CONFIG_HOTPLUG_CPU
case CPU_UP_CANCELED:
- if (!per_cpu(watchdog_task, hotcpu))
- break;
/* Unbind so it can run. Fall thru. */
kthread_bind(per_cpu(watchdog_task, hotcpu),
any_online_cpu(cpu_online_map));
return NOTIFY_OK;
}
-static struct notifier_block __cpuinitdata cpu_nfb = {
+static struct notifier_block __devinitdata cpu_nfb = {
.notifier_call = cpu_callback
};
cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
register_cpu_notifier(&cpu_nfb);
- atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+ notifier_chain_register(&panic_notifier_list, &panic_block);
}
+