*/
#include <linux/mm.h>
#include <linux/cpu.h>
+#include <linux/nmi.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
+#include <linux/lockdep.h>
#include <linux/notifier.h>
#include <linux/module.h>
+#include <linux/sysctl.h>
#include <asm/irq_regs.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(struct task_struct *, watchdog_task);
+static DEFINE_PER_CPU(unsigned long, softlockup_touch_ts); /* touch timestamp */
+static DEFINE_PER_CPU(unsigned long, softlockup_print_ts); /* print timestamp */
+static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
+static DEFINE_PER_CPU(bool, softlock_touch_sync);
-static int did_panic;
-int softlockup_thresh = 10;
+static int __read_mostly did_panic;
+int __read_mostly softlockup_thresh = 60;
+
+/*
+ * Should we panic (and reboot, if panic_timeout= is set) when a
+ * soft-lockup occurs:
+ */
+unsigned int __read_mostly softlockup_panic =
+ CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE;
+
+static int __init softlockup_panic_setup(char *str)
+{
+ softlockup_panic = simple_strtoul(str, NULL, 0);
+
+ return 1;
+}
+__setup("softlockup_panic=", softlockup_panic_setup);
static int
softlock_panic(struct notifier_block *this, unsigned long event, void *ptr)
*/
static unsigned long get_timestamp(int this_cpu)
{
- return cpu_clock(this_cpu) >> 30; /* 2^30 ~= 10^9 */
+ return cpu_clock(this_cpu) >> 30LL; /* 2^30 ~= 10^9 */
}
-void touch_softlockup_watchdog(void)
+static void __touch_softlockup_watchdog(void)
{
int this_cpu = raw_smp_processor_id();
- __raw_get_cpu_var(touch_timestamp) = get_timestamp(this_cpu);
+ __raw_get_cpu_var(softlockup_touch_ts) = get_timestamp(this_cpu);
+}
+
+void touch_softlockup_watchdog(void)
+{
+ __raw_get_cpu_var(softlockup_touch_ts) = 0;
}
EXPORT_SYMBOL(touch_softlockup_watchdog);
+void touch_softlockup_watchdog_sync(void)
+{
+ __raw_get_cpu_var(softlock_touch_sync) = true;
+ __raw_get_cpu_var(softlockup_touch_ts) = 0;
+}
+
void touch_all_softlockup_watchdogs(void)
{
int cpu;
/* Cause each CPU to re-update its timestamp rather than complain */
for_each_online_cpu(cpu)
- per_cpu(touch_timestamp, cpu) = 0;
+ per_cpu(softlockup_touch_ts, cpu) = 0;
}
EXPORT_SYMBOL(touch_all_softlockup_watchdogs);
+int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
+ void __user *buffer,
+ size_t *lenp, loff_t *ppos)
+{
+ touch_all_softlockup_watchdogs();
+ return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+}
+
/*
* This callback runs from the timer interrupt, and checks
* whether the watchdog thread has hung or not:
void softlockup_tick(void)
{
int this_cpu = smp_processor_id();
- unsigned long touch_timestamp = per_cpu(touch_timestamp, this_cpu);
- unsigned long print_timestamp;
+ unsigned long touch_ts = per_cpu(softlockup_touch_ts, this_cpu);
+ unsigned long print_ts;
struct pt_regs *regs = get_irq_regs();
unsigned long now;
- if (touch_timestamp == 0) {
- touch_softlockup_watchdog();
+ /* Is detection switched off? */
+ if (!per_cpu(softlockup_watchdog, this_cpu) || softlockup_thresh <= 0) {
+ /* Be sure we don't false trigger if switched back on */
+ if (touch_ts)
+ per_cpu(softlockup_touch_ts, this_cpu) = 0;
return;
}
- print_timestamp = per_cpu(print_timestamp, this_cpu);
+ if (touch_ts == 0) {
+ if (unlikely(per_cpu(softlock_touch_sync, this_cpu))) {
+ /*
+ * If the time stamp was touched atomically
+ * make sure the scheduler tick is up to date.
+ */
+ per_cpu(softlock_touch_sync, this_cpu) = false;
+ sched_clock_tick();
+ }
+ __touch_softlockup_watchdog();
+ return;
+ }
+
+ print_ts = per_cpu(softlockup_print_ts, this_cpu);
/* report at most once a second */
- if ((print_timestamp >= touch_timestamp &&
- print_timestamp < (touch_timestamp + 1)) ||
- did_panic || !per_cpu(watchdog_task, this_cpu)) {
+ if (print_ts == touch_ts || did_panic)
return;
- }
/* do not print during early bootup: */
if (unlikely(system_state != SYSTEM_RUNNING)) {
- touch_softlockup_watchdog();
+ __touch_softlockup_watchdog();
return;
}
now = get_timestamp(this_cpu);
- /* Wake up the high-prio watchdog task every second: */
- if (now > (touch_timestamp + 1))
- wake_up_process(per_cpu(watchdog_task, this_cpu));
+ /*
+ * Wake up the high-prio watchdog task twice per
+ * threshold timespan.
+ */
+ if (now > touch_ts + softlockup_thresh/2)
+ wake_up_process(per_cpu(softlockup_watchdog, this_cpu));
- /* Warn about unreasonable 10+ seconds delays: */
- if (now <= (touch_timestamp + softlockup_thresh))
+ /* Warn about unreasonable delays: */
+ if (now <= (touch_ts + softlockup_thresh))
return;
- per_cpu(print_timestamp, this_cpu) = touch_timestamp;
+ per_cpu(softlockup_print_ts, this_cpu) = touch_ts;
spin_lock(&print_lock);
printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %lus! [%s:%d]\n",
- this_cpu, now - touch_timestamp,
+ this_cpu, now - touch_ts,
current->comm, task_pid_nr(current));
+ print_modules();
+ print_irqtrace_events(current);
if (regs)
show_regs(regs);
else
dump_stack();
spin_unlock(&print_lock);
+
+ if (softlockup_panic)
+ panic("softlockup: hung tasks");
}
/*
sched_setscheduler(current, SCHED_FIFO, ¶m);
/* initialize timestamp */
- touch_softlockup_watchdog();
+ __touch_softlockup_watchdog();
+ 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
+ * If this gets delayed for more than 60 seconds then the
* debug-printout triggers in softlockup_tick().
*/
while (!kthread_should_stop()) {
- set_current_state(TASK_INTERRUPTIBLE);
- touch_softlockup_watchdog();
+ __touch_softlockup_watchdog();
schedule();
+
+ if (kthread_should_stop())
+ break;
+
+ set_current_state(TASK_INTERRUPTIBLE);
}
+ __set_current_state(TASK_RUNNING);
return 0;
}
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
- BUG_ON(per_cpu(watchdog_task, hotcpu));
+ BUG_ON(per_cpu(softlockup_watchdog, hotcpu));
p = kthread_create(watchdog, hcpu, "watchdog/%d", hotcpu);
if (IS_ERR(p)) {
printk(KERN_ERR "watchdog for %i failed\n", hotcpu);
return NOTIFY_BAD;
}
- per_cpu(touch_timestamp, hotcpu) = 0;
- per_cpu(watchdog_task, hotcpu) = p;
+ per_cpu(softlockup_touch_ts, hotcpu) = 0;
+ per_cpu(softlockup_watchdog, hotcpu) = p;
kthread_bind(p, hotcpu);
break;
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
- wake_up_process(per_cpu(watchdog_task, hotcpu));
+ wake_up_process(per_cpu(softlockup_watchdog, hotcpu));
break;
#ifdef CONFIG_HOTPLUG_CPU
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
- if (!per_cpu(watchdog_task, hotcpu))
+ if (!per_cpu(softlockup_watchdog, hotcpu))
break;
/* Unbind so it can run. Fall thru. */
- kthread_bind(per_cpu(watchdog_task, hotcpu),
- any_online_cpu(cpu_online_map));
+ kthread_bind(per_cpu(softlockup_watchdog, hotcpu),
+ cpumask_any(cpu_online_mask));
case CPU_DEAD:
case CPU_DEAD_FROZEN:
- p = per_cpu(watchdog_task, hotcpu);
- per_cpu(watchdog_task, hotcpu) = NULL;
+ p = per_cpu(softlockup_watchdog, hotcpu);
+ per_cpu(softlockup_watchdog, hotcpu) = NULL;
kthread_stop(p);
break;
#endif /* CONFIG_HOTPLUG_CPU */
.notifier_call = cpu_callback
};
-__init void spawn_softlockup_task(void)
+static int __initdata nosoftlockup;
+
+static int __init nosoftlockup_setup(char *str)
+{
+ nosoftlockup = 1;
+ return 1;
+}
+__setup("nosoftlockup", nosoftlockup_setup);
+
+static int __init spawn_softlockup_task(void)
{
void *cpu = (void *)(long)smp_processor_id();
- int err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
+ int err;
- BUG_ON(err == NOTIFY_BAD);
+ if (nosoftlockup)
+ return 0;
+
+ err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
+ if (err == NOTIFY_BAD) {
+ BUG();
+ return 1;
+ }
cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
register_cpu_notifier(&cpu_nfb);
atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+
+ return 0;
}
+early_initcall(spawn_softlockup_task);
Code Review / linux-2.6.git / blobdiff