nousb [USB] Disable the USB subsystem
+ nowatchdog [KNL] Disable the lockup detector.
+
nowb [ARM]
nox2apic [X86-64,APIC] Do not enable x2APIC mode.
config HAVE_USER_RETURN_NOTIFIER
bool
+config HAVE_PERF_EVENTS_NMI
+ bool
+ help
+ System hardware can generate an NMI using the perf event
+ subsystem. Also has support for calculating CPU cycle events
+ to determine how many clock cycles in a given period.
+
source "kernel/gcov/Kconfig"
select HAVE_HW_BREAKPOINT
select HAVE_MIXED_BREAKPOINTS_REGS
select PERF_EVENTS
+ select HAVE_PERF_EVENTS_NMI
select ANON_INODES
select HAVE_ARCH_KMEMCHECK
select HAVE_USER_RETURN_NOTIFIER
extern void die_nmi(char *str, struct pt_regs *regs, int do_panic);
extern int check_nmi_watchdog(void);
+#if !defined(CONFIG_LOCKUP_DETECTOR)
extern int nmi_watchdog_enabled;
+#endif
extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);
extern int reserve_perfctr_nmi(unsigned int);
extern void release_perfctr_nmi(unsigned int);
# Makefile for local APIC drivers and for the IO-APIC code
#
-obj-$(CONFIG_X86_LOCAL_APIC) += apic.o apic_noop.o probe_$(BITS).o ipi.o nmi.o
+obj-$(CONFIG_X86_LOCAL_APIC) += apic.o apic_noop.o probe_$(BITS).o ipi.o
+ifneq ($(CONFIG_HARDLOCKUP_DETECTOR),y)
+obj-$(CONFIG_X86_LOCAL_APIC) += nmi.o
+endif
+obj-$(CONFIG_HARDLOCKUP_DETECTOR) += hw_nmi.o
+
obj-$(CONFIG_X86_IO_APIC) += io_apic.o
obj-$(CONFIG_SMP) += ipi.o
--- /dev/null
+/*
+ * HW NMI watchdog support
+ *
+ * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
+ *
+ * Arch specific calls to support NMI watchdog
+ *
+ * Bits copied from original nmi.c file
+ *
+ */
+#include <asm/apic.h>
+
+#include <linux/cpumask.h>
+#include <linux/kdebug.h>
+#include <linux/notifier.h>
+#include <linux/kprobes.h>
+#include <linux/nmi.h>
+#include <linux/module.h>
+
+/* For reliability, we're prepared to waste bits here. */
+static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
+
+u64 hw_nmi_get_sample_period(void)
+{
+ return (u64)(cpu_khz) * 1000 * 60;
+}
+
+#ifdef ARCH_HAS_NMI_WATCHDOG
+void arch_trigger_all_cpu_backtrace(void)
+{
+ int i;
+
+ cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
+
+ printk(KERN_INFO "sending NMI to all CPUs:\n");
+ apic->send_IPI_all(NMI_VECTOR);
+
+ /* Wait for up to 10 seconds for all CPUs to do the backtrace */
+ for (i = 0; i < 10 * 1000; i++) {
+ if (cpumask_empty(to_cpumask(backtrace_mask)))
+ break;
+ mdelay(1);
+ }
+}
+
+static int __kprobes
+arch_trigger_all_cpu_backtrace_handler(struct notifier_block *self,
+ unsigned long cmd, void *__args)
+{
+ struct die_args *args = __args;
+ struct pt_regs *regs;
+ int cpu = smp_processor_id();
+
+ switch (cmd) {
+ case DIE_NMI:
+ case DIE_NMI_IPI:
+ break;
+
+ default:
+ return NOTIFY_DONE;
+ }
+
+ regs = args->regs;
+
+ if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
+ static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
+
+ arch_spin_lock(&lock);
+ printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
+ show_regs(regs);
+ dump_stack();
+ arch_spin_unlock(&lock);
+ cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
+ return NOTIFY_STOP;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static __read_mostly struct notifier_block backtrace_notifier = {
+ .notifier_call = arch_trigger_all_cpu_backtrace_handler,
+ .next = NULL,
+ .priority = 1
+};
+
+static int __init register_trigger_all_cpu_backtrace(void)
+{
+ register_die_notifier(&backtrace_notifier);
+ return 0;
+}
+early_initcall(register_trigger_all_cpu_backtrace);
+#endif
+
+/* STUB calls to mimic old nmi_watchdog behaviour */
+#if defined(CONFIG_X86_LOCAL_APIC)
+unsigned int nmi_watchdog = NMI_NONE;
+EXPORT_SYMBOL(nmi_watchdog);
+void acpi_nmi_enable(void) { return; }
+void acpi_nmi_disable(void) { return; }
+#endif
+atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
+EXPORT_SYMBOL(nmi_active);
+int unknown_nmi_panic;
+void cpu_nmi_set_wd_enabled(void) { return; }
+void stop_apic_nmi_watchdog(void *unused) { return; }
+void setup_apic_nmi_watchdog(void *unused) { return; }
+int __init check_nmi_watchdog(void) { return 0; }
int cpu = smp_processor_id();
int rc = 0;
- /* check for other users first */
- if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
- == NOTIFY_STOP) {
- rc = 1;
- touched = 1;
- }
-
sum = get_timer_irqs(cpu);
if (__get_cpu_var(nmi_touch)) {
if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
== NOTIFY_STOP)
return;
+
#ifdef CONFIG_X86_LOCAL_APIC
+ if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
+ == NOTIFY_STOP)
+ return;
+
+#ifndef CONFIG_LOCKUP_DETECTOR
/*
* Ok, so this is none of the documented NMI sources,
* so it must be the NMI watchdog.
if (nmi_watchdog_tick(regs, reason))
return;
if (!do_nmi_callback(regs, cpu))
+#endif /* !CONFIG_LOCKUP_DETECTOR */
unknown_nmi_error(reason, regs);
#else
unknown_nmi_error(reason, regs);
extern void acpi_nmi_disable(void);
extern void acpi_nmi_enable(void);
#else
+#ifndef CONFIG_HARDLOCKUP_DETECTOR
static inline void touch_nmi_watchdog(void)
{
touch_softlockup_watchdog();
}
+#else
+extern void touch_nmi_watchdog(void);
+#endif
static inline void acpi_nmi_disable(void) { }
static inline void acpi_nmi_enable(void) { }
#endif
}
#endif
+#ifdef CONFIG_LOCKUP_DETECTOR
+int hw_nmi_is_cpu_stuck(struct pt_regs *);
+u64 hw_nmi_get_sample_period(void);
+extern int watchdog_enabled;
+struct ctl_table;
+extern int proc_dowatchdog_enabled(struct ctl_table *, int ,
+ void __user *, size_t *, loff_t *);
+#endif
+
#endif
extern void sched_show_task(struct task_struct *p);
-#ifdef CONFIG_DETECT_SOFTLOCKUP
-extern void softlockup_tick(void);
+#ifdef CONFIG_LOCKUP_DETECTOR
extern void touch_softlockup_watchdog(void);
extern void touch_softlockup_watchdog_sync(void);
extern void touch_all_softlockup_watchdogs(void);
-extern int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
- void __user *buffer,
- size_t *lenp, loff_t *ppos);
+extern int proc_dowatchdog_thresh(struct ctl_table *table, int write,
+ void __user *buffer,
+ size_t *lenp, loff_t *ppos);
extern unsigned int softlockup_panic;
extern int softlockup_thresh;
#else
-static inline void softlockup_tick(void)
-{
-}
static inline void touch_softlockup_watchdog(void)
{
}
obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_KGDB) += debug/
-obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
+obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
obj-$(CONFIG_SECCOMP) += seccomp.o
obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
+++ /dev/null
-/*
- * Detect Soft Lockups
- *
- * started by Ingo Molnar, Copyright (C) 2005, 2006 Red Hat, Inc.
- *
- * 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/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, 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 __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)
-{
- did_panic = 1;
-
- return NOTIFY_DONE;
-}
-
-static struct notifier_block panic_block = {
- .notifier_call = softlock_panic,
-};
-
-/*
- * Returns seconds, approximately. We don't need nanosecond
- * resolution, and we don't need to waste time with a big divide when
- * 2^30ns == 1.074s.
- */
-static unsigned long get_timestamp(int this_cpu)
-{
- return cpu_clock(this_cpu) >> 30LL; /* 2^30 ~= 10^9 */
-}
-
-static void __touch_softlockup_watchdog(void)
-{
- int this_cpu = raw_smp_processor_id();
-
- __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(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_ts = per_cpu(softlockup_touch_ts, this_cpu);
- unsigned long print_ts;
- struct pt_regs *regs = get_irq_regs();
- unsigned long now;
-
- /* 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;
- }
-
- 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_ts == touch_ts || did_panic)
- return;
-
- /* do not print during early bootup: */
- if (unlikely(system_state != SYSTEM_RUNNING)) {
- __touch_softlockup_watchdog();
- return;
- }
-
- now = get_timestamp(this_cpu);
-
- /*
- * Wake up the high-prio watchdog task twice per
- * threshold timespan.
- */
- if (time_after(now - softlockup_thresh/2, touch_ts))
- wake_up_process(per_cpu(softlockup_watchdog, this_cpu));
-
- /* Warn about unreasonable delays: */
- if (time_before_eq(now - softlockup_thresh, touch_ts))
- return;
-
- 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_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");
-}
-
-/*
- * The watchdog thread - runs every second and touches the timestamp.
- */
-static int watchdog(void *__bind_cpu)
-{
- struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
-
- sched_setscheduler(current, SCHED_FIFO, ¶m);
-
- /* initialize timestamp */
- __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 60 seconds then the
- * debug-printout triggers in softlockup_tick().
- */
- while (!kthread_should_stop()) {
- __touch_softlockup_watchdog();
- schedule();
-
- if (kthread_should_stop())
- break;
-
- set_current_state(TASK_INTERRUPTIBLE);
- }
- __set_current_state(TASK_RUNNING);
-
- return 0;
-}
-
-/*
- * Create/destroy watchdog threads as CPUs come and go:
- */
-static int __cpuinit
-cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
-{
- int hotcpu = (unsigned long)hcpu;
- struct task_struct *p;
-
- switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- 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(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(softlockup_watchdog, hotcpu));
- break;
-#ifdef CONFIG_HOTPLUG_CPU
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- if (!per_cpu(softlockup_watchdog, hotcpu))
- break;
- /* Unbind so it can run. Fall thru. */
- kthread_bind(per_cpu(softlockup_watchdog, hotcpu),
- cpumask_any(cpu_online_mask));
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- p = per_cpu(softlockup_watchdog, hotcpu);
- per_cpu(softlockup_watchdog, hotcpu) = NULL;
- kthread_stop(p);
- break;
-#endif /* CONFIG_HOTPLUG_CPU */
- }
- return NOTIFY_OK;
-}
-
-static struct notifier_block __cpuinitdata cpu_nfb = {
- .notifier_call = cpu_callback
-};
-
-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;
-
- 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);
#include <scsi/sg.h>
#endif
+#ifdef CONFIG_LOCKUP_DETECTOR
+#include <linux/nmi.h>
+#endif
+
#if defined(CONFIG_SYSCTL)
#endif
/* Constants used for minimum and maximum */
-#ifdef CONFIG_DETECT_SOFTLOCKUP
+#ifdef CONFIG_LOCKUP_DETECTOR
static int sixty = 60;
static int neg_one = -1;
#endif
.mode = 0444,
.proc_handler = proc_dointvec,
},
-#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
+#if defined(CONFIG_LOCKUP_DETECTOR)
+ {
+ .procname = "watchdog",
+ .data = &watchdog_enabled,
+ .maxlen = sizeof (int),
+ .mode = 0644,
+ .proc_handler = proc_dowatchdog_enabled,
+ },
+ {
+ .procname = "watchdog_thresh",
+ .data = &softlockup_thresh,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dowatchdog_thresh,
+ .extra1 = &neg_one,
+ .extra2 = &sixty,
+ },
+ {
+ .procname = "softlockup_panic",
+ .data = &softlockup_panic,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+#endif
+#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) && !defined(CONFIG_LOCKUP_DETECTOR)
{
.procname = "unknown_nmi_panic",
.data = &unknown_nmi_panic,
.proc_handler = proc_dointvec,
},
#endif
-#ifdef CONFIG_DETECT_SOFTLOCKUP
- {
- .procname = "softlockup_panic",
- .data = &softlockup_panic,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = &zero,
- .extra2 = &one,
- },
- {
- .procname = "softlockup_thresh",
- .data = &softlockup_thresh,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dosoftlockup_thresh,
- .extra1 = &neg_one,
- .extra2 = &sixty,
- },
-#endif
#ifdef CONFIG_DETECT_HUNG_TASK
{
.procname = "hung_task_panic",
{
hrtimer_run_queues();
raise_softirq(TIMER_SOFTIRQ);
- softlockup_tick();
}
/*
--- /dev/null
+/*
+ * Detect hard and soft lockups on a system
+ *
+ * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
+ *
+ * this code detects hard lockups: incidents in where on a CPU
+ * the kernel does not respond to anything except NMI.
+ *
+ * Note: Most of this code is borrowed heavily from softlockup.c,
+ * so thanks to Ingo for the initial implementation.
+ * Some chunks also taken from arch/x86/kernel/apic/nmi.c, thanks
+ * to those contributors as well.
+ */
+
+#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>
+#include <linux/perf_event.h>
+
+int watchdog_enabled;
+int __read_mostly softlockup_thresh = 60;
+
+static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
+static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
+static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
+static DEFINE_PER_CPU(bool, softlockup_touch_sync);
+static DEFINE_PER_CPU(bool, soft_watchdog_warn);
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+static DEFINE_PER_CPU(bool, hard_watchdog_warn);
+static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
+static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
+static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
+static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
+#endif
+
+static int __read_mostly did_panic;
+static int __initdata no_watchdog;
+
+
+/* boot commands */
+/*
+ * Should we panic when a soft-lockup or hard-lockup occurs:
+ */
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+static int hardlockup_panic;
+
+static int __init hardlockup_panic_setup(char *str)
+{
+ if (!strncmp(str, "panic", 5))
+ hardlockup_panic = 1;
+ return 1;
+}
+__setup("nmi_watchdog=", hardlockup_panic_setup);
+#endif
+
+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 __init nowatchdog_setup(char *str)
+{
+ no_watchdog = 1;
+ return 1;
+}
+__setup("nowatchdog", nowatchdog_setup);
+
+/* deprecated */
+static int __init nosoftlockup_setup(char *str)
+{
+ no_watchdog = 1;
+ return 1;
+}
+__setup("nosoftlockup", nosoftlockup_setup);
+/* */
+
+
+/*
+ * Returns seconds, approximately. We don't need nanosecond
+ * resolution, and we don't need to waste time with a big divide when
+ * 2^30ns == 1.074s.
+ */
+static unsigned long get_timestamp(int this_cpu)
+{
+ return cpu_clock(this_cpu) >> 30LL; /* 2^30 ~= 10^9 */
+}
+
+static unsigned long get_sample_period(void)
+{
+ /*
+ * convert softlockup_thresh from seconds to ns
+ * the divide by 5 is to give hrtimer 5 chances to
+ * increment before the hardlockup detector generates
+ * a warning
+ */
+ return softlockup_thresh / 5 * NSEC_PER_SEC;
+}
+
+/* Commands for resetting the watchdog */
+static void __touch_watchdog(void)
+{
+ int this_cpu = smp_processor_id();
+
+ __get_cpu_var(watchdog_touch_ts) = get_timestamp(this_cpu);
+}
+
+void touch_softlockup_watchdog(void)
+{
+ __get_cpu_var(watchdog_touch_ts) = 0;
+}
+EXPORT_SYMBOL(touch_softlockup_watchdog);
+
+void touch_all_softlockup_watchdogs(void)
+{
+ int cpu;
+
+ /*
+ * this is done lockless
+ * do we care if a 0 races with a timestamp?
+ * all it means is the softlock check starts one cycle later
+ */
+ for_each_online_cpu(cpu)
+ per_cpu(watchdog_touch_ts, cpu) = 0;
+}
+
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+void touch_nmi_watchdog(void)
+{
+ __get_cpu_var(watchdog_nmi_touch) = true;
+ touch_softlockup_watchdog();
+}
+EXPORT_SYMBOL(touch_nmi_watchdog);
+
+#endif
+
+void touch_softlockup_watchdog_sync(void)
+{
+ __raw_get_cpu_var(softlockup_touch_sync) = true;
+ __raw_get_cpu_var(watchdog_touch_ts) = 0;
+}
+
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+/* watchdog detector functions */
+static int is_hardlockup(void)
+{
+ unsigned long hrint = __get_cpu_var(hrtimer_interrupts);
+
+ if (__get_cpu_var(hrtimer_interrupts_saved) == hrint)
+ return 1;
+
+ __get_cpu_var(hrtimer_interrupts_saved) = hrint;
+ return 0;
+}
+#endif
+
+static int is_softlockup(unsigned long touch_ts)
+{
+ unsigned long now = get_timestamp(smp_processor_id());
+
+ /* Warn about unreasonable delays: */
+ if (time_after(now, touch_ts + softlockup_thresh))
+ return now - touch_ts;
+
+ return 0;
+}
+
+static int
+watchdog_panic(struct notifier_block *this, unsigned long event, void *ptr)
+{
+ did_panic = 1;
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block panic_block = {
+ .notifier_call = watchdog_panic,
+};
+
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+static struct perf_event_attr wd_hw_attr = {
+ .type = PERF_TYPE_HARDWARE,
+ .config = PERF_COUNT_HW_CPU_CYCLES,
+ .size = sizeof(struct perf_event_attr),
+ .pinned = 1,
+ .disabled = 1,
+};
+
+/* Callback function for perf event subsystem */
+void watchdog_overflow_callback(struct perf_event *event, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
+{
+ if (__get_cpu_var(watchdog_nmi_touch) == true) {
+ __get_cpu_var(watchdog_nmi_touch) = false;
+ return;
+ }
+
+ /* check for a hardlockup
+ * This is done by making sure our timer interrupt
+ * is incrementing. The timer interrupt should have
+ * fired multiple times before we overflow'd. If it hasn't
+ * then this is a good indication the cpu is stuck
+ */
+ if (is_hardlockup()) {
+ int this_cpu = smp_processor_id();
+
+ /* only print hardlockups once */
+ if (__get_cpu_var(hard_watchdog_warn) == true)
+ return;
+
+ if (hardlockup_panic)
+ panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu);
+ else
+ WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu);
+
+ __get_cpu_var(hard_watchdog_warn) = true;
+ return;
+ }
+
+ __get_cpu_var(hard_watchdog_warn) = false;
+ return;
+}
+static void watchdog_interrupt_count(void)
+{
+ __get_cpu_var(hrtimer_interrupts)++;
+}
+#else
+static inline void watchdog_interrupt_count(void) { return; }
+#endif /* CONFIG_HARDLOCKUP_DETECTOR */
+
+/* watchdog kicker functions */
+static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
+{
+ unsigned long touch_ts = __get_cpu_var(watchdog_touch_ts);
+ struct pt_regs *regs = get_irq_regs();
+ int duration;
+
+ /* kick the hardlockup detector */
+ watchdog_interrupt_count();
+
+ /* kick the softlockup detector */
+ wake_up_process(__get_cpu_var(softlockup_watchdog));
+
+ /* .. and repeat */
+ hrtimer_forward_now(hrtimer, ns_to_ktime(get_sample_period()));
+
+ if (touch_ts == 0) {
+ if (unlikely(__get_cpu_var(softlockup_touch_sync))) {
+ /*
+ * If the time stamp was touched atomically
+ * make sure the scheduler tick is up to date.
+ */
+ __get_cpu_var(softlockup_touch_sync) = false;
+ sched_clock_tick();
+ }
+ __touch_watchdog();
+ return HRTIMER_RESTART;
+ }
+
+ /* check for a softlockup
+ * This is done by making sure a high priority task is
+ * being scheduled. The task touches the watchdog to
+ * indicate it is getting cpu time. If it hasn't then
+ * this is a good indication some task is hogging the cpu
+ */
+ duration = is_softlockup(touch_ts);
+ if (unlikely(duration)) {
+ /* only warn once */
+ if (__get_cpu_var(soft_watchdog_warn) == true)
+ return HRTIMER_RESTART;
+
+ printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
+ smp_processor_id(), duration,
+ current->comm, task_pid_nr(current));
+ print_modules();
+ print_irqtrace_events(current);
+ if (regs)
+ show_regs(regs);
+ else
+ dump_stack();
+
+ if (softlockup_panic)
+ panic("softlockup: hung tasks");
+ __get_cpu_var(soft_watchdog_warn) = true;
+ } else
+ __get_cpu_var(soft_watchdog_warn) = false;
+
+ return HRTIMER_RESTART;
+}
+
+
+/*
+ * The watchdog thread - touches the timestamp.
+ */
+static int watchdog(void *unused)
+{
+ struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+ struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer);
+
+ sched_setscheduler(current, SCHED_FIFO, ¶m);
+
+ /* initialize timestamp */
+ __touch_watchdog();
+
+ /* kick off the timer for the hardlockup detector */
+ /* done here because hrtimer_start can only pin to smp_processor_id() */
+ hrtimer_start(hrtimer, ns_to_ktime(get_sample_period()),
+ HRTIMER_MODE_REL_PINNED);
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ /*
+ * Run briefly once per second to reset the softlockup timestamp.
+ * If this gets delayed for more than 60 seconds then the
+ * debug-printout triggers in watchdog_timer_fn().
+ */
+ while (!kthread_should_stop()) {
+ __touch_watchdog();
+ schedule();
+
+ if (kthread_should_stop())
+ break;
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ }
+ __set_current_state(TASK_RUNNING);
+
+ return 0;
+}
+
+
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+static int watchdog_nmi_enable(int cpu)
+{
+ struct perf_event_attr *wd_attr;
+ struct perf_event *event = per_cpu(watchdog_ev, cpu);
+
+ /* is it already setup and enabled? */
+ if (event && event->state > PERF_EVENT_STATE_OFF)
+ goto out;
+
+ /* it is setup but not enabled */
+ if (event != NULL)
+ goto out_enable;
+
+ /* Try to register using hardware perf events */
+ wd_attr = &wd_hw_attr;
+ wd_attr->sample_period = hw_nmi_get_sample_period();
+ event = perf_event_create_kernel_counter(wd_attr, cpu, -1, watchdog_overflow_callback);
+ if (!IS_ERR(event)) {
+ printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");
+ goto out_save;
+ }
+
+ printk(KERN_ERR "NMI watchdog failed to create perf event on cpu%i: %p\n", cpu, event);
+ return -1;
+
+ /* success path */
+out_save:
+ per_cpu(watchdog_ev, cpu) = event;
+out_enable:
+ perf_event_enable(per_cpu(watchdog_ev, cpu));
+out:
+ return 0;
+}
+
+static void watchdog_nmi_disable(int cpu)
+{
+ struct perf_event *event = per_cpu(watchdog_ev, cpu);
+
+ if (event) {
+ perf_event_disable(event);
+ per_cpu(watchdog_ev, cpu) = NULL;
+
+ /* should be in cleanup, but blocks oprofile */
+ perf_event_release_kernel(event);
+ }
+ return;
+}
+#else
+static int watchdog_nmi_enable(int cpu) { return 0; }
+static void watchdog_nmi_disable(int cpu) { return; }
+#endif /* CONFIG_HARDLOCKUP_DETECTOR */
+
+/* prepare/enable/disable routines */
+static int watchdog_prepare_cpu(int cpu)
+{
+ struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu);
+
+ WARN_ON(per_cpu(softlockup_watchdog, cpu));
+ hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hrtimer->function = watchdog_timer_fn;
+
+ return 0;
+}
+
+static int watchdog_enable(int cpu)
+{
+ struct task_struct *p = per_cpu(softlockup_watchdog, cpu);
+
+ /* enable the perf event */
+ if (watchdog_nmi_enable(cpu) != 0)
+ return -1;
+
+ /* create the watchdog thread */
+ if (!p) {
+ p = kthread_create(watchdog, (void *)(unsigned long)cpu, "watchdog/%d", cpu);
+ if (IS_ERR(p)) {
+ printk(KERN_ERR "softlockup watchdog for %i failed\n", cpu);
+ return -1;
+ }
+ kthread_bind(p, cpu);
+ per_cpu(watchdog_touch_ts, cpu) = 0;
+ per_cpu(softlockup_watchdog, cpu) = p;
+ wake_up_process(p);
+ }
+
+ return 0;
+}
+
+static void watchdog_disable(int cpu)
+{
+ struct task_struct *p = per_cpu(softlockup_watchdog, cpu);
+ struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu);
+
+ /*
+ * cancel the timer first to stop incrementing the stats
+ * and waking up the kthread
+ */
+ hrtimer_cancel(hrtimer);
+
+ /* disable the perf event */
+ watchdog_nmi_disable(cpu);
+
+ /* stop the watchdog thread */
+ if (p) {
+ per_cpu(softlockup_watchdog, cpu) = NULL;
+ kthread_stop(p);
+ }
+
+ /* if any cpu succeeds, watchdog is considered enabled for the system */
+ watchdog_enabled = 1;
+}
+
+static void watchdog_enable_all_cpus(void)
+{
+ int cpu;
+ int result = 0;
+
+ for_each_online_cpu(cpu)
+ result += watchdog_enable(cpu);
+
+ if (result)
+ printk(KERN_ERR "watchdog: failed to be enabled on some cpus\n");
+
+}
+
+static void watchdog_disable_all_cpus(void)
+{
+ int cpu;
+
+ for_each_online_cpu(cpu)
+ watchdog_disable(cpu);
+
+ /* if all watchdogs are disabled, then they are disabled for the system */
+ watchdog_enabled = 0;
+}
+
+
+/* sysctl functions */
+#ifdef CONFIG_SYSCTL
+/*
+ * proc handler for /proc/sys/kernel/nmi_watchdog
+ */
+
+int proc_dowatchdog_enabled(struct ctl_table *table, int write,
+ void __user *buffer, size_t *length, loff_t *ppos)
+{
+ proc_dointvec(table, write, buffer, length, ppos);
+
+ if (watchdog_enabled)
+ watchdog_enable_all_cpus();
+ else
+ watchdog_disable_all_cpus();
+ return 0;
+}
+
+int proc_dowatchdog_thresh(struct ctl_table *table, int write,
+ void __user *buffer,
+ size_t *lenp, loff_t *ppos)
+{
+ return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+}
+#endif /* CONFIG_SYSCTL */
+
+
+/*
+ * Create/destroy watchdog threads as CPUs come and go:
+ */
+static int __cpuinit
+cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+ int hotcpu = (unsigned long)hcpu;
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ if (watchdog_prepare_cpu(hotcpu))
+ return NOTIFY_BAD;
+ break;
+ case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
+ if (watchdog_enable(hotcpu))
+ return NOTIFY_BAD;
+ break;
+#ifdef CONFIG_HOTPLUG_CPU
+ case CPU_UP_CANCELED:
+ case CPU_UP_CANCELED_FROZEN:
+ watchdog_disable(hotcpu);
+ break;
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ watchdog_disable(hotcpu);
+ break;
+#endif /* CONFIG_HOTPLUG_CPU */
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata cpu_nfb = {
+ .notifier_call = cpu_callback
+};
+
+static int __init spawn_watchdog_task(void)
+{
+ void *cpu = (void *)(long)smp_processor_id();
+ int err;
+
+ if (no_watchdog)
+ return 0;
+
+ err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
+ WARN_ON(err == NOTIFY_BAD);
+
+ 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_watchdog_task);
Drivers ought to be able to handle interrupts coming in at those
points; some don't and need to be caught.
-config DETECT_SOFTLOCKUP
- bool "Detect Soft Lockups"
+config LOCKUP_DETECTOR
+ bool "Detect Hard and Soft Lockups"
depends on DEBUG_KERNEL && !S390
- default y
help
- Say Y here to enable the kernel to detect "soft lockups",
- which are bugs that cause the kernel to loop in kernel
+ Say Y here to enable the kernel to act as a watchdog to detect
+ hard and soft lockups.
+
+ Softlockups are bugs that cause the kernel to loop in kernel
mode for more than 60 seconds, without giving other tasks a
- chance to run.
+ chance to run. The current stack trace is displayed upon
+ detection and the system will stay locked up.
- When a soft-lockup is detected, the kernel will print the
- current stack trace (which you should report), but the
- system will stay locked up. This feature has negligible
- overhead.
+ Hardlockups are bugs that cause the CPU to loop in kernel mode
+ for more than 60 seconds, without letting other interrupts have a
+ chance to run. The current stack trace is displayed upon detection
+ and the system will stay locked up.
+
+ The overhead should be minimal. A periodic hrtimer runs to
+ generate interrupts and kick the watchdog task every 10-12 seconds.
+ An NMI is generated every 60 seconds or so to check for hardlockups.
- (Note that "hard lockups" are separate type of bugs that
- can be detected via the NMI-watchdog, on platforms that
- support it.)
+config HARDLOCKUP_DETECTOR
+ def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI
config BOOTPARAM_SOFTLOCKUP_PANIC
bool "Panic (Reboot) On Soft Lockups"
- depends on DETECT_SOFTLOCKUP
+ depends on LOCKUP_DETECTOR
help
Say Y here to enable the kernel to panic on "soft lockups",
which are bugs that cause the kernel to loop in kernel
config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
int
- depends on DETECT_SOFTLOCKUP
+ depends on LOCKUP_DETECTOR
range 0 1
default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
git://bbs.cooldavid.org / net-next-2.6.git / commitdiff