Merge branch 'perf/nmi' into perf/core

Conflicts:
	kernel/Makefile

Merge reason: Add the now complete topic, fix the conflict.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2010-08-05 08:45:05 +02:00
commit 61be7fdec2
16 changed files with 770 additions and 348 deletions

View File

@ -1812,6 +1812,8 @@ and is between 256 and 4096 characters. It is defined in the file
nousb [USB] Disable the USB subsystem
nowatchdog [KNL] Disable the lockup detector.
nowb [ARM]
nox2apic [X86-64,APIC] Do not enable x2APIC mode.

View File

@ -151,4 +151,11 @@ config HAVE_MIXED_BREAKPOINTS_REGS
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"

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@ -55,6 +55,7 @@ config X86
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

View File

@ -17,7 +17,9 @@ int do_nmi_callback(struct pt_regs *regs, int cpu);
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);

View File

@ -2,7 +2,12 @@
# 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

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@ -0,0 +1,107 @@
/*
* 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; }

View File

@ -401,13 +401,6 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
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)) {

View File

@ -392,7 +392,13 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
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.
@ -400,6 +406,7 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
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);

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@ -20,10 +20,14 @@ extern void touch_nmi_watchdog(void);
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
@ -47,4 +51,13 @@ static inline bool trigger_all_cpu_backtrace(void)
}
#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

View File

@ -316,20 +316,16 @@ extern void scheduler_tick(void);
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)
{
}

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@ -76,8 +76,8 @@ obj-$(CONFIG_GCOV_KERNEL) += gcov/
obj-$(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

View File

@ -1,293 +0,0 @@
/*
* 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, &param);
/* 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);

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@ -76,6 +76,10 @@
#include <scsi/sg.h>
#endif
#ifdef CONFIG_LOCKUP_DETECTOR
#include <linux/nmi.h>
#endif
#if defined(CONFIG_SYSCTL)
@ -106,7 +110,7 @@ extern int blk_iopoll_enabled;
#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
@ -710,7 +714,34 @@ static struct ctl_table kern_table[] = {
.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,
@ -813,26 +844,6 @@ static struct ctl_table kern_table[] = {
.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",

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@ -1289,7 +1289,6 @@ void run_local_timers(void)
{
hrtimer_run_queues();
raise_softirq(TIMER_SOFTIRQ);
softlockup_tick();
}
/*

567
kernel/watchdog.c Normal file
View File

@ -0,0 +1,567 @@
/*
* 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, &param);
/* 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);

View File

@ -152,28 +152,33 @@ config DEBUG_SHIRQ
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.
(Note that "hard lockups" are separate type of bugs that
can be detected via the NMI-watchdog, on platforms that
support it.)
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.
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
@ -190,7 +195,7 @@ config BOOTPARAM_SOFTLOCKUP_PANIC
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