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authorIngo Molnar <mingo@elte.hu>2010-08-05 02:45:05 -0400
committerIngo Molnar <mingo@elte.hu>2010-08-05 02:45:05 -0400
commit61be7fdec2f51b99570cd5dcc30c7848c8e56513 (patch)
tree4a73ee635bc3e35dc54f75caddd26ffb6238bb5c /kernel
parent12a81c8df13c60904febcafcf6b90ca1acb67122 (diff)
parenteb703f98191a505f78d0066712ad67d5dedc4c90 (diff)
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/Makefile2
-rw-r--r--kernel/softlockup.c293
-rw-r--r--kernel/sysctl.c55
-rw-r--r--kernel/timer.c1
-rw-r--r--kernel/watchdog.c567
5 files changed, 601 insertions, 317 deletions
diff --git a/kernel/Makefile b/kernel/Makefile
index 057472fbc272..ce53fb2bd1d9 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -76,8 +76,8 @@ obj-$(CONFIG_GCOV_KERNEL) += gcov/
76obj-$(CONFIG_AUDIT_TREE) += audit_tree.o 76obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
77obj-$(CONFIG_KPROBES) += kprobes.o 77obj-$(CONFIG_KPROBES) += kprobes.o
78obj-$(CONFIG_KGDB) += debug/ 78obj-$(CONFIG_KGDB) += debug/
79obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
80obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o 79obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
80obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
81obj-$(CONFIG_GENERIC_HARDIRQS) += irq/ 81obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
82obj-$(CONFIG_SECCOMP) += seccomp.o 82obj-$(CONFIG_SECCOMP) += seccomp.o
83obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o 83obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
diff --git a/kernel/softlockup.c b/kernel/softlockup.c
deleted file mode 100644
index 4b493f67dcb5..000000000000
--- a/kernel/softlockup.c
+++ /dev/null
@@ -1,293 +0,0 @@
1/*
2 * Detect Soft Lockups
3 *
4 * started by Ingo Molnar, Copyright (C) 2005, 2006 Red Hat, Inc.
5 *
6 * this code detects soft lockups: incidents in where on a CPU
7 * the kernel does not reschedule for 10 seconds or more.
8 */
9#include <linux/mm.h>
10#include <linux/cpu.h>
11#include <linux/nmi.h>
12#include <linux/init.h>
13#include <linux/delay.h>
14#include <linux/freezer.h>
15#include <linux/kthread.h>
16#include <linux/lockdep.h>
17#include <linux/notifier.h>
18#include <linux/module.h>
19#include <linux/sysctl.h>
20
21#include <asm/irq_regs.h>
22
23static DEFINE_SPINLOCK(print_lock);
24
25static DEFINE_PER_CPU(unsigned long, softlockup_touch_ts); /* touch timestamp */
26static DEFINE_PER_CPU(unsigned long, softlockup_print_ts); /* print timestamp */
27static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
28static DEFINE_PER_CPU(bool, softlock_touch_sync);
29
30static int __read_mostly did_panic;
31int __read_mostly softlockup_thresh = 60;
32
33/*
34 * Should we panic (and reboot, if panic_timeout= is set) when a
35 * soft-lockup occurs:
36 */
37unsigned int __read_mostly softlockup_panic =
38 CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE;
39
40static int __init softlockup_panic_setup(char *str)
41{
42 softlockup_panic = simple_strtoul(str, NULL, 0);
43
44 return 1;
45}
46__setup("softlockup_panic=", softlockup_panic_setup);
47
48static int
49softlock_panic(struct notifier_block *this, unsigned long event, void *ptr)
50{
51 did_panic = 1;
52
53 return NOTIFY_DONE;
54}
55
56static struct notifier_block panic_block = {
57 .notifier_call = softlock_panic,
58};
59
60/*
61 * Returns seconds, approximately. We don't need nanosecond
62 * resolution, and we don't need to waste time with a big divide when
63 * 2^30ns == 1.074s.
64 */
65static unsigned long get_timestamp(int this_cpu)
66{
67 return cpu_clock(this_cpu) >> 30LL; /* 2^30 ~= 10^9 */
68}
69
70static void __touch_softlockup_watchdog(void)
71{
72 int this_cpu = raw_smp_processor_id();
73
74 __raw_get_cpu_var(softlockup_touch_ts) = get_timestamp(this_cpu);
75}
76
77void touch_softlockup_watchdog(void)
78{
79 __raw_get_cpu_var(softlockup_touch_ts) = 0;
80}
81EXPORT_SYMBOL(touch_softlockup_watchdog);
82
83void touch_softlockup_watchdog_sync(void)
84{
85 __raw_get_cpu_var(softlock_touch_sync) = true;
86 __raw_get_cpu_var(softlockup_touch_ts) = 0;
87}
88
89void touch_all_softlockup_watchdogs(void)
90{
91 int cpu;
92
93 /* Cause each CPU to re-update its timestamp rather than complain */
94 for_each_online_cpu(cpu)
95 per_cpu(softlockup_touch_ts, cpu) = 0;
96}
97EXPORT_SYMBOL(touch_all_softlockup_watchdogs);
98
99int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
100 void __user *buffer,
101 size_t *lenp, loff_t *ppos)
102{
103 touch_all_softlockup_watchdogs();
104 return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
105}
106
107/*
108 * This callback runs from the timer interrupt, and checks
109 * whether the watchdog thread has hung or not:
110 */
111void softlockup_tick(void)
112{
113 int this_cpu = smp_processor_id();
114 unsigned long touch_ts = per_cpu(softlockup_touch_ts, this_cpu);
115 unsigned long print_ts;
116 struct pt_regs *regs = get_irq_regs();
117 unsigned long now;
118
119 /* Is detection switched off? */
120 if (!per_cpu(softlockup_watchdog, this_cpu) || softlockup_thresh <= 0) {
121 /* Be sure we don't false trigger if switched back on */
122 if (touch_ts)
123 per_cpu(softlockup_touch_ts, this_cpu) = 0;
124 return;
125 }
126
127 if (touch_ts == 0) {
128 if (unlikely(per_cpu(softlock_touch_sync, this_cpu))) {
129 /*
130 * If the time stamp was touched atomically
131 * make sure the scheduler tick is up to date.
132 */
133 per_cpu(softlock_touch_sync, this_cpu) = false;
134 sched_clock_tick();
135 }
136 __touch_softlockup_watchdog();
137 return;
138 }
139
140 print_ts = per_cpu(softlockup_print_ts, this_cpu);
141
142 /* report at most once a second */
143 if (print_ts == touch_ts || did_panic)
144 return;
145
146 /* do not print during early bootup: */
147 if (unlikely(system_state != SYSTEM_RUNNING)) {
148 __touch_softlockup_watchdog();
149 return;
150 }
151
152 now = get_timestamp(this_cpu);
153
154 /*
155 * Wake up the high-prio watchdog task twice per
156 * threshold timespan.
157 */
158 if (time_after(now - softlockup_thresh/2, touch_ts))
159 wake_up_process(per_cpu(softlockup_watchdog, this_cpu));
160
161 /* Warn about unreasonable delays: */
162 if (time_before_eq(now - softlockup_thresh, touch_ts))
163 return;
164
165 per_cpu(softlockup_print_ts, this_cpu) = touch_ts;
166
167 spin_lock(&print_lock);
168 printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %lus! [%s:%d]\n",
169 this_cpu, now - touch_ts,
170 current->comm, task_pid_nr(current));
171 print_modules();
172 print_irqtrace_events(current);
173 if (regs)
174 show_regs(regs);
175 else
176 dump_stack();
177 spin_unlock(&print_lock);
178
179 if (softlockup_panic)
180 panic("softlockup: hung tasks");
181}
182
183/*
184 * The watchdog thread - runs every second and touches the timestamp.
185 */
186static int watchdog(void *__bind_cpu)
187{
188 struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
189
190 sched_setscheduler(current, SCHED_FIFO, &param);
191
192 /* initialize timestamp */
193 __touch_softlockup_watchdog();
194
195 set_current_state(TASK_INTERRUPTIBLE);
196 /*
197 * Run briefly once per second to reset the softlockup timestamp.
198 * If this gets delayed for more than 60 seconds then the
199 * debug-printout triggers in softlockup_tick().
200 */
201 while (!kthread_should_stop()) {
202 __touch_softlockup_watchdog();
203 schedule();
204
205 if (kthread_should_stop())
206 break;
207
208 set_current_state(TASK_INTERRUPTIBLE);
209 }
210 __set_current_state(TASK_RUNNING);
211
212 return 0;
213}
214
215/*
216 * Create/destroy watchdog threads as CPUs come and go:
217 */
218static int __cpuinit
219cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
220{
221 int hotcpu = (unsigned long)hcpu;
222 struct task_struct *p;
223
224 switch (action) {
225 case CPU_UP_PREPARE:
226 case CPU_UP_PREPARE_FROZEN:
227 BUG_ON(per_cpu(softlockup_watchdog, hotcpu));
228 p = kthread_create(watchdog, hcpu, "watchdog/%d", hotcpu);
229 if (IS_ERR(p)) {
230 printk(KERN_ERR "watchdog for %i failed\n", hotcpu);
231 return NOTIFY_BAD;
232 }
233 per_cpu(softlockup_touch_ts, hotcpu) = 0;
234 per_cpu(softlockup_watchdog, hotcpu) = p;
235 kthread_bind(p, hotcpu);
236 break;
237 case CPU_ONLINE:
238 case CPU_ONLINE_FROZEN:
239 wake_up_process(per_cpu(softlockup_watchdog, hotcpu));
240 break;
241#ifdef CONFIG_HOTPLUG_CPU
242 case CPU_UP_CANCELED:
243 case CPU_UP_CANCELED_FROZEN:
244 if (!per_cpu(softlockup_watchdog, hotcpu))
245 break;
246 /* Unbind so it can run. Fall thru. */
247 kthread_bind(per_cpu(softlockup_watchdog, hotcpu),
248 cpumask_any(cpu_online_mask));
249 case CPU_DEAD:
250 case CPU_DEAD_FROZEN:
251 p = per_cpu(softlockup_watchdog, hotcpu);
252 per_cpu(softlockup_watchdog, hotcpu) = NULL;
253 kthread_stop(p);
254 break;
255#endif /* CONFIG_HOTPLUG_CPU */
256 }
257 return NOTIFY_OK;
258}
259
260static struct notifier_block __cpuinitdata cpu_nfb = {
261 .notifier_call = cpu_callback
262};
263
264static int __initdata nosoftlockup;
265
266static int __init nosoftlockup_setup(char *str)
267{
268 nosoftlockup = 1;
269 return 1;
270}
271__setup("nosoftlockup", nosoftlockup_setup);
272
273static int __init spawn_softlockup_task(void)
274{
275 void *cpu = (void *)(long)smp_processor_id();
276 int err;
277
278 if (nosoftlockup)
279 return 0;
280
281 err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
282 if (err == NOTIFY_BAD) {
283 BUG();
284 return 1;
285 }
286 cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
287 register_cpu_notifier(&cpu_nfb);
288
289 atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
290
291 return 0;
292}
293early_initcall(spawn_softlockup_task);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index d24f761f4876..6f79c7f81c96 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -76,6 +76,10 @@
76#include <scsi/sg.h> 76#include <scsi/sg.h>
77#endif 77#endif
78 78
79#ifdef CONFIG_LOCKUP_DETECTOR
80#include <linux/nmi.h>
81#endif
82
79 83
80#if defined(CONFIG_SYSCTL) 84#if defined(CONFIG_SYSCTL)
81 85
@@ -106,7 +110,7 @@ extern int blk_iopoll_enabled;
106#endif 110#endif
107 111
108/* Constants used for minimum and maximum */ 112/* Constants used for minimum and maximum */
109#ifdef CONFIG_DETECT_SOFTLOCKUP 113#ifdef CONFIG_LOCKUP_DETECTOR
110static int sixty = 60; 114static int sixty = 60;
111static int neg_one = -1; 115static int neg_one = -1;
112#endif 116#endif
@@ -710,7 +714,34 @@ static struct ctl_table kern_table[] = {
710 .mode = 0444, 714 .mode = 0444,
711 .proc_handler = proc_dointvec, 715 .proc_handler = proc_dointvec,
712 }, 716 },
713#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) 717#if defined(CONFIG_LOCKUP_DETECTOR)
718 {
719 .procname = "watchdog",
720 .data = &watchdog_enabled,
721 .maxlen = sizeof (int),
722 .mode = 0644,
723 .proc_handler = proc_dowatchdog_enabled,
724 },
725 {
726 .procname = "watchdog_thresh",
727 .data = &softlockup_thresh,
728 .maxlen = sizeof(int),
729 .mode = 0644,
730 .proc_handler = proc_dowatchdog_thresh,
731 .extra1 = &neg_one,
732 .extra2 = &sixty,
733 },
734 {
735 .procname = "softlockup_panic",
736 .data = &softlockup_panic,
737 .maxlen = sizeof(int),
738 .mode = 0644,
739 .proc_handler = proc_dointvec_minmax,
740 .extra1 = &zero,
741 .extra2 = &one,
742 },
743#endif
744#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) && !defined(CONFIG_LOCKUP_DETECTOR)
714 { 745 {
715 .procname = "unknown_nmi_panic", 746 .procname = "unknown_nmi_panic",
716 .data = &unknown_nmi_panic, 747 .data = &unknown_nmi_panic,
@@ -813,26 +844,6 @@ static struct ctl_table kern_table[] = {
813 .proc_handler = proc_dointvec, 844 .proc_handler = proc_dointvec,
814 }, 845 },
815#endif 846#endif
816#ifdef CONFIG_DETECT_SOFTLOCKUP
817 {
818 .procname = "softlockup_panic",
819 .data = &softlockup_panic,
820 .maxlen = sizeof(int),
821 .mode = 0644,
822 .proc_handler = proc_dointvec_minmax,
823 .extra1 = &zero,
824 .extra2 = &one,
825 },
826 {
827 .procname = "softlockup_thresh",
828 .data = &softlockup_thresh,
829 .maxlen = sizeof(int),
830 .mode = 0644,
831 .proc_handler = proc_dosoftlockup_thresh,
832 .extra1 = &neg_one,
833 .extra2 = &sixty,
834 },
835#endif
836#ifdef CONFIG_DETECT_HUNG_TASK 847#ifdef CONFIG_DETECT_HUNG_TASK
837 { 848 {
838 .procname = "hung_task_panic", 849 .procname = "hung_task_panic",
diff --git a/kernel/timer.c b/kernel/timer.c
index ee305c8d4e18..c29e2d4d2a66 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1289,7 +1289,6 @@ void run_local_timers(void)
1289{ 1289{
1290 hrtimer_run_queues(); 1290 hrtimer_run_queues();
1291 raise_softirq(TIMER_SOFTIRQ); 1291 raise_softirq(TIMER_SOFTIRQ);
1292 softlockup_tick();
1293} 1292}
1294 1293
1295/* 1294/*
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
new file mode 100644
index 000000000000..613bc1f04610
--- /dev/null
+++ b/kernel/watchdog.c
@@ -0,0 +1,567 @@
1/*
2 * Detect hard and soft lockups on a system
3 *
4 * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
5 *
6 * this code detects hard lockups: incidents in where on a CPU
7 * the kernel does not respond to anything except NMI.
8 *
9 * Note: Most of this code is borrowed heavily from softlockup.c,
10 * so thanks to Ingo for the initial implementation.
11 * Some chunks also taken from arch/x86/kernel/apic/nmi.c, thanks
12 * to those contributors as well.
13 */
14
15#include <linux/mm.h>
16#include <linux/cpu.h>
17#include <linux/nmi.h>
18#include <linux/init.h>
19#include <linux/delay.h>
20#include <linux/freezer.h>
21#include <linux/kthread.h>
22#include <linux/lockdep.h>
23#include <linux/notifier.h>
24#include <linux/module.h>
25#include <linux/sysctl.h>
26
27#include <asm/irq_regs.h>
28#include <linux/perf_event.h>
29
30int watchdog_enabled;
31int __read_mostly softlockup_thresh = 60;
32
33static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
34static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
35static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
36static DEFINE_PER_CPU(bool, softlockup_touch_sync);
37static DEFINE_PER_CPU(bool, soft_watchdog_warn);
38#ifdef CONFIG_HARDLOCKUP_DETECTOR
39static DEFINE_PER_CPU(bool, hard_watchdog_warn);
40static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
41static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
42static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
43static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
44#endif
45
46static int __read_mostly did_panic;
47static int __initdata no_watchdog;
48
49
50/* boot commands */
51/*
52 * Should we panic when a soft-lockup or hard-lockup occurs:
53 */
54#ifdef CONFIG_HARDLOCKUP_DETECTOR
55static int hardlockup_panic;
56
57static int __init hardlockup_panic_setup(char *str)
58{
59 if (!strncmp(str, "panic", 5))
60 hardlockup_panic = 1;
61 return 1;
62}
63__setup("nmi_watchdog=", hardlockup_panic_setup);
64#endif
65
66unsigned int __read_mostly softlockup_panic =
67 CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE;
68
69static int __init softlockup_panic_setup(char *str)
70{
71 softlockup_panic = simple_strtoul(str, NULL, 0);
72
73 return 1;
74}
75__setup("softlockup_panic=", softlockup_panic_setup);
76
77static int __init nowatchdog_setup(char *str)
78{
79 no_watchdog = 1;
80 return 1;
81}
82__setup("nowatchdog", nowatchdog_setup);
83
84/* deprecated */
85static int __init nosoftlockup_setup(char *str)
86{
87 no_watchdog = 1;
88 return 1;
89}
90__setup("nosoftlockup", nosoftlockup_setup);
91/* */
92
93
94/*
95 * Returns seconds, approximately. We don't need nanosecond
96 * resolution, and we don't need to waste time with a big divide when
97 * 2^30ns == 1.074s.
98 */
99static unsigned long get_timestamp(int this_cpu)
100{
101 return cpu_clock(this_cpu) >> 30LL; /* 2^30 ~= 10^9 */
102}
103
104static unsigned long get_sample_period(void)
105{
106 /*
107 * convert softlockup_thresh from seconds to ns
108 * the divide by 5 is to give hrtimer 5 chances to
109 * increment before the hardlockup detector generates
110 * a warning
111 */
112 return softlockup_thresh / 5 * NSEC_PER_SEC;
113}
114
115/* Commands for resetting the watchdog */
116static void __touch_watchdog(void)
117{
118 int this_cpu = smp_processor_id();
119
120 __get_cpu_var(watchdog_touch_ts) = get_timestamp(this_cpu);
121}
122
123void touch_softlockup_watchdog(void)
124{
125 __get_cpu_var(watchdog_touch_ts) = 0;
126}
127EXPORT_SYMBOL(touch_softlockup_watchdog);
128
129void touch_all_softlockup_watchdogs(void)
130{
131 int cpu;
132
133 /*
134 * this is done lockless
135 * do we care if a 0 races with a timestamp?
136 * all it means is the softlock check starts one cycle later
137 */
138 for_each_online_cpu(cpu)
139 per_cpu(watchdog_touch_ts, cpu) = 0;
140}
141
142#ifdef CONFIG_HARDLOCKUP_DETECTOR
143void touch_nmi_watchdog(void)
144{
145 __get_cpu_var(watchdog_nmi_touch) = true;
146 touch_softlockup_watchdog();
147}
148EXPORT_SYMBOL(touch_nmi_watchdog);
149
150#endif
151
152void touch_softlockup_watchdog_sync(void)
153{
154 __raw_get_cpu_var(softlockup_touch_sync) = true;
155 __raw_get_cpu_var(watchdog_touch_ts) = 0;
156}
157
158#ifdef CONFIG_HARDLOCKUP_DETECTOR
159/* watchdog detector functions */
160static int is_hardlockup(void)
161{
162 unsigned long hrint = __get_cpu_var(hrtimer_interrupts);
163
164 if (__get_cpu_var(hrtimer_interrupts_saved) == hrint)
165 return 1;
166
167 __get_cpu_var(hrtimer_interrupts_saved) = hrint;
168 return 0;
169}
170#endif
171
172static int is_softlockup(unsigned long touch_ts)
173{
174 unsigned long now = get_timestamp(smp_processor_id());
175
176 /* Warn about unreasonable delays: */
177 if (time_after(now, touch_ts + softlockup_thresh))
178 return now - touch_ts;
179
180 return 0;
181}
182
183static int
184watchdog_panic(struct notifier_block *this, unsigned long event, void *ptr)
185{
186 did_panic = 1;
187
188 return NOTIFY_DONE;
189}
190
191static struct notifier_block panic_block = {
192 .notifier_call = watchdog_panic,
193};
194
195#ifdef CONFIG_HARDLOCKUP_DETECTOR
196static struct perf_event_attr wd_hw_attr = {
197 .type = PERF_TYPE_HARDWARE,
198 .config = PERF_COUNT_HW_CPU_CYCLES,
199 .size = sizeof(struct perf_event_attr),
200 .pinned = 1,
201 .disabled = 1,
202};
203
204/* Callback function for perf event subsystem */
205void watchdog_overflow_callback(struct perf_event *event, int nmi,
206 struct perf_sample_data *data,
207 struct pt_regs *regs)
208{
209 if (__get_cpu_var(watchdog_nmi_touch) == true) {
210 __get_cpu_var(watchdog_nmi_touch) = false;
211 return;
212 }
213
214 /* check for a hardlockup
215 * This is done by making sure our timer interrupt
216 * is incrementing. The timer interrupt should have
217 * fired multiple times before we overflow'd. If it hasn't
218 * then this is a good indication the cpu is stuck
219 */
220 if (is_hardlockup()) {
221 int this_cpu = smp_processor_id();
222
223 /* only print hardlockups once */
224 if (__get_cpu_var(hard_watchdog_warn) == true)
225 return;
226
227 if (hardlockup_panic)
228 panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu);
229 else
230 WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu);
231
232 __get_cpu_var(hard_watchdog_warn) = true;
233 return;
234 }
235
236 __get_cpu_var(hard_watchdog_warn) = false;
237 return;
238}
239static void watchdog_interrupt_count(void)
240{
241 __get_cpu_var(hrtimer_interrupts)++;
242}
243#else
244static inline void watchdog_interrupt_count(void) { return; }
245#endif /* CONFIG_HARDLOCKUP_DETECTOR */
246
247/* watchdog kicker functions */
248static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
249{
250 unsigned long touch_ts = __get_cpu_var(watchdog_touch_ts);
251 struct pt_regs *regs = get_irq_regs();
252 int duration;
253
254 /* kick the hardlockup detector */
255 watchdog_interrupt_count();
256
257 /* kick the softlockup detector */
258 wake_up_process(__get_cpu_var(softlockup_watchdog));
259
260 /* .. and repeat */
261 hrtimer_forward_now(hrtimer, ns_to_ktime(get_sample_period()));
262
263 if (touch_ts == 0) {
264 if (unlikely(__get_cpu_var(softlockup_touch_sync))) {
265 /*
266 * If the time stamp was touched atomically
267 * make sure the scheduler tick is up to date.
268 */
269 __get_cpu_var(softlockup_touch_sync) = false;
270 sched_clock_tick();
271 }
272 __touch_watchdog();
273 return HRTIMER_RESTART;
274 }
275
276 /* check for a softlockup
277 * This is done by making sure a high priority task is
278 * being scheduled. The task touches the watchdog to
279 * indicate it is getting cpu time. If it hasn't then
280 * this is a good indication some task is hogging the cpu
281 */
282 duration = is_softlockup(touch_ts);
283 if (unlikely(duration)) {
284 /* only warn once */
285 if (__get_cpu_var(soft_watchdog_warn) == true)
286 return HRTIMER_RESTART;
287
288 printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
289 smp_processor_id(), duration,
290 current->comm, task_pid_nr(current));
291 print_modules();
292 print_irqtrace_events(current);
293 if (regs)
294 show_regs(regs);
295 else
296 dump_stack();
297
298 if (softlockup_panic)
299 panic("softlockup: hung tasks");
300 __get_cpu_var(soft_watchdog_warn) = true;
301 } else
302 __get_cpu_var(soft_watchdog_warn) = false;
303
304 return HRTIMER_RESTART;
305}
306
307
308/*
309 * The watchdog thread - touches the timestamp.
310 */
311static int watchdog(void *unused)
312{
313 struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
314 struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer);
315
316 sched_setscheduler(current, SCHED_FIFO, &param);
317
318 /* initialize timestamp */
319 __touch_watchdog();
320
321 /* kick off the timer for the hardlockup detector */
322 /* done here because hrtimer_start can only pin to smp_processor_id() */
323 hrtimer_start(hrtimer, ns_to_ktime(get_sample_period()),
324 HRTIMER_MODE_REL_PINNED);
325
326 set_current_state(TASK_INTERRUPTIBLE);
327 /*
328 * Run briefly once per second to reset the softlockup timestamp.
329 * If this gets delayed for more than 60 seconds then the
330 * debug-printout triggers in watchdog_timer_fn().
331 */
332 while (!kthread_should_stop()) {
333 __touch_watchdog();
334 schedule();
335
336 if (kthread_should_stop())
337 break;
338
339 set_current_state(TASK_INTERRUPTIBLE);
340 }
341 __set_current_state(TASK_RUNNING);
342
343 return 0;
344}
345
346
347#ifdef CONFIG_HARDLOCKUP_DETECTOR
348static int watchdog_nmi_enable(int cpu)
349{
350 struct perf_event_attr *wd_attr;
351 struct perf_event *event = per_cpu(watchdog_ev, cpu);
352
353 /* is it already setup and enabled? */
354 if (event && event->state > PERF_EVENT_STATE_OFF)
355 goto out;
356
357 /* it is setup but not enabled */
358 if (event != NULL)
359 goto out_enable;
360
361 /* Try to register using hardware perf events */
362 wd_attr = &wd_hw_attr;
363 wd_attr->sample_period = hw_nmi_get_sample_period();
364 event = perf_event_create_kernel_counter(wd_attr, cpu, -1, watchdog_overflow_callback);
365 if (!IS_ERR(event)) {
366 printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");
367 goto out_save;
368 }
369
370 printk(KERN_ERR "NMI watchdog failed to create perf event on cpu%i: %p\n", cpu, event);
371 return -1;
372
373 /* success path */
374out_save:
375 per_cpu(watchdog_ev, cpu) = event;
376out_enable:
377 perf_event_enable(per_cpu(watchdog_ev, cpu));
378out:
379 return 0;
380}
381
382static void watchdog_nmi_disable(int cpu)
383{
384 struct perf_event *event = per_cpu(watchdog_ev, cpu);
385
386 if (event) {
387 perf_event_disable(event);
388 per_cpu(watchdog_ev, cpu) = NULL;
389
390 /* should be in cleanup, but blocks oprofile */
391 perf_event_release_kernel(event);
392 }
393 return;
394}
395#else
396static int watchdog_nmi_enable(int cpu) { return 0; }
397static void watchdog_nmi_disable(int cpu) { return; }
398#endif /* CONFIG_HARDLOCKUP_DETECTOR */
399
400/* prepare/enable/disable routines */
401static int watchdog_prepare_cpu(int cpu)
402{
403 struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu);
404
405 WARN_ON(per_cpu(softlockup_watchdog, cpu));
406 hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
407 hrtimer->function = watchdog_timer_fn;
408
409 return 0;
410}
411
412static int watchdog_enable(int cpu)
413{
414 struct task_struct *p = per_cpu(softlockup_watchdog, cpu);
415
416 /* enable the perf event */
417 if (watchdog_nmi_enable(cpu) != 0)
418 return -1;
419
420 /* create the watchdog thread */
421 if (!p) {
422 p = kthread_create(watchdog, (void *)(unsigned long)cpu, "watchdog/%d", cpu);
423 if (IS_ERR(p)) {
424 printk(KERN_ERR "softlockup watchdog for %i failed\n", cpu);
425 return -1;
426 }
427 kthread_bind(p, cpu);
428 per_cpu(watchdog_touch_ts, cpu) = 0;
429 per_cpu(softlockup_watchdog, cpu) = p;
430 wake_up_process(p);
431 }
432
433 return 0;
434}
435
436static void watchdog_disable(int cpu)
437{
438 struct task_struct *p = per_cpu(softlockup_watchdog, cpu);
439 struct hrtimer *hrtimer = &per_cpu(watchdog_hrtimer, cpu);
440
441 /*
442 * cancel the timer first to stop incrementing the stats
443 * and waking up the kthread
444 */
445 hrtimer_cancel(hrtimer);
446
447 /* disable the perf event */
448 watchdog_nmi_disable(cpu);
449
450 /* stop the watchdog thread */
451 if (p) {
452 per_cpu(softlockup_watchdog, cpu) = NULL;
453 kthread_stop(p);
454 }
455
456 /* if any cpu succeeds, watchdog is considered enabled for the system */
457 watchdog_enabled = 1;
458}
459
460static void watchdog_enable_all_cpus(void)
461{
462 int cpu;
463 int result = 0;
464
465 for_each_online_cpu(cpu)
466 result += watchdog_enable(cpu);
467
468 if (result)
469 printk(KERN_ERR "watchdog: failed to be enabled on some cpus\n");
470
471}
472
473static void watchdog_disable_all_cpus(void)
474{
475 int cpu;
476
477 for_each_online_cpu(cpu)
478 watchdog_disable(cpu);
479
480 /* if all watchdogs are disabled, then they are disabled for the system */
481 watchdog_enabled = 0;
482}
483
484
485/* sysctl functions */
486#ifdef CONFIG_SYSCTL
487/*
488 * proc handler for /proc/sys/kernel/nmi_watchdog
489 */
490
491int proc_dowatchdog_enabled(struct ctl_table *table, int write,
492 void __user *buffer, size_t *length, loff_t *ppos)
493{
494 proc_dointvec(table, write, buffer, length, ppos);
495
496 if (watchdog_enabled)
497 watchdog_enable_all_cpus();
498 else
499 watchdog_disable_all_cpus();
500 return 0;
501}
502
503int proc_dowatchdog_thresh(struct ctl_table *table, int write,
504 void __user *buffer,
505 size_t *lenp, loff_t *ppos)
506{
507 return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
508}
509#endif /* CONFIG_SYSCTL */
510
511
512/*
513 * Create/destroy watchdog threads as CPUs come and go:
514 */
515static int __cpuinit
516cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
517{
518 int hotcpu = (unsigned long)hcpu;
519
520 switch (action) {
521 case CPU_UP_PREPARE:
522 case CPU_UP_PREPARE_FROZEN:
523 if (watchdog_prepare_cpu(hotcpu))
524 return NOTIFY_BAD;
525 break;
526 case CPU_ONLINE:
527 case CPU_ONLINE_FROZEN:
528 if (watchdog_enable(hotcpu))
529 return NOTIFY_BAD;
530 break;
531#ifdef CONFIG_HOTPLUG_CPU
532 case CPU_UP_CANCELED:
533 case CPU_UP_CANCELED_FROZEN:
534 watchdog_disable(hotcpu);
535 break;
536 case CPU_DEAD:
537 case CPU_DEAD_FROZEN:
538 watchdog_disable(hotcpu);
539 break;
540#endif /* CONFIG_HOTPLUG_CPU */
541 }
542 return NOTIFY_OK;
543}
544
545static struct notifier_block __cpuinitdata cpu_nfb = {
546 .notifier_call = cpu_callback
547};
548
549static int __init spawn_watchdog_task(void)
550{
551 void *cpu = (void *)(long)smp_processor_id();
552 int err;
553
554 if (no_watchdog)
555 return 0;
556
557 err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
558 WARN_ON(err == NOTIFY_BAD);
559
560 cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
561 register_cpu_notifier(&cpu_nfb);
562
563 atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
564
565 return 0;
566}
567early_initcall(spawn_watchdog_task);
generated by cgit v1.2.2 (git 2.25.0) at 2025-01-09 08:33:19 -0500