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-rw-r--r--kernel/softlockup.c293
1 files changed, 0 insertions, 293 deletions
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);
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