1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
2e162b39aSMandeep Singh Baines /*
3e162b39aSMandeep Singh Baines * Detect Hung Task
4e162b39aSMandeep Singh Baines *
5e162b39aSMandeep Singh Baines * kernel/hung_task.c - kernel thread for detecting tasks stuck in D state
6e162b39aSMandeep Singh Baines *
7e162b39aSMandeep Singh Baines */
8e162b39aSMandeep Singh Baines
9e162b39aSMandeep Singh Baines #include <linux/mm.h>
10e162b39aSMandeep Singh Baines #include <linux/cpu.h>
11e162b39aSMandeep Singh Baines #include <linux/nmi.h>
12e162b39aSMandeep Singh Baines #include <linux/init.h>
13e162b39aSMandeep Singh Baines #include <linux/delay.h>
14e162b39aSMandeep Singh Baines #include <linux/freezer.h>
15e162b39aSMandeep Singh Baines #include <linux/kthread.h>
16e162b39aSMandeep Singh Baines #include <linux/lockdep.h>
179984de1aSPaul Gortmaker #include <linux/export.h>
18f39650deSAndy Shevchenko #include <linux/panic_notifier.h>
19e162b39aSMandeep Singh Baines #include <linux/sysctl.h>
20a1c6ca3cSVitaly Kuznetsov #include <linux/suspend.h>
2141e85ce8SOleg Nesterov #include <linux/utsname.h>
223f07c014SIngo Molnar #include <linux/sched/signal.h>
23b17b0153SIngo Molnar #include <linux/sched/debug.h>
24a98eb6f1SValdis Kletnieks #include <linux/sched/sysctl.h>
253f07c014SIngo Molnar
266a716c90SOleg Nesterov #include <trace/events/sched.h>
27e162b39aSMandeep Singh Baines
28e162b39aSMandeep Singh Baines /*
29ce9dbe24SMandeep Singh Baines * The number of tasks checked:
30e162b39aSMandeep Singh Baines */
31*882c5b26STom Rix static int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
32ce9dbe24SMandeep Singh Baines
33ce9dbe24SMandeep Singh Baines /*
34ce9dbe24SMandeep Singh Baines * Limit number of tasks checked in a batch.
35ce9dbe24SMandeep Singh Baines *
36ce9dbe24SMandeep Singh Baines * This value controls the preemptibility of khungtaskd since preemption
37ce9dbe24SMandeep Singh Baines * is disabled during the critical section. It also controls the size of
38ce9dbe24SMandeep Singh Baines * the RCU grace period. So it needs to be upper-bound.
39ce9dbe24SMandeep Singh Baines */
40304ae427STetsuo Handa #define HUNG_TASK_LOCK_BREAK (HZ / 10)
41e162b39aSMandeep Singh Baines
42e162b39aSMandeep Singh Baines /*
43e162b39aSMandeep Singh Baines * Zero means infinite timeout - no checking done:
44e162b39aSMandeep Singh Baines */
45e11feaa1SJeff Mahoney unsigned long __read_mostly sysctl_hung_task_timeout_secs = CONFIG_DEFAULT_HUNG_TASK_TIMEOUT;
46e162b39aSMandeep Singh Baines
47a2e51445SDmitry Vyukov /*
48a2e51445SDmitry Vyukov * Zero (default value) means use sysctl_hung_task_timeout_secs:
49a2e51445SDmitry Vyukov */
50*882c5b26STom Rix static unsigned long __read_mostly sysctl_hung_task_check_interval_secs;
51a2e51445SDmitry Vyukov
52*882c5b26STom Rix static int __read_mostly sysctl_hung_task_warnings = 10;
53e162b39aSMandeep Singh Baines
54e162b39aSMandeep Singh Baines static int __read_mostly did_panic;
55780cbcf2STetsuo Handa static bool hung_task_show_lock;
56401c636aSTetsuo Handa static bool hung_task_call_panic;
570ec9dc9bSGuilherme G. Piccoli static bool hung_task_show_all_bt;
58e162b39aSMandeep Singh Baines
59e162b39aSMandeep Singh Baines static struct task_struct *watchdog_task;
60e162b39aSMandeep Singh Baines
610ec9dc9bSGuilherme G. Piccoli #ifdef CONFIG_SMP
620ec9dc9bSGuilherme G. Piccoli /*
630ec9dc9bSGuilherme G. Piccoli * Should we dump all CPUs backtraces in a hung task event?
640ec9dc9bSGuilherme G. Piccoli * Defaults to 0, can be changed via sysctl.
650ec9dc9bSGuilherme G. Piccoli */
66bbe7a10eSXiaoming Ni static unsigned int __read_mostly sysctl_hung_task_all_cpu_backtrace;
67bbe7a10eSXiaoming Ni #else
68bbe7a10eSXiaoming Ni #define sysctl_hung_task_all_cpu_backtrace 0
690ec9dc9bSGuilherme G. Piccoli #endif /* CONFIG_SMP */
700ec9dc9bSGuilherme G. Piccoli
71e162b39aSMandeep Singh Baines /*
72e162b39aSMandeep Singh Baines * Should we panic (and reboot, if panic_timeout= is set) when a
73e162b39aSMandeep Singh Baines * hung task is detected:
74e162b39aSMandeep Singh Baines */
75*882c5b26STom Rix static unsigned int __read_mostly sysctl_hung_task_panic =
7667fca000SRasmus Villemoes IS_ENABLED(CONFIG_BOOTPARAM_HUNG_TASK_PANIC);
77e162b39aSMandeep Singh Baines
78e162b39aSMandeep Singh Baines static int
hung_task_panic(struct notifier_block * this,unsigned long event,void * ptr)79e162b39aSMandeep Singh Baines hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr)
80e162b39aSMandeep Singh Baines {
81e162b39aSMandeep Singh Baines did_panic = 1;
82e162b39aSMandeep Singh Baines
83e162b39aSMandeep Singh Baines return NOTIFY_DONE;
84e162b39aSMandeep Singh Baines }
85e162b39aSMandeep Singh Baines
86e162b39aSMandeep Singh Baines static struct notifier_block panic_block = {
87e162b39aSMandeep Singh Baines .notifier_call = hung_task_panic,
88e162b39aSMandeep Singh Baines };
89e162b39aSMandeep Singh Baines
check_hung_task(struct task_struct * t,unsigned long timeout)9017406b82SMandeep Singh Baines static void check_hung_task(struct task_struct *t, unsigned long timeout)
91e162b39aSMandeep Singh Baines {
92e162b39aSMandeep Singh Baines unsigned long switch_count = t->nvcsw + t->nivcsw;
93e162b39aSMandeep Singh Baines
94cf2592f5SFrederic Weisbecker /*
95cf2592f5SFrederic Weisbecker * Ensure the task is not frozen.
96f9fab10bSMandeep Singh Baines * Also, skip vfork and any other user process that freezer should skip.
97cf2592f5SFrederic Weisbecker */
98fdf756f7SPeter Zijlstra if (unlikely(READ_ONCE(t->__state) & TASK_FROZEN))
99f9fab10bSMandeep Singh Baines return;
100f9fab10bSMandeep Singh Baines
101f9fab10bSMandeep Singh Baines /*
102f9fab10bSMandeep Singh Baines * When a freshly created task is scheduled once, changes its state to
103f9fab10bSMandeep Singh Baines * TASK_UNINTERRUPTIBLE without having ever been switched out once, it
104f9fab10bSMandeep Singh Baines * musn't be checked.
105f9fab10bSMandeep Singh Baines */
106f9fab10bSMandeep Singh Baines if (unlikely(!switch_count))
107e162b39aSMandeep Singh Baines return;
108e162b39aSMandeep Singh Baines
10917406b82SMandeep Singh Baines if (switch_count != t->last_switch_count) {
110e162b39aSMandeep Singh Baines t->last_switch_count = switch_count;
111a2e51445SDmitry Vyukov t->last_switch_time = jiffies;
112e162b39aSMandeep Singh Baines return;
113e162b39aSMandeep Singh Baines }
114a2e51445SDmitry Vyukov if (time_is_after_jiffies(t->last_switch_time + timeout * HZ))
115a2e51445SDmitry Vyukov return;
1166a716c90SOleg Nesterov
1176a716c90SOleg Nesterov trace_sched_process_hang(t);
1186a716c90SOleg Nesterov
119168e06f7SLiu, Chuansheng if (sysctl_hung_task_panic) {
120168e06f7SLiu, Chuansheng console_verbose();
121168e06f7SLiu, Chuansheng hung_task_show_lock = true;
122168e06f7SLiu, Chuansheng hung_task_call_panic = true;
123168e06f7SLiu, Chuansheng }
124270750dbSAaron Tomlin
125e162b39aSMandeep Singh Baines /*
126e162b39aSMandeep Singh Baines * Ok, the task did not get scheduled for more than 2 minutes,
127e162b39aSMandeep Singh Baines * complain:
128e162b39aSMandeep Singh Baines */
12948a6d64eSJohn Siddle if (sysctl_hung_task_warnings) {
1304ca5ede0STetsuo Handa if (sysctl_hung_task_warnings > 0)
13148a6d64eSJohn Siddle sysctl_hung_task_warnings--;
13241e85ce8SOleg Nesterov pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n",
133b014bebaSTetsuo Handa t->comm, t->pid, (jiffies - t->last_switch_time) / HZ);
13441e85ce8SOleg Nesterov pr_err(" %s %s %.*s\n",
13541e85ce8SOleg Nesterov print_tainted(), init_utsname()->release,
13641e85ce8SOleg Nesterov (int)strcspn(init_utsname()->version, " "),
13741e85ce8SOleg Nesterov init_utsname()->version);
13841e85ce8SOleg Nesterov pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
139e162b39aSMandeep Singh Baines " disables this message.\n");
140e162b39aSMandeep Singh Baines sched_show_task(t);
141780cbcf2STetsuo Handa hung_task_show_lock = true;
1420ec9dc9bSGuilherme G. Piccoli
1430ec9dc9bSGuilherme G. Piccoli if (sysctl_hung_task_all_cpu_backtrace)
1440ec9dc9bSGuilherme G. Piccoli hung_task_show_all_bt = true;
145b1f712b3Sfuyuanli if (!sysctl_hung_task_warnings)
146b1f712b3Sfuyuanli pr_info("Future hung task reports are suppressed, see sysctl kernel.hung_task_warnings\n");
14748a6d64eSJohn Siddle }
148e162b39aSMandeep Singh Baines
149e162b39aSMandeep Singh Baines touch_nmi_watchdog();
150625056b6SSasha Levin }
151e162b39aSMandeep Singh Baines
152e162b39aSMandeep Singh Baines /*
153ce9dbe24SMandeep Singh Baines * To avoid extending the RCU grace period for an unbounded amount of time,
154ce9dbe24SMandeep Singh Baines * periodically exit the critical section and enter a new one.
155ce9dbe24SMandeep Singh Baines *
156ce9dbe24SMandeep Singh Baines * For preemptible RCU it is sufficient to call rcu_read_unlock in order
1576a103b0dSJohn Kacur * to exit the grace period. For classic RCU, a reschedule is required.
158ce9dbe24SMandeep Singh Baines */
rcu_lock_break(struct task_struct * g,struct task_struct * t)1596027ce49SOleg Nesterov static bool rcu_lock_break(struct task_struct *g, struct task_struct *t)
160ce9dbe24SMandeep Singh Baines {
1616027ce49SOleg Nesterov bool can_cont;
1626027ce49SOleg Nesterov
163ce9dbe24SMandeep Singh Baines get_task_struct(g);
164ce9dbe24SMandeep Singh Baines get_task_struct(t);
165ce9dbe24SMandeep Singh Baines rcu_read_unlock();
166ce9dbe24SMandeep Singh Baines cond_resched();
167ce9dbe24SMandeep Singh Baines rcu_read_lock();
1686027ce49SOleg Nesterov can_cont = pid_alive(g) && pid_alive(t);
169ce9dbe24SMandeep Singh Baines put_task_struct(t);
170ce9dbe24SMandeep Singh Baines put_task_struct(g);
1716027ce49SOleg Nesterov
1726027ce49SOleg Nesterov return can_cont;
173ce9dbe24SMandeep Singh Baines }
174ce9dbe24SMandeep Singh Baines
175ce9dbe24SMandeep Singh Baines /*
176e162b39aSMandeep Singh Baines * Check whether a TASK_UNINTERRUPTIBLE does not get woken up for
177e162b39aSMandeep Singh Baines * a really long time (120 seconds). If that happens, print out
178e162b39aSMandeep Singh Baines * a warning.
179e162b39aSMandeep Singh Baines */
check_hung_uninterruptible_tasks(unsigned long timeout)180603a148fSMandeep Singh Baines static void check_hung_uninterruptible_tasks(unsigned long timeout)
181e162b39aSMandeep Singh Baines {
182e162b39aSMandeep Singh Baines int max_count = sysctl_hung_task_check_count;
183304ae427STetsuo Handa unsigned long last_break = jiffies;
184e162b39aSMandeep Singh Baines struct task_struct *g, *t;
185e162b39aSMandeep Singh Baines
186e162b39aSMandeep Singh Baines /*
187e162b39aSMandeep Singh Baines * If the system crashed already then all bets are off,
188e162b39aSMandeep Singh Baines * do not report extra hung tasks:
189e162b39aSMandeep Singh Baines */
190e162b39aSMandeep Singh Baines if (test_taint(TAINT_DIE) || did_panic)
191e162b39aSMandeep Singh Baines return;
192e162b39aSMandeep Singh Baines
193780cbcf2STetsuo Handa hung_task_show_lock = false;
19494be52dcSMandeep Singh Baines rcu_read_lock();
195972fae69SAaron Tomlin for_each_process_thread(g, t) {
1965aec788aSPeter Zijlstra unsigned int state;
1975aec788aSPeter Zijlstra
198e5af0226SAnton Blanchard if (!max_count--)
199e162b39aSMandeep Singh Baines goto unlock;
200304ae427STetsuo Handa if (time_after(jiffies, last_break + HUNG_TASK_LOCK_BREAK)) {
2016027ce49SOleg Nesterov if (!rcu_lock_break(g, t))
202ce9dbe24SMandeep Singh Baines goto unlock;
203304ae427STetsuo Handa last_break = jiffies;
204ce9dbe24SMandeep Singh Baines }
205fdf756f7SPeter Zijlstra /*
206fdf756f7SPeter Zijlstra * skip the TASK_KILLABLE tasks -- these can be killed
207fdf756f7SPeter Zijlstra * skip the TASK_IDLE tasks -- those are genuinely idle
208fdf756f7SPeter Zijlstra */
2095aec788aSPeter Zijlstra state = READ_ONCE(t->__state);
2105aec788aSPeter Zijlstra if ((state & TASK_UNINTERRUPTIBLE) &&
211fdf756f7SPeter Zijlstra !(state & TASK_WAKEKILL) &&
212fdf756f7SPeter Zijlstra !(state & TASK_NOLOAD))
21317406b82SMandeep Singh Baines check_hung_task(t, timeout);
214972fae69SAaron Tomlin }
215e162b39aSMandeep Singh Baines unlock:
21694be52dcSMandeep Singh Baines rcu_read_unlock();
21707a22b61SPetr Mladek if (hung_task_show_lock)
218780cbcf2STetsuo Handa debug_show_all_locks();
2190ec9dc9bSGuilherme G. Piccoli
2200ec9dc9bSGuilherme G. Piccoli if (hung_task_show_all_bt) {
2210ec9dc9bSGuilherme G. Piccoli hung_task_show_all_bt = false;
222401c636aSTetsuo Handa trigger_all_cpu_backtrace();
223401c636aSTetsuo Handa }
2240ec9dc9bSGuilherme G. Piccoli
2250ec9dc9bSGuilherme G. Piccoli if (hung_task_call_panic)
2260ec9dc9bSGuilherme G. Piccoli panic("hung_task: blocked tasks");
227e162b39aSMandeep Singh Baines }
228e162b39aSMandeep Singh Baines
hung_timeout_jiffies(unsigned long last_checked,unsigned long timeout)229b4aa14a6STetsuo Handa static long hung_timeout_jiffies(unsigned long last_checked,
230b4aa14a6STetsuo Handa unsigned long timeout)
231e162b39aSMandeep Singh Baines {
232e162b39aSMandeep Singh Baines /* timeout of 0 will disable the watchdog */
233b4aa14a6STetsuo Handa return timeout ? last_checked - jiffies + timeout * HZ :
234b4aa14a6STetsuo Handa MAX_SCHEDULE_TIMEOUT;
235e162b39aSMandeep Singh Baines }
236e162b39aSMandeep Singh Baines
237bbe7a10eSXiaoming Ni #ifdef CONFIG_SYSCTL
238e162b39aSMandeep Singh Baines /*
239e162b39aSMandeep Singh Baines * Process updating of timeout sysctl
240e162b39aSMandeep Singh Baines */
proc_dohung_task_timeout_secs(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)241bbe7a10eSXiaoming Ni static int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
242591c32bdSBen Dooks void *buffer,
243bbe7a10eSXiaoming Ni size_t *lenp, loff_t *ppos)
244e162b39aSMandeep Singh Baines {
245e162b39aSMandeep Singh Baines int ret;
246e162b39aSMandeep Singh Baines
2478d65af78SAlexey Dobriyan ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
248e162b39aSMandeep Singh Baines
249e162b39aSMandeep Singh Baines if (ret || !write)
250e162b39aSMandeep Singh Baines goto out;
251e162b39aSMandeep Singh Baines
252e162b39aSMandeep Singh Baines wake_up_process(watchdog_task);
253e162b39aSMandeep Singh Baines
254e162b39aSMandeep Singh Baines out:
255e162b39aSMandeep Singh Baines return ret;
256e162b39aSMandeep Singh Baines }
257e162b39aSMandeep Singh Baines
258bbe7a10eSXiaoming Ni /*
259bbe7a10eSXiaoming Ni * This is needed for proc_doulongvec_minmax of sysctl_hung_task_timeout_secs
260bbe7a10eSXiaoming Ni * and hung_task_check_interval_secs
261bbe7a10eSXiaoming Ni */
262bbe7a10eSXiaoming Ni static const unsigned long hung_task_timeout_max = (LONG_MAX / HZ);
263bbe7a10eSXiaoming Ni static struct ctl_table hung_task_sysctls[] = {
264bbe7a10eSXiaoming Ni #ifdef CONFIG_SMP
265bbe7a10eSXiaoming Ni {
266bbe7a10eSXiaoming Ni .procname = "hung_task_all_cpu_backtrace",
267bbe7a10eSXiaoming Ni .data = &sysctl_hung_task_all_cpu_backtrace,
268bbe7a10eSXiaoming Ni .maxlen = sizeof(int),
269bbe7a10eSXiaoming Ni .mode = 0644,
270bbe7a10eSXiaoming Ni .proc_handler = proc_dointvec_minmax,
271bbe7a10eSXiaoming Ni .extra1 = SYSCTL_ZERO,
272bbe7a10eSXiaoming Ni .extra2 = SYSCTL_ONE,
273bbe7a10eSXiaoming Ni },
274bbe7a10eSXiaoming Ni #endif /* CONFIG_SMP */
275bbe7a10eSXiaoming Ni {
276bbe7a10eSXiaoming Ni .procname = "hung_task_panic",
277bbe7a10eSXiaoming Ni .data = &sysctl_hung_task_panic,
278bbe7a10eSXiaoming Ni .maxlen = sizeof(int),
279bbe7a10eSXiaoming Ni .mode = 0644,
280bbe7a10eSXiaoming Ni .proc_handler = proc_dointvec_minmax,
281bbe7a10eSXiaoming Ni .extra1 = SYSCTL_ZERO,
282bbe7a10eSXiaoming Ni .extra2 = SYSCTL_ONE,
283bbe7a10eSXiaoming Ni },
284bbe7a10eSXiaoming Ni {
285bbe7a10eSXiaoming Ni .procname = "hung_task_check_count",
286bbe7a10eSXiaoming Ni .data = &sysctl_hung_task_check_count,
287bbe7a10eSXiaoming Ni .maxlen = sizeof(int),
288bbe7a10eSXiaoming Ni .mode = 0644,
289bbe7a10eSXiaoming Ni .proc_handler = proc_dointvec_minmax,
290bbe7a10eSXiaoming Ni .extra1 = SYSCTL_ZERO,
291bbe7a10eSXiaoming Ni },
292bbe7a10eSXiaoming Ni {
293bbe7a10eSXiaoming Ni .procname = "hung_task_timeout_secs",
294bbe7a10eSXiaoming Ni .data = &sysctl_hung_task_timeout_secs,
295bbe7a10eSXiaoming Ni .maxlen = sizeof(unsigned long),
296bbe7a10eSXiaoming Ni .mode = 0644,
297bbe7a10eSXiaoming Ni .proc_handler = proc_dohung_task_timeout_secs,
298bbe7a10eSXiaoming Ni .extra2 = (void *)&hung_task_timeout_max,
299bbe7a10eSXiaoming Ni },
300bbe7a10eSXiaoming Ni {
301bbe7a10eSXiaoming Ni .procname = "hung_task_check_interval_secs",
302bbe7a10eSXiaoming Ni .data = &sysctl_hung_task_check_interval_secs,
303bbe7a10eSXiaoming Ni .maxlen = sizeof(unsigned long),
304bbe7a10eSXiaoming Ni .mode = 0644,
305bbe7a10eSXiaoming Ni .proc_handler = proc_dohung_task_timeout_secs,
306bbe7a10eSXiaoming Ni .extra2 = (void *)&hung_task_timeout_max,
307bbe7a10eSXiaoming Ni },
308bbe7a10eSXiaoming Ni {
309bbe7a10eSXiaoming Ni .procname = "hung_task_warnings",
310bbe7a10eSXiaoming Ni .data = &sysctl_hung_task_warnings,
311bbe7a10eSXiaoming Ni .maxlen = sizeof(int),
312bbe7a10eSXiaoming Ni .mode = 0644,
313bbe7a10eSXiaoming Ni .proc_handler = proc_dointvec_minmax,
314bbe7a10eSXiaoming Ni .extra1 = SYSCTL_NEG_ONE,
315bbe7a10eSXiaoming Ni },
316bbe7a10eSXiaoming Ni {}
317bbe7a10eSXiaoming Ni };
318bbe7a10eSXiaoming Ni
hung_task_sysctl_init(void)319bbe7a10eSXiaoming Ni static void __init hung_task_sysctl_init(void)
320bbe7a10eSXiaoming Ni {
321bbe7a10eSXiaoming Ni register_sysctl_init("kernel", hung_task_sysctls);
322bbe7a10eSXiaoming Ni }
323bbe7a10eSXiaoming Ni #else
324bbe7a10eSXiaoming Ni #define hung_task_sysctl_init() do { } while (0)
325bbe7a10eSXiaoming Ni #endif /* CONFIG_SYSCTL */
326bbe7a10eSXiaoming Ni
327bbe7a10eSXiaoming Ni
3288b414521SMarcelo Tosatti static atomic_t reset_hung_task = ATOMIC_INIT(0);
3298b414521SMarcelo Tosatti
reset_hung_task_detector(void)3308b414521SMarcelo Tosatti void reset_hung_task_detector(void)
3318b414521SMarcelo Tosatti {
3328b414521SMarcelo Tosatti atomic_set(&reset_hung_task, 1);
3338b414521SMarcelo Tosatti }
3348b414521SMarcelo Tosatti EXPORT_SYMBOL_GPL(reset_hung_task_detector);
3358b414521SMarcelo Tosatti
336a1c6ca3cSVitaly Kuznetsov static bool hung_detector_suspended;
337a1c6ca3cSVitaly Kuznetsov
hungtask_pm_notify(struct notifier_block * self,unsigned long action,void * hcpu)338a1c6ca3cSVitaly Kuznetsov static int hungtask_pm_notify(struct notifier_block *self,
339a1c6ca3cSVitaly Kuznetsov unsigned long action, void *hcpu)
340a1c6ca3cSVitaly Kuznetsov {
341a1c6ca3cSVitaly Kuznetsov switch (action) {
342a1c6ca3cSVitaly Kuznetsov case PM_SUSPEND_PREPARE:
343a1c6ca3cSVitaly Kuznetsov case PM_HIBERNATION_PREPARE:
344a1c6ca3cSVitaly Kuznetsov case PM_RESTORE_PREPARE:
345a1c6ca3cSVitaly Kuznetsov hung_detector_suspended = true;
346a1c6ca3cSVitaly Kuznetsov break;
347a1c6ca3cSVitaly Kuznetsov case PM_POST_SUSPEND:
348a1c6ca3cSVitaly Kuznetsov case PM_POST_HIBERNATION:
349a1c6ca3cSVitaly Kuznetsov case PM_POST_RESTORE:
350a1c6ca3cSVitaly Kuznetsov hung_detector_suspended = false;
351a1c6ca3cSVitaly Kuznetsov break;
352a1c6ca3cSVitaly Kuznetsov default:
353a1c6ca3cSVitaly Kuznetsov break;
354a1c6ca3cSVitaly Kuznetsov }
355a1c6ca3cSVitaly Kuznetsov return NOTIFY_OK;
356a1c6ca3cSVitaly Kuznetsov }
357a1c6ca3cSVitaly Kuznetsov
358e162b39aSMandeep Singh Baines /*
359e162b39aSMandeep Singh Baines * kthread which checks for tasks stuck in D state
360e162b39aSMandeep Singh Baines */
watchdog(void * dummy)361e162b39aSMandeep Singh Baines static int watchdog(void *dummy)
362e162b39aSMandeep Singh Baines {
363b4aa14a6STetsuo Handa unsigned long hung_last_checked = jiffies;
364b4aa14a6STetsuo Handa
365e162b39aSMandeep Singh Baines set_user_nice(current, 0);
366e162b39aSMandeep Singh Baines
367e162b39aSMandeep Singh Baines for ( ; ; ) {
36817406b82SMandeep Singh Baines unsigned long timeout = sysctl_hung_task_timeout_secs;
369a2e51445SDmitry Vyukov unsigned long interval = sysctl_hung_task_check_interval_secs;
370a2e51445SDmitry Vyukov long t;
371603a148fSMandeep Singh Baines
372a2e51445SDmitry Vyukov if (interval == 0)
373a2e51445SDmitry Vyukov interval = timeout;
374a2e51445SDmitry Vyukov interval = min_t(unsigned long, interval, timeout);
375a2e51445SDmitry Vyukov t = hung_timeout_jiffies(hung_last_checked, interval);
376b4aa14a6STetsuo Handa if (t <= 0) {
377a1c6ca3cSVitaly Kuznetsov if (!atomic_xchg(&reset_hung_task, 0) &&
378a1c6ca3cSVitaly Kuznetsov !hung_detector_suspended)
379603a148fSMandeep Singh Baines check_hung_uninterruptible_tasks(timeout);
380b4aa14a6STetsuo Handa hung_last_checked = jiffies;
381b4aa14a6STetsuo Handa continue;
382b4aa14a6STetsuo Handa }
383b4aa14a6STetsuo Handa schedule_timeout_interruptible(t);
384e162b39aSMandeep Singh Baines }
385e162b39aSMandeep Singh Baines
386e162b39aSMandeep Singh Baines return 0;
387e162b39aSMandeep Singh Baines }
388e162b39aSMandeep Singh Baines
hung_task_init(void)389e162b39aSMandeep Singh Baines static int __init hung_task_init(void)
390e162b39aSMandeep Singh Baines {
391e162b39aSMandeep Singh Baines atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
392a1c6ca3cSVitaly Kuznetsov
393a1c6ca3cSVitaly Kuznetsov /* Disable hung task detector on suspend */
394a1c6ca3cSVitaly Kuznetsov pm_notifier(hungtask_pm_notify, 0);
395a1c6ca3cSVitaly Kuznetsov
396e162b39aSMandeep Singh Baines watchdog_task = kthread_run(watchdog, NULL, "khungtaskd");
397bbe7a10eSXiaoming Ni hung_task_sysctl_init();
398e162b39aSMandeep Singh Baines
399e162b39aSMandeep Singh Baines return 0;
400e162b39aSMandeep Singh Baines }
401c96d6660SPaul Gortmaker subsys_initcall(hung_task_init);
402