Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Detect Hung Task
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * kernel/hung_task.c - kernel thread for detecting tasks stuck in D state
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/cpu.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/nmi.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/delay.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/freezer.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/kthread.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/lockdep.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/sysctl.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <linux/suspend.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include <linux/utsname.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #include <linux/sched/signal.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) #include <linux/sched/debug.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #include <linux/sched/sysctl.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) #include <trace/events/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) #undef CREATE_TRACE_POINTS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #include <trace/hooks/hung_task.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30)  * The number of tasks checked:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35)  * Limit number of tasks checked in a batch.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37)  * This value controls the preemptibility of khungtaskd since preemption
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38)  * is disabled during the critical section. It also controls the size of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39)  * the RCU grace period. So it needs to be upper-bound.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) #define HUNG_TASK_LOCK_BREAK (HZ / 10)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44)  * Zero means infinite timeout - no checking done:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) unsigned long __read_mostly sysctl_hung_task_timeout_secs = CONFIG_DEFAULT_HUNG_TASK_TIMEOUT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49)  * Zero (default value) means use sysctl_hung_task_timeout_secs:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) unsigned long __read_mostly sysctl_hung_task_check_interval_secs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) int __read_mostly sysctl_hung_task_warnings = 10;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) static int __read_mostly did_panic;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) static bool hung_task_show_lock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) static bool hung_task_call_panic;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) static bool hung_task_show_all_bt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) static struct task_struct *watchdog_task;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) #ifdef CONFIG_SMP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64)  * Should we dump all CPUs backtraces in a hung task event?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65)  * Defaults to 0, can be changed via sysctl.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) unsigned int __read_mostly sysctl_hung_task_all_cpu_backtrace;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) #endif /* CONFIG_SMP */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71)  * Should we panic (and reboot, if panic_timeout= is set) when a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72)  * hung task is detected:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) unsigned int __read_mostly sysctl_hung_task_panic =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 				CONFIG_BOOTPARAM_HUNG_TASK_PANIC_VALUE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) static int
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	did_panic = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	return NOTIFY_DONE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) static struct notifier_block panic_block = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 	.notifier_call = hung_task_panic,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) static void check_hung_task(struct task_struct *t, unsigned long timeout)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 	unsigned long switch_count = t->nvcsw + t->nivcsw;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	 * Ensure the task is not frozen.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	 * Also, skip vfork and any other user process that freezer should skip.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	if (unlikely(frozen_or_skipped(t)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	 * When a freshly created task is scheduled once, changes its state to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	 * TASK_UNINTERRUPTIBLE without having ever been switched out once, it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 	 * musn't be checked.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	if (unlikely(!switch_count))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	if (switch_count != t->last_switch_count) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 		t->last_switch_count = switch_count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 		t->last_switch_time = jiffies;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	if (time_is_after_jiffies(t->last_switch_time + timeout * HZ))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	trace_sched_process_hang(t);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	if (sysctl_hung_task_panic) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 		console_verbose();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 		hung_task_show_lock = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 		hung_task_call_panic = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	 * Ok, the task did not get scheduled for more than 2 minutes,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	 * complain:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	if (sysctl_hung_task_warnings) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 		if (sysctl_hung_task_warnings > 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 			sysctl_hung_task_warnings--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 		pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		       t->comm, t->pid, (jiffies - t->last_switch_time) / HZ);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 		pr_err("      %s %s %.*s\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 			print_tainted(), init_utsname()->release,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 			(int)strcspn(init_utsname()->version, " "),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 			init_utsname()->version);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 			" disables this message.\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		sched_show_task(t);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 		hung_task_show_lock = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 		if (sysctl_hung_task_all_cpu_backtrace)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 			hung_task_show_all_bt = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	touch_nmi_watchdog();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150)  * To avoid extending the RCU grace period for an unbounded amount of time,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151)  * periodically exit the critical section and enter a new one.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153)  * For preemptible RCU it is sufficient to call rcu_read_unlock in order
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154)  * to exit the grace period. For classic RCU, a reschedule is required.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) static bool rcu_lock_break(struct task_struct *g, struct task_struct *t)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	bool can_cont;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	get_task_struct(g);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	get_task_struct(t);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	cond_resched();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	can_cont = pid_alive(g) && pid_alive(t);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	put_task_struct(t);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	put_task_struct(g);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	return can_cont;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173)  * Check whether a TASK_UNINTERRUPTIBLE does not get woken up for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174)  * a really long time (120 seconds). If that happens, print out
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175)  * a warning.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) static void check_hung_uninterruptible_tasks(unsigned long timeout)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	int max_count = sysctl_hung_task_check_count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	unsigned long last_break = jiffies;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	struct task_struct *g, *t;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	bool need_check = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 	 * If the system crashed already then all bets are off,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 	 * do not report extra hung tasks:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	if (test_taint(TAINT_DIE) || did_panic)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	hung_task_show_lock = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	for_each_process_thread(g, t) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 		if (!max_count--)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 			goto unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 		if (time_after(jiffies, last_break + HUNG_TASK_LOCK_BREAK)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 			if (!rcu_lock_break(g, t))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 				goto unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 			last_break = jiffies;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 		trace_android_vh_check_uninterruptible_tasks(t, timeout, &need_check);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 		if (need_check)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 			/* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 			if (t->state == TASK_UNINTERRUPTIBLE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 				check_hung_task(t, timeout);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	trace_android_vh_check_uninterruptible_tasks_dn(NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208)  unlock:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	if (hung_task_show_lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 		debug_show_all_locks();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	if (hung_task_show_all_bt) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 		hung_task_show_all_bt = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 		trigger_all_cpu_backtrace();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	if (hung_task_call_panic)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 		panic("hung_task: blocked tasks");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) static long hung_timeout_jiffies(unsigned long last_checked,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 				 unsigned long timeout)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 	/* timeout of 0 will disable the watchdog */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 	return timeout ? last_checked - jiffies + timeout * HZ :
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 		MAX_SCHEDULE_TIMEOUT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231)  * Process updating of timeout sysctl
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 				  void *buffer, size_t *lenp, loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	if (ret || !write)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 	wake_up_process(watchdog_task);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245)  out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) static atomic_t reset_hung_task = ATOMIC_INIT(0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) void reset_hung_task_detector(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 	atomic_set(&reset_hung_task, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) EXPORT_SYMBOL_GPL(reset_hung_task_detector);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) static bool hung_detector_suspended;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) static int hungtask_pm_notify(struct notifier_block *self,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 			      unsigned long action, void *hcpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	switch (action) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	case PM_SUSPEND_PREPARE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	case PM_HIBERNATION_PREPARE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 	case PM_RESTORE_PREPARE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 		hung_detector_suspended = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	case PM_POST_SUSPEND:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 	case PM_POST_HIBERNATION:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	case PM_POST_RESTORE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 		hung_detector_suspended = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 	return NOTIFY_OK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280)  * kthread which checks for tasks stuck in D state
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) static int watchdog(void *dummy)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 	unsigned long hung_last_checked = jiffies;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 	set_user_nice(current, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 	for ( ; ; ) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 		unsigned long timeout = sysctl_hung_task_timeout_secs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 		unsigned long interval = sysctl_hung_task_check_interval_secs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 		long t;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 		if (interval == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 			interval = timeout;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 		interval = min_t(unsigned long, interval, timeout);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 		t = hung_timeout_jiffies(hung_last_checked, interval);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 		if (t <= 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 			if (!atomic_xchg(&reset_hung_task, 0) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 			    !hung_detector_suspended)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 				check_hung_uninterruptible_tasks(timeout);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 			hung_last_checked = jiffies;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 		schedule_timeout_interruptible(t);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) static int __init hung_task_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 	/* Disable hung task detector on suspend */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 	pm_notifier(hungtask_pm_notify, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	watchdog_task = kthread_run(watchdog, NULL, "khungtaskd");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) subsys_initcall(hung_task_init);