1 // SPDX-License-Identifier: GPL-2.0-only
5  * kernel/hung_task.c - kernel thread for detecting tasks stuck in D state
43  * the RCU grace period. So it needs to be upper-bound.
48  * Zero means infinite timeout - no checking done:
54  * Zero (default value) means use sysctl_hung_task_timeout_secs:
106 	lock = READ_ONCE(task->blocker_mutex);  in debug_show_blocker()
112 		pr_err("INFO: task %s:%d is blocked on a mutex, but the owner is not found.\n",  in debug_show_blocker()
113 			task->comm, task->pid);  in debug_show_blocker()
120 			pr_err("INFO: task %s:%d is blocked on a mutex likely owned by task %s:%d.\n",  in debug_show_blocker()
121 				task->comm, task->pid, t->comm, t->pid);  in debug_show_blocker()
135 	unsigned long switch_count = t->nvcsw + t->nivcsw;  in check_hung_task()
141 	if (unlikely(READ_ONCE(t->__state) & TASK_FROZEN))  in check_hung_task()
152 	if (switch_count != t->last_switch_count) {  in check_hung_task()
153 		t->last_switch_count = switch_count;  in check_hung_task()
154 		t->last_switch_time = jiffies;  in check_hung_task()
157 	if (time_is_after_jiffies(t->last_switch_time + timeout * HZ))  in check_hung_task()
180 			sysctl_hung_task_warnings--;  in check_hung_task()
181 		pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n",  in check_hung_task()
182 		       t->comm, t->pid, (jiffies - t->last_switch_time) / HZ);  in check_hung_task()
184 			print_tainted(), init_utsname()->release,  in check_hung_task()
185 			(int)strcspn(init_utsname()->version, " "),  in check_hung_task()
186 			init_utsname()->version);  in check_hung_task()
187 		if (t->flags & PF_POSTCOREDUMP)  in check_hung_task()
188 			pr_err("      Blocked by coredump.\n");  in check_hung_task()
250 		if (!max_count--)  in check_hung_uninterruptible_tasks()
258 		 * skip the TASK_KILLABLE tasks -- these can be killed  in check_hung_uninterruptible_tasks()
259 		 * skip the TASK_IDLE tasks -- those are genuinely idle  in check_hung_uninterruptible_tasks()
261 		state = READ_ONCE(t->__state);  in check_hung_uninterruptible_tasks()
278 		panic("hung_task: blocked tasks");  in check_hung_uninterruptible_tasks()
285 	return timeout ? last_checked - jiffies + timeout * HZ :  in hung_timeout_jiffies()
410 	default:  in hungtask_pm_notify()