xref: /openbmc/linux/kernel/torture.c (revision 0b962c8fe0e5c72a252b236814a6b6e9df799061)
18f8e76c0SPaul E. McKenney // SPDX-License-Identifier: GPL-2.0+
251b1130eSPaul E. McKenney /*
351b1130eSPaul E. McKenney  * Common functions for in-kernel torture tests.
451b1130eSPaul E. McKenney  *
551b1130eSPaul E. McKenney  * Copyright (C) IBM Corporation, 2014
651b1130eSPaul E. McKenney  *
78f8e76c0SPaul E. McKenney  * Author: Paul E. McKenney <paulmck@linux.ibm.com>
851b1130eSPaul E. McKenney  *	Based on kernel/rcu/torture.c.
951b1130eSPaul E. McKenney  */
1060500037SPaul E. McKenney 
1160500037SPaul E. McKenney #define pr_fmt(fmt) fmt
1260500037SPaul E. McKenney 
1351b1130eSPaul E. McKenney #include <linux/types.h>
1451b1130eSPaul E. McKenney #include <linux/kernel.h>
1551b1130eSPaul E. McKenney #include <linux/init.h>
1651b1130eSPaul E. McKenney #include <linux/module.h>
1751b1130eSPaul E. McKenney #include <linux/kthread.h>
1851b1130eSPaul E. McKenney #include <linux/err.h>
1951b1130eSPaul E. McKenney #include <linux/spinlock.h>
2051b1130eSPaul E. McKenney #include <linux/smp.h>
2151b1130eSPaul E. McKenney #include <linux/interrupt.h>
2251b1130eSPaul E. McKenney #include <linux/sched.h>
23e6017571SIngo Molnar #include <linux/sched/clock.h>
2451b1130eSPaul E. McKenney #include <linux/atomic.h>
2551b1130eSPaul E. McKenney #include <linux/bitops.h>
2651b1130eSPaul E. McKenney #include <linux/completion.h>
2751b1130eSPaul E. McKenney #include <linux/moduleparam.h>
2851b1130eSPaul E. McKenney #include <linux/percpu.h>
2951b1130eSPaul E. McKenney #include <linux/notifier.h>
3051b1130eSPaul E. McKenney #include <linux/reboot.h>
3151b1130eSPaul E. McKenney #include <linux/freezer.h>
3251b1130eSPaul E. McKenney #include <linux/cpu.h>
3351b1130eSPaul E. McKenney #include <linux/delay.h>
3451b1130eSPaul E. McKenney #include <linux/stat.h>
3551b1130eSPaul E. McKenney #include <linux/slab.h>
3651b1130eSPaul E. McKenney #include <linux/trace_clock.h>
3731257c3cSPaul E. McKenney #include <linux/ktime.h>
3851b1130eSPaul E. McKenney #include <asm/byteorder.h>
3951b1130eSPaul E. McKenney #include <linux/torture.h>
40dac95906SPaul E. McKenney #include "rcu/rcu.h"
4151b1130eSPaul E. McKenney 
4251b1130eSPaul E. McKenney MODULE_LICENSE("GPL");
438f8e76c0SPaul E. McKenney MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
4451b1130eSPaul E. McKenney 
458171d3e0SPaul E. McKenney static bool disable_onoff_at_boot;
468171d3e0SPaul E. McKenney module_param(disable_onoff_at_boot, bool, 0444);
478171d3e0SPaul E. McKenney 
482102ad29SPaul E. McKenney static bool ftrace_dump_at_shutdown;
492102ad29SPaul E. McKenney module_param(ftrace_dump_at_shutdown, bool, 0444);
502102ad29SPaul E. McKenney 
518a67a20bSPaul E. McKenney static int verbose_sleep_frequency;
528a67a20bSPaul E. McKenney module_param(verbose_sleep_frequency, int, 0444);
538a67a20bSPaul E. McKenney 
548a67a20bSPaul E. McKenney static int verbose_sleep_duration = 1;
558a67a20bSPaul E. McKenney module_param(verbose_sleep_duration, int, 0444);
568a67a20bSPaul E. McKenney 
57b5daa8f3SPaul E. McKenney static char *torture_type;
5890127d60SPaul E. McKenney static int verbose;
59b5daa8f3SPaul E. McKenney 
6036970bb9SPaul E. McKenney /* Mediate rmmod and system shutdown.  Concurrent rmmod & shutdown illegal! */
6136970bb9SPaul E. McKenney #define FULLSTOP_DONTSTOP 0	/* Normal operation. */
6236970bb9SPaul E. McKenney #define FULLSTOP_SHUTDOWN 1	/* System shutdown with torture running. */
6336970bb9SPaul E. McKenney #define FULLSTOP_RMMOD    2	/* Normal rmmod of torture. */
6436970bb9SPaul E. McKenney static int fullstop = FULLSTOP_RMMOD;
654622b487SPaul E. McKenney static DEFINE_MUTEX(fullstop_mutex);
66f67a3356SPaul E. McKenney 
678a67a20bSPaul E. McKenney static atomic_t verbose_sleep_counter;
688a67a20bSPaul E. McKenney 
698a67a20bSPaul E. McKenney /*
708a67a20bSPaul E. McKenney  * Sleep if needed from VERBOSE_TOROUT*().
718a67a20bSPaul E. McKenney  */
728a67a20bSPaul E. McKenney void verbose_torout_sleep(void)
738a67a20bSPaul E. McKenney {
748a67a20bSPaul E. McKenney 	if (verbose_sleep_frequency > 0 &&
758a67a20bSPaul E. McKenney 	    verbose_sleep_duration > 0 &&
768a67a20bSPaul E. McKenney 	    !(atomic_inc_return(&verbose_sleep_counter) % verbose_sleep_frequency))
778a67a20bSPaul E. McKenney 		schedule_timeout_uninterruptible(verbose_sleep_duration);
788a67a20bSPaul E. McKenney }
798a67a20bSPaul E. McKenney EXPORT_SYMBOL_GPL(verbose_torout_sleep);
808a67a20bSPaul E. McKenney 
81ae19aaafSPaul E. McKenney /*
82ae19aaafSPaul E. McKenney  * Schedule a high-resolution-timer sleep in nanoseconds, with a 32-bit
83ae19aaafSPaul E. McKenney  * nanosecond random fuzz.  This function and its friends desynchronize
84ae19aaafSPaul E. McKenney  * testing from the timer wheel.
85ae19aaafSPaul E. McKenney  */
86ae19aaafSPaul E. McKenney int torture_hrtimeout_ns(ktime_t baset_ns, u32 fuzzt_ns, struct torture_random_state *trsp)
87ae19aaafSPaul E. McKenney {
88ae19aaafSPaul E. McKenney 	ktime_t hto = baset_ns;
89ae19aaafSPaul E. McKenney 
90ae19aaafSPaul E. McKenney 	if (trsp)
91ae19aaafSPaul E. McKenney 		hto += (torture_random(trsp) >> 3) % fuzzt_ns;
92ae19aaafSPaul E. McKenney 	set_current_state(TASK_UNINTERRUPTIBLE);
93ae19aaafSPaul E. McKenney 	return schedule_hrtimeout(&hto, HRTIMER_MODE_REL);
94ae19aaafSPaul E. McKenney }
95ae19aaafSPaul E. McKenney EXPORT_SYMBOL_GPL(torture_hrtimeout_ns);
96ae19aaafSPaul E. McKenney 
97ae19aaafSPaul E. McKenney /*
98ae19aaafSPaul E. McKenney  * Schedule a high-resolution-timer sleep in microseconds, with a 32-bit
99ae19aaafSPaul E. McKenney  * nanosecond (not microsecond!) random fuzz.
100ae19aaafSPaul E. McKenney  */
101ae19aaafSPaul E. McKenney int torture_hrtimeout_us(u32 baset_us, u32 fuzzt_ns, struct torture_random_state *trsp)
102ae19aaafSPaul E. McKenney {
103ae19aaafSPaul E. McKenney 	ktime_t baset_ns = baset_us * NSEC_PER_USEC;
104ae19aaafSPaul E. McKenney 
105ae19aaafSPaul E. McKenney 	return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp);
106ae19aaafSPaul E. McKenney }
107ae19aaafSPaul E. McKenney EXPORT_SYMBOL_GPL(torture_hrtimeout_us);
108ae19aaafSPaul E. McKenney 
109ae19aaafSPaul E. McKenney /*
110ae19aaafSPaul E. McKenney  * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit
111ae19aaafSPaul E. McKenney  * microsecond (not millisecond!) random fuzz.
112ae19aaafSPaul E. McKenney  */
113ae19aaafSPaul E. McKenney int torture_hrtimeout_ms(u32 baset_ms, u32 fuzzt_us, struct torture_random_state *trsp)
114ae19aaafSPaul E. McKenney {
115ae19aaafSPaul E. McKenney 	ktime_t baset_ns = baset_ms * NSEC_PER_MSEC;
116ae19aaafSPaul E. McKenney 	u32 fuzzt_ns;
117ae19aaafSPaul E. McKenney 
118ae19aaafSPaul E. McKenney 	if ((u32)~0U / NSEC_PER_USEC < fuzzt_us)
119ae19aaafSPaul E. McKenney 		fuzzt_ns = (u32)~0U;
120ae19aaafSPaul E. McKenney 	else
121ae19aaafSPaul E. McKenney 		fuzzt_ns = fuzzt_us * NSEC_PER_USEC;
122ae19aaafSPaul E. McKenney 	return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp);
123ae19aaafSPaul E. McKenney }
124ae19aaafSPaul E. McKenney EXPORT_SYMBOL_GPL(torture_hrtimeout_ms);
125ae19aaafSPaul E. McKenney 
126ae19aaafSPaul E. McKenney /*
127ae19aaafSPaul E. McKenney  * Schedule a high-resolution-timer sleep in jiffies, with an
128ae19aaafSPaul E. McKenney  * implied one-jiffy random fuzz.  This is intended to replace calls to
129ae19aaafSPaul E. McKenney  * schedule_timeout_interruptible() and friends.
130ae19aaafSPaul E. McKenney  */
131ae19aaafSPaul E. McKenney int torture_hrtimeout_jiffies(u32 baset_j, struct torture_random_state *trsp)
132ae19aaafSPaul E. McKenney {
133ae19aaafSPaul E. McKenney 	ktime_t baset_ns = jiffies_to_nsecs(baset_j);
134ae19aaafSPaul E. McKenney 
135ae19aaafSPaul E. McKenney 	return torture_hrtimeout_ns(baset_ns, jiffies_to_nsecs(1), trsp);
136ae19aaafSPaul E. McKenney }
137ae19aaafSPaul E. McKenney EXPORT_SYMBOL_GPL(torture_hrtimeout_jiffies);
138ae19aaafSPaul E. McKenney 
139ae19aaafSPaul E. McKenney /*
140ae19aaafSPaul E. McKenney  * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit
141ae19aaafSPaul E. McKenney  * millisecond (not second!) random fuzz.
142ae19aaafSPaul E. McKenney  */
143ae19aaafSPaul E. McKenney int torture_hrtimeout_s(u32 baset_s, u32 fuzzt_ms, struct torture_random_state *trsp)
144ae19aaafSPaul E. McKenney {
145ae19aaafSPaul E. McKenney 	ktime_t baset_ns = baset_s * NSEC_PER_SEC;
146ae19aaafSPaul E. McKenney 	u32 fuzzt_ns;
147ae19aaafSPaul E. McKenney 
148ae19aaafSPaul E. McKenney 	if ((u32)~0U / NSEC_PER_MSEC < fuzzt_ms)
149ae19aaafSPaul E. McKenney 		fuzzt_ns = (u32)~0U;
150ae19aaafSPaul E. McKenney 	else
151ae19aaafSPaul E. McKenney 		fuzzt_ns = fuzzt_ms * NSEC_PER_MSEC;
152ae19aaafSPaul E. McKenney 	return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp);
153ae19aaafSPaul E. McKenney }
154ae19aaafSPaul E. McKenney EXPORT_SYMBOL_GPL(torture_hrtimeout_s);
155ae19aaafSPaul E. McKenney 
1562e9e8081SPaul E. McKenney #ifdef CONFIG_HOTPLUG_CPU
1572e9e8081SPaul E. McKenney 
1582e9e8081SPaul E. McKenney /*
1592e9e8081SPaul E. McKenney  * Variables for online-offline handling.  Only present if CPU hotplug
1602e9e8081SPaul E. McKenney  * is enabled, otherwise does nothing.
1612e9e8081SPaul E. McKenney  */
1622e9e8081SPaul E. McKenney 
1632e9e8081SPaul E. McKenney static struct task_struct *onoff_task;
1642e9e8081SPaul E. McKenney static long onoff_holdoff;
1652e9e8081SPaul E. McKenney static long onoff_interval;
1663a6cb58fSPaul E. McKenney static torture_ofl_func *onoff_f;
1672e9e8081SPaul E. McKenney static long n_offline_attempts;
1682e9e8081SPaul E. McKenney static long n_offline_successes;
1692e9e8081SPaul E. McKenney static unsigned long sum_offline;
1702e9e8081SPaul E. McKenney static int min_offline = -1;
1712e9e8081SPaul E. McKenney static int max_offline;
1722e9e8081SPaul E. McKenney static long n_online_attempts;
1732e9e8081SPaul E. McKenney static long n_online_successes;
1742e9e8081SPaul E. McKenney static unsigned long sum_online;
1752e9e8081SPaul E. McKenney static int min_online = -1;
1762e9e8081SPaul E. McKenney static int max_online;
1772e9e8081SPaul E. McKenney 
1782e9e8081SPaul E. McKenney /*
179d95f5ba9SPaul E. McKenney  * Attempt to take a CPU offline.  Return false if the CPU is already
180d95f5ba9SPaul E. McKenney  * offline or if it is not subject to CPU-hotplug operations.  The
181d95f5ba9SPaul E. McKenney  * caller can detect other failures by looking at the statistics.
182d95f5ba9SPaul E. McKenney  */
183d95f5ba9SPaul E. McKenney bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
184d95f5ba9SPaul E. McKenney 		     unsigned long *sum_offl, int *min_offl, int *max_offl)
185d95f5ba9SPaul E. McKenney {
186d95f5ba9SPaul E. McKenney 	unsigned long delta;
187d95f5ba9SPaul E. McKenney 	int ret;
188a59ee765SPaul E. McKenney 	char *s;
189d95f5ba9SPaul E. McKenney 	unsigned long starttime;
190d95f5ba9SPaul E. McKenney 
191d95f5ba9SPaul E. McKenney 	if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
192d95f5ba9SPaul E. McKenney 		return false;
19324aca4aeSPaul E. McKenney 	if (num_online_cpus() <= 1)
19424aca4aeSPaul E. McKenney 		return false;  /* Can't offline the last CPU. */
195d95f5ba9SPaul E. McKenney 
19690127d60SPaul E. McKenney 	if (verbose > 1)
197d95f5ba9SPaul E. McKenney 		pr_alert("%s" TORTURE_FLAG
198d95f5ba9SPaul E. McKenney 			 "torture_onoff task: offlining %d\n",
199d95f5ba9SPaul E. McKenney 			 torture_type, cpu);
200d95f5ba9SPaul E. McKenney 	starttime = jiffies;
201d95f5ba9SPaul E. McKenney 	(*n_offl_attempts)++;
202457bc8edSQais Yousef 	ret = remove_cpu(cpu);
203d95f5ba9SPaul E. McKenney 	if (ret) {
204a59ee765SPaul E. McKenney 		s = "";
205a59ee765SPaul E. McKenney 		if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {
206a59ee765SPaul E. McKenney 			// PCI probe frequently disables hotplug during boot.
207a59ee765SPaul E. McKenney 			(*n_offl_attempts)--;
208a59ee765SPaul E. McKenney 			s = " (-EBUSY forgiven during boot)";
209a59ee765SPaul E. McKenney 		}
210d95f5ba9SPaul E. McKenney 		if (verbose)
211d95f5ba9SPaul E. McKenney 			pr_alert("%s" TORTURE_FLAG
212a59ee765SPaul E. McKenney 				 "torture_onoff task: offline %d failed%s: errno %d\n",
213a59ee765SPaul E. McKenney 				 torture_type, cpu, s, ret);
214d95f5ba9SPaul E. McKenney 	} else {
21590127d60SPaul E. McKenney 		if (verbose > 1)
216d95f5ba9SPaul E. McKenney 			pr_alert("%s" TORTURE_FLAG
217d95f5ba9SPaul E. McKenney 				 "torture_onoff task: offlined %d\n",
218d95f5ba9SPaul E. McKenney 				 torture_type, cpu);
2193a6cb58fSPaul E. McKenney 		if (onoff_f)
2203a6cb58fSPaul E. McKenney 			onoff_f();
221d95f5ba9SPaul E. McKenney 		(*n_offl_successes)++;
222d95f5ba9SPaul E. McKenney 		delta = jiffies - starttime;
223a2b2df20SPaul E. McKenney 		*sum_offl += delta;
224d95f5ba9SPaul E. McKenney 		if (*min_offl < 0) {
225d95f5ba9SPaul E. McKenney 			*min_offl = delta;
226d95f5ba9SPaul E. McKenney 			*max_offl = delta;
227d95f5ba9SPaul E. McKenney 		}
228d95f5ba9SPaul E. McKenney 		if (*min_offl > delta)
229d95f5ba9SPaul E. McKenney 			*min_offl = delta;
230d95f5ba9SPaul E. McKenney 		if (*max_offl < delta)
231d95f5ba9SPaul E. McKenney 			*max_offl = delta;
232d95f5ba9SPaul E. McKenney 	}
233d95f5ba9SPaul E. McKenney 
234d95f5ba9SPaul E. McKenney 	return true;
235d95f5ba9SPaul E. McKenney }
236d95f5ba9SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_offline);
237d95f5ba9SPaul E. McKenney 
238d95f5ba9SPaul E. McKenney /*
239d95f5ba9SPaul E. McKenney  * Attempt to bring a CPU online.  Return false if the CPU is already
240d95f5ba9SPaul E. McKenney  * online or if it is not subject to CPU-hotplug operations.  The
241d95f5ba9SPaul E. McKenney  * caller can detect other failures by looking at the statistics.
242d95f5ba9SPaul E. McKenney  */
243d95f5ba9SPaul E. McKenney bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
244d95f5ba9SPaul E. McKenney 		    unsigned long *sum_onl, int *min_onl, int *max_onl)
245d95f5ba9SPaul E. McKenney {
246d95f5ba9SPaul E. McKenney 	unsigned long delta;
247d95f5ba9SPaul E. McKenney 	int ret;
248a59ee765SPaul E. McKenney 	char *s;
249d95f5ba9SPaul E. McKenney 	unsigned long starttime;
250d95f5ba9SPaul E. McKenney 
251d95f5ba9SPaul E. McKenney 	if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
252d95f5ba9SPaul E. McKenney 		return false;
253d95f5ba9SPaul E. McKenney 
25490127d60SPaul E. McKenney 	if (verbose > 1)
255d95f5ba9SPaul E. McKenney 		pr_alert("%s" TORTURE_FLAG
256d95f5ba9SPaul E. McKenney 			 "torture_onoff task: onlining %d\n",
257d95f5ba9SPaul E. McKenney 			 torture_type, cpu);
258d95f5ba9SPaul E. McKenney 	starttime = jiffies;
259d95f5ba9SPaul E. McKenney 	(*n_onl_attempts)++;
260457bc8edSQais Yousef 	ret = add_cpu(cpu);
261d95f5ba9SPaul E. McKenney 	if (ret) {
262a59ee765SPaul E. McKenney 		s = "";
263a59ee765SPaul E. McKenney 		if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {
264a59ee765SPaul E. McKenney 			// PCI probe frequently disables hotplug during boot.
265a59ee765SPaul E. McKenney 			(*n_onl_attempts)--;
266a59ee765SPaul E. McKenney 			s = " (-EBUSY forgiven during boot)";
267a59ee765SPaul E. McKenney 		}
268d95f5ba9SPaul E. McKenney 		if (verbose)
269d95f5ba9SPaul E. McKenney 			pr_alert("%s" TORTURE_FLAG
270a59ee765SPaul E. McKenney 				 "torture_onoff task: online %d failed%s: errno %d\n",
271a59ee765SPaul E. McKenney 				 torture_type, cpu, s, ret);
272d95f5ba9SPaul E. McKenney 	} else {
27390127d60SPaul E. McKenney 		if (verbose > 1)
274d95f5ba9SPaul E. McKenney 			pr_alert("%s" TORTURE_FLAG
275d95f5ba9SPaul E. McKenney 				 "torture_onoff task: onlined %d\n",
276d95f5ba9SPaul E. McKenney 				 torture_type, cpu);
277d95f5ba9SPaul E. McKenney 		(*n_onl_successes)++;
278d95f5ba9SPaul E. McKenney 		delta = jiffies - starttime;
279d95f5ba9SPaul E. McKenney 		*sum_onl += delta;
280d95f5ba9SPaul E. McKenney 		if (*min_onl < 0) {
281d95f5ba9SPaul E. McKenney 			*min_onl = delta;
282d95f5ba9SPaul E. McKenney 			*max_onl = delta;
283d95f5ba9SPaul E. McKenney 		}
284d95f5ba9SPaul E. McKenney 		if (*min_onl > delta)
285d95f5ba9SPaul E. McKenney 			*min_onl = delta;
286d95f5ba9SPaul E. McKenney 		if (*max_onl < delta)
287d95f5ba9SPaul E. McKenney 			*max_onl = delta;
288d95f5ba9SPaul E. McKenney 	}
289d95f5ba9SPaul E. McKenney 
290d95f5ba9SPaul E. McKenney 	return true;
291d95f5ba9SPaul E. McKenney }
292d95f5ba9SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_online);
293d95f5ba9SPaul E. McKenney 
294d95f5ba9SPaul E. McKenney /*
295*0b962c8fSPaul E. McKenney  * Get everything online at the beginning and ends of tests.
296*0b962c8fSPaul E. McKenney  */
297*0b962c8fSPaul E. McKenney static void torture_online_all(char *phase)
298*0b962c8fSPaul E. McKenney {
299*0b962c8fSPaul E. McKenney 	int cpu;
300*0b962c8fSPaul E. McKenney 	int ret;
301*0b962c8fSPaul E. McKenney 
302*0b962c8fSPaul E. McKenney 	for_each_possible_cpu(cpu) {
303*0b962c8fSPaul E. McKenney 		if (cpu_online(cpu))
304*0b962c8fSPaul E. McKenney 			continue;
305*0b962c8fSPaul E. McKenney 		ret = add_cpu(cpu);
306*0b962c8fSPaul E. McKenney 		if (ret && verbose) {
307*0b962c8fSPaul E. McKenney 			pr_alert("%s" TORTURE_FLAG
308*0b962c8fSPaul E. McKenney 				 "%s: %s online %d: errno %d\n",
309*0b962c8fSPaul E. McKenney 				 __func__, phase, torture_type, cpu, ret);
310*0b962c8fSPaul E. McKenney 		}
311*0b962c8fSPaul E. McKenney 	}
312*0b962c8fSPaul E. McKenney }
313*0b962c8fSPaul E. McKenney 
314*0b962c8fSPaul E. McKenney /*
3152e9e8081SPaul E. McKenney  * Execute random CPU-hotplug operations at the interval specified
3162e9e8081SPaul E. McKenney  * by the onoff_interval.
3172e9e8081SPaul E. McKenney  */
3182e9e8081SPaul E. McKenney static int
3192e9e8081SPaul E. McKenney torture_onoff(void *arg)
3202e9e8081SPaul E. McKenney {
3212e9e8081SPaul E. McKenney 	int cpu;
3222e9e8081SPaul E. McKenney 	int maxcpu = -1;
3232e9e8081SPaul E. McKenney 	DEFINE_TORTURE_RANDOM(rand);
3242e9e8081SPaul E. McKenney 
3252e9e8081SPaul E. McKenney 	VERBOSE_TOROUT_STRING("torture_onoff task started");
3262e9e8081SPaul E. McKenney 	for_each_online_cpu(cpu)
3272e9e8081SPaul E. McKenney 		maxcpu = cpu;
3282e9e8081SPaul E. McKenney 	WARN_ON(maxcpu < 0);
329*0b962c8fSPaul E. McKenney 	torture_online_all("Initial");
330750db0f5SBoqun Feng 	if (maxcpu == 0) {
331750db0f5SBoqun Feng 		VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
332750db0f5SBoqun Feng 		goto stop;
333750db0f5SBoqun Feng 	}
334750db0f5SBoqun Feng 
3352e9e8081SPaul E. McKenney 	if (onoff_holdoff > 0) {
3362e9e8081SPaul E. McKenney 		VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
3372e9e8081SPaul E. McKenney 		schedule_timeout_interruptible(onoff_holdoff);
3382e9e8081SPaul E. McKenney 		VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
3392e9e8081SPaul E. McKenney 	}
3402e9e8081SPaul E. McKenney 	while (!torture_must_stop()) {
3418171d3e0SPaul E. McKenney 		if (disable_onoff_at_boot && !rcu_inkernel_boot_has_ended()) {
3428171d3e0SPaul E. McKenney 			schedule_timeout_interruptible(HZ / 10);
3438171d3e0SPaul E. McKenney 			continue;
3448171d3e0SPaul E. McKenney 		}
3452e9e8081SPaul E. McKenney 		cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
346d95f5ba9SPaul E. McKenney 		if (!torture_offline(cpu,
347d95f5ba9SPaul E. McKenney 				     &n_offline_attempts, &n_offline_successes,
348d95f5ba9SPaul E. McKenney 				     &sum_offline, &min_offline, &max_offline))
349d95f5ba9SPaul E. McKenney 			torture_online(cpu,
350d95f5ba9SPaul E. McKenney 				       &n_online_attempts, &n_online_successes,
351d95f5ba9SPaul E. McKenney 				       &sum_online, &min_online, &max_online);
3522e9e8081SPaul E. McKenney 		schedule_timeout_interruptible(onoff_interval);
3532e9e8081SPaul E. McKenney 	}
354750db0f5SBoqun Feng 
355750db0f5SBoqun Feng stop:
3567fafaac5SPaul E. McKenney 	torture_kthread_stopping("torture_onoff");
357*0b962c8fSPaul E. McKenney 	torture_online_all("Final");
3582e9e8081SPaul E. McKenney 	return 0;
3592e9e8081SPaul E. McKenney }
3602e9e8081SPaul E. McKenney 
3612e9e8081SPaul E. McKenney #endif /* #ifdef CONFIG_HOTPLUG_CPU */
3622e9e8081SPaul E. McKenney 
3632e9e8081SPaul E. McKenney /*
3642e9e8081SPaul E. McKenney  * Initiate online-offline handling.
3652e9e8081SPaul E. McKenney  */
3663a6cb58fSPaul E. McKenney int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f)
3672e9e8081SPaul E. McKenney {
36847cf29b9SPaul E. McKenney #ifdef CONFIG_HOTPLUG_CPU
3692e9e8081SPaul E. McKenney 	onoff_holdoff = ooholdoff;
3702e9e8081SPaul E. McKenney 	onoff_interval = oointerval;
3713a6cb58fSPaul E. McKenney 	onoff_f = f;
3722e9e8081SPaul E. McKenney 	if (onoff_interval <= 0)
3732e9e8081SPaul E. McKenney 		return 0;
3742a7d9688SPierce Griffiths 	return torture_create_kthread(torture_onoff, NULL, onoff_task);
3752a7d9688SPierce Griffiths #else /* #ifdef CONFIG_HOTPLUG_CPU */
3762a7d9688SPierce Griffiths 	return 0;
3772a7d9688SPierce Griffiths #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
3782e9e8081SPaul E. McKenney }
3792e9e8081SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_onoff_init);
3802e9e8081SPaul E. McKenney 
3812e9e8081SPaul E. McKenney /*
3822e9e8081SPaul E. McKenney  * Clean up after online/offline testing.
3832e9e8081SPaul E. McKenney  */
384cc47ae08SPaul E. McKenney static void torture_onoff_cleanup(void)
3852e9e8081SPaul E. McKenney {
3862e9e8081SPaul E. McKenney #ifdef CONFIG_HOTPLUG_CPU
3872e9e8081SPaul E. McKenney 	if (onoff_task == NULL)
3882e9e8081SPaul E. McKenney 		return;
3892e9e8081SPaul E. McKenney 	VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
3902e9e8081SPaul E. McKenney 	kthread_stop(onoff_task);
3912e9e8081SPaul E. McKenney 	onoff_task = NULL;
3922e9e8081SPaul E. McKenney #endif /* #ifdef CONFIG_HOTPLUG_CPU */
3932e9e8081SPaul E. McKenney }
3942e9e8081SPaul E. McKenney 
3952e9e8081SPaul E. McKenney /*
3962e9e8081SPaul E. McKenney  * Print online/offline testing statistics.
3972e9e8081SPaul E. McKenney  */
398eea203feSJoe Perches void torture_onoff_stats(void)
3992e9e8081SPaul E. McKenney {
4002e9e8081SPaul E. McKenney #ifdef CONFIG_HOTPLUG_CPU
401eea203feSJoe Perches 	pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
4022e9e8081SPaul E. McKenney 		n_online_successes, n_online_attempts,
4032e9e8081SPaul E. McKenney 		n_offline_successes, n_offline_attempts,
4042e9e8081SPaul E. McKenney 		min_online, max_online,
4052e9e8081SPaul E. McKenney 		min_offline, max_offline,
4062e9e8081SPaul E. McKenney 		sum_online, sum_offline, HZ);
4072e9e8081SPaul E. McKenney #endif /* #ifdef CONFIG_HOTPLUG_CPU */
4082e9e8081SPaul E. McKenney }
4092e9e8081SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_onoff_stats);
4102e9e8081SPaul E. McKenney 
4112e9e8081SPaul E. McKenney /*
4122e9e8081SPaul E. McKenney  * Were all the online/offline operations successful?
4132e9e8081SPaul E. McKenney  */
4142e9e8081SPaul E. McKenney bool torture_onoff_failures(void)
4152e9e8081SPaul E. McKenney {
4162e9e8081SPaul E. McKenney #ifdef CONFIG_HOTPLUG_CPU
4172e9e8081SPaul E. McKenney 	return n_online_successes != n_online_attempts ||
4182e9e8081SPaul E. McKenney 	       n_offline_successes != n_offline_attempts;
4192e9e8081SPaul E. McKenney #else /* #ifdef CONFIG_HOTPLUG_CPU */
4202e9e8081SPaul E. McKenney 	return false;
4212e9e8081SPaul E. McKenney #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
4222e9e8081SPaul E. McKenney }
4232e9e8081SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_onoff_failures);
4242e9e8081SPaul E. McKenney 
42551b1130eSPaul E. McKenney #define TORTURE_RANDOM_MULT	39916801  /* prime */
42651b1130eSPaul E. McKenney #define TORTURE_RANDOM_ADD	479001701 /* prime */
42751b1130eSPaul E. McKenney #define TORTURE_RANDOM_REFRESH	10000
42851b1130eSPaul E. McKenney 
42951b1130eSPaul E. McKenney /*
43051b1130eSPaul E. McKenney  * Crude but fast random-number generator.  Uses a linear congruential
43151b1130eSPaul E. McKenney  * generator, with occasional help from cpu_clock().
43251b1130eSPaul E. McKenney  */
43351b1130eSPaul E. McKenney unsigned long
43451b1130eSPaul E. McKenney torture_random(struct torture_random_state *trsp)
43551b1130eSPaul E. McKenney {
43651b1130eSPaul E. McKenney 	if (--trsp->trs_count < 0) {
43751b1130eSPaul E. McKenney 		trsp->trs_state += (unsigned long)local_clock();
43851b1130eSPaul E. McKenney 		trsp->trs_count = TORTURE_RANDOM_REFRESH;
43951b1130eSPaul E. McKenney 	}
44051b1130eSPaul E. McKenney 	trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
44151b1130eSPaul E. McKenney 		TORTURE_RANDOM_ADD;
44251b1130eSPaul E. McKenney 	return swahw32(trsp->trs_state);
44351b1130eSPaul E. McKenney }
44451b1130eSPaul E. McKenney EXPORT_SYMBOL_GPL(torture_random);
445f67a3356SPaul E. McKenney 
446f67a3356SPaul E. McKenney /*
4473808dc9fSPaul E. McKenney  * Variables for shuffling.  The idea is to ensure that each CPU stays
4483808dc9fSPaul E. McKenney  * idle for an extended period to test interactions with dyntick idle,
449b564d62eSMasahiro Yamada  * as well as interactions with any per-CPU variables.
4503808dc9fSPaul E. McKenney  */
4513808dc9fSPaul E. McKenney struct shuffle_task {
4523808dc9fSPaul E. McKenney 	struct list_head st_l;
4533808dc9fSPaul E. McKenney 	struct task_struct *st_t;
4543808dc9fSPaul E. McKenney };
4553808dc9fSPaul E. McKenney 
4563808dc9fSPaul E. McKenney static long shuffle_interval;	/* In jiffies. */
4573808dc9fSPaul E. McKenney static struct task_struct *shuffler_task;
4583808dc9fSPaul E. McKenney static cpumask_var_t shuffle_tmp_mask;
4593808dc9fSPaul E. McKenney static int shuffle_idle_cpu;	/* Force all torture tasks off this CPU */
4603808dc9fSPaul E. McKenney static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
4613808dc9fSPaul E. McKenney static DEFINE_MUTEX(shuffle_task_mutex);
4623808dc9fSPaul E. McKenney 
4633808dc9fSPaul E. McKenney /*
4643808dc9fSPaul E. McKenney  * Register a task to be shuffled.  If there is no memory, just splat
4653808dc9fSPaul E. McKenney  * and don't bother registering.
4663808dc9fSPaul E. McKenney  */
4673808dc9fSPaul E. McKenney void torture_shuffle_task_register(struct task_struct *tp)
4683808dc9fSPaul E. McKenney {
4693808dc9fSPaul E. McKenney 	struct shuffle_task *stp;
4703808dc9fSPaul E. McKenney 
4713808dc9fSPaul E. McKenney 	if (WARN_ON_ONCE(tp == NULL))
4723808dc9fSPaul E. McKenney 		return;
4733808dc9fSPaul E. McKenney 	stp = kmalloc(sizeof(*stp), GFP_KERNEL);
4743808dc9fSPaul E. McKenney 	if (WARN_ON_ONCE(stp == NULL))
4753808dc9fSPaul E. McKenney 		return;
4763808dc9fSPaul E. McKenney 	stp->st_t = tp;
4773808dc9fSPaul E. McKenney 	mutex_lock(&shuffle_task_mutex);
4783808dc9fSPaul E. McKenney 	list_add(&stp->st_l, &shuffle_task_list);
4793808dc9fSPaul E. McKenney 	mutex_unlock(&shuffle_task_mutex);
4803808dc9fSPaul E. McKenney }
4813808dc9fSPaul E. McKenney EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
4823808dc9fSPaul E. McKenney 
4833808dc9fSPaul E. McKenney /*
4843808dc9fSPaul E. McKenney  * Unregister all tasks, for example, at the end of the torture run.
4853808dc9fSPaul E. McKenney  */
4863808dc9fSPaul E. McKenney static void torture_shuffle_task_unregister_all(void)
4873808dc9fSPaul E. McKenney {
4883808dc9fSPaul E. McKenney 	struct shuffle_task *stp;
4893808dc9fSPaul E. McKenney 	struct shuffle_task *p;
4903808dc9fSPaul E. McKenney 
4913808dc9fSPaul E. McKenney 	mutex_lock(&shuffle_task_mutex);
4923808dc9fSPaul E. McKenney 	list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
4933808dc9fSPaul E. McKenney 		list_del(&stp->st_l);
4943808dc9fSPaul E. McKenney 		kfree(stp);
4953808dc9fSPaul E. McKenney 	}
4963808dc9fSPaul E. McKenney 	mutex_unlock(&shuffle_task_mutex);
4973808dc9fSPaul E. McKenney }
4983808dc9fSPaul E. McKenney 
4993808dc9fSPaul E. McKenney /* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
5003808dc9fSPaul E. McKenney  * A special case is when shuffle_idle_cpu = -1, in which case we allow
5013808dc9fSPaul E. McKenney  * the tasks to run on all CPUs.
5023808dc9fSPaul E. McKenney  */
5033808dc9fSPaul E. McKenney static void torture_shuffle_tasks(void)
5043808dc9fSPaul E. McKenney {
5053808dc9fSPaul E. McKenney 	struct shuffle_task *stp;
5063808dc9fSPaul E. McKenney 
5073808dc9fSPaul E. McKenney 	cpumask_setall(shuffle_tmp_mask);
5083808dc9fSPaul E. McKenney 	get_online_cpus();
5093808dc9fSPaul E. McKenney 
5103808dc9fSPaul E. McKenney 	/* No point in shuffling if there is only one online CPU (ex: UP) */
5113808dc9fSPaul E. McKenney 	if (num_online_cpus() == 1) {
5123808dc9fSPaul E. McKenney 		put_online_cpus();
5133808dc9fSPaul E. McKenney 		return;
5143808dc9fSPaul E. McKenney 	}
5153808dc9fSPaul E. McKenney 
5163808dc9fSPaul E. McKenney 	/* Advance to the next CPU.  Upon overflow, don't idle any CPUs. */
5173808dc9fSPaul E. McKenney 	shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
5183808dc9fSPaul E. McKenney 	if (shuffle_idle_cpu >= nr_cpu_ids)
5193808dc9fSPaul E. McKenney 		shuffle_idle_cpu = -1;
5205ed63b19SIulia Manda 	else
5213808dc9fSPaul E. McKenney 		cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
5223808dc9fSPaul E. McKenney 
5233808dc9fSPaul E. McKenney 	mutex_lock(&shuffle_task_mutex);
5243808dc9fSPaul E. McKenney 	list_for_each_entry(stp, &shuffle_task_list, st_l)
5253808dc9fSPaul E. McKenney 		set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
5263808dc9fSPaul E. McKenney 	mutex_unlock(&shuffle_task_mutex);
5273808dc9fSPaul E. McKenney 
5283808dc9fSPaul E. McKenney 	put_online_cpus();
5293808dc9fSPaul E. McKenney }
5303808dc9fSPaul E. McKenney 
5313808dc9fSPaul E. McKenney /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
5323808dc9fSPaul E. McKenney  * system to become idle at a time and cut off its timer ticks. This is meant
5333808dc9fSPaul E. McKenney  * to test the support for such tickless idle CPU in RCU.
5343808dc9fSPaul E. McKenney  */
5353808dc9fSPaul E. McKenney static int torture_shuffle(void *arg)
5363808dc9fSPaul E. McKenney {
5373808dc9fSPaul E. McKenney 	VERBOSE_TOROUT_STRING("torture_shuffle task started");
5383808dc9fSPaul E. McKenney 	do {
5393808dc9fSPaul E. McKenney 		schedule_timeout_interruptible(shuffle_interval);
5403808dc9fSPaul E. McKenney 		torture_shuffle_tasks();
5413808dc9fSPaul E. McKenney 		torture_shutdown_absorb("torture_shuffle");
5423808dc9fSPaul E. McKenney 	} while (!torture_must_stop());
5437fafaac5SPaul E. McKenney 	torture_kthread_stopping("torture_shuffle");
5443808dc9fSPaul E. McKenney 	return 0;
5453808dc9fSPaul E. McKenney }
5463808dc9fSPaul E. McKenney 
5473808dc9fSPaul E. McKenney /*
5483808dc9fSPaul E. McKenney  * Start the shuffler, with shuffint in jiffies.
5493808dc9fSPaul E. McKenney  */
5503808dc9fSPaul E. McKenney int torture_shuffle_init(long shuffint)
5513808dc9fSPaul E. McKenney {
5523808dc9fSPaul E. McKenney 	shuffle_interval = shuffint;
5533808dc9fSPaul E. McKenney 
5543808dc9fSPaul E. McKenney 	shuffle_idle_cpu = -1;
5553808dc9fSPaul E. McKenney 
5563808dc9fSPaul E. McKenney 	if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
5573808dc9fSPaul E. McKenney 		VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
5583808dc9fSPaul E. McKenney 		return -ENOMEM;
5593808dc9fSPaul E. McKenney 	}
5603808dc9fSPaul E. McKenney 
5613808dc9fSPaul E. McKenney 	/* Create the shuffler thread */
56247cf29b9SPaul E. McKenney 	return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
5633808dc9fSPaul E. McKenney }
5643808dc9fSPaul E. McKenney EXPORT_SYMBOL_GPL(torture_shuffle_init);
5653808dc9fSPaul E. McKenney 
5663808dc9fSPaul E. McKenney /*
5673808dc9fSPaul E. McKenney  * Stop the shuffling.
5683808dc9fSPaul E. McKenney  */
569cc47ae08SPaul E. McKenney static void torture_shuffle_cleanup(void)
5703808dc9fSPaul E. McKenney {
5713808dc9fSPaul E. McKenney 	torture_shuffle_task_unregister_all();
5723808dc9fSPaul E. McKenney 	if (shuffler_task) {
5733808dc9fSPaul E. McKenney 		VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
5743808dc9fSPaul E. McKenney 		kthread_stop(shuffler_task);
5753808dc9fSPaul E. McKenney 		free_cpumask_var(shuffle_tmp_mask);
5763808dc9fSPaul E. McKenney 	}
5773808dc9fSPaul E. McKenney 	shuffler_task = NULL;
5783808dc9fSPaul E. McKenney }
5793808dc9fSPaul E. McKenney 
5803808dc9fSPaul E. McKenney /*
581e991dbc0SPaul E. McKenney  * Variables for auto-shutdown.  This allows "lights out" torture runs
582e991dbc0SPaul E. McKenney  * to be fully scripted.
583e991dbc0SPaul E. McKenney  */
584e991dbc0SPaul E. McKenney static struct task_struct *shutdown_task;
58531257c3cSPaul E. McKenney static ktime_t shutdown_time;		/* time to system shutdown. */
586e991dbc0SPaul E. McKenney static void (*torture_shutdown_hook)(void);
587e991dbc0SPaul E. McKenney 
588e991dbc0SPaul E. McKenney /*
589f67a3356SPaul E. McKenney  * Absorb kthreads into a kernel function that won't return, so that
590f67a3356SPaul E. McKenney  * they won't ever access module text or data again.
591f67a3356SPaul E. McKenney  */
592f67a3356SPaul E. McKenney void torture_shutdown_absorb(const char *title)
593f67a3356SPaul E. McKenney {
5947d0ae808SPaul E. McKenney 	while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
5954622b487SPaul E. McKenney 		pr_notice("torture thread %s parking due to system shutdown\n",
596f67a3356SPaul E. McKenney 			  title);
597f67a3356SPaul E. McKenney 		schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
598f67a3356SPaul E. McKenney 	}
599f67a3356SPaul E. McKenney }
600f67a3356SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
601b5daa8f3SPaul E. McKenney 
602b5daa8f3SPaul E. McKenney /*
603e991dbc0SPaul E. McKenney  * Cause the torture test to shutdown the system after the test has
604e991dbc0SPaul E. McKenney  * run for the time specified by the shutdown_secs parameter.
605e991dbc0SPaul E. McKenney  */
606e991dbc0SPaul E. McKenney static int torture_shutdown(void *arg)
607e991dbc0SPaul E. McKenney {
60831257c3cSPaul E. McKenney 	ktime_t ktime_snap;
609e991dbc0SPaul E. McKenney 
610e991dbc0SPaul E. McKenney 	VERBOSE_TOROUT_STRING("torture_shutdown task started");
61131257c3cSPaul E. McKenney 	ktime_snap = ktime_get();
61231257c3cSPaul E. McKenney 	while (ktime_before(ktime_snap, shutdown_time) &&
613e991dbc0SPaul E. McKenney 	       !torture_must_stop()) {
614e991dbc0SPaul E. McKenney 		if (verbose)
615e991dbc0SPaul E. McKenney 			pr_alert("%s" TORTURE_FLAG
61631257c3cSPaul E. McKenney 				 "torture_shutdown task: %llu ms remaining\n",
61731257c3cSPaul E. McKenney 				 torture_type,
61831257c3cSPaul E. McKenney 				 ktime_ms_delta(shutdown_time, ktime_snap));
61931257c3cSPaul E. McKenney 		set_current_state(TASK_INTERRUPTIBLE);
62031257c3cSPaul E. McKenney 		schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
62131257c3cSPaul E. McKenney 		ktime_snap = ktime_get();
622e991dbc0SPaul E. McKenney 	}
623e991dbc0SPaul E. McKenney 	if (torture_must_stop()) {
6247fafaac5SPaul E. McKenney 		torture_kthread_stopping("torture_shutdown");
625e991dbc0SPaul E. McKenney 		return 0;
626e991dbc0SPaul E. McKenney 	}
627e991dbc0SPaul E. McKenney 
628e991dbc0SPaul E. McKenney 	/* OK, shut down the system. */
629e991dbc0SPaul E. McKenney 
630e991dbc0SPaul E. McKenney 	VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
631e991dbc0SPaul E. McKenney 	shutdown_task = NULL;	/* Avoid self-kill deadlock. */
632f881825aSPaul E. McKenney 	if (torture_shutdown_hook)
633f881825aSPaul E. McKenney 		torture_shutdown_hook();
634f881825aSPaul E. McKenney 	else
635f881825aSPaul E. McKenney 		VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
6362102ad29SPaul E. McKenney 	if (ftrace_dump_at_shutdown)
637dac95906SPaul E. McKenney 		rcu_ftrace_dump(DUMP_ALL);
638e991dbc0SPaul E. McKenney 	kernel_power_off();	/* Shut down the system. */
639e991dbc0SPaul E. McKenney 	return 0;
640e991dbc0SPaul E. McKenney }
641e991dbc0SPaul E. McKenney 
642e991dbc0SPaul E. McKenney /*
643e991dbc0SPaul E. McKenney  * Start up the shutdown task.
644e991dbc0SPaul E. McKenney  */
645e991dbc0SPaul E. McKenney int torture_shutdown_init(int ssecs, void (*cleanup)(void))
646e991dbc0SPaul E. McKenney {
647e991dbc0SPaul E. McKenney 	torture_shutdown_hook = cleanup;
64831257c3cSPaul E. McKenney 	if (ssecs > 0) {
64931257c3cSPaul E. McKenney 		shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
6502a7d9688SPierce Griffiths 		return torture_create_kthread(torture_shutdown, NULL,
65147cf29b9SPaul E. McKenney 					     shutdown_task);
65247cf29b9SPaul E. McKenney 	}
6532a7d9688SPierce Griffiths 	return 0;
654e991dbc0SPaul E. McKenney }
655e991dbc0SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_shutdown_init);
656e991dbc0SPaul E. McKenney 
657e991dbc0SPaul E. McKenney /*
6584622b487SPaul E. McKenney  * Detect and respond to a system shutdown.
6594622b487SPaul E. McKenney  */
6604622b487SPaul E. McKenney static int torture_shutdown_notify(struct notifier_block *unused1,
6614622b487SPaul E. McKenney 				   unsigned long unused2, void *unused3)
6624622b487SPaul E. McKenney {
6634622b487SPaul E. McKenney 	mutex_lock(&fullstop_mutex);
6647d0ae808SPaul E. McKenney 	if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
665fac480efSPaul E. McKenney 		VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
6667d0ae808SPaul E. McKenney 		WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN);
667fac480efSPaul E. McKenney 	} else {
6684622b487SPaul E. McKenney 		pr_warn("Concurrent rmmod and shutdown illegal!\n");
669fac480efSPaul E. McKenney 	}
6704622b487SPaul E. McKenney 	mutex_unlock(&fullstop_mutex);
6714622b487SPaul E. McKenney 	return NOTIFY_DONE;
6724622b487SPaul E. McKenney }
6734622b487SPaul E. McKenney 
6744622b487SPaul E. McKenney static struct notifier_block torture_shutdown_nb = {
6754622b487SPaul E. McKenney 	.notifier_call = torture_shutdown_notify,
6764622b487SPaul E. McKenney };
6774622b487SPaul E. McKenney 
6784622b487SPaul E. McKenney /*
679bfefc73aSPaul E. McKenney  * Shut down the shutdown task.  Say what???  Heh!  This can happen if
680bfefc73aSPaul E. McKenney  * the torture module gets an rmmod before the shutdown time arrives.  ;-)
681bfefc73aSPaul E. McKenney  */
682bfefc73aSPaul E. McKenney static void torture_shutdown_cleanup(void)
683bfefc73aSPaul E. McKenney {
684bfefc73aSPaul E. McKenney 	unregister_reboot_notifier(&torture_shutdown_nb);
685bfefc73aSPaul E. McKenney 	if (shutdown_task != NULL) {
686bfefc73aSPaul E. McKenney 		VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
687bfefc73aSPaul E. McKenney 		kthread_stop(shutdown_task);
688bfefc73aSPaul E. McKenney 	}
689bfefc73aSPaul E. McKenney 	shutdown_task = NULL;
690bfefc73aSPaul E. McKenney }
691bfefc73aSPaul E. McKenney 
692bfefc73aSPaul E. McKenney /*
693628edaa5SPaul E. McKenney  * Variables for stuttering, which means to periodically pause and
694628edaa5SPaul E. McKenney  * restart testing in order to catch bugs that appear when load is
695628edaa5SPaul E. McKenney  * suddenly applied to or removed from the system.
696628edaa5SPaul E. McKenney  */
697628edaa5SPaul E. McKenney static struct task_struct *stutter_task;
698628edaa5SPaul E. McKenney static int stutter_pause_test;
699628edaa5SPaul E. McKenney static int stutter;
700ff3bf92dSPaul E. McKenney static int stutter_gap;
701628edaa5SPaul E. McKenney 
702628edaa5SPaul E. McKenney /*
703628edaa5SPaul E. McKenney  * Block until the stutter interval ends.  This must be called periodically
704628edaa5SPaul E. McKenney  * by all running kthreads that need to be subject to stuttering.
705628edaa5SPaul E. McKenney  */
706474e59b4SPaul E. McKenney bool stutter_wait(const char *title)
707628edaa5SPaul E. McKenney {
70819012b78SPaul E. McKenney 	unsigned int i = 0;
709e8516c64SPaul E. McKenney 	bool ret = false;
71019012b78SPaul E. McKenney 	int spt;
7114ced3314SPaul E. McKenney 
712cee43939SPaul E. McKenney 	cond_resched_tasks_rcu_qs();
7134ced3314SPaul E. McKenney 	spt = READ_ONCE(stutter_pause_test);
71429d39390SPaul E. McKenney 	for (; spt; spt = READ_ONCE(stutter_pause_test)) {
715ab1b7880SPaul E. McKenney 		if (!ret) {
716ab1b7880SPaul E. McKenney 			sched_set_normal(current, MAX_NICE);
717e8516c64SPaul E. McKenney 			ret = true;
718ab1b7880SPaul E. McKenney 		}
7194ced3314SPaul E. McKenney 		if (spt == 1) {
720628edaa5SPaul E. McKenney 			schedule_timeout_interruptible(1);
7214ced3314SPaul E. McKenney 		} else if (spt == 2) {
72219012b78SPaul E. McKenney 			while (READ_ONCE(stutter_pause_test)) {
723ed24affaSPaul E. McKenney 				if (!(i++ & 0xffff))
724ed24affaSPaul E. McKenney 					torture_hrtimeout_us(10, 0, NULL);
725ab7d4505SPaul E. McKenney 				cond_resched();
72619012b78SPaul E. McKenney 			}
7274ced3314SPaul E. McKenney 		} else {
728628edaa5SPaul E. McKenney 			schedule_timeout_interruptible(round_jiffies_relative(HZ));
7294ced3314SPaul E. McKenney 		}
730628edaa5SPaul E. McKenney 		torture_shutdown_absorb(title);
731628edaa5SPaul E. McKenney 	}
732e8516c64SPaul E. McKenney 	return ret;
733628edaa5SPaul E. McKenney }
734628edaa5SPaul E. McKenney EXPORT_SYMBOL_GPL(stutter_wait);
735628edaa5SPaul E. McKenney 
736628edaa5SPaul E. McKenney /*
737628edaa5SPaul E. McKenney  * Cause the torture test to "stutter", starting and stopping all
738628edaa5SPaul E. McKenney  * threads periodically.
739628edaa5SPaul E. McKenney  */
740628edaa5SPaul E. McKenney static int torture_stutter(void *arg)
741628edaa5SPaul E. McKenney {
742fda5ba9eSPaul E. McKenney 	DEFINE_TORTURE_RANDOM(rand);
743e8516c64SPaul E. McKenney 	int wtime;
744e8516c64SPaul E. McKenney 
745628edaa5SPaul E. McKenney 	VERBOSE_TOROUT_STRING("torture_stutter task started");
746628edaa5SPaul E. McKenney 	do {
7474ced3314SPaul E. McKenney 		if (!torture_must_stop() && stutter > 1) {
748e8516c64SPaul E. McKenney 			wtime = stutter;
749fda5ba9eSPaul E. McKenney 			if (stutter > 2) {
7504ced3314SPaul E. McKenney 				WRITE_ONCE(stutter_pause_test, 1);
751fda5ba9eSPaul E. McKenney 				wtime = stutter - 3;
752ed24affaSPaul E. McKenney 				torture_hrtimeout_jiffies(wtime, &rand);
753fda5ba9eSPaul E. McKenney 				wtime = 2;
754e8516c64SPaul E. McKenney 			}
7557d0ae808SPaul E. McKenney 			WRITE_ONCE(stutter_pause_test, 2);
756ed24affaSPaul E. McKenney 			torture_hrtimeout_jiffies(wtime, NULL);
757628edaa5SPaul E. McKenney 		}
7584ced3314SPaul E. McKenney 		WRITE_ONCE(stutter_pause_test, 0);
759628edaa5SPaul E. McKenney 		if (!torture_must_stop())
760ed24affaSPaul E. McKenney 			torture_hrtimeout_jiffies(stutter_gap, NULL);
761628edaa5SPaul E. McKenney 		torture_shutdown_absorb("torture_stutter");
762628edaa5SPaul E. McKenney 	} while (!torture_must_stop());
7637fafaac5SPaul E. McKenney 	torture_kthread_stopping("torture_stutter");
764628edaa5SPaul E. McKenney 	return 0;
765628edaa5SPaul E. McKenney }
766628edaa5SPaul E. McKenney 
767628edaa5SPaul E. McKenney /*
768628edaa5SPaul E. McKenney  * Initialize and kick off the torture_stutter kthread.
769628edaa5SPaul E. McKenney  */
770ff3bf92dSPaul E. McKenney int torture_stutter_init(const int s, const int sgap)
771628edaa5SPaul E. McKenney {
772628edaa5SPaul E. McKenney 	stutter = s;
773ff3bf92dSPaul E. McKenney 	stutter_gap = sgap;
7742a7d9688SPierce Griffiths 	return torture_create_kthread(torture_stutter, NULL, stutter_task);
775628edaa5SPaul E. McKenney }
776628edaa5SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_stutter_init);
777628edaa5SPaul E. McKenney 
778628edaa5SPaul E. McKenney /*
779628edaa5SPaul E. McKenney  * Cleanup after the torture_stutter kthread.
780628edaa5SPaul E. McKenney  */
781bfefc73aSPaul E. McKenney static void torture_stutter_cleanup(void)
782628edaa5SPaul E. McKenney {
783628edaa5SPaul E. McKenney 	if (!stutter_task)
784628edaa5SPaul E. McKenney 		return;
785628edaa5SPaul E. McKenney 	VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
786628edaa5SPaul E. McKenney 	kthread_stop(stutter_task);
787628edaa5SPaul E. McKenney 	stutter_task = NULL;
788628edaa5SPaul E. McKenney }
789628edaa5SPaul E. McKenney 
790628edaa5SPaul E. McKenney /*
791b5daa8f3SPaul E. McKenney  * Initialize torture module.  Please note that this is -not- invoked via
792b5daa8f3SPaul E. McKenney  * the usual module_init() mechanism, but rather by an explicit call from
793b5daa8f3SPaul E. McKenney  * the client torture module.  This call must be paired with a later
794b5daa8f3SPaul E. McKenney  * torture_init_end().
795628edaa5SPaul E. McKenney  *
796628edaa5SPaul E. McKenney  * The runnable parameter points to a flag that controls whether or not
797628edaa5SPaul E. McKenney  * the test is currently runnable.  If there is no such flag, pass in NULL.
798b5daa8f3SPaul E. McKenney  */
79990127d60SPaul E. McKenney bool torture_init_begin(char *ttype, int v)
800b5daa8f3SPaul E. McKenney {
801b5daa8f3SPaul E. McKenney 	mutex_lock(&fullstop_mutex);
8025228084eSPaul E. McKenney 	if (torture_type != NULL) {
8039eb5188aSPaul E. McKenney 		pr_alert("torture_init_begin: Refusing %s init: %s running.\n",
8045228084eSPaul E. McKenney 			 ttype, torture_type);
8059eb5188aSPaul E. McKenney 		pr_alert("torture_init_begin: One torture test at a time!\n");
8065228084eSPaul E. McKenney 		mutex_unlock(&fullstop_mutex);
8075228084eSPaul E. McKenney 		return false;
8085228084eSPaul E. McKenney 	}
809b5daa8f3SPaul E. McKenney 	torture_type = ttype;
810b5daa8f3SPaul E. McKenney 	verbose = v;
81136970bb9SPaul E. McKenney 	fullstop = FULLSTOP_DONTSTOP;
8125228084eSPaul E. McKenney 	return true;
813b5daa8f3SPaul E. McKenney }
814b5daa8f3SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_init_begin);
815b5daa8f3SPaul E. McKenney 
816b5daa8f3SPaul E. McKenney /*
817b5daa8f3SPaul E. McKenney  * Tell the torture module that initialization is complete.
818b5daa8f3SPaul E. McKenney  */
8192b3f8ffeSPranith Kumar void torture_init_end(void)
820b5daa8f3SPaul E. McKenney {
821b5daa8f3SPaul E. McKenney 	mutex_unlock(&fullstop_mutex);
8224622b487SPaul E. McKenney 	register_reboot_notifier(&torture_shutdown_nb);
823b5daa8f3SPaul E. McKenney }
824b5daa8f3SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_init_end);
825cc47ae08SPaul E. McKenney 
826cc47ae08SPaul E. McKenney /*
827cc47ae08SPaul E. McKenney  * Clean up torture module.  Please note that this is -not- invoked via
828cc47ae08SPaul E. McKenney  * the usual module_exit() mechanism, but rather by an explicit call from
829cc47ae08SPaul E. McKenney  * the client torture module.  Returns true if a race with system shutdown
830bfefc73aSPaul E. McKenney  * is detected, otherwise, all kthreads started by functions in this file
831bfefc73aSPaul E. McKenney  * will be shut down.
832cc47ae08SPaul E. McKenney  *
833cc47ae08SPaul E. McKenney  * This must be called before the caller starts shutting down its own
834cc47ae08SPaul E. McKenney  * kthreads.
835d36a7a0dSDavidlohr Bueso  *
836d36a7a0dSDavidlohr Bueso  * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
837d36a7a0dSDavidlohr Bueso  * in order to correctly perform the cleanup. They are separated because
838d36a7a0dSDavidlohr Bueso  * threads can still need to reference the torture_type type, thus nullify
839d36a7a0dSDavidlohr Bueso  * only after completing all other relevant calls.
840cc47ae08SPaul E. McKenney  */
841d36a7a0dSDavidlohr Bueso bool torture_cleanup_begin(void)
842cc47ae08SPaul E. McKenney {
843cc47ae08SPaul E. McKenney 	mutex_lock(&fullstop_mutex);
8447d0ae808SPaul E. McKenney 	if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
845cc47ae08SPaul E. McKenney 		pr_warn("Concurrent rmmod and shutdown illegal!\n");
846cc47ae08SPaul E. McKenney 		mutex_unlock(&fullstop_mutex);
847cc47ae08SPaul E. McKenney 		schedule_timeout_uninterruptible(10);
848cc47ae08SPaul E. McKenney 		return true;
849cc47ae08SPaul E. McKenney 	}
8507d0ae808SPaul E. McKenney 	WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
851cc47ae08SPaul E. McKenney 	mutex_unlock(&fullstop_mutex);
852bfefc73aSPaul E. McKenney 	torture_shutdown_cleanup();
853cc47ae08SPaul E. McKenney 	torture_shuffle_cleanup();
854bfefc73aSPaul E. McKenney 	torture_stutter_cleanup();
855cc47ae08SPaul E. McKenney 	torture_onoff_cleanup();
856d36a7a0dSDavidlohr Bueso 	return false;
857d36a7a0dSDavidlohr Bueso }
858d36a7a0dSDavidlohr Bueso EXPORT_SYMBOL_GPL(torture_cleanup_begin);
859d36a7a0dSDavidlohr Bueso 
860d36a7a0dSDavidlohr Bueso void torture_cleanup_end(void)
861d36a7a0dSDavidlohr Bueso {
8625228084eSPaul E. McKenney 	mutex_lock(&fullstop_mutex);
8635228084eSPaul E. McKenney 	torture_type = NULL;
8645228084eSPaul E. McKenney 	mutex_unlock(&fullstop_mutex);
865cc47ae08SPaul E. McKenney }
866d36a7a0dSDavidlohr Bueso EXPORT_SYMBOL_GPL(torture_cleanup_end);
86736970bb9SPaul E. McKenney 
86836970bb9SPaul E. McKenney /*
86936970bb9SPaul E. McKenney  * Is it time for the current torture test to stop?
87036970bb9SPaul E. McKenney  */
87136970bb9SPaul E. McKenney bool torture_must_stop(void)
87236970bb9SPaul E. McKenney {
87336970bb9SPaul E. McKenney 	return torture_must_stop_irq() || kthread_should_stop();
87436970bb9SPaul E. McKenney }
87536970bb9SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_must_stop);
87636970bb9SPaul E. McKenney 
87736970bb9SPaul E. McKenney /*
87836970bb9SPaul E. McKenney  * Is it time for the current torture test to stop?  This is the irq-safe
87936970bb9SPaul E. McKenney  * version, hence no check for kthread_should_stop().
88036970bb9SPaul E. McKenney  */
88136970bb9SPaul E. McKenney bool torture_must_stop_irq(void)
88236970bb9SPaul E. McKenney {
8837d0ae808SPaul E. McKenney 	return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
88436970bb9SPaul E. McKenney }
88536970bb9SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_must_stop_irq);
8867fafaac5SPaul E. McKenney 
8877fafaac5SPaul E. McKenney /*
8887fafaac5SPaul E. McKenney  * Each kthread must wait for kthread_should_stop() before returning from
8897fafaac5SPaul E. McKenney  * its top-level function, otherwise segfaults ensue.  This function
8907fafaac5SPaul E. McKenney  * prints a "stopping" message and waits for kthread_should_stop(), and
8917fafaac5SPaul E. McKenney  * should be called from all torture kthreads immediately prior to
8927fafaac5SPaul E. McKenney  * returning.
8937fafaac5SPaul E. McKenney  */
8947fafaac5SPaul E. McKenney void torture_kthread_stopping(char *title)
8957fafaac5SPaul E. McKenney {
8960d6821d5SPaul E. McKenney 	char buf[128];
8970d6821d5SPaul E. McKenney 
8980d6821d5SPaul E. McKenney 	snprintf(buf, sizeof(buf), "Stopping %s", title);
8990d6821d5SPaul E. McKenney 	VERBOSE_TOROUT_STRING(buf);
9007fafaac5SPaul E. McKenney 	while (!kthread_should_stop()) {
9017fafaac5SPaul E. McKenney 		torture_shutdown_absorb(title);
9027fafaac5SPaul E. McKenney 		schedule_timeout_uninterruptible(1);
9037fafaac5SPaul E. McKenney 	}
9047fafaac5SPaul E. McKenney }
9057fafaac5SPaul E. McKenney EXPORT_SYMBOL_GPL(torture_kthread_stopping);
90647cf29b9SPaul E. McKenney 
90747cf29b9SPaul E. McKenney /*
90847cf29b9SPaul E. McKenney  * Create a generic torture kthread that is immediately runnable.  If you
90947cf29b9SPaul E. McKenney  * need the kthread to be stopped so that you can do something to it before
91047cf29b9SPaul E. McKenney  * it starts, you will need to open-code your own.
91147cf29b9SPaul E. McKenney  */
91247cf29b9SPaul E. McKenney int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
91347cf29b9SPaul E. McKenney 			    char *f, struct task_struct **tp)
91447cf29b9SPaul E. McKenney {
91547cf29b9SPaul E. McKenney 	int ret = 0;
91647cf29b9SPaul E. McKenney 
91747cf29b9SPaul E. McKenney 	VERBOSE_TOROUT_STRING(m);
9186945915eSKees Cook 	*tp = kthread_run(fn, arg, "%s", s);
91947cf29b9SPaul E. McKenney 	if (IS_ERR(*tp)) {
92047cf29b9SPaul E. McKenney 		ret = PTR_ERR(*tp);
92147cf29b9SPaul E. McKenney 		VERBOSE_TOROUT_ERRSTRING(f);
92247cf29b9SPaul E. McKenney 		*tp = NULL;
92347cf29b9SPaul E. McKenney 	}
92447cf29b9SPaul E. McKenney 	torture_shuffle_task_register(*tp);
92547cf29b9SPaul E. McKenney 	return ret;
92647cf29b9SPaul E. McKenney }
92747cf29b9SPaul E. McKenney EXPORT_SYMBOL_GPL(_torture_create_kthread);
9289c029b86SPaul E. McKenney 
9299c029b86SPaul E. McKenney /*
9309c029b86SPaul E. McKenney  * Stop a generic kthread, emitting a message.
9319c029b86SPaul E. McKenney  */
9329c029b86SPaul E. McKenney void _torture_stop_kthread(char *m, struct task_struct **tp)
9339c029b86SPaul E. McKenney {
9349c029b86SPaul E. McKenney 	if (*tp == NULL)
9359c029b86SPaul E. McKenney 		return;
9369c029b86SPaul E. McKenney 	VERBOSE_TOROUT_STRING(m);
9379c029b86SPaul E. McKenney 	kthread_stop(*tp);
9389c029b86SPaul E. McKenney 	*tp = NULL;
9399c029b86SPaul E. McKenney }
9409c029b86SPaul E. McKenney EXPORT_SYMBOL_GPL(_torture_stop_kthread);
941