2 * Module-based torture test facility for locking
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
18 * Copyright (C) IBM Corporation, 2014
20 * Author: Paul E. McKenney <paulmck@us.ibm.com>
21 * Based on kernel/rcu/torture.c.
23 #include <linux/types.h>
24 #include <linux/kernel.h>
25 #include <linux/init.h>
26 #include <linux/module.h>
27 #include <linux/kthread.h>
28 #include <linux/err.h>
29 #include <linux/spinlock.h>
30 #include <linux/smp.h>
31 #include <linux/interrupt.h>
32 #include <linux/sched.h>
33 #include <linux/atomic.h>
34 #include <linux/bitops.h>
35 #include <linux/completion.h>
36 #include <linux/moduleparam.h>
37 #include <linux/percpu.h>
38 #include <linux/notifier.h>
39 #include <linux/reboot.h>
40 #include <linux/freezer.h>
41 #include <linux/cpu.h>
42 #include <linux/delay.h>
43 #include <linux/stat.h>
44 #include <linux/slab.h>
45 #include <linux/trace_clock.h>
46 #include <asm/byteorder.h>
47 #include <linux/torture.h>
49 MODULE_LICENSE("GPL");
50 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
52 torture_param(int, nwriters_stress
, -1,
53 "Number of write-locking stress-test threads");
54 torture_param(int, onoff_holdoff
, 0, "Time after boot before CPU hotplugs (s)");
55 torture_param(int, onoff_interval
, 0,
56 "Time between CPU hotplugs (s), 0=disable");
57 torture_param(int, shuffle_interval
, 3,
58 "Number of jiffies between shuffles, 0=disable");
59 torture_param(int, shutdown_secs
, 0, "Shutdown time (j), <= zero to disable.");
60 torture_param(int, stat_interval
, 60,
61 "Number of seconds between stats printk()s");
62 torture_param(int, stutter
, 5, "Number of jiffies to run/halt test, 0=disable");
63 torture_param(bool, verbose
, true,
64 "Enable verbose debugging printk()s");
66 static char *torture_type
= "spin_lock";
67 module_param(torture_type
, charp
, 0444);
68 MODULE_PARM_DESC(torture_type
,
69 "Type of lock to torture (spin_lock, spin_lock_irq, ...)");
71 static atomic_t n_lock_torture_errors
;
73 static struct task_struct
*stats_task
;
74 static struct task_struct
**writer_tasks
;
76 static int nrealwriters_stress
;
77 static bool lock_is_write_held
;
79 struct lock_writer_stress_stats
{
80 long n_write_lock_fail
;
81 long n_write_lock_acquired
;
83 static struct lock_writer_stress_stats
*lwsa
;
85 #if defined(MODULE) || defined(CONFIG_LOCK_TORTURE_TEST_RUNNABLE)
86 #define LOCKTORTURE_RUNNABLE_INIT 1
88 #define LOCKTORTURE_RUNNABLE_INIT 0
90 int locktorture_runnable
= LOCKTORTURE_RUNNABLE_INIT
;
91 module_param(locktorture_runnable
, int, 0444);
92 MODULE_PARM_DESC(locktorture_runnable
, "Start locktorture at boot");
94 /* Forward reference. */
95 static void lock_torture_cleanup(void);
98 * Operations vector for selecting different types of tests.
100 struct lock_torture_ops
{
102 int (*writelock
)(void);
103 void (*write_delay
)(struct torture_random_state
*trsp
);
104 void (*writeunlock
)(void);
109 static struct lock_torture_ops
*cur_ops
;
112 * Definitions for lock torture testing.
115 static int torture_lock_busted_write_lock(void)
117 return 0; /* BUGGY, do not use in real life!!! */
120 static void torture_lock_busted_write_delay(struct torture_random_state
*trsp
)
122 const unsigned long longdelay_us
= 100;
124 /* We want a long delay occasionally to force massive contention. */
125 if (!(torture_random(trsp
) %
126 (nrealwriters_stress
* 2000 * longdelay_us
)))
127 mdelay(longdelay_us
);
128 #ifdef CONFIG_PREEMPT
129 if (!(torture_random(trsp
) % (nrealwriters_stress
* 20000)))
130 preempt_schedule(); /* Allow test to be preempted. */
134 static void torture_lock_busted_write_unlock(void)
136 /* BUGGY, do not use in real life!!! */
139 static struct lock_torture_ops lock_busted_ops
= {
140 .writelock
= torture_lock_busted_write_lock
,
141 .write_delay
= torture_lock_busted_write_delay
,
142 .writeunlock
= torture_lock_busted_write_unlock
,
143 .name
= "lock_busted"
146 static DEFINE_SPINLOCK(torture_spinlock
);
148 static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock
)
150 spin_lock(&torture_spinlock
);
154 static void torture_spin_lock_write_delay(struct torture_random_state
*trsp
)
156 const unsigned long shortdelay_us
= 2;
157 const unsigned long longdelay_us
= 100;
159 /* We want a short delay mostly to emulate likely code, and
160 * we want a long delay occasionally to force massive contention.
162 if (!(torture_random(trsp
) %
163 (nrealwriters_stress
* 2000 * longdelay_us
)))
164 mdelay(longdelay_us
);
165 if (!(torture_random(trsp
) %
166 (nrealwriters_stress
* 2 * shortdelay_us
)))
167 udelay(shortdelay_us
);
168 #ifdef CONFIG_PREEMPT
169 if (!(torture_random(trsp
) % (nrealwriters_stress
* 20000)))
170 preempt_schedule(); /* Allow test to be preempted. */
174 static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock
)
176 spin_unlock(&torture_spinlock
);
179 static struct lock_torture_ops spin_lock_ops
= {
180 .writelock
= torture_spin_lock_write_lock
,
181 .write_delay
= torture_spin_lock_write_delay
,
182 .writeunlock
= torture_spin_lock_write_unlock
,
186 static int torture_spin_lock_write_lock_irq(void)
187 __acquires(torture_spinlock_irq
)
191 spin_lock_irqsave(&torture_spinlock
, flags
);
192 cur_ops
->flags
= flags
;
196 static void torture_lock_spin_write_unlock_irq(void)
197 __releases(torture_spinlock
)
199 spin_unlock_irqrestore(&torture_spinlock
, cur_ops
->flags
);
202 static struct lock_torture_ops spin_lock_irq_ops
= {
203 .writelock
= torture_spin_lock_write_lock_irq
,
204 .write_delay
= torture_spin_lock_write_delay
,
205 .writeunlock
= torture_lock_spin_write_unlock_irq
,
206 .name
= "spin_lock_irq"
210 * Lock torture writer kthread. Repeatedly acquires and releases
211 * the lock, checking for duplicate acquisitions.
213 static int lock_torture_writer(void *arg
)
215 struct lock_writer_stress_stats
*lwsp
= arg
;
216 static DEFINE_TORTURE_RANDOM(rand
);
218 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
219 set_user_nice(current
, 19);
222 schedule_timeout_uninterruptible(1);
223 cur_ops
->writelock();
224 if (WARN_ON_ONCE(lock_is_write_held
))
225 lwsp
->n_write_lock_fail
++;
226 lock_is_write_held
= 1;
227 lwsp
->n_write_lock_acquired
++;
228 cur_ops
->write_delay(&rand
);
229 lock_is_write_held
= 0;
230 cur_ops
->writeunlock();
231 stutter_wait("lock_torture_writer");
232 } while (!torture_must_stop());
233 torture_kthread_stopping("lock_torture_writer");
238 * Create an lock-torture-statistics message in the specified buffer.
240 static void lock_torture_printk(char *page
)
245 long min
= lwsa
[0].n_write_lock_acquired
;
248 for (i
= 0; i
< nrealwriters_stress
; i
++) {
249 if (lwsa
[i
].n_write_lock_fail
)
251 sum
+= lwsa
[i
].n_write_lock_acquired
;
252 if (max
< lwsa
[i
].n_write_lock_fail
)
253 max
= lwsa
[i
].n_write_lock_fail
;
254 if (min
> lwsa
[i
].n_write_lock_fail
)
255 min
= lwsa
[i
].n_write_lock_fail
;
257 page
+= sprintf(page
, "%s%s ", torture_type
, TORTURE_FLAG
);
258 page
+= sprintf(page
,
259 "Writes: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
260 sum
, max
, min
, max
/ 2 > min
? "???" : "",
261 fail
, fail
? "!!!" : "");
263 atomic_inc(&n_lock_torture_errors
);
267 * Print torture statistics. Caller must ensure that there is only one
268 * call to this function at a given time!!! This is normally accomplished
269 * by relying on the module system to only have one copy of the module
270 * loaded, and then by giving the lock_torture_stats kthread full control
271 * (or the init/cleanup functions when lock_torture_stats thread is not
274 static void lock_torture_stats_print(void)
276 int size
= nrealwriters_stress
* 200 + 8192;
279 buf
= kmalloc(size
, GFP_KERNEL
);
281 pr_err("lock_torture_stats_print: Out of memory, need: %d",
285 lock_torture_printk(buf
);
291 * Periodically prints torture statistics, if periodic statistics printing
292 * was specified via the stat_interval module parameter.
294 * No need to worry about fullstop here, since this one doesn't reference
295 * volatile state or register callbacks.
297 static int lock_torture_stats(void *arg
)
299 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
301 schedule_timeout_interruptible(stat_interval
* HZ
);
302 lock_torture_stats_print();
303 torture_shutdown_absorb("lock_torture_stats");
304 } while (!torture_must_stop());
305 torture_kthread_stopping("lock_torture_stats");
310 lock_torture_print_module_parms(struct lock_torture_ops
*cur_ops
,
313 pr_alert("%s" TORTURE_FLAG
314 "--- %s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
315 torture_type
, tag
, nrealwriters_stress
, stat_interval
, verbose
,
316 shuffle_interval
, stutter
, shutdown_secs
,
317 onoff_interval
, onoff_holdoff
);
320 static void lock_torture_cleanup(void)
324 if (torture_cleanup())
328 for (i
= 0; i
< nrealwriters_stress
; i
++)
329 torture_stop_kthread(lock_torture_writer
,
335 torture_stop_kthread(lock_torture_stats
, stats_task
);
336 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
338 if (atomic_read(&n_lock_torture_errors
))
339 lock_torture_print_module_parms(cur_ops
,
340 "End of test: FAILURE");
341 else if (torture_onoff_failures())
342 lock_torture_print_module_parms(cur_ops
,
343 "End of test: LOCK_HOTPLUG");
345 lock_torture_print_module_parms(cur_ops
,
346 "End of test: SUCCESS");
349 static int __init
lock_torture_init(void)
353 static struct lock_torture_ops
*torture_ops
[] = {
354 &lock_busted_ops
, &spin_lock_ops
, &spin_lock_irq_ops
,
357 torture_init_begin(torture_type
, verbose
, &locktorture_runnable
);
359 /* Process args and tell the world that the torturer is on the job. */
360 for (i
= 0; i
< ARRAY_SIZE(torture_ops
); i
++) {
361 cur_ops
= torture_ops
[i
];
362 if (strcmp(torture_type
, cur_ops
->name
) == 0)
365 if (i
== ARRAY_SIZE(torture_ops
)) {
366 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
368 pr_alert("lock-torture types:");
369 for (i
= 0; i
< ARRAY_SIZE(torture_ops
); i
++)
370 pr_alert(" %s", torture_ops
[i
]->name
);
376 cur_ops
->init(); /* no "goto unwind" prior to this point!!! */
378 if (nwriters_stress
>= 0)
379 nrealwriters_stress
= nwriters_stress
;
381 nrealwriters_stress
= 2 * num_online_cpus();
382 lock_torture_print_module_parms(cur_ops
, "Start of test");
384 /* Initialize the statistics so that each run gets its own numbers. */
386 lock_is_write_held
= 0;
387 lwsa
= kmalloc(sizeof(*lwsa
) * nrealwriters_stress
, GFP_KERNEL
);
389 VERBOSE_TOROUT_STRING("lwsa: Out of memory");
393 for (i
= 0; i
< nrealwriters_stress
; i
++) {
394 lwsa
[i
].n_write_lock_fail
= 0;
395 lwsa
[i
].n_write_lock_acquired
= 0;
398 /* Start up the kthreads. */
400 if (onoff_interval
> 0) {
401 firsterr
= torture_onoff_init(onoff_holdoff
* HZ
,
402 onoff_interval
* HZ
);
406 if (shuffle_interval
> 0) {
407 firsterr
= torture_shuffle_init(shuffle_interval
);
411 if (shutdown_secs
> 0) {
412 firsterr
= torture_shutdown_init(shutdown_secs
,
413 lock_torture_cleanup
);
418 firsterr
= torture_stutter_init(stutter
);
423 writer_tasks
= kzalloc(nrealwriters_stress
* sizeof(writer_tasks
[0]),
425 if (writer_tasks
== NULL
) {
426 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
430 for (i
= 0; i
< nrealwriters_stress
; i
++) {
431 firsterr
= torture_create_kthread(lock_torture_writer
, &lwsa
[i
],
436 if (stat_interval
> 0) {
437 firsterr
= torture_create_kthread(lock_torture_stats
, NULL
,
447 lock_torture_cleanup();
451 module_init(lock_torture_init
);
452 module_exit(lock_torture_cleanup
);