2 * Read-Copy Update module-based torture test facility
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, 2005, 2006
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Josh Triplett <josh@joshtriplett.org>
23 * See also: Documentation/RCU/torture.txt
25 #include <linux/types.h>
26 #include <linux/kernel.h>
27 #include <linux/init.h>
28 #include <linux/module.h>
29 #include <linux/kthread.h>
30 #include <linux/err.h>
31 #include <linux/spinlock.h>
32 #include <linux/smp.h>
33 #include <linux/rcupdate.h>
34 #include <linux/interrupt.h>
35 #include <linux/sched.h>
36 #include <linux/atomic.h>
37 #include <linux/bitops.h>
38 #include <linux/completion.h>
39 #include <linux/moduleparam.h>
40 #include <linux/percpu.h>
41 #include <linux/notifier.h>
42 #include <linux/reboot.h>
43 #include <linux/freezer.h>
44 #include <linux/cpu.h>
45 #include <linux/delay.h>
46 #include <linux/stat.h>
47 #include <linux/srcu.h>
48 #include <linux/slab.h>
49 #include <linux/trace_clock.h>
50 #include <asm/byteorder.h>
51 #include <linux/torture.h>
52 #include <linux/vmalloc.h>
54 MODULE_LICENSE("GPL");
55 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
58 torture_param(int, cbflood_inter_holdoff
, HZ
,
59 "Holdoff between floods (jiffies)");
60 torture_param(int, cbflood_intra_holdoff
, 1,
61 "Holdoff between bursts (jiffies)");
62 torture_param(int, cbflood_n_burst
, 3, "# bursts in flood, zero to disable");
63 torture_param(int, cbflood_n_per_burst
, 20000,
64 "# callbacks per burst in flood");
65 torture_param(int, fqs_duration
, 0,
66 "Duration of fqs bursts (us), 0 to disable");
67 torture_param(int, fqs_holdoff
, 0, "Holdoff time within fqs bursts (us)");
68 torture_param(int, fqs_stutter
, 3, "Wait time between fqs bursts (s)");
69 torture_param(bool, gp_cond
, false, "Use conditional/async GP wait primitives");
70 torture_param(bool, gp_exp
, false, "Use expedited GP wait primitives");
71 torture_param(bool, gp_normal
, false,
72 "Use normal (non-expedited) GP wait primitives");
73 torture_param(bool, gp_sync
, false, "Use synchronous GP wait primitives");
74 torture_param(int, irqreader
, 1, "Allow RCU readers from irq handlers");
75 torture_param(int, n_barrier_cbs
, 0,
76 "# of callbacks/kthreads for barrier testing");
77 torture_param(int, nfakewriters
, 4, "Number of RCU fake writer threads");
78 torture_param(int, nreaders
, -1, "Number of RCU reader threads");
79 torture_param(int, object_debug
, 0,
80 "Enable debug-object double call_rcu() testing");
81 torture_param(int, onoff_holdoff
, 0, "Time after boot before CPU hotplugs (s)");
82 torture_param(int, onoff_interval
, 0,
83 "Time between CPU hotplugs (s), 0=disable");
84 torture_param(int, shuffle_interval
, 3, "Number of seconds between shuffles");
85 torture_param(int, shutdown_secs
, 0, "Shutdown time (s), <= zero to disable.");
86 torture_param(int, stall_cpu
, 0, "Stall duration (s), zero to disable.");
87 torture_param(int, stall_cpu_holdoff
, 10,
88 "Time to wait before starting stall (s).");
89 torture_param(int, stat_interval
, 60,
90 "Number of seconds between stats printk()s");
91 torture_param(int, stutter
, 5, "Number of seconds to run/halt test");
92 torture_param(int, test_boost
, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
93 torture_param(int, test_boost_duration
, 4,
94 "Duration of each boost test, seconds.");
95 torture_param(int, test_boost_interval
, 7,
96 "Interval between boost tests, seconds.");
97 torture_param(bool, test_no_idle_hz
, true,
98 "Test support for tickless idle CPUs");
99 torture_param(bool, verbose
, true,
100 "Enable verbose debugging printk()s");
102 static char *torture_type
= "rcu";
103 module_param(torture_type
, charp
, 0444);
104 MODULE_PARM_DESC(torture_type
, "Type of RCU to torture (rcu, rcu_bh, ...)");
106 static int nrealreaders
;
107 static int ncbflooders
;
108 static struct task_struct
*writer_task
;
109 static struct task_struct
**fakewriter_tasks
;
110 static struct task_struct
**reader_tasks
;
111 static struct task_struct
*stats_task
;
112 static struct task_struct
**cbflood_task
;
113 static struct task_struct
*fqs_task
;
114 static struct task_struct
*boost_tasks
[NR_CPUS
];
115 static struct task_struct
*stall_task
;
116 static struct task_struct
**barrier_cbs_tasks
;
117 static struct task_struct
*barrier_task
;
119 #define RCU_TORTURE_PIPE_LEN 10
122 struct rcu_head rtort_rcu
;
123 int rtort_pipe_count
;
124 struct list_head rtort_free
;
128 static LIST_HEAD(rcu_torture_freelist
);
129 static struct rcu_torture __rcu
*rcu_torture_current
;
130 static unsigned long rcu_torture_current_version
;
131 static struct rcu_torture rcu_tortures
[10 * RCU_TORTURE_PIPE_LEN
];
132 static DEFINE_SPINLOCK(rcu_torture_lock
);
133 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN
+ 1],
134 rcu_torture_count
) = { 0 };
135 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN
+ 1],
136 rcu_torture_batch
) = { 0 };
137 static atomic_t rcu_torture_wcount
[RCU_TORTURE_PIPE_LEN
+ 1];
138 static atomic_t n_rcu_torture_alloc
;
139 static atomic_t n_rcu_torture_alloc_fail
;
140 static atomic_t n_rcu_torture_free
;
141 static atomic_t n_rcu_torture_mberror
;
142 static atomic_t n_rcu_torture_error
;
143 static long n_rcu_torture_barrier_error
;
144 static long n_rcu_torture_boost_ktrerror
;
145 static long n_rcu_torture_boost_rterror
;
146 static long n_rcu_torture_boost_failure
;
147 static long n_rcu_torture_boosts
;
148 static long n_rcu_torture_timers
;
149 static long n_barrier_attempts
;
150 static long n_barrier_successes
;
151 static atomic_long_t n_cbfloods
;
152 static struct list_head rcu_torture_removed
;
154 static int rcu_torture_writer_state
;
155 #define RTWS_FIXED_DELAY 0
157 #define RTWS_REPLACE 2
158 #define RTWS_DEF_FREE 3
159 #define RTWS_EXP_SYNC 4
160 #define RTWS_COND_GET 5
161 #define RTWS_COND_SYNC 6
163 #define RTWS_STUTTER 8
164 #define RTWS_STOPPING 9
166 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
167 #define RCUTORTURE_RUNNABLE_INIT 1
169 #define RCUTORTURE_RUNNABLE_INIT 0
171 static int torture_runnable
= RCUTORTURE_RUNNABLE_INIT
;
172 module_param(torture_runnable
, int, 0444);
173 MODULE_PARM_DESC(torture_runnable
, "Start rcutorture at boot");
175 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
176 #define rcu_can_boost() 1
177 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
178 #define rcu_can_boost() 0
179 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
181 #ifdef CONFIG_RCU_TRACE
182 static u64 notrace
rcu_trace_clock_local(void)
184 u64 ts
= trace_clock_local();
185 unsigned long __maybe_unused ts_rem
= do_div(ts
, NSEC_PER_USEC
);
188 #else /* #ifdef CONFIG_RCU_TRACE */
189 static u64 notrace
rcu_trace_clock_local(void)
193 #endif /* #else #ifdef CONFIG_RCU_TRACE */
195 static unsigned long boost_starttime
; /* jiffies of next boost test start. */
196 static DEFINE_MUTEX(boost_mutex
); /* protect setting boost_starttime */
197 /* and boost task create/destroy. */
198 static atomic_t barrier_cbs_count
; /* Barrier callbacks registered. */
199 static bool barrier_phase
; /* Test phase. */
200 static atomic_t barrier_cbs_invoked
; /* Barrier callbacks invoked. */
201 static wait_queue_head_t
*barrier_cbs_wq
; /* Coordinate barrier testing. */
202 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq
);
205 * Allocate an element from the rcu_tortures pool.
207 static struct rcu_torture
*
208 rcu_torture_alloc(void)
212 spin_lock_bh(&rcu_torture_lock
);
213 if (list_empty(&rcu_torture_freelist
)) {
214 atomic_inc(&n_rcu_torture_alloc_fail
);
215 spin_unlock_bh(&rcu_torture_lock
);
218 atomic_inc(&n_rcu_torture_alloc
);
219 p
= rcu_torture_freelist
.next
;
221 spin_unlock_bh(&rcu_torture_lock
);
222 return container_of(p
, struct rcu_torture
, rtort_free
);
226 * Free an element to the rcu_tortures pool.
229 rcu_torture_free(struct rcu_torture
*p
)
231 atomic_inc(&n_rcu_torture_free
);
232 spin_lock_bh(&rcu_torture_lock
);
233 list_add_tail(&p
->rtort_free
, &rcu_torture_freelist
);
234 spin_unlock_bh(&rcu_torture_lock
);
238 * Operations vector for selecting different types of tests.
241 struct rcu_torture_ops
{
244 void (*cleanup
)(void);
245 int (*readlock
)(void);
246 void (*read_delay
)(struct torture_random_state
*rrsp
);
247 void (*readunlock
)(int idx
);
248 unsigned long (*started
)(void);
249 unsigned long (*completed
)(void);
250 void (*deferred_free
)(struct rcu_torture
*p
);
252 void (*exp_sync
)(void);
253 unsigned long (*get_state
)(void);
254 void (*cond_sync
)(unsigned long oldstate
);
255 void (*call
)(struct rcu_head
*head
, void (*func
)(struct rcu_head
*rcu
));
256 void (*cb_barrier
)(void);
264 static struct rcu_torture_ops
*cur_ops
;
267 * Definitions for rcu torture testing.
270 static int rcu_torture_read_lock(void) __acquires(RCU
)
276 static void rcu_read_delay(struct torture_random_state
*rrsp
)
278 const unsigned long shortdelay_us
= 200;
279 const unsigned long longdelay_ms
= 50;
281 /* We want a short delay sometimes to make a reader delay the grace
282 * period, and we want a long delay occasionally to trigger
283 * force_quiescent_state. */
285 if (!(torture_random(rrsp
) % (nrealreaders
* 2000 * longdelay_ms
)))
286 mdelay(longdelay_ms
);
287 if (!(torture_random(rrsp
) % (nrealreaders
* 2 * shortdelay_us
)))
288 udelay(shortdelay_us
);
289 #ifdef CONFIG_PREEMPT
290 if (!preempt_count() &&
291 !(torture_random(rrsp
) % (nrealreaders
* 20000)))
292 preempt_schedule(); /* No QS if preempt_disable() in effect */
296 static void rcu_torture_read_unlock(int idx
) __releases(RCU
)
302 * Update callback in the pipe. This should be invoked after a grace period.
305 rcu_torture_pipe_update_one(struct rcu_torture
*rp
)
309 i
= rp
->rtort_pipe_count
;
310 if (i
> RCU_TORTURE_PIPE_LEN
)
311 i
= RCU_TORTURE_PIPE_LEN
;
312 atomic_inc(&rcu_torture_wcount
[i
]);
313 if (++rp
->rtort_pipe_count
>= RCU_TORTURE_PIPE_LEN
) {
314 rp
->rtort_mbtest
= 0;
321 * Update all callbacks in the pipe. Suitable for synchronous grace-period
325 rcu_torture_pipe_update(struct rcu_torture
*old_rp
)
327 struct rcu_torture
*rp
;
328 struct rcu_torture
*rp1
;
331 list_add(&old_rp
->rtort_free
, &rcu_torture_removed
);
332 list_for_each_entry_safe(rp
, rp1
, &rcu_torture_removed
, rtort_free
) {
333 if (rcu_torture_pipe_update_one(rp
)) {
334 list_del(&rp
->rtort_free
);
335 rcu_torture_free(rp
);
341 rcu_torture_cb(struct rcu_head
*p
)
343 struct rcu_torture
*rp
= container_of(p
, struct rcu_torture
, rtort_rcu
);
345 if (torture_must_stop_irq()) {
346 /* Test is ending, just drop callbacks on the floor. */
347 /* The next initialization will pick up the pieces. */
350 if (rcu_torture_pipe_update_one(rp
))
351 rcu_torture_free(rp
);
353 cur_ops
->deferred_free(rp
);
356 static unsigned long rcu_no_completed(void)
361 static void rcu_torture_deferred_free(struct rcu_torture
*p
)
363 call_rcu(&p
->rtort_rcu
, rcu_torture_cb
);
366 static void rcu_sync_torture_init(void)
368 INIT_LIST_HEAD(&rcu_torture_removed
);
371 static struct rcu_torture_ops rcu_ops
= {
373 .init
= rcu_sync_torture_init
,
374 .readlock
= rcu_torture_read_lock
,
375 .read_delay
= rcu_read_delay
,
376 .readunlock
= rcu_torture_read_unlock
,
377 .started
= rcu_batches_started
,
378 .completed
= rcu_batches_completed
,
379 .deferred_free
= rcu_torture_deferred_free
,
380 .sync
= synchronize_rcu
,
381 .exp_sync
= synchronize_rcu_expedited
,
382 .get_state
= get_state_synchronize_rcu
,
383 .cond_sync
= cond_synchronize_rcu
,
385 .cb_barrier
= rcu_barrier
,
386 .fqs
= rcu_force_quiescent_state
,
389 .can_boost
= rcu_can_boost(),
394 * Definitions for rcu_bh torture testing.
397 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH
)
403 static void rcu_bh_torture_read_unlock(int idx
) __releases(RCU_BH
)
405 rcu_read_unlock_bh();
408 static void rcu_bh_torture_deferred_free(struct rcu_torture
*p
)
410 call_rcu_bh(&p
->rtort_rcu
, rcu_torture_cb
);
413 static struct rcu_torture_ops rcu_bh_ops
= {
414 .ttype
= RCU_BH_FLAVOR
,
415 .init
= rcu_sync_torture_init
,
416 .readlock
= rcu_bh_torture_read_lock
,
417 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
418 .readunlock
= rcu_bh_torture_read_unlock
,
419 .started
= rcu_batches_started_bh
,
420 .completed
= rcu_batches_completed_bh
,
421 .deferred_free
= rcu_bh_torture_deferred_free
,
422 .sync
= synchronize_rcu_bh
,
423 .exp_sync
= synchronize_rcu_bh_expedited
,
425 .cb_barrier
= rcu_barrier_bh
,
426 .fqs
= rcu_bh_force_quiescent_state
,
433 * Don't even think about trying any of these in real life!!!
434 * The names includes "busted", and they really means it!
435 * The only purpose of these functions is to provide a buggy RCU
436 * implementation to make sure that rcutorture correctly emits
437 * buggy-RCU error messages.
439 static void rcu_busted_torture_deferred_free(struct rcu_torture
*p
)
441 /* This is a deliberate bug for testing purposes only! */
442 rcu_torture_cb(&p
->rtort_rcu
);
445 static void synchronize_rcu_busted(void)
447 /* This is a deliberate bug for testing purposes only! */
451 call_rcu_busted(struct rcu_head
*head
, void (*func
)(struct rcu_head
*rcu
))
453 /* This is a deliberate bug for testing purposes only! */
457 static struct rcu_torture_ops rcu_busted_ops
= {
458 .ttype
= INVALID_RCU_FLAVOR
,
459 .init
= rcu_sync_torture_init
,
460 .readlock
= rcu_torture_read_lock
,
461 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
462 .readunlock
= rcu_torture_read_unlock
,
463 .started
= rcu_no_completed
,
464 .completed
= rcu_no_completed
,
465 .deferred_free
= rcu_busted_torture_deferred_free
,
466 .sync
= synchronize_rcu_busted
,
467 .exp_sync
= synchronize_rcu_busted
,
468 .call
= call_rcu_busted
,
477 * Definitions for srcu torture testing.
480 DEFINE_STATIC_SRCU(srcu_ctl
);
481 static struct srcu_struct srcu_ctld
;
482 static struct srcu_struct
*srcu_ctlp
= &srcu_ctl
;
484 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp
)
486 return srcu_read_lock(srcu_ctlp
);
489 static void srcu_read_delay(struct torture_random_state
*rrsp
)
492 const long uspertick
= 1000000 / HZ
;
493 const long longdelay
= 10;
495 /* We want there to be long-running readers, but not all the time. */
497 delay
= torture_random(rrsp
) %
498 (nrealreaders
* 2 * longdelay
* uspertick
);
500 schedule_timeout_interruptible(longdelay
);
502 rcu_read_delay(rrsp
);
505 static void srcu_torture_read_unlock(int idx
) __releases(srcu_ctlp
)
507 srcu_read_unlock(srcu_ctlp
, idx
);
510 static unsigned long srcu_torture_completed(void)
512 return srcu_batches_completed(srcu_ctlp
);
515 static void srcu_torture_deferred_free(struct rcu_torture
*rp
)
517 call_srcu(srcu_ctlp
, &rp
->rtort_rcu
, rcu_torture_cb
);
520 static void srcu_torture_synchronize(void)
522 synchronize_srcu(srcu_ctlp
);
525 static void srcu_torture_call(struct rcu_head
*head
,
526 void (*func
)(struct rcu_head
*head
))
528 call_srcu(srcu_ctlp
, head
, func
);
531 static void srcu_torture_barrier(void)
533 srcu_barrier(srcu_ctlp
);
536 static void srcu_torture_stats(void)
539 int idx
= srcu_ctlp
->completed
& 0x1;
541 pr_alert("%s%s per-CPU(idx=%d):",
542 torture_type
, TORTURE_FLAG
, idx
);
543 for_each_possible_cpu(cpu
) {
546 c0
= (long)per_cpu_ptr(srcu_ctlp
->per_cpu_ref
, cpu
)->c
[!idx
];
547 c1
= (long)per_cpu_ptr(srcu_ctlp
->per_cpu_ref
, cpu
)->c
[idx
];
548 pr_cont(" %d(%ld,%ld)", cpu
, c0
, c1
);
553 static void srcu_torture_synchronize_expedited(void)
555 synchronize_srcu_expedited(srcu_ctlp
);
558 static struct rcu_torture_ops srcu_ops
= {
559 .ttype
= SRCU_FLAVOR
,
560 .init
= rcu_sync_torture_init
,
561 .readlock
= srcu_torture_read_lock
,
562 .read_delay
= srcu_read_delay
,
563 .readunlock
= srcu_torture_read_unlock
,
565 .completed
= srcu_torture_completed
,
566 .deferred_free
= srcu_torture_deferred_free
,
567 .sync
= srcu_torture_synchronize
,
568 .exp_sync
= srcu_torture_synchronize_expedited
,
569 .call
= srcu_torture_call
,
570 .cb_barrier
= srcu_torture_barrier
,
571 .stats
= srcu_torture_stats
,
575 static void srcu_torture_init(void)
577 rcu_sync_torture_init();
578 WARN_ON(init_srcu_struct(&srcu_ctld
));
579 srcu_ctlp
= &srcu_ctld
;
582 static void srcu_torture_cleanup(void)
584 cleanup_srcu_struct(&srcu_ctld
);
585 srcu_ctlp
= &srcu_ctl
; /* In case of a later rcutorture run. */
588 /* As above, but dynamically allocated. */
589 static struct rcu_torture_ops srcud_ops
= {
590 .ttype
= SRCU_FLAVOR
,
591 .init
= srcu_torture_init
,
592 .cleanup
= srcu_torture_cleanup
,
593 .readlock
= srcu_torture_read_lock
,
594 .read_delay
= srcu_read_delay
,
595 .readunlock
= srcu_torture_read_unlock
,
597 .completed
= srcu_torture_completed
,
598 .deferred_free
= srcu_torture_deferred_free
,
599 .sync
= srcu_torture_synchronize
,
600 .exp_sync
= srcu_torture_synchronize_expedited
,
601 .call
= srcu_torture_call
,
602 .cb_barrier
= srcu_torture_barrier
,
603 .stats
= srcu_torture_stats
,
608 * Definitions for sched torture testing.
611 static int sched_torture_read_lock(void)
617 static void sched_torture_read_unlock(int idx
)
622 static void rcu_sched_torture_deferred_free(struct rcu_torture
*p
)
624 call_rcu_sched(&p
->rtort_rcu
, rcu_torture_cb
);
627 static struct rcu_torture_ops sched_ops
= {
628 .ttype
= RCU_SCHED_FLAVOR
,
629 .init
= rcu_sync_torture_init
,
630 .readlock
= sched_torture_read_lock
,
631 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
632 .readunlock
= sched_torture_read_unlock
,
633 .started
= rcu_batches_started_sched
,
634 .completed
= rcu_batches_completed_sched
,
635 .deferred_free
= rcu_sched_torture_deferred_free
,
636 .sync
= synchronize_sched
,
637 .exp_sync
= synchronize_sched_expedited
,
638 .get_state
= get_state_synchronize_sched
,
639 .cond_sync
= cond_synchronize_sched
,
640 .call
= call_rcu_sched
,
641 .cb_barrier
= rcu_barrier_sched
,
642 .fqs
= rcu_sched_force_quiescent_state
,
648 #ifdef CONFIG_TASKS_RCU
651 * Definitions for RCU-tasks torture testing.
654 static int tasks_torture_read_lock(void)
659 static void tasks_torture_read_unlock(int idx
)
663 static void rcu_tasks_torture_deferred_free(struct rcu_torture
*p
)
665 call_rcu_tasks(&p
->rtort_rcu
, rcu_torture_cb
);
668 static struct rcu_torture_ops tasks_ops
= {
669 .ttype
= RCU_TASKS_FLAVOR
,
670 .init
= rcu_sync_torture_init
,
671 .readlock
= tasks_torture_read_lock
,
672 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
673 .readunlock
= tasks_torture_read_unlock
,
674 .started
= rcu_no_completed
,
675 .completed
= rcu_no_completed
,
676 .deferred_free
= rcu_tasks_torture_deferred_free
,
677 .sync
= synchronize_rcu_tasks
,
678 .exp_sync
= synchronize_rcu_tasks
,
679 .call
= call_rcu_tasks
,
680 .cb_barrier
= rcu_barrier_tasks
,
687 #define RCUTORTURE_TASKS_OPS &tasks_ops,
689 static bool __maybe_unused
torturing_tasks(void)
691 return cur_ops
== &tasks_ops
;
694 #else /* #ifdef CONFIG_TASKS_RCU */
696 #define RCUTORTURE_TASKS_OPS
698 static bool torturing_tasks(void)
703 #endif /* #else #ifdef CONFIG_TASKS_RCU */
706 * RCU torture priority-boost testing. Runs one real-time thread per
707 * CPU for moderate bursts, repeatedly registering RCU callbacks and
708 * spinning waiting for them to be invoked. If a given callback takes
709 * too long to be invoked, we assume that priority inversion has occurred.
712 struct rcu_boost_inflight
{
717 static void rcu_torture_boost_cb(struct rcu_head
*head
)
719 struct rcu_boost_inflight
*rbip
=
720 container_of(head
, struct rcu_boost_inflight
, rcu
);
722 /* Ensure RCU-core accesses precede clearing ->inflight */
723 smp_store_release(&rbip
->inflight
, 0);
726 static int rcu_torture_boost(void *arg
)
728 unsigned long call_rcu_time
;
729 unsigned long endtime
;
730 unsigned long oldstarttime
;
731 struct rcu_boost_inflight rbi
= { .inflight
= 0 };
732 struct sched_param sp
;
734 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
736 /* Set real-time priority. */
737 sp
.sched_priority
= 1;
738 if (sched_setscheduler(current
, SCHED_FIFO
, &sp
) < 0) {
739 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
740 n_rcu_torture_boost_rterror
++;
743 init_rcu_head_on_stack(&rbi
.rcu
);
744 /* Each pass through the following loop does one boost-test cycle. */
746 /* Wait for the next test interval. */
747 oldstarttime
= boost_starttime
;
748 while (ULONG_CMP_LT(jiffies
, oldstarttime
)) {
749 schedule_timeout_interruptible(oldstarttime
- jiffies
);
750 stutter_wait("rcu_torture_boost");
751 if (torture_must_stop())
755 /* Do one boost-test interval. */
756 endtime
= oldstarttime
+ test_boost_duration
* HZ
;
757 call_rcu_time
= jiffies
;
758 while (ULONG_CMP_LT(jiffies
, endtime
)) {
759 /* If we don't have a callback in flight, post one. */
760 if (!smp_load_acquire(&rbi
.inflight
)) {
761 /* RCU core before ->inflight = 1. */
762 smp_store_release(&rbi
.inflight
, 1);
763 call_rcu(&rbi
.rcu
, rcu_torture_boost_cb
);
764 if (jiffies
- call_rcu_time
>
765 test_boost_duration
* HZ
- HZ
/ 2) {
766 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
767 n_rcu_torture_boost_failure
++;
769 call_rcu_time
= jiffies
;
771 cond_resched_rcu_qs();
772 stutter_wait("rcu_torture_boost");
773 if (torture_must_stop())
778 * Set the start time of the next test interval.
779 * Yes, this is vulnerable to long delays, but such
780 * delays simply cause a false negative for the next
781 * interval. Besides, we are running at RT priority,
782 * so delays should be relatively rare.
784 while (oldstarttime
== boost_starttime
&&
785 !kthread_should_stop()) {
786 if (mutex_trylock(&boost_mutex
)) {
787 boost_starttime
= jiffies
+
788 test_boost_interval
* HZ
;
789 n_rcu_torture_boosts
++;
790 mutex_unlock(&boost_mutex
);
793 schedule_timeout_uninterruptible(1);
796 /* Go do the stutter. */
797 checkwait
: stutter_wait("rcu_torture_boost");
798 } while (!torture_must_stop());
800 /* Clean up and exit. */
801 while (!kthread_should_stop() || smp_load_acquire(&rbi
.inflight
)) {
802 torture_shutdown_absorb("rcu_torture_boost");
803 schedule_timeout_uninterruptible(1);
805 destroy_rcu_head_on_stack(&rbi
.rcu
);
806 torture_kthread_stopping("rcu_torture_boost");
810 static void rcu_torture_cbflood_cb(struct rcu_head
*rhp
)
815 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
816 * to call_rcu() or analogous, increasing the probability of occurrence
817 * of callback-overflow corner cases.
820 rcu_torture_cbflood(void *arg
)
825 struct rcu_head
*rhp
;
827 if (cbflood_n_per_burst
> 0 &&
828 cbflood_inter_holdoff
> 0 &&
829 cbflood_intra_holdoff
> 0 &&
831 cur_ops
->cb_barrier
) {
832 rhp
= vmalloc(sizeof(*rhp
) *
833 cbflood_n_burst
* cbflood_n_per_burst
);
837 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
840 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
842 schedule_timeout_interruptible(cbflood_inter_holdoff
);
843 atomic_long_inc(&n_cbfloods
);
844 WARN_ON(signal_pending(current
));
845 for (i
= 0; i
< cbflood_n_burst
; i
++) {
846 for (j
= 0; j
< cbflood_n_per_burst
; j
++) {
847 cur_ops
->call(&rhp
[i
* cbflood_n_per_burst
+ j
],
848 rcu_torture_cbflood_cb
);
850 schedule_timeout_interruptible(cbflood_intra_holdoff
);
851 WARN_ON(signal_pending(current
));
853 cur_ops
->cb_barrier();
854 stutter_wait("rcu_torture_cbflood");
855 } while (!torture_must_stop());
858 torture_kthread_stopping("rcu_torture_cbflood");
863 * RCU torture force-quiescent-state kthread. Repeatedly induces
864 * bursts of calls to force_quiescent_state(), increasing the probability
865 * of occurrence of some important types of race conditions.
868 rcu_torture_fqs(void *arg
)
870 unsigned long fqs_resume_time
;
871 int fqs_burst_remaining
;
873 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
875 fqs_resume_time
= jiffies
+ fqs_stutter
* HZ
;
876 while (ULONG_CMP_LT(jiffies
, fqs_resume_time
) &&
877 !kthread_should_stop()) {
878 schedule_timeout_interruptible(1);
880 fqs_burst_remaining
= fqs_duration
;
881 while (fqs_burst_remaining
> 0 &&
882 !kthread_should_stop()) {
885 fqs_burst_remaining
-= fqs_holdoff
;
887 stutter_wait("rcu_torture_fqs");
888 } while (!torture_must_stop());
889 torture_kthread_stopping("rcu_torture_fqs");
894 * RCU torture writer kthread. Repeatedly substitutes a new structure
895 * for that pointed to by rcu_torture_current, freeing the old structure
896 * after a series of grace periods (the "pipeline").
899 rcu_torture_writer(void *arg
)
901 bool can_expedite
= !rcu_gp_is_expedited();
903 unsigned long gp_snap
;
904 bool gp_cond1
= gp_cond
, gp_exp1
= gp_exp
, gp_normal1
= gp_normal
;
905 bool gp_sync1
= gp_sync
;
907 struct rcu_torture
*rp
;
908 struct rcu_torture
*old_rp
;
909 static DEFINE_TORTURE_RANDOM(rand
);
910 int synctype
[] = { RTWS_DEF_FREE
, RTWS_EXP_SYNC
,
911 RTWS_COND_GET
, RTWS_SYNC
};
914 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
915 pr_alert("%s" TORTURE_FLAG
916 " Grace periods expedited from boot/sysfs for %s,\n",
917 torture_type
, cur_ops
->name
);
918 pr_alert("%s" TORTURE_FLAG
919 " Testing of dynamic grace-period expediting diabled.\n",
922 /* Initialize synctype[] array. If none set, take default. */
923 if (!gp_cond1
&& !gp_exp1
&& !gp_normal1
&& !gp_sync1
)
924 gp_cond1
= gp_exp1
= gp_normal1
= gp_sync1
= true;
925 if (gp_cond1
&& cur_ops
->get_state
&& cur_ops
->cond_sync
)
926 synctype
[nsynctypes
++] = RTWS_COND_GET
;
927 else if (gp_cond
&& (!cur_ops
->get_state
|| !cur_ops
->cond_sync
))
928 pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
929 if (gp_exp1
&& cur_ops
->exp_sync
)
930 synctype
[nsynctypes
++] = RTWS_EXP_SYNC
;
931 else if (gp_exp
&& !cur_ops
->exp_sync
)
932 pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
933 if (gp_normal1
&& cur_ops
->deferred_free
)
934 synctype
[nsynctypes
++] = RTWS_DEF_FREE
;
935 else if (gp_normal
&& !cur_ops
->deferred_free
)
936 pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
937 if (gp_sync1
&& cur_ops
->sync
)
938 synctype
[nsynctypes
++] = RTWS_SYNC
;
939 else if (gp_sync
&& !cur_ops
->sync
)
940 pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
941 if (WARN_ONCE(nsynctypes
== 0,
942 "rcu_torture_writer: No update-side primitives.\n")) {
944 * No updates primitives, so don't try updating.
945 * The resulting test won't be testing much, hence the
948 rcu_torture_writer_state
= RTWS_STOPPING
;
949 torture_kthread_stopping("rcu_torture_writer");
953 rcu_torture_writer_state
= RTWS_FIXED_DELAY
;
954 schedule_timeout_uninterruptible(1);
955 rp
= rcu_torture_alloc();
958 rp
->rtort_pipe_count
= 0;
959 rcu_torture_writer_state
= RTWS_DELAY
;
960 udelay(torture_random(&rand
) & 0x3ff);
961 rcu_torture_writer_state
= RTWS_REPLACE
;
962 old_rp
= rcu_dereference_check(rcu_torture_current
,
963 current
== writer_task
);
964 rp
->rtort_mbtest
= 1;
965 rcu_assign_pointer(rcu_torture_current
, rp
);
966 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
968 i
= old_rp
->rtort_pipe_count
;
969 if (i
> RCU_TORTURE_PIPE_LEN
)
970 i
= RCU_TORTURE_PIPE_LEN
;
971 atomic_inc(&rcu_torture_wcount
[i
]);
972 old_rp
->rtort_pipe_count
++;
973 switch (synctype
[torture_random(&rand
) % nsynctypes
]) {
975 rcu_torture_writer_state
= RTWS_DEF_FREE
;
976 cur_ops
->deferred_free(old_rp
);
979 rcu_torture_writer_state
= RTWS_EXP_SYNC
;
981 rcu_torture_pipe_update(old_rp
);
984 rcu_torture_writer_state
= RTWS_COND_GET
;
985 gp_snap
= cur_ops
->get_state();
986 i
= torture_random(&rand
) % 16;
988 schedule_timeout_interruptible(i
);
989 udelay(torture_random(&rand
) % 1000);
990 rcu_torture_writer_state
= RTWS_COND_SYNC
;
991 cur_ops
->cond_sync(gp_snap
);
992 rcu_torture_pipe_update(old_rp
);
995 rcu_torture_writer_state
= RTWS_SYNC
;
997 rcu_torture_pipe_update(old_rp
);
1004 rcutorture_record_progress(++rcu_torture_current_version
);
1005 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1007 !(torture_random(&rand
) & 0xff & (!!expediting
- 1))) {
1008 WARN_ON_ONCE(expediting
== 0 && rcu_gp_is_expedited());
1009 if (expediting
>= 0)
1012 rcu_unexpedite_gp();
1013 if (++expediting
> 3)
1014 expediting
= -expediting
;
1016 rcu_torture_writer_state
= RTWS_STUTTER
;
1017 stutter_wait("rcu_torture_writer");
1018 } while (!torture_must_stop());
1019 /* Reset expediting back to unexpedited. */
1021 expediting
= -expediting
;
1022 while (can_expedite
&& expediting
++ < 0)
1023 rcu_unexpedite_gp();
1024 WARN_ON_ONCE(can_expedite
&& rcu_gp_is_expedited());
1025 rcu_torture_writer_state
= RTWS_STOPPING
;
1026 torture_kthread_stopping("rcu_torture_writer");
1031 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1032 * delay between calls.
1035 rcu_torture_fakewriter(void *arg
)
1037 DEFINE_TORTURE_RANDOM(rand
);
1039 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1040 set_user_nice(current
, MAX_NICE
);
1043 schedule_timeout_uninterruptible(1 + torture_random(&rand
)%10);
1044 udelay(torture_random(&rand
) & 0x3ff);
1045 if (cur_ops
->cb_barrier
!= NULL
&&
1046 torture_random(&rand
) % (nfakewriters
* 8) == 0) {
1047 cur_ops
->cb_barrier();
1048 } else if (gp_normal
== gp_exp
) {
1049 if (torture_random(&rand
) & 0x80)
1052 cur_ops
->exp_sync();
1053 } else if (gp_normal
) {
1056 cur_ops
->exp_sync();
1058 stutter_wait("rcu_torture_fakewriter");
1059 } while (!torture_must_stop());
1061 torture_kthread_stopping("rcu_torture_fakewriter");
1065 static void rcutorture_trace_dump(void)
1067 static atomic_t beenhere
= ATOMIC_INIT(0);
1069 if (atomic_read(&beenhere
))
1071 if (atomic_xchg(&beenhere
, 1) != 0)
1073 ftrace_dump(DUMP_ALL
);
1077 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1078 * incrementing the corresponding element of the pipeline array. The
1079 * counter in the element should never be greater than 1, otherwise, the
1080 * RCU implementation is broken.
1082 static void rcu_torture_timer(unsigned long unused
)
1085 unsigned long started
;
1086 unsigned long completed
;
1087 static DEFINE_TORTURE_RANDOM(rand
);
1088 static DEFINE_SPINLOCK(rand_lock
);
1089 struct rcu_torture
*p
;
1091 unsigned long long ts
;
1093 idx
= cur_ops
->readlock();
1094 if (cur_ops
->started
)
1095 started
= cur_ops
->started();
1097 started
= cur_ops
->completed();
1098 ts
= rcu_trace_clock_local();
1099 p
= rcu_dereference_check(rcu_torture_current
,
1100 rcu_read_lock_bh_held() ||
1101 rcu_read_lock_sched_held() ||
1102 srcu_read_lock_held(srcu_ctlp
) ||
1105 /* Leave because rcu_torture_writer is not yet underway */
1106 cur_ops
->readunlock(idx
);
1109 if (p
->rtort_mbtest
== 0)
1110 atomic_inc(&n_rcu_torture_mberror
);
1111 spin_lock(&rand_lock
);
1112 cur_ops
->read_delay(&rand
);
1113 n_rcu_torture_timers
++;
1114 spin_unlock(&rand_lock
);
1116 pipe_count
= p
->rtort_pipe_count
;
1117 if (pipe_count
> RCU_TORTURE_PIPE_LEN
) {
1118 /* Should not happen, but... */
1119 pipe_count
= RCU_TORTURE_PIPE_LEN
;
1121 completed
= cur_ops
->completed();
1122 if (pipe_count
> 1) {
1123 do_trace_rcu_torture_read(cur_ops
->name
, &p
->rtort_rcu
, ts
,
1124 started
, completed
);
1125 rcutorture_trace_dump();
1127 __this_cpu_inc(rcu_torture_count
[pipe_count
]);
1128 completed
= completed
- started
;
1129 if (cur_ops
->started
)
1131 if (completed
> RCU_TORTURE_PIPE_LEN
) {
1132 /* Should not happen, but... */
1133 completed
= RCU_TORTURE_PIPE_LEN
;
1135 __this_cpu_inc(rcu_torture_batch
[completed
]);
1137 cur_ops
->readunlock(idx
);
1141 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1142 * incrementing the corresponding element of the pipeline array. The
1143 * counter in the element should never be greater than 1, otherwise, the
1144 * RCU implementation is broken.
1147 rcu_torture_reader(void *arg
)
1149 unsigned long started
;
1150 unsigned long completed
;
1152 DEFINE_TORTURE_RANDOM(rand
);
1153 struct rcu_torture
*p
;
1155 struct timer_list t
;
1156 unsigned long long ts
;
1158 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1159 set_user_nice(current
, MAX_NICE
);
1160 if (irqreader
&& cur_ops
->irq_capable
)
1161 setup_timer_on_stack(&t
, rcu_torture_timer
, 0);
1164 if (irqreader
&& cur_ops
->irq_capable
) {
1165 if (!timer_pending(&t
))
1166 mod_timer(&t
, jiffies
+ 1);
1168 idx
= cur_ops
->readlock();
1169 if (cur_ops
->started
)
1170 started
= cur_ops
->started();
1172 started
= cur_ops
->completed();
1173 ts
= rcu_trace_clock_local();
1174 p
= rcu_dereference_check(rcu_torture_current
,
1175 rcu_read_lock_bh_held() ||
1176 rcu_read_lock_sched_held() ||
1177 srcu_read_lock_held(srcu_ctlp
) ||
1180 /* Wait for rcu_torture_writer to get underway */
1181 cur_ops
->readunlock(idx
);
1182 schedule_timeout_interruptible(HZ
);
1185 if (p
->rtort_mbtest
== 0)
1186 atomic_inc(&n_rcu_torture_mberror
);
1187 cur_ops
->read_delay(&rand
);
1189 pipe_count
= p
->rtort_pipe_count
;
1190 if (pipe_count
> RCU_TORTURE_PIPE_LEN
) {
1191 /* Should not happen, but... */
1192 pipe_count
= RCU_TORTURE_PIPE_LEN
;
1194 completed
= cur_ops
->completed();
1195 if (pipe_count
> 1) {
1196 do_trace_rcu_torture_read(cur_ops
->name
, &p
->rtort_rcu
,
1197 ts
, started
, completed
);
1198 rcutorture_trace_dump();
1200 __this_cpu_inc(rcu_torture_count
[pipe_count
]);
1201 completed
= completed
- started
;
1202 if (cur_ops
->started
)
1204 if (completed
> RCU_TORTURE_PIPE_LEN
) {
1205 /* Should not happen, but... */
1206 completed
= RCU_TORTURE_PIPE_LEN
;
1208 __this_cpu_inc(rcu_torture_batch
[completed
]);
1210 cur_ops
->readunlock(idx
);
1211 cond_resched_rcu_qs();
1212 stutter_wait("rcu_torture_reader");
1213 } while (!torture_must_stop());
1214 if (irqreader
&& cur_ops
->irq_capable
) {
1216 destroy_timer_on_stack(&t
);
1218 torture_kthread_stopping("rcu_torture_reader");
1223 * Print torture statistics. Caller must ensure that there is only
1224 * one call to this function at a given time!!! This is normally
1225 * accomplished by relying on the module system to only have one copy
1226 * of the module loaded, and then by giving the rcu_torture_stats
1227 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1228 * thread is not running).
1231 rcu_torture_stats_print(void)
1235 long pipesummary
[RCU_TORTURE_PIPE_LEN
+ 1] = { 0 };
1236 long batchsummary
[RCU_TORTURE_PIPE_LEN
+ 1] = { 0 };
1237 static unsigned long rtcv_snap
= ULONG_MAX
;
1239 for_each_possible_cpu(cpu
) {
1240 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
1241 pipesummary
[i
] += per_cpu(rcu_torture_count
, cpu
)[i
];
1242 batchsummary
[i
] += per_cpu(rcu_torture_batch
, cpu
)[i
];
1245 for (i
= RCU_TORTURE_PIPE_LEN
- 1; i
>= 0; i
--) {
1246 if (pipesummary
[i
] != 0)
1250 pr_alert("%s%s ", torture_type
, TORTURE_FLAG
);
1251 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1252 rcu_torture_current
,
1253 rcu_torture_current_version
,
1254 list_empty(&rcu_torture_freelist
),
1255 atomic_read(&n_rcu_torture_alloc
),
1256 atomic_read(&n_rcu_torture_alloc_fail
),
1257 atomic_read(&n_rcu_torture_free
));
1258 pr_cont("rtmbe: %d rtbke: %ld rtbre: %ld ",
1259 atomic_read(&n_rcu_torture_mberror
),
1260 n_rcu_torture_boost_ktrerror
,
1261 n_rcu_torture_boost_rterror
);
1262 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1263 n_rcu_torture_boost_failure
,
1264 n_rcu_torture_boosts
,
1265 n_rcu_torture_timers
);
1266 torture_onoff_stats();
1267 pr_cont("barrier: %ld/%ld:%ld ",
1268 n_barrier_successes
,
1270 n_rcu_torture_barrier_error
);
1271 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods
));
1273 pr_alert("%s%s ", torture_type
, TORTURE_FLAG
);
1274 if (atomic_read(&n_rcu_torture_mberror
) != 0 ||
1275 n_rcu_torture_barrier_error
!= 0 ||
1276 n_rcu_torture_boost_ktrerror
!= 0 ||
1277 n_rcu_torture_boost_rterror
!= 0 ||
1278 n_rcu_torture_boost_failure
!= 0 ||
1280 pr_cont("%s", "!!! ");
1281 atomic_inc(&n_rcu_torture_error
);
1284 pr_cont("Reader Pipe: ");
1285 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
1286 pr_cont(" %ld", pipesummary
[i
]);
1289 pr_alert("%s%s ", torture_type
, TORTURE_FLAG
);
1290 pr_cont("Reader Batch: ");
1291 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
1292 pr_cont(" %ld", batchsummary
[i
]);
1295 pr_alert("%s%s ", torture_type
, TORTURE_FLAG
);
1296 pr_cont("Free-Block Circulation: ");
1297 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
1298 pr_cont(" %d", atomic_read(&rcu_torture_wcount
[i
]));
1304 if (rtcv_snap
== rcu_torture_current_version
&&
1305 rcu_torture_current
!= NULL
) {
1306 int __maybe_unused flags
;
1307 unsigned long __maybe_unused gpnum
;
1308 unsigned long __maybe_unused completed
;
1310 rcutorture_get_gp_data(cur_ops
->ttype
,
1311 &flags
, &gpnum
, &completed
);
1312 pr_alert("??? Writer stall state %d g%lu c%lu f%#x\n",
1313 rcu_torture_writer_state
,
1314 gpnum
, completed
, flags
);
1315 show_rcu_gp_kthreads();
1316 rcutorture_trace_dump();
1318 rtcv_snap
= rcu_torture_current_version
;
1322 * Periodically prints torture statistics, if periodic statistics printing
1323 * was specified via the stat_interval module parameter.
1326 rcu_torture_stats(void *arg
)
1328 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1330 schedule_timeout_interruptible(stat_interval
* HZ
);
1331 rcu_torture_stats_print();
1332 torture_shutdown_absorb("rcu_torture_stats");
1333 } while (!torture_must_stop());
1334 torture_kthread_stopping("rcu_torture_stats");
1339 rcu_torture_print_module_parms(struct rcu_torture_ops
*cur_ops
, const char *tag
)
1341 pr_alert("%s" TORTURE_FLAG
1342 "--- %s: nreaders=%d nfakewriters=%d "
1343 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1344 "shuffle_interval=%d stutter=%d irqreader=%d "
1345 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1346 "test_boost=%d/%d test_boost_interval=%d "
1347 "test_boost_duration=%d shutdown_secs=%d "
1348 "stall_cpu=%d stall_cpu_holdoff=%d "
1350 "onoff_interval=%d onoff_holdoff=%d\n",
1351 torture_type
, tag
, nrealreaders
, nfakewriters
,
1352 stat_interval
, verbose
, test_no_idle_hz
, shuffle_interval
,
1353 stutter
, irqreader
, fqs_duration
, fqs_holdoff
, fqs_stutter
,
1354 test_boost
, cur_ops
->can_boost
,
1355 test_boost_interval
, test_boost_duration
, shutdown_secs
,
1356 stall_cpu
, stall_cpu_holdoff
,
1358 onoff_interval
, onoff_holdoff
);
1361 static void rcutorture_booster_cleanup(int cpu
)
1363 struct task_struct
*t
;
1365 if (boost_tasks
[cpu
] == NULL
)
1367 mutex_lock(&boost_mutex
);
1368 t
= boost_tasks
[cpu
];
1369 boost_tasks
[cpu
] = NULL
;
1370 mutex_unlock(&boost_mutex
);
1372 /* This must be outside of the mutex, otherwise deadlock! */
1373 torture_stop_kthread(rcu_torture_boost
, t
);
1376 static int rcutorture_booster_init(int cpu
)
1380 if (boost_tasks
[cpu
] != NULL
)
1381 return 0; /* Already created, nothing more to do. */
1383 /* Don't allow time recalculation while creating a new task. */
1384 mutex_lock(&boost_mutex
);
1385 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1386 boost_tasks
[cpu
] = kthread_create_on_node(rcu_torture_boost
, NULL
,
1388 "rcu_torture_boost");
1389 if (IS_ERR(boost_tasks
[cpu
])) {
1390 retval
= PTR_ERR(boost_tasks
[cpu
]);
1391 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1392 n_rcu_torture_boost_ktrerror
++;
1393 boost_tasks
[cpu
] = NULL
;
1394 mutex_unlock(&boost_mutex
);
1397 kthread_bind(boost_tasks
[cpu
], cpu
);
1398 wake_up_process(boost_tasks
[cpu
]);
1399 mutex_unlock(&boost_mutex
);
1404 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1405 * induces a CPU stall for the time specified by stall_cpu.
1407 static int rcu_torture_stall(void *args
)
1409 unsigned long stop_at
;
1411 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1412 if (stall_cpu_holdoff
> 0) {
1413 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1414 schedule_timeout_interruptible(stall_cpu_holdoff
* HZ
);
1415 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1417 if (!kthread_should_stop()) {
1418 stop_at
= get_seconds() + stall_cpu
;
1419 /* RCU CPU stall is expected behavior in following code. */
1420 pr_alert("rcu_torture_stall start.\n");
1423 while (ULONG_CMP_LT(get_seconds(), stop_at
))
1424 continue; /* Induce RCU CPU stall warning. */
1427 pr_alert("rcu_torture_stall end.\n");
1429 torture_shutdown_absorb("rcu_torture_stall");
1430 while (!kthread_should_stop())
1431 schedule_timeout_interruptible(10 * HZ
);
1435 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1436 static int __init
rcu_torture_stall_init(void)
1440 return torture_create_kthread(rcu_torture_stall
, NULL
, stall_task
);
1443 /* Callback function for RCU barrier testing. */
1444 static void rcu_torture_barrier_cbf(struct rcu_head
*rcu
)
1446 atomic_inc(&barrier_cbs_invoked
);
1449 /* kthread function to register callbacks used to test RCU barriers. */
1450 static int rcu_torture_barrier_cbs(void *arg
)
1452 long myid
= (long)arg
;
1455 struct rcu_head rcu
;
1457 init_rcu_head_on_stack(&rcu
);
1458 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1459 set_user_nice(current
, MAX_NICE
);
1461 wait_event(barrier_cbs_wq
[myid
],
1463 smp_load_acquire(&barrier_phase
)) != lastphase
||
1464 torture_must_stop());
1465 lastphase
= newphase
;
1466 if (torture_must_stop())
1469 * The above smp_load_acquire() ensures barrier_phase load
1470 * is ordered before the folloiwng ->call().
1472 cur_ops
->call(&rcu
, rcu_torture_barrier_cbf
);
1473 if (atomic_dec_and_test(&barrier_cbs_count
))
1474 wake_up(&barrier_wq
);
1475 } while (!torture_must_stop());
1476 if (cur_ops
->cb_barrier
!= NULL
)
1477 cur_ops
->cb_barrier();
1478 destroy_rcu_head_on_stack(&rcu
);
1479 torture_kthread_stopping("rcu_torture_barrier_cbs");
1483 /* kthread function to drive and coordinate RCU barrier testing. */
1484 static int rcu_torture_barrier(void *arg
)
1488 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1490 atomic_set(&barrier_cbs_invoked
, 0);
1491 atomic_set(&barrier_cbs_count
, n_barrier_cbs
);
1492 /* Ensure barrier_phase ordered after prior assignments. */
1493 smp_store_release(&barrier_phase
, !barrier_phase
);
1494 for (i
= 0; i
< n_barrier_cbs
; i
++)
1495 wake_up(&barrier_cbs_wq
[i
]);
1496 wait_event(barrier_wq
,
1497 atomic_read(&barrier_cbs_count
) == 0 ||
1498 torture_must_stop());
1499 if (torture_must_stop())
1501 n_barrier_attempts
++;
1502 cur_ops
->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1503 if (atomic_read(&barrier_cbs_invoked
) != n_barrier_cbs
) {
1504 n_rcu_torture_barrier_error
++;
1505 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1506 atomic_read(&barrier_cbs_invoked
),
1510 n_barrier_successes
++;
1511 schedule_timeout_interruptible(HZ
/ 10);
1512 } while (!torture_must_stop());
1513 torture_kthread_stopping("rcu_torture_barrier");
1517 /* Initialize RCU barrier testing. */
1518 static int rcu_torture_barrier_init(void)
1523 if (n_barrier_cbs
<= 0)
1525 if (cur_ops
->call
== NULL
|| cur_ops
->cb_barrier
== NULL
) {
1526 pr_alert("%s" TORTURE_FLAG
1527 " Call or barrier ops missing for %s,\n",
1528 torture_type
, cur_ops
->name
);
1529 pr_alert("%s" TORTURE_FLAG
1530 " RCU barrier testing omitted from run.\n",
1534 atomic_set(&barrier_cbs_count
, 0);
1535 atomic_set(&barrier_cbs_invoked
, 0);
1537 kzalloc(n_barrier_cbs
* sizeof(barrier_cbs_tasks
[0]),
1540 kzalloc(n_barrier_cbs
* sizeof(barrier_cbs_wq
[0]),
1542 if (barrier_cbs_tasks
== NULL
|| !barrier_cbs_wq
)
1544 for (i
= 0; i
< n_barrier_cbs
; i
++) {
1545 init_waitqueue_head(&barrier_cbs_wq
[i
]);
1546 ret
= torture_create_kthread(rcu_torture_barrier_cbs
,
1548 barrier_cbs_tasks
[i
]);
1552 return torture_create_kthread(rcu_torture_barrier
, NULL
, barrier_task
);
1555 /* Clean up after RCU barrier testing. */
1556 static void rcu_torture_barrier_cleanup(void)
1560 torture_stop_kthread(rcu_torture_barrier
, barrier_task
);
1561 if (barrier_cbs_tasks
!= NULL
) {
1562 for (i
= 0; i
< n_barrier_cbs
; i
++)
1563 torture_stop_kthread(rcu_torture_barrier_cbs
,
1564 barrier_cbs_tasks
[i
]);
1565 kfree(barrier_cbs_tasks
);
1566 barrier_cbs_tasks
= NULL
;
1568 if (barrier_cbs_wq
!= NULL
) {
1569 kfree(barrier_cbs_wq
);
1570 barrier_cbs_wq
= NULL
;
1574 static int rcutorture_cpu_notify(struct notifier_block
*self
,
1575 unsigned long action
, void *hcpu
)
1577 long cpu
= (long)hcpu
;
1581 case CPU_DOWN_FAILED
:
1582 (void)rcutorture_booster_init(cpu
);
1584 case CPU_DOWN_PREPARE
:
1585 rcutorture_booster_cleanup(cpu
);
1593 static struct notifier_block rcutorture_cpu_nb
= {
1594 .notifier_call
= rcutorture_cpu_notify
,
1598 rcu_torture_cleanup(void)
1602 rcutorture_record_test_transition();
1603 if (torture_cleanup_begin()) {
1604 if (cur_ops
->cb_barrier
!= NULL
)
1605 cur_ops
->cb_barrier();
1609 rcu_torture_barrier_cleanup();
1610 torture_stop_kthread(rcu_torture_stall
, stall_task
);
1611 torture_stop_kthread(rcu_torture_writer
, writer_task
);
1614 for (i
= 0; i
< nrealreaders
; i
++)
1615 torture_stop_kthread(rcu_torture_reader
,
1617 kfree(reader_tasks
);
1619 rcu_torture_current
= NULL
;
1621 if (fakewriter_tasks
) {
1622 for (i
= 0; i
< nfakewriters
; i
++) {
1623 torture_stop_kthread(rcu_torture_fakewriter
,
1624 fakewriter_tasks
[i
]);
1626 kfree(fakewriter_tasks
);
1627 fakewriter_tasks
= NULL
;
1630 torture_stop_kthread(rcu_torture_stats
, stats_task
);
1631 torture_stop_kthread(rcu_torture_fqs
, fqs_task
);
1632 for (i
= 0; i
< ncbflooders
; i
++)
1633 torture_stop_kthread(rcu_torture_cbflood
, cbflood_task
[i
]);
1634 if ((test_boost
== 1 && cur_ops
->can_boost
) ||
1636 unregister_cpu_notifier(&rcutorture_cpu_nb
);
1637 for_each_possible_cpu(i
)
1638 rcutorture_booster_cleanup(i
);
1642 * Wait for all RCU callbacks to fire, then do flavor-specific
1643 * cleanup operations.
1645 if (cur_ops
->cb_barrier
!= NULL
)
1646 cur_ops
->cb_barrier();
1647 if (cur_ops
->cleanup
!= NULL
)
1650 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1652 if (atomic_read(&n_rcu_torture_error
) || n_rcu_torture_barrier_error
)
1653 rcu_torture_print_module_parms(cur_ops
, "End of test: FAILURE");
1654 else if (torture_onoff_failures())
1655 rcu_torture_print_module_parms(cur_ops
,
1656 "End of test: RCU_HOTPLUG");
1658 rcu_torture_print_module_parms(cur_ops
, "End of test: SUCCESS");
1659 torture_cleanup_end();
1662 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1663 static void rcu_torture_leak_cb(struct rcu_head
*rhp
)
1667 static void rcu_torture_err_cb(struct rcu_head
*rhp
)
1670 * This -might- happen due to race conditions, but is unlikely.
1671 * The scenario that leads to this happening is that the
1672 * first of the pair of duplicate callbacks is queued,
1673 * someone else starts a grace period that includes that
1674 * callback, then the second of the pair must wait for the
1675 * next grace period. Unlikely, but can happen. If it
1676 * does happen, the debug-objects subsystem won't have splatted.
1678 pr_alert("rcutorture: duplicated callback was invoked.\n");
1680 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1683 * Verify that double-free causes debug-objects to complain, but only
1684 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1685 * cannot be carried out.
1687 static void rcu_test_debug_objects(void)
1689 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1690 struct rcu_head rh1
;
1691 struct rcu_head rh2
;
1693 init_rcu_head_on_stack(&rh1
);
1694 init_rcu_head_on_stack(&rh2
);
1695 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1697 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1698 preempt_disable(); /* Prevent preemption from interrupting test. */
1699 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1700 call_rcu(&rh1
, rcu_torture_leak_cb
); /* Start grace period. */
1701 local_irq_disable(); /* Make it harder to start a new grace period. */
1702 call_rcu(&rh2
, rcu_torture_leak_cb
);
1703 call_rcu(&rh2
, rcu_torture_err_cb
); /* Duplicate callback. */
1708 /* Wait for them all to get done so we can safely return. */
1710 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1711 destroy_rcu_head_on_stack(&rh1
);
1712 destroy_rcu_head_on_stack(&rh2
);
1713 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1714 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1715 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1719 rcu_torture_init(void)
1724 static struct rcu_torture_ops
*torture_ops
[] = {
1725 &rcu_ops
, &rcu_bh_ops
, &rcu_busted_ops
, &srcu_ops
, &srcud_ops
,
1726 &sched_ops
, RCUTORTURE_TASKS_OPS
1729 if (!torture_init_begin(torture_type
, verbose
, &torture_runnable
))
1732 /* Process args and tell the world that the torturer is on the job. */
1733 for (i
= 0; i
< ARRAY_SIZE(torture_ops
); i
++) {
1734 cur_ops
= torture_ops
[i
];
1735 if (strcmp(torture_type
, cur_ops
->name
) == 0)
1738 if (i
== ARRAY_SIZE(torture_ops
)) {
1739 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1741 pr_alert("rcu-torture types:");
1742 for (i
= 0; i
< ARRAY_SIZE(torture_ops
); i
++)
1743 pr_alert(" %s", torture_ops
[i
]->name
);
1748 if (cur_ops
->fqs
== NULL
&& fqs_duration
!= 0) {
1749 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1753 cur_ops
->init(); /* no "goto unwind" prior to this point!!! */
1755 if (nreaders
>= 0) {
1756 nrealreaders
= nreaders
;
1758 nrealreaders
= num_online_cpus() - 2 - nreaders
;
1759 if (nrealreaders
<= 0)
1762 rcu_torture_print_module_parms(cur_ops
, "Start of test");
1764 /* Set up the freelist. */
1766 INIT_LIST_HEAD(&rcu_torture_freelist
);
1767 for (i
= 0; i
< ARRAY_SIZE(rcu_tortures
); i
++) {
1768 rcu_tortures
[i
].rtort_mbtest
= 0;
1769 list_add_tail(&rcu_tortures
[i
].rtort_free
,
1770 &rcu_torture_freelist
);
1773 /* Initialize the statistics so that each run gets its own numbers. */
1775 rcu_torture_current
= NULL
;
1776 rcu_torture_current_version
= 0;
1777 atomic_set(&n_rcu_torture_alloc
, 0);
1778 atomic_set(&n_rcu_torture_alloc_fail
, 0);
1779 atomic_set(&n_rcu_torture_free
, 0);
1780 atomic_set(&n_rcu_torture_mberror
, 0);
1781 atomic_set(&n_rcu_torture_error
, 0);
1782 n_rcu_torture_barrier_error
= 0;
1783 n_rcu_torture_boost_ktrerror
= 0;
1784 n_rcu_torture_boost_rterror
= 0;
1785 n_rcu_torture_boost_failure
= 0;
1786 n_rcu_torture_boosts
= 0;
1787 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
1788 atomic_set(&rcu_torture_wcount
[i
], 0);
1789 for_each_possible_cpu(cpu
) {
1790 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
1791 per_cpu(rcu_torture_count
, cpu
)[i
] = 0;
1792 per_cpu(rcu_torture_batch
, cpu
)[i
] = 0;
1796 /* Start up the kthreads. */
1798 firsterr
= torture_create_kthread(rcu_torture_writer
, NULL
,
1802 if (nfakewriters
> 0) {
1803 fakewriter_tasks
= kzalloc(nfakewriters
*
1804 sizeof(fakewriter_tasks
[0]),
1806 if (fakewriter_tasks
== NULL
) {
1807 VERBOSE_TOROUT_ERRSTRING("out of memory");
1812 for (i
= 0; i
< nfakewriters
; i
++) {
1813 firsterr
= torture_create_kthread(rcu_torture_fakewriter
,
1814 NULL
, fakewriter_tasks
[i
]);
1818 reader_tasks
= kzalloc(nrealreaders
* sizeof(reader_tasks
[0]),
1820 if (reader_tasks
== NULL
) {
1821 VERBOSE_TOROUT_ERRSTRING("out of memory");
1825 for (i
= 0; i
< nrealreaders
; i
++) {
1826 firsterr
= torture_create_kthread(rcu_torture_reader
, NULL
,
1831 if (stat_interval
> 0) {
1832 firsterr
= torture_create_kthread(rcu_torture_stats
, NULL
,
1837 if (test_no_idle_hz
&& shuffle_interval
> 0) {
1838 firsterr
= torture_shuffle_init(shuffle_interval
* HZ
);
1845 firsterr
= torture_stutter_init(stutter
* HZ
);
1849 if (fqs_duration
< 0)
1852 /* Create the fqs thread */
1853 firsterr
= torture_create_kthread(rcu_torture_fqs
, NULL
,
1858 if (test_boost_interval
< 1)
1859 test_boost_interval
= 1;
1860 if (test_boost_duration
< 2)
1861 test_boost_duration
= 2;
1862 if ((test_boost
== 1 && cur_ops
->can_boost
) ||
1865 boost_starttime
= jiffies
+ test_boost_interval
* HZ
;
1866 register_cpu_notifier(&rcutorture_cpu_nb
);
1867 for_each_possible_cpu(i
) {
1868 if (cpu_is_offline(i
))
1869 continue; /* Heuristic: CPU can go offline. */
1870 firsterr
= rcutorture_booster_init(i
);
1875 firsterr
= torture_shutdown_init(shutdown_secs
, rcu_torture_cleanup
);
1878 firsterr
= torture_onoff_init(onoff_holdoff
* HZ
, onoff_interval
* HZ
);
1881 firsterr
= rcu_torture_stall_init();
1884 firsterr
= rcu_torture_barrier_init();
1888 rcu_test_debug_objects();
1889 if (cbflood_n_burst
> 0) {
1890 /* Create the cbflood threads */
1891 ncbflooders
= (num_online_cpus() + 3) / 4;
1892 cbflood_task
= kcalloc(ncbflooders
, sizeof(*cbflood_task
),
1894 if (!cbflood_task
) {
1895 VERBOSE_TOROUT_ERRSTRING("out of memory");
1899 for (i
= 0; i
< ncbflooders
; i
++) {
1900 firsterr
= torture_create_kthread(rcu_torture_cbflood
,
1907 rcutorture_record_test_transition();
1913 rcu_torture_cleanup();
1917 module_init(rcu_torture_init
);
1918 module_exit(rcu_torture_cleanup
);