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 int (*readlock
)(void);
245 void (*read_delay
)(struct torture_random_state
*rrsp
);
246 void (*readunlock
)(int idx
);
247 unsigned long (*started
)(void);
248 unsigned long (*completed
)(void);
249 void (*deferred_free
)(struct rcu_torture
*p
);
251 void (*exp_sync
)(void);
252 unsigned long (*get_state
)(void);
253 void (*cond_sync
)(unsigned long oldstate
);
254 void (*call
)(struct rcu_head
*head
, void (*func
)(struct rcu_head
*rcu
));
255 void (*cb_barrier
)(void);
263 static struct rcu_torture_ops
*cur_ops
;
266 * Definitions for rcu torture testing.
269 static int rcu_torture_read_lock(void) __acquires(RCU
)
275 static void rcu_read_delay(struct torture_random_state
*rrsp
)
277 const unsigned long shortdelay_us
= 200;
278 const unsigned long longdelay_ms
= 50;
280 /* We want a short delay sometimes to make a reader delay the grace
281 * period, and we want a long delay occasionally to trigger
282 * force_quiescent_state. */
284 if (!(torture_random(rrsp
) % (nrealreaders
* 2000 * longdelay_ms
)))
285 mdelay(longdelay_ms
);
286 if (!(torture_random(rrsp
) % (nrealreaders
* 2 * shortdelay_us
)))
287 udelay(shortdelay_us
);
288 #ifdef CONFIG_PREEMPT
289 if (!preempt_count() &&
290 !(torture_random(rrsp
) % (nrealreaders
* 20000)))
291 preempt_schedule(); /* No QS if preempt_disable() in effect */
295 static void rcu_torture_read_unlock(int idx
) __releases(RCU
)
301 * Update callback in the pipe. This should be invoked after a grace period.
304 rcu_torture_pipe_update_one(struct rcu_torture
*rp
)
308 i
= rp
->rtort_pipe_count
;
309 if (i
> RCU_TORTURE_PIPE_LEN
)
310 i
= RCU_TORTURE_PIPE_LEN
;
311 atomic_inc(&rcu_torture_wcount
[i
]);
312 if (++rp
->rtort_pipe_count
>= RCU_TORTURE_PIPE_LEN
) {
313 rp
->rtort_mbtest
= 0;
320 * Update all callbacks in the pipe. Suitable for synchronous grace-period
324 rcu_torture_pipe_update(struct rcu_torture
*old_rp
)
326 struct rcu_torture
*rp
;
327 struct rcu_torture
*rp1
;
330 list_add(&old_rp
->rtort_free
, &rcu_torture_removed
);
331 list_for_each_entry_safe(rp
, rp1
, &rcu_torture_removed
, rtort_free
) {
332 if (rcu_torture_pipe_update_one(rp
)) {
333 list_del(&rp
->rtort_free
);
334 rcu_torture_free(rp
);
340 rcu_torture_cb(struct rcu_head
*p
)
342 struct rcu_torture
*rp
= container_of(p
, struct rcu_torture
, rtort_rcu
);
344 if (torture_must_stop_irq()) {
345 /* Test is ending, just drop callbacks on the floor. */
346 /* The next initialization will pick up the pieces. */
349 if (rcu_torture_pipe_update_one(rp
))
350 rcu_torture_free(rp
);
352 cur_ops
->deferred_free(rp
);
355 static unsigned long rcu_no_completed(void)
360 static void rcu_torture_deferred_free(struct rcu_torture
*p
)
362 call_rcu(&p
->rtort_rcu
, rcu_torture_cb
);
365 static void rcu_sync_torture_init(void)
367 INIT_LIST_HEAD(&rcu_torture_removed
);
370 static struct rcu_torture_ops rcu_ops
= {
372 .init
= rcu_sync_torture_init
,
373 .readlock
= rcu_torture_read_lock
,
374 .read_delay
= rcu_read_delay
,
375 .readunlock
= rcu_torture_read_unlock
,
376 .started
= rcu_batches_started
,
377 .completed
= rcu_batches_completed
,
378 .deferred_free
= rcu_torture_deferred_free
,
379 .sync
= synchronize_rcu
,
380 .exp_sync
= synchronize_rcu_expedited
,
381 .get_state
= get_state_synchronize_rcu
,
382 .cond_sync
= cond_synchronize_rcu
,
384 .cb_barrier
= rcu_barrier
,
385 .fqs
= rcu_force_quiescent_state
,
388 .can_boost
= rcu_can_boost(),
393 * Definitions for rcu_bh torture testing.
396 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH
)
402 static void rcu_bh_torture_read_unlock(int idx
) __releases(RCU_BH
)
404 rcu_read_unlock_bh();
407 static void rcu_bh_torture_deferred_free(struct rcu_torture
*p
)
409 call_rcu_bh(&p
->rtort_rcu
, rcu_torture_cb
);
412 static struct rcu_torture_ops rcu_bh_ops
= {
413 .ttype
= RCU_BH_FLAVOR
,
414 .init
= rcu_sync_torture_init
,
415 .readlock
= rcu_bh_torture_read_lock
,
416 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
417 .readunlock
= rcu_bh_torture_read_unlock
,
418 .started
= rcu_batches_started_bh
,
419 .completed
= rcu_batches_completed_bh
,
420 .deferred_free
= rcu_bh_torture_deferred_free
,
421 .sync
= synchronize_rcu_bh
,
422 .exp_sync
= synchronize_rcu_bh_expedited
,
424 .cb_barrier
= rcu_barrier_bh
,
425 .fqs
= rcu_bh_force_quiescent_state
,
432 * Don't even think about trying any of these in real life!!!
433 * The names includes "busted", and they really means it!
434 * The only purpose of these functions is to provide a buggy RCU
435 * implementation to make sure that rcutorture correctly emits
436 * buggy-RCU error messages.
438 static void rcu_busted_torture_deferred_free(struct rcu_torture
*p
)
440 /* This is a deliberate bug for testing purposes only! */
441 rcu_torture_cb(&p
->rtort_rcu
);
444 static void synchronize_rcu_busted(void)
446 /* This is a deliberate bug for testing purposes only! */
450 call_rcu_busted(struct rcu_head
*head
, void (*func
)(struct rcu_head
*rcu
))
452 /* This is a deliberate bug for testing purposes only! */
456 static struct rcu_torture_ops rcu_busted_ops
= {
457 .ttype
= INVALID_RCU_FLAVOR
,
458 .init
= rcu_sync_torture_init
,
459 .readlock
= rcu_torture_read_lock
,
460 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
461 .readunlock
= rcu_torture_read_unlock
,
462 .started
= rcu_no_completed
,
463 .completed
= rcu_no_completed
,
464 .deferred_free
= rcu_busted_torture_deferred_free
,
465 .sync
= synchronize_rcu_busted
,
466 .exp_sync
= synchronize_rcu_busted
,
467 .call
= call_rcu_busted
,
476 * Definitions for srcu torture testing.
479 DEFINE_STATIC_SRCU(srcu_ctl
);
481 static int srcu_torture_read_lock(void) __acquires(&srcu_ctl
)
483 return srcu_read_lock(&srcu_ctl
);
486 static void srcu_read_delay(struct torture_random_state
*rrsp
)
489 const long uspertick
= 1000000 / HZ
;
490 const long longdelay
= 10;
492 /* We want there to be long-running readers, but not all the time. */
494 delay
= torture_random(rrsp
) %
495 (nrealreaders
* 2 * longdelay
* uspertick
);
497 schedule_timeout_interruptible(longdelay
);
499 rcu_read_delay(rrsp
);
502 static void srcu_torture_read_unlock(int idx
) __releases(&srcu_ctl
)
504 srcu_read_unlock(&srcu_ctl
, idx
);
507 static unsigned long srcu_torture_completed(void)
509 return srcu_batches_completed(&srcu_ctl
);
512 static void srcu_torture_deferred_free(struct rcu_torture
*rp
)
514 call_srcu(&srcu_ctl
, &rp
->rtort_rcu
, rcu_torture_cb
);
517 static void srcu_torture_synchronize(void)
519 synchronize_srcu(&srcu_ctl
);
522 static void srcu_torture_call(struct rcu_head
*head
,
523 void (*func
)(struct rcu_head
*head
))
525 call_srcu(&srcu_ctl
, head
, func
);
528 static void srcu_torture_barrier(void)
530 srcu_barrier(&srcu_ctl
);
533 static void srcu_torture_stats(void)
536 int idx
= srcu_ctl
.completed
& 0x1;
538 pr_alert("%s%s per-CPU(idx=%d):",
539 torture_type
, TORTURE_FLAG
, idx
);
540 for_each_possible_cpu(cpu
) {
543 c0
= (long)per_cpu_ptr(srcu_ctl
.per_cpu_ref
, cpu
)->c
[!idx
];
544 c1
= (long)per_cpu_ptr(srcu_ctl
.per_cpu_ref
, cpu
)->c
[idx
];
545 pr_cont(" %d(%ld,%ld)", cpu
, c0
, c1
);
550 static void srcu_torture_synchronize_expedited(void)
552 synchronize_srcu_expedited(&srcu_ctl
);
555 static struct rcu_torture_ops srcu_ops
= {
556 .ttype
= SRCU_FLAVOR
,
557 .init
= rcu_sync_torture_init
,
558 .readlock
= srcu_torture_read_lock
,
559 .read_delay
= srcu_read_delay
,
560 .readunlock
= srcu_torture_read_unlock
,
562 .completed
= srcu_torture_completed
,
563 .deferred_free
= srcu_torture_deferred_free
,
564 .sync
= srcu_torture_synchronize
,
565 .exp_sync
= srcu_torture_synchronize_expedited
,
566 .call
= srcu_torture_call
,
567 .cb_barrier
= srcu_torture_barrier
,
568 .stats
= srcu_torture_stats
,
573 * Definitions for sched torture testing.
576 static int sched_torture_read_lock(void)
582 static void sched_torture_read_unlock(int idx
)
587 static void rcu_sched_torture_deferred_free(struct rcu_torture
*p
)
589 call_rcu_sched(&p
->rtort_rcu
, rcu_torture_cb
);
592 static struct rcu_torture_ops sched_ops
= {
593 .ttype
= RCU_SCHED_FLAVOR
,
594 .init
= rcu_sync_torture_init
,
595 .readlock
= sched_torture_read_lock
,
596 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
597 .readunlock
= sched_torture_read_unlock
,
598 .started
= rcu_batches_started_sched
,
599 .completed
= rcu_batches_completed_sched
,
600 .deferred_free
= rcu_sched_torture_deferred_free
,
601 .sync
= synchronize_sched
,
602 .exp_sync
= synchronize_sched_expedited
,
603 .call
= call_rcu_sched
,
604 .cb_barrier
= rcu_barrier_sched
,
605 .fqs
= rcu_sched_force_quiescent_state
,
611 #ifdef CONFIG_TASKS_RCU
614 * Definitions for RCU-tasks torture testing.
617 static int tasks_torture_read_lock(void)
622 static void tasks_torture_read_unlock(int idx
)
626 static void rcu_tasks_torture_deferred_free(struct rcu_torture
*p
)
628 call_rcu_tasks(&p
->rtort_rcu
, rcu_torture_cb
);
631 static struct rcu_torture_ops tasks_ops
= {
632 .ttype
= RCU_TASKS_FLAVOR
,
633 .init
= rcu_sync_torture_init
,
634 .readlock
= tasks_torture_read_lock
,
635 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
636 .readunlock
= tasks_torture_read_unlock
,
637 .started
= rcu_no_completed
,
638 .completed
= rcu_no_completed
,
639 .deferred_free
= rcu_tasks_torture_deferred_free
,
640 .sync
= synchronize_rcu_tasks
,
641 .exp_sync
= synchronize_rcu_tasks
,
642 .call
= call_rcu_tasks
,
643 .cb_barrier
= rcu_barrier_tasks
,
650 #define RCUTORTURE_TASKS_OPS &tasks_ops,
652 #else /* #ifdef CONFIG_TASKS_RCU */
654 #define RCUTORTURE_TASKS_OPS
656 #endif /* #else #ifdef CONFIG_TASKS_RCU */
659 * RCU torture priority-boost testing. Runs one real-time thread per
660 * CPU for moderate bursts, repeatedly registering RCU callbacks and
661 * spinning waiting for them to be invoked. If a given callback takes
662 * too long to be invoked, we assume that priority inversion has occurred.
665 struct rcu_boost_inflight
{
670 static void rcu_torture_boost_cb(struct rcu_head
*head
)
672 struct rcu_boost_inflight
*rbip
=
673 container_of(head
, struct rcu_boost_inflight
, rcu
);
675 smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
679 static int rcu_torture_boost(void *arg
)
681 unsigned long call_rcu_time
;
682 unsigned long endtime
;
683 unsigned long oldstarttime
;
684 struct rcu_boost_inflight rbi
= { .inflight
= 0 };
685 struct sched_param sp
;
687 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
689 /* Set real-time priority. */
690 sp
.sched_priority
= 1;
691 if (sched_setscheduler(current
, SCHED_FIFO
, &sp
) < 0) {
692 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
693 n_rcu_torture_boost_rterror
++;
696 init_rcu_head_on_stack(&rbi
.rcu
);
697 /* Each pass through the following loop does one boost-test cycle. */
699 /* Wait for the next test interval. */
700 oldstarttime
= boost_starttime
;
701 while (ULONG_CMP_LT(jiffies
, oldstarttime
)) {
702 schedule_timeout_interruptible(oldstarttime
- jiffies
);
703 stutter_wait("rcu_torture_boost");
704 if (torture_must_stop())
708 /* Do one boost-test interval. */
709 endtime
= oldstarttime
+ test_boost_duration
* HZ
;
710 call_rcu_time
= jiffies
;
711 while (ULONG_CMP_LT(jiffies
, endtime
)) {
712 /* If we don't have a callback in flight, post one. */
714 smp_mb(); /* RCU core before ->inflight = 1. */
716 call_rcu(&rbi
.rcu
, rcu_torture_boost_cb
);
717 if (jiffies
- call_rcu_time
>
718 test_boost_duration
* HZ
- HZ
/ 2) {
719 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
720 n_rcu_torture_boost_failure
++;
722 call_rcu_time
= jiffies
;
724 cond_resched_rcu_qs();
725 stutter_wait("rcu_torture_boost");
726 if (torture_must_stop())
731 * Set the start time of the next test interval.
732 * Yes, this is vulnerable to long delays, but such
733 * delays simply cause a false negative for the next
734 * interval. Besides, we are running at RT priority,
735 * so delays should be relatively rare.
737 while (oldstarttime
== boost_starttime
&&
738 !kthread_should_stop()) {
739 if (mutex_trylock(&boost_mutex
)) {
740 boost_starttime
= jiffies
+
741 test_boost_interval
* HZ
;
742 n_rcu_torture_boosts
++;
743 mutex_unlock(&boost_mutex
);
746 schedule_timeout_uninterruptible(1);
749 /* Go do the stutter. */
750 checkwait
: stutter_wait("rcu_torture_boost");
751 } while (!torture_must_stop());
753 /* Clean up and exit. */
754 while (!kthread_should_stop() || rbi
.inflight
) {
755 torture_shutdown_absorb("rcu_torture_boost");
756 schedule_timeout_uninterruptible(1);
758 smp_mb(); /* order accesses to ->inflight before stack-frame death. */
759 destroy_rcu_head_on_stack(&rbi
.rcu
);
760 torture_kthread_stopping("rcu_torture_boost");
764 static void rcu_torture_cbflood_cb(struct rcu_head
*rhp
)
769 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
770 * to call_rcu() or analogous, increasing the probability of occurrence
771 * of callback-overflow corner cases.
774 rcu_torture_cbflood(void *arg
)
779 struct rcu_head
*rhp
;
781 if (cbflood_n_per_burst
> 0 &&
782 cbflood_inter_holdoff
> 0 &&
783 cbflood_intra_holdoff
> 0 &&
785 cur_ops
->cb_barrier
) {
786 rhp
= vmalloc(sizeof(*rhp
) *
787 cbflood_n_burst
* cbflood_n_per_burst
);
791 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
792 while (!torture_must_stop())
793 schedule_timeout_interruptible(HZ
);
796 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
798 schedule_timeout_interruptible(cbflood_inter_holdoff
);
799 atomic_long_inc(&n_cbfloods
);
800 WARN_ON(signal_pending(current
));
801 for (i
= 0; i
< cbflood_n_burst
; i
++) {
802 for (j
= 0; j
< cbflood_n_per_burst
; j
++) {
803 cur_ops
->call(&rhp
[i
* cbflood_n_per_burst
+ j
],
804 rcu_torture_cbflood_cb
);
806 schedule_timeout_interruptible(cbflood_intra_holdoff
);
807 WARN_ON(signal_pending(current
));
809 cur_ops
->cb_barrier();
810 stutter_wait("rcu_torture_cbflood");
811 } while (!torture_must_stop());
813 torture_kthread_stopping("rcu_torture_cbflood");
818 * RCU torture force-quiescent-state kthread. Repeatedly induces
819 * bursts of calls to force_quiescent_state(), increasing the probability
820 * of occurrence of some important types of race conditions.
823 rcu_torture_fqs(void *arg
)
825 unsigned long fqs_resume_time
;
826 int fqs_burst_remaining
;
828 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
830 fqs_resume_time
= jiffies
+ fqs_stutter
* HZ
;
831 while (ULONG_CMP_LT(jiffies
, fqs_resume_time
) &&
832 !kthread_should_stop()) {
833 schedule_timeout_interruptible(1);
835 fqs_burst_remaining
= fqs_duration
;
836 while (fqs_burst_remaining
> 0 &&
837 !kthread_should_stop()) {
840 fqs_burst_remaining
-= fqs_holdoff
;
842 stutter_wait("rcu_torture_fqs");
843 } while (!torture_must_stop());
844 torture_kthread_stopping("rcu_torture_fqs");
849 * RCU torture writer kthread. Repeatedly substitutes a new structure
850 * for that pointed to by rcu_torture_current, freeing the old structure
851 * after a series of grace periods (the "pipeline").
854 rcu_torture_writer(void *arg
)
856 unsigned long gp_snap
;
857 bool gp_cond1
= gp_cond
, gp_exp1
= gp_exp
, gp_normal1
= gp_normal
;
858 bool gp_sync1
= gp_sync
;
860 struct rcu_torture
*rp
;
861 struct rcu_torture
*old_rp
;
862 static DEFINE_TORTURE_RANDOM(rand
);
863 int synctype
[] = { RTWS_DEF_FREE
, RTWS_EXP_SYNC
,
864 RTWS_COND_GET
, RTWS_SYNC
};
867 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
869 /* Initialize synctype[] array. If none set, take default. */
870 if (!gp_cond1
&& !gp_exp1
&& !gp_normal1
&& !gp_sync
)
871 gp_cond1
= gp_exp1
= gp_normal1
= gp_sync1
= true;
872 if (gp_cond1
&& cur_ops
->get_state
&& cur_ops
->cond_sync
)
873 synctype
[nsynctypes
++] = RTWS_COND_GET
;
874 else if (gp_cond
&& (!cur_ops
->get_state
|| !cur_ops
->cond_sync
))
875 pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
876 if (gp_exp1
&& cur_ops
->exp_sync
)
877 synctype
[nsynctypes
++] = RTWS_EXP_SYNC
;
878 else if (gp_exp
&& !cur_ops
->exp_sync
)
879 pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
880 if (gp_normal1
&& cur_ops
->deferred_free
)
881 synctype
[nsynctypes
++] = RTWS_DEF_FREE
;
882 else if (gp_normal
&& !cur_ops
->deferred_free
)
883 pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
884 if (gp_sync1
&& cur_ops
->sync
)
885 synctype
[nsynctypes
++] = RTWS_SYNC
;
886 else if (gp_sync
&& !cur_ops
->sync
)
887 pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
888 if (WARN_ONCE(nsynctypes
== 0,
889 "rcu_torture_writer: No update-side primitives.\n")) {
891 * No updates primitives, so don't try updating.
892 * The resulting test won't be testing much, hence the
895 rcu_torture_writer_state
= RTWS_STOPPING
;
896 torture_kthread_stopping("rcu_torture_writer");
900 rcu_torture_writer_state
= RTWS_FIXED_DELAY
;
901 schedule_timeout_uninterruptible(1);
902 rp
= rcu_torture_alloc();
905 rp
->rtort_pipe_count
= 0;
906 rcu_torture_writer_state
= RTWS_DELAY
;
907 udelay(torture_random(&rand
) & 0x3ff);
908 rcu_torture_writer_state
= RTWS_REPLACE
;
909 old_rp
= rcu_dereference_check(rcu_torture_current
,
910 current
== writer_task
);
911 rp
->rtort_mbtest
= 1;
912 rcu_assign_pointer(rcu_torture_current
, rp
);
913 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
915 i
= old_rp
->rtort_pipe_count
;
916 if (i
> RCU_TORTURE_PIPE_LEN
)
917 i
= RCU_TORTURE_PIPE_LEN
;
918 atomic_inc(&rcu_torture_wcount
[i
]);
919 old_rp
->rtort_pipe_count
++;
920 switch (synctype
[torture_random(&rand
) % nsynctypes
]) {
922 rcu_torture_writer_state
= RTWS_DEF_FREE
;
923 cur_ops
->deferred_free(old_rp
);
926 rcu_torture_writer_state
= RTWS_EXP_SYNC
;
928 rcu_torture_pipe_update(old_rp
);
931 rcu_torture_writer_state
= RTWS_COND_GET
;
932 gp_snap
= cur_ops
->get_state();
933 i
= torture_random(&rand
) % 16;
935 schedule_timeout_interruptible(i
);
936 udelay(torture_random(&rand
) % 1000);
937 rcu_torture_writer_state
= RTWS_COND_SYNC
;
938 cur_ops
->cond_sync(gp_snap
);
939 rcu_torture_pipe_update(old_rp
);
942 rcu_torture_writer_state
= RTWS_SYNC
;
944 rcu_torture_pipe_update(old_rp
);
951 rcutorture_record_progress(++rcu_torture_current_version
);
952 rcu_torture_writer_state
= RTWS_STUTTER
;
953 stutter_wait("rcu_torture_writer");
954 } while (!torture_must_stop());
955 rcu_torture_writer_state
= RTWS_STOPPING
;
956 torture_kthread_stopping("rcu_torture_writer");
961 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
962 * delay between calls.
965 rcu_torture_fakewriter(void *arg
)
967 DEFINE_TORTURE_RANDOM(rand
);
969 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
970 set_user_nice(current
, MAX_NICE
);
973 schedule_timeout_uninterruptible(1 + torture_random(&rand
)%10);
974 udelay(torture_random(&rand
) & 0x3ff);
975 if (cur_ops
->cb_barrier
!= NULL
&&
976 torture_random(&rand
) % (nfakewriters
* 8) == 0) {
977 cur_ops
->cb_barrier();
978 } else if (gp_normal
== gp_exp
) {
979 if (torture_random(&rand
) & 0x80)
983 } else if (gp_normal
) {
988 stutter_wait("rcu_torture_fakewriter");
989 } while (!torture_must_stop());
991 torture_kthread_stopping("rcu_torture_fakewriter");
995 static void rcutorture_trace_dump(void)
997 static atomic_t beenhere
= ATOMIC_INIT(0);
999 if (atomic_read(&beenhere
))
1001 if (atomic_xchg(&beenhere
, 1) != 0)
1003 ftrace_dump(DUMP_ALL
);
1007 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1008 * incrementing the corresponding element of the pipeline array. The
1009 * counter in the element should never be greater than 1, otherwise, the
1010 * RCU implementation is broken.
1012 static void rcu_torture_timer(unsigned long unused
)
1015 unsigned long started
;
1016 unsigned long completed
;
1017 static DEFINE_TORTURE_RANDOM(rand
);
1018 static DEFINE_SPINLOCK(rand_lock
);
1019 struct rcu_torture
*p
;
1021 unsigned long long ts
;
1023 idx
= cur_ops
->readlock();
1024 if (cur_ops
->started
)
1025 started
= cur_ops
->started();
1027 started
= cur_ops
->completed();
1028 ts
= rcu_trace_clock_local();
1029 p
= rcu_dereference_check(rcu_torture_current
,
1030 rcu_read_lock_bh_held() ||
1031 rcu_read_lock_sched_held() ||
1032 srcu_read_lock_held(&srcu_ctl
));
1034 /* Leave because rcu_torture_writer is not yet underway */
1035 cur_ops
->readunlock(idx
);
1038 if (p
->rtort_mbtest
== 0)
1039 atomic_inc(&n_rcu_torture_mberror
);
1040 spin_lock(&rand_lock
);
1041 cur_ops
->read_delay(&rand
);
1042 n_rcu_torture_timers
++;
1043 spin_unlock(&rand_lock
);
1045 pipe_count
= p
->rtort_pipe_count
;
1046 if (pipe_count
> RCU_TORTURE_PIPE_LEN
) {
1047 /* Should not happen, but... */
1048 pipe_count
= RCU_TORTURE_PIPE_LEN
;
1050 completed
= cur_ops
->completed();
1051 if (pipe_count
> 1) {
1052 do_trace_rcu_torture_read(cur_ops
->name
, &p
->rtort_rcu
, ts
,
1053 started
, completed
);
1054 rcutorture_trace_dump();
1056 __this_cpu_inc(rcu_torture_count
[pipe_count
]);
1057 completed
= completed
- started
;
1058 if (cur_ops
->started
)
1060 if (completed
> RCU_TORTURE_PIPE_LEN
) {
1061 /* Should not happen, but... */
1062 completed
= RCU_TORTURE_PIPE_LEN
;
1064 __this_cpu_inc(rcu_torture_batch
[completed
]);
1066 cur_ops
->readunlock(idx
);
1070 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1071 * incrementing the corresponding element of the pipeline array. The
1072 * counter in the element should never be greater than 1, otherwise, the
1073 * RCU implementation is broken.
1076 rcu_torture_reader(void *arg
)
1078 unsigned long started
;
1079 unsigned long completed
;
1081 DEFINE_TORTURE_RANDOM(rand
);
1082 struct rcu_torture
*p
;
1084 struct timer_list t
;
1085 unsigned long long ts
;
1087 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1088 set_user_nice(current
, MAX_NICE
);
1089 if (irqreader
&& cur_ops
->irq_capable
)
1090 setup_timer_on_stack(&t
, rcu_torture_timer
, 0);
1093 if (irqreader
&& cur_ops
->irq_capable
) {
1094 if (!timer_pending(&t
))
1095 mod_timer(&t
, jiffies
+ 1);
1097 idx
= cur_ops
->readlock();
1098 if (cur_ops
->started
)
1099 started
= cur_ops
->started();
1101 started
= cur_ops
->completed();
1102 ts
= rcu_trace_clock_local();
1103 p
= rcu_dereference_check(rcu_torture_current
,
1104 rcu_read_lock_bh_held() ||
1105 rcu_read_lock_sched_held() ||
1106 srcu_read_lock_held(&srcu_ctl
));
1108 /* Wait for rcu_torture_writer to get underway */
1109 cur_ops
->readunlock(idx
);
1110 schedule_timeout_interruptible(HZ
);
1113 if (p
->rtort_mbtest
== 0)
1114 atomic_inc(&n_rcu_torture_mberror
);
1115 cur_ops
->read_delay(&rand
);
1117 pipe_count
= p
->rtort_pipe_count
;
1118 if (pipe_count
> RCU_TORTURE_PIPE_LEN
) {
1119 /* Should not happen, but... */
1120 pipe_count
= RCU_TORTURE_PIPE_LEN
;
1122 completed
= cur_ops
->completed();
1123 if (pipe_count
> 1) {
1124 do_trace_rcu_torture_read(cur_ops
->name
, &p
->rtort_rcu
,
1125 ts
, started
, completed
);
1126 rcutorture_trace_dump();
1128 __this_cpu_inc(rcu_torture_count
[pipe_count
]);
1129 completed
= completed
- started
;
1130 if (cur_ops
->started
)
1132 if (completed
> RCU_TORTURE_PIPE_LEN
) {
1133 /* Should not happen, but... */
1134 completed
= RCU_TORTURE_PIPE_LEN
;
1136 __this_cpu_inc(rcu_torture_batch
[completed
]);
1138 cur_ops
->readunlock(idx
);
1139 cond_resched_rcu_qs();
1140 stutter_wait("rcu_torture_reader");
1141 } while (!torture_must_stop());
1142 if (irqreader
&& cur_ops
->irq_capable
) {
1144 destroy_timer_on_stack(&t
);
1146 torture_kthread_stopping("rcu_torture_reader");
1151 * Print torture statistics. Caller must ensure that there is only
1152 * one call to this function at a given time!!! This is normally
1153 * accomplished by relying on the module system to only have one copy
1154 * of the module loaded, and then by giving the rcu_torture_stats
1155 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1156 * thread is not running).
1159 rcu_torture_stats_print(void)
1163 long pipesummary
[RCU_TORTURE_PIPE_LEN
+ 1] = { 0 };
1164 long batchsummary
[RCU_TORTURE_PIPE_LEN
+ 1] = { 0 };
1165 static unsigned long rtcv_snap
= ULONG_MAX
;
1167 for_each_possible_cpu(cpu
) {
1168 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
1169 pipesummary
[i
] += per_cpu(rcu_torture_count
, cpu
)[i
];
1170 batchsummary
[i
] += per_cpu(rcu_torture_batch
, cpu
)[i
];
1173 for (i
= RCU_TORTURE_PIPE_LEN
- 1; i
>= 0; i
--) {
1174 if (pipesummary
[i
] != 0)
1178 pr_alert("%s%s ", torture_type
, TORTURE_FLAG
);
1179 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1180 rcu_torture_current
,
1181 rcu_torture_current_version
,
1182 list_empty(&rcu_torture_freelist
),
1183 atomic_read(&n_rcu_torture_alloc
),
1184 atomic_read(&n_rcu_torture_alloc_fail
),
1185 atomic_read(&n_rcu_torture_free
));
1186 pr_cont("rtmbe: %d rtbke: %ld rtbre: %ld ",
1187 atomic_read(&n_rcu_torture_mberror
),
1188 n_rcu_torture_boost_ktrerror
,
1189 n_rcu_torture_boost_rterror
);
1190 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1191 n_rcu_torture_boost_failure
,
1192 n_rcu_torture_boosts
,
1193 n_rcu_torture_timers
);
1194 torture_onoff_stats();
1195 pr_cont("barrier: %ld/%ld:%ld ",
1196 n_barrier_successes
,
1198 n_rcu_torture_barrier_error
);
1199 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods
));
1201 pr_alert("%s%s ", torture_type
, TORTURE_FLAG
);
1202 if (atomic_read(&n_rcu_torture_mberror
) != 0 ||
1203 n_rcu_torture_barrier_error
!= 0 ||
1204 n_rcu_torture_boost_ktrerror
!= 0 ||
1205 n_rcu_torture_boost_rterror
!= 0 ||
1206 n_rcu_torture_boost_failure
!= 0 ||
1208 pr_cont("%s", "!!! ");
1209 atomic_inc(&n_rcu_torture_error
);
1212 pr_cont("Reader Pipe: ");
1213 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
1214 pr_cont(" %ld", pipesummary
[i
]);
1217 pr_alert("%s%s ", torture_type
, TORTURE_FLAG
);
1218 pr_cont("Reader Batch: ");
1219 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
1220 pr_cont(" %ld", batchsummary
[i
]);
1223 pr_alert("%s%s ", torture_type
, TORTURE_FLAG
);
1224 pr_cont("Free-Block Circulation: ");
1225 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
1226 pr_cont(" %d", atomic_read(&rcu_torture_wcount
[i
]));
1232 if (rtcv_snap
== rcu_torture_current_version
&&
1233 rcu_torture_current
!= NULL
) {
1234 int __maybe_unused flags
;
1235 unsigned long __maybe_unused gpnum
;
1236 unsigned long __maybe_unused completed
;
1238 rcutorture_get_gp_data(cur_ops
->ttype
,
1239 &flags
, &gpnum
, &completed
);
1240 pr_alert("??? Writer stall state %d g%lu c%lu f%#x\n",
1241 rcu_torture_writer_state
,
1242 gpnum
, completed
, flags
);
1243 show_rcu_gp_kthreads();
1244 rcutorture_trace_dump();
1246 rtcv_snap
= rcu_torture_current_version
;
1250 * Periodically prints torture statistics, if periodic statistics printing
1251 * was specified via the stat_interval module parameter.
1254 rcu_torture_stats(void *arg
)
1256 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1258 schedule_timeout_interruptible(stat_interval
* HZ
);
1259 rcu_torture_stats_print();
1260 torture_shutdown_absorb("rcu_torture_stats");
1261 } while (!torture_must_stop());
1262 torture_kthread_stopping("rcu_torture_stats");
1267 rcu_torture_print_module_parms(struct rcu_torture_ops
*cur_ops
, const char *tag
)
1269 pr_alert("%s" TORTURE_FLAG
1270 "--- %s: nreaders=%d nfakewriters=%d "
1271 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1272 "shuffle_interval=%d stutter=%d irqreader=%d "
1273 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1274 "test_boost=%d/%d test_boost_interval=%d "
1275 "test_boost_duration=%d shutdown_secs=%d "
1276 "stall_cpu=%d stall_cpu_holdoff=%d "
1278 "onoff_interval=%d onoff_holdoff=%d\n",
1279 torture_type
, tag
, nrealreaders
, nfakewriters
,
1280 stat_interval
, verbose
, test_no_idle_hz
, shuffle_interval
,
1281 stutter
, irqreader
, fqs_duration
, fqs_holdoff
, fqs_stutter
,
1282 test_boost
, cur_ops
->can_boost
,
1283 test_boost_interval
, test_boost_duration
, shutdown_secs
,
1284 stall_cpu
, stall_cpu_holdoff
,
1286 onoff_interval
, onoff_holdoff
);
1289 static void rcutorture_booster_cleanup(int cpu
)
1291 struct task_struct
*t
;
1293 if (boost_tasks
[cpu
] == NULL
)
1295 mutex_lock(&boost_mutex
);
1296 t
= boost_tasks
[cpu
];
1297 boost_tasks
[cpu
] = NULL
;
1298 mutex_unlock(&boost_mutex
);
1300 /* This must be outside of the mutex, otherwise deadlock! */
1301 torture_stop_kthread(rcu_torture_boost
, t
);
1304 static int rcutorture_booster_init(int cpu
)
1308 if (boost_tasks
[cpu
] != NULL
)
1309 return 0; /* Already created, nothing more to do. */
1311 /* Don't allow time recalculation while creating a new task. */
1312 mutex_lock(&boost_mutex
);
1313 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1314 boost_tasks
[cpu
] = kthread_create_on_node(rcu_torture_boost
, NULL
,
1316 "rcu_torture_boost");
1317 if (IS_ERR(boost_tasks
[cpu
])) {
1318 retval
= PTR_ERR(boost_tasks
[cpu
]);
1319 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1320 n_rcu_torture_boost_ktrerror
++;
1321 boost_tasks
[cpu
] = NULL
;
1322 mutex_unlock(&boost_mutex
);
1325 kthread_bind(boost_tasks
[cpu
], cpu
);
1326 wake_up_process(boost_tasks
[cpu
]);
1327 mutex_unlock(&boost_mutex
);
1332 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1333 * induces a CPU stall for the time specified by stall_cpu.
1335 static int rcu_torture_stall(void *args
)
1337 unsigned long stop_at
;
1339 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1340 if (stall_cpu_holdoff
> 0) {
1341 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1342 schedule_timeout_interruptible(stall_cpu_holdoff
* HZ
);
1343 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1345 if (!kthread_should_stop()) {
1346 stop_at
= get_seconds() + stall_cpu
;
1347 /* RCU CPU stall is expected behavior in following code. */
1348 pr_alert("rcu_torture_stall start.\n");
1351 while (ULONG_CMP_LT(get_seconds(), stop_at
))
1352 continue; /* Induce RCU CPU stall warning. */
1355 pr_alert("rcu_torture_stall end.\n");
1357 torture_shutdown_absorb("rcu_torture_stall");
1358 while (!kthread_should_stop())
1359 schedule_timeout_interruptible(10 * HZ
);
1363 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1364 static int __init
rcu_torture_stall_init(void)
1368 return torture_create_kthread(rcu_torture_stall
, NULL
, stall_task
);
1371 /* Callback function for RCU barrier testing. */
1372 static void rcu_torture_barrier_cbf(struct rcu_head
*rcu
)
1374 atomic_inc(&barrier_cbs_invoked
);
1377 /* kthread function to register callbacks used to test RCU barriers. */
1378 static int rcu_torture_barrier_cbs(void *arg
)
1380 long myid
= (long)arg
;
1383 struct rcu_head rcu
;
1385 init_rcu_head_on_stack(&rcu
);
1386 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1387 set_user_nice(current
, MAX_NICE
);
1389 wait_event(barrier_cbs_wq
[myid
],
1391 ACCESS_ONCE(barrier_phase
)) != lastphase
||
1392 torture_must_stop());
1393 lastphase
= newphase
;
1394 smp_mb(); /* ensure barrier_phase load before ->call(). */
1395 if (torture_must_stop())
1397 cur_ops
->call(&rcu
, rcu_torture_barrier_cbf
);
1398 if (atomic_dec_and_test(&barrier_cbs_count
))
1399 wake_up(&barrier_wq
);
1400 } while (!torture_must_stop());
1401 if (cur_ops
->cb_barrier
!= NULL
)
1402 cur_ops
->cb_barrier();
1403 destroy_rcu_head_on_stack(&rcu
);
1404 torture_kthread_stopping("rcu_torture_barrier_cbs");
1408 /* kthread function to drive and coordinate RCU barrier testing. */
1409 static int rcu_torture_barrier(void *arg
)
1413 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1415 atomic_set(&barrier_cbs_invoked
, 0);
1416 atomic_set(&barrier_cbs_count
, n_barrier_cbs
);
1417 smp_mb(); /* Ensure barrier_phase after prior assignments. */
1418 barrier_phase
= !barrier_phase
;
1419 for (i
= 0; i
< n_barrier_cbs
; i
++)
1420 wake_up(&barrier_cbs_wq
[i
]);
1421 wait_event(barrier_wq
,
1422 atomic_read(&barrier_cbs_count
) == 0 ||
1423 torture_must_stop());
1424 if (torture_must_stop())
1426 n_barrier_attempts
++;
1427 cur_ops
->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1428 if (atomic_read(&barrier_cbs_invoked
) != n_barrier_cbs
) {
1429 n_rcu_torture_barrier_error
++;
1430 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1431 atomic_read(&barrier_cbs_invoked
),
1435 n_barrier_successes
++;
1436 schedule_timeout_interruptible(HZ
/ 10);
1437 } while (!torture_must_stop());
1438 torture_kthread_stopping("rcu_torture_barrier");
1442 /* Initialize RCU barrier testing. */
1443 static int rcu_torture_barrier_init(void)
1448 if (n_barrier_cbs
== 0)
1450 if (cur_ops
->call
== NULL
|| cur_ops
->cb_barrier
== NULL
) {
1451 pr_alert("%s" TORTURE_FLAG
1452 " Call or barrier ops missing for %s,\n",
1453 torture_type
, cur_ops
->name
);
1454 pr_alert("%s" TORTURE_FLAG
1455 " RCU barrier testing omitted from run.\n",
1459 atomic_set(&barrier_cbs_count
, 0);
1460 atomic_set(&barrier_cbs_invoked
, 0);
1462 kzalloc(n_barrier_cbs
* sizeof(barrier_cbs_tasks
[0]),
1465 kzalloc(n_barrier_cbs
* sizeof(barrier_cbs_wq
[0]),
1467 if (barrier_cbs_tasks
== NULL
|| !barrier_cbs_wq
)
1469 for (i
= 0; i
< n_barrier_cbs
; i
++) {
1470 init_waitqueue_head(&barrier_cbs_wq
[i
]);
1471 ret
= torture_create_kthread(rcu_torture_barrier_cbs
,
1473 barrier_cbs_tasks
[i
]);
1477 return torture_create_kthread(rcu_torture_barrier
, NULL
, barrier_task
);
1480 /* Clean up after RCU barrier testing. */
1481 static void rcu_torture_barrier_cleanup(void)
1485 torture_stop_kthread(rcu_torture_barrier
, barrier_task
);
1486 if (barrier_cbs_tasks
!= NULL
) {
1487 for (i
= 0; i
< n_barrier_cbs
; i
++)
1488 torture_stop_kthread(rcu_torture_barrier_cbs
,
1489 barrier_cbs_tasks
[i
]);
1490 kfree(barrier_cbs_tasks
);
1491 barrier_cbs_tasks
= NULL
;
1493 if (barrier_cbs_wq
!= NULL
) {
1494 kfree(barrier_cbs_wq
);
1495 barrier_cbs_wq
= NULL
;
1499 static int rcutorture_cpu_notify(struct notifier_block
*self
,
1500 unsigned long action
, void *hcpu
)
1502 long cpu
= (long)hcpu
;
1506 case CPU_DOWN_FAILED
:
1507 (void)rcutorture_booster_init(cpu
);
1509 case CPU_DOWN_PREPARE
:
1510 rcutorture_booster_cleanup(cpu
);
1518 static struct notifier_block rcutorture_cpu_nb
= {
1519 .notifier_call
= rcutorture_cpu_notify
,
1523 rcu_torture_cleanup(void)
1527 rcutorture_record_test_transition();
1528 if (torture_cleanup_begin()) {
1529 if (cur_ops
->cb_barrier
!= NULL
)
1530 cur_ops
->cb_barrier();
1534 rcu_torture_barrier_cleanup();
1535 torture_stop_kthread(rcu_torture_stall
, stall_task
);
1536 torture_stop_kthread(rcu_torture_writer
, writer_task
);
1539 for (i
= 0; i
< nrealreaders
; i
++)
1540 torture_stop_kthread(rcu_torture_reader
,
1542 kfree(reader_tasks
);
1544 rcu_torture_current
= NULL
;
1546 if (fakewriter_tasks
) {
1547 for (i
= 0; i
< nfakewriters
; i
++) {
1548 torture_stop_kthread(rcu_torture_fakewriter
,
1549 fakewriter_tasks
[i
]);
1551 kfree(fakewriter_tasks
);
1552 fakewriter_tasks
= NULL
;
1555 torture_stop_kthread(rcu_torture_stats
, stats_task
);
1556 torture_stop_kthread(rcu_torture_fqs
, fqs_task
);
1557 for (i
= 0; i
< ncbflooders
; i
++)
1558 torture_stop_kthread(rcu_torture_cbflood
, cbflood_task
[i
]);
1559 if ((test_boost
== 1 && cur_ops
->can_boost
) ||
1561 unregister_cpu_notifier(&rcutorture_cpu_nb
);
1562 for_each_possible_cpu(i
)
1563 rcutorture_booster_cleanup(i
);
1566 /* Wait for all RCU callbacks to fire. */
1568 if (cur_ops
->cb_barrier
!= NULL
)
1569 cur_ops
->cb_barrier();
1571 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1573 if (atomic_read(&n_rcu_torture_error
) || n_rcu_torture_barrier_error
)
1574 rcu_torture_print_module_parms(cur_ops
, "End of test: FAILURE");
1575 else if (torture_onoff_failures())
1576 rcu_torture_print_module_parms(cur_ops
,
1577 "End of test: RCU_HOTPLUG");
1579 rcu_torture_print_module_parms(cur_ops
, "End of test: SUCCESS");
1580 torture_cleanup_end();
1583 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1584 static void rcu_torture_leak_cb(struct rcu_head
*rhp
)
1588 static void rcu_torture_err_cb(struct rcu_head
*rhp
)
1591 * This -might- happen due to race conditions, but is unlikely.
1592 * The scenario that leads to this happening is that the
1593 * first of the pair of duplicate callbacks is queued,
1594 * someone else starts a grace period that includes that
1595 * callback, then the second of the pair must wait for the
1596 * next grace period. Unlikely, but can happen. If it
1597 * does happen, the debug-objects subsystem won't have splatted.
1599 pr_alert("rcutorture: duplicated callback was invoked.\n");
1601 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1604 * Verify that double-free causes debug-objects to complain, but only
1605 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1606 * cannot be carried out.
1608 static void rcu_test_debug_objects(void)
1610 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1611 struct rcu_head rh1
;
1612 struct rcu_head rh2
;
1614 init_rcu_head_on_stack(&rh1
);
1615 init_rcu_head_on_stack(&rh2
);
1616 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1618 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1619 preempt_disable(); /* Prevent preemption from interrupting test. */
1620 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1621 call_rcu(&rh1
, rcu_torture_leak_cb
); /* Start grace period. */
1622 local_irq_disable(); /* Make it harder to start a new grace period. */
1623 call_rcu(&rh2
, rcu_torture_leak_cb
);
1624 call_rcu(&rh2
, rcu_torture_err_cb
); /* Duplicate callback. */
1629 /* Wait for them all to get done so we can safely return. */
1631 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1632 destroy_rcu_head_on_stack(&rh1
);
1633 destroy_rcu_head_on_stack(&rh2
);
1634 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1635 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1636 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1640 rcu_torture_init(void)
1645 static struct rcu_torture_ops
*torture_ops
[] = {
1646 &rcu_ops
, &rcu_bh_ops
, &rcu_busted_ops
, &srcu_ops
, &sched_ops
,
1647 RCUTORTURE_TASKS_OPS
1650 if (!torture_init_begin(torture_type
, verbose
, &torture_runnable
))
1653 /* Process args and tell the world that the torturer is on the job. */
1654 for (i
= 0; i
< ARRAY_SIZE(torture_ops
); i
++) {
1655 cur_ops
= torture_ops
[i
];
1656 if (strcmp(torture_type
, cur_ops
->name
) == 0)
1659 if (i
== ARRAY_SIZE(torture_ops
)) {
1660 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1662 pr_alert("rcu-torture types:");
1663 for (i
= 0; i
< ARRAY_SIZE(torture_ops
); i
++)
1664 pr_alert(" %s", torture_ops
[i
]->name
);
1669 if (cur_ops
->fqs
== NULL
&& fqs_duration
!= 0) {
1670 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1674 cur_ops
->init(); /* no "goto unwind" prior to this point!!! */
1676 if (nreaders
>= 0) {
1677 nrealreaders
= nreaders
;
1679 nrealreaders
= num_online_cpus() - 1;
1680 if (nrealreaders
<= 0)
1683 rcu_torture_print_module_parms(cur_ops
, "Start of test");
1685 /* Set up the freelist. */
1687 INIT_LIST_HEAD(&rcu_torture_freelist
);
1688 for (i
= 0; i
< ARRAY_SIZE(rcu_tortures
); i
++) {
1689 rcu_tortures
[i
].rtort_mbtest
= 0;
1690 list_add_tail(&rcu_tortures
[i
].rtort_free
,
1691 &rcu_torture_freelist
);
1694 /* Initialize the statistics so that each run gets its own numbers. */
1696 rcu_torture_current
= NULL
;
1697 rcu_torture_current_version
= 0;
1698 atomic_set(&n_rcu_torture_alloc
, 0);
1699 atomic_set(&n_rcu_torture_alloc_fail
, 0);
1700 atomic_set(&n_rcu_torture_free
, 0);
1701 atomic_set(&n_rcu_torture_mberror
, 0);
1702 atomic_set(&n_rcu_torture_error
, 0);
1703 n_rcu_torture_barrier_error
= 0;
1704 n_rcu_torture_boost_ktrerror
= 0;
1705 n_rcu_torture_boost_rterror
= 0;
1706 n_rcu_torture_boost_failure
= 0;
1707 n_rcu_torture_boosts
= 0;
1708 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
1709 atomic_set(&rcu_torture_wcount
[i
], 0);
1710 for_each_possible_cpu(cpu
) {
1711 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
1712 per_cpu(rcu_torture_count
, cpu
)[i
] = 0;
1713 per_cpu(rcu_torture_batch
, cpu
)[i
] = 0;
1717 /* Start up the kthreads. */
1719 firsterr
= torture_create_kthread(rcu_torture_writer
, NULL
,
1723 fakewriter_tasks
= kzalloc(nfakewriters
* sizeof(fakewriter_tasks
[0]),
1725 if (fakewriter_tasks
== NULL
) {
1726 VERBOSE_TOROUT_ERRSTRING("out of memory");
1730 for (i
= 0; i
< nfakewriters
; i
++) {
1731 firsterr
= torture_create_kthread(rcu_torture_fakewriter
,
1732 NULL
, fakewriter_tasks
[i
]);
1736 reader_tasks
= kzalloc(nrealreaders
* sizeof(reader_tasks
[0]),
1738 if (reader_tasks
== NULL
) {
1739 VERBOSE_TOROUT_ERRSTRING("out of memory");
1743 for (i
= 0; i
< nrealreaders
; i
++) {
1744 firsterr
= torture_create_kthread(rcu_torture_reader
, NULL
,
1749 if (stat_interval
> 0) {
1750 firsterr
= torture_create_kthread(rcu_torture_stats
, NULL
,
1755 if (test_no_idle_hz
) {
1756 firsterr
= torture_shuffle_init(shuffle_interval
* HZ
);
1763 firsterr
= torture_stutter_init(stutter
* HZ
);
1767 if (fqs_duration
< 0)
1770 /* Create the fqs thread */
1771 firsterr
= torture_create_kthread(rcu_torture_fqs
, NULL
,
1776 if (test_boost_interval
< 1)
1777 test_boost_interval
= 1;
1778 if (test_boost_duration
< 2)
1779 test_boost_duration
= 2;
1780 if ((test_boost
== 1 && cur_ops
->can_boost
) ||
1783 boost_starttime
= jiffies
+ test_boost_interval
* HZ
;
1784 register_cpu_notifier(&rcutorture_cpu_nb
);
1785 for_each_possible_cpu(i
) {
1786 if (cpu_is_offline(i
))
1787 continue; /* Heuristic: CPU can go offline. */
1788 firsterr
= rcutorture_booster_init(i
);
1793 firsterr
= torture_shutdown_init(shutdown_secs
, rcu_torture_cleanup
);
1796 firsterr
= torture_onoff_init(onoff_holdoff
* HZ
, onoff_interval
* HZ
);
1799 firsterr
= rcu_torture_stall_init();
1802 firsterr
= rcu_torture_barrier_init();
1806 rcu_test_debug_objects();
1807 if (cbflood_n_burst
> 0) {
1808 /* Create the cbflood threads */
1809 ncbflooders
= (num_online_cpus() + 3) / 4;
1810 cbflood_task
= kcalloc(ncbflooders
, sizeof(*cbflood_task
),
1812 if (!cbflood_task
) {
1813 VERBOSE_TOROUT_ERRSTRING("out of memory");
1817 for (i
= 0; i
< ncbflooders
; i
++) {
1818 firsterr
= torture_create_kthread(rcu_torture_cbflood
,
1825 rcutorture_record_test_transition();
1831 rcu_torture_cleanup();
1835 module_init(rcu_torture_init
);
1836 module_exit(rcu_torture_cleanup
);