1 // SPDX-License-Identifier: GPL-2.0+
3 * Read-Copy Update module-based torture test facility
5 * Copyright (C) IBM Corporation, 2005, 2006
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 * Josh Triplett <josh@joshtriplett.org>
10 * See also: Documentation/RCU/torture.rst
13 #define pr_fmt(fmt) fmt
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/kthread.h>
20 #include <linux/err.h>
21 #include <linux/spinlock.h>
22 #include <linux/smp.h>
23 #include <linux/rcupdate_wait.h>
24 #include <linux/rcu_notifier.h>
25 #include <linux/interrupt.h>
26 #include <linux/sched/signal.h>
27 #include <uapi/linux/sched/types.h>
28 #include <linux/atomic.h>
29 #include <linux/bitops.h>
30 #include <linux/completion.h>
31 #include <linux/moduleparam.h>
32 #include <linux/percpu.h>
33 #include <linux/notifier.h>
34 #include <linux/reboot.h>
35 #include <linux/freezer.h>
36 #include <linux/cpu.h>
37 #include <linux/delay.h>
38 #include <linux/stat.h>
39 #include <linux/srcu.h>
40 #include <linux/slab.h>
41 #include <linux/trace_clock.h>
42 #include <asm/byteorder.h>
43 #include <linux/torture.h>
44 #include <linux/vmalloc.h>
45 #include <linux/sched/debug.h>
46 #include <linux/sched/sysctl.h>
47 #include <linux/oom.h>
48 #include <linux/tick.h>
49 #include <linux/rcupdate_trace.h>
50 #include <linux/nmi.h>
54 MODULE_LICENSE("GPL");
55 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
57 /* Bits for ->extendables field, extendables param, and related definitions. */
58 #define RCUTORTURE_RDR_SHIFT_1 8 /* Put SRCU index in upper bits. */
59 #define RCUTORTURE_RDR_MASK_1 (1 << RCUTORTURE_RDR_SHIFT_1)
60 #define RCUTORTURE_RDR_SHIFT_2 9 /* Put SRCU index in upper bits. */
61 #define RCUTORTURE_RDR_MASK_2 (1 << RCUTORTURE_RDR_SHIFT_2)
62 #define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */
63 #define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */
64 #define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */
65 #define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */
66 #define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */
67 #define RCUTORTURE_RDR_RCU_1 0x20 /* ... entering another RCU reader. */
68 #define RCUTORTURE_RDR_RCU_2 0x40 /* ... entering another RCU reader. */
69 #define RCUTORTURE_RDR_NBITS 7 /* Number of bits defined above. */
70 #define RCUTORTURE_MAX_EXTEND \
71 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
72 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
73 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
74 /* Must be power of two minus one. */
75 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
77 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
78 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
79 torture_param(int, fqs_duration, 0, "Duration of fqs bursts (us), 0 to disable");
80 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
81 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
82 torture_param(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)");
83 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
84 torture_param(int, fwd_progress_holdoff, 60, "Time between forward-progress tests (s)");
85 torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched() behind need_resched()");
86 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
87 torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait primitives");
88 torture_param(bool, gp_cond_full, false, "Use conditional/async full-state GP wait primitives");
89 torture_param(bool, gp_cond_exp_full, false,
90 "Use conditional/async full-stateexpedited GP wait primitives");
91 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
92 torture_param(bool, gp_normal, false, "Use normal (non-expedited) GP wait primitives");
93 torture_param(bool, gp_poll, false, "Use polling GP wait primitives");
94 torture_param(bool, gp_poll_exp, false, "Use polling expedited GP wait primitives");
95 torture_param(bool, gp_poll_full, false, "Use polling full-state GP wait primitives");
96 torture_param(bool, gp_poll_exp_full, false, "Use polling full-state expedited GP wait primitives");
97 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
98 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
99 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers");
100 torture_param(int, n_barrier_cbs, 0, "# of callbacks/kthreads for barrier testing");
101 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
102 torture_param(int, nreaders, -1, "Number of RCU reader threads");
103 torture_param(int, object_debug, 0, "Enable debug-object double call_rcu() testing");
104 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
105 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (jiffies), 0=disable");
106 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable");
107 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
108 torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
109 torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
110 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
111 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
112 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
113 torture_param(int, stall_cpu_holdoff, 10, "Time to wait before starting stall (s).");
114 torture_param(bool, stall_no_softlockup, false, "Avoid softlockup warning during cpu stall.");
115 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
116 torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
117 torture_param(int, stall_gp_kthread, 0, "Grace-period kthread stall duration (s).");
118 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s");
119 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
120 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
121 torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds.");
122 torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds.");
123 torture_param(int, test_nmis, 0, "End-test NMI tests, 0 to disable.");
124 torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs");
125 torture_param(int, test_srcu_lockdep, 0, "Test specified SRCU deadlock scenario.");
126 torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
128 static char *torture_type = "rcu";
129 module_param(torture_type, charp, 0444);
130 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
132 static int nrealnocbers;
133 static int nrealreaders;
134 static struct task_struct *writer_task;
135 static struct task_struct **fakewriter_tasks;
136 static struct task_struct **reader_tasks;
137 static struct task_struct **nocb_tasks;
138 static struct task_struct *stats_task;
139 static struct task_struct *fqs_task;
140 static struct task_struct *boost_tasks[NR_CPUS];
141 static struct task_struct *stall_task;
142 static struct task_struct **fwd_prog_tasks;
143 static struct task_struct **barrier_cbs_tasks;
144 static struct task_struct *barrier_task;
145 static struct task_struct *read_exit_task;
147 #define RCU_TORTURE_PIPE_LEN 10
149 // Mailbox-like structure to check RCU global memory ordering.
150 struct rcu_torture_reader_check {
151 unsigned long rtc_myloops;
153 unsigned long rtc_chkloops;
155 struct rcu_torture_reader_check *rtc_assigner;
156 } ____cacheline_internodealigned_in_smp;
158 // Update-side data structure used to check RCU readers.
160 struct rcu_head rtort_rcu;
161 int rtort_pipe_count;
162 struct list_head rtort_free;
164 struct rcu_torture_reader_check *rtort_chkp;
167 static LIST_HEAD(rcu_torture_freelist);
168 static struct rcu_torture __rcu *rcu_torture_current;
169 static unsigned long rcu_torture_current_version;
170 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
171 static DEFINE_SPINLOCK(rcu_torture_lock);
172 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
173 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
174 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
175 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk;
176 static atomic_t n_rcu_torture_alloc;
177 static atomic_t n_rcu_torture_alloc_fail;
178 static atomic_t n_rcu_torture_free;
179 static atomic_t n_rcu_torture_mberror;
180 static atomic_t n_rcu_torture_mbchk_fail;
181 static atomic_t n_rcu_torture_mbchk_tries;
182 static atomic_t n_rcu_torture_error;
183 static long n_rcu_torture_barrier_error;
184 static long n_rcu_torture_boost_ktrerror;
185 static long n_rcu_torture_boost_failure;
186 static long n_rcu_torture_boosts;
187 static atomic_long_t n_rcu_torture_timers;
188 static long n_barrier_attempts;
189 static long n_barrier_successes; /* did rcu_barrier test succeed? */
190 static unsigned long n_read_exits;
191 static struct list_head rcu_torture_removed;
192 static unsigned long shutdown_jiffies;
193 static unsigned long start_gp_seq;
194 static atomic_long_t n_nocb_offload;
195 static atomic_long_t n_nocb_deoffload;
197 static int rcu_torture_writer_state;
198 #define RTWS_FIXED_DELAY 0
200 #define RTWS_REPLACE 2
201 #define RTWS_DEF_FREE 3
202 #define RTWS_EXP_SYNC 4
203 #define RTWS_COND_GET 5
204 #define RTWS_COND_GET_FULL 6
205 #define RTWS_COND_GET_EXP 7
206 #define RTWS_COND_GET_EXP_FULL 8
207 #define RTWS_COND_SYNC 9
208 #define RTWS_COND_SYNC_FULL 10
209 #define RTWS_COND_SYNC_EXP 11
210 #define RTWS_COND_SYNC_EXP_FULL 12
211 #define RTWS_POLL_GET 13
212 #define RTWS_POLL_GET_FULL 14
213 #define RTWS_POLL_GET_EXP 15
214 #define RTWS_POLL_GET_EXP_FULL 16
215 #define RTWS_POLL_WAIT 17
216 #define RTWS_POLL_WAIT_FULL 18
217 #define RTWS_POLL_WAIT_EXP 19
218 #define RTWS_POLL_WAIT_EXP_FULL 20
220 #define RTWS_STUTTER 22
221 #define RTWS_STOPPING 23
222 static const char * const rcu_torture_writer_state_names[] = {
229 "RTWS_COND_GET_FULL",
231 "RTWS_COND_GET_EXP_FULL",
233 "RTWS_COND_SYNC_FULL",
234 "RTWS_COND_SYNC_EXP",
235 "RTWS_COND_SYNC_EXP_FULL",
237 "RTWS_POLL_GET_FULL",
239 "RTWS_POLL_GET_EXP_FULL",
241 "RTWS_POLL_WAIT_FULL",
242 "RTWS_POLL_WAIT_EXP",
243 "RTWS_POLL_WAIT_EXP_FULL",
249 /* Record reader segment types and duration for first failing read. */
252 unsigned long rt_delay_jiffies;
253 unsigned long rt_delay_ms;
254 unsigned long rt_delay_us;
257 static int err_segs_recorded;
258 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
259 static int rt_read_nsegs;
261 static const char *rcu_torture_writer_state_getname(void)
263 unsigned int i = READ_ONCE(rcu_torture_writer_state);
265 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
267 return rcu_torture_writer_state_names[i];
270 #ifdef CONFIG_RCU_TRACE
271 static u64 notrace rcu_trace_clock_local(void)
273 u64 ts = trace_clock_local();
275 (void)do_div(ts, NSEC_PER_USEC);
278 #else /* #ifdef CONFIG_RCU_TRACE */
279 static u64 notrace rcu_trace_clock_local(void)
283 #endif /* #else #ifdef CONFIG_RCU_TRACE */
286 * Stop aggressive CPU-hog tests a bit before the end of the test in order
287 * to avoid interfering with test shutdown.
289 static bool shutdown_time_arrived(void)
291 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
294 static unsigned long boost_starttime; /* jiffies of next boost test start. */
295 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
296 /* and boost task create/destroy. */
297 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
298 static bool barrier_phase; /* Test phase. */
299 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
300 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
301 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
303 static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
306 * Allocate an element from the rcu_tortures pool.
308 static struct rcu_torture *
309 rcu_torture_alloc(void)
313 spin_lock_bh(&rcu_torture_lock);
314 if (list_empty(&rcu_torture_freelist)) {
315 atomic_inc(&n_rcu_torture_alloc_fail);
316 spin_unlock_bh(&rcu_torture_lock);
319 atomic_inc(&n_rcu_torture_alloc);
320 p = rcu_torture_freelist.next;
322 spin_unlock_bh(&rcu_torture_lock);
323 return container_of(p, struct rcu_torture, rtort_free);
327 * Free an element to the rcu_tortures pool.
330 rcu_torture_free(struct rcu_torture *p)
332 atomic_inc(&n_rcu_torture_free);
333 spin_lock_bh(&rcu_torture_lock);
334 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
335 spin_unlock_bh(&rcu_torture_lock);
339 * Operations vector for selecting different types of tests.
342 struct rcu_torture_ops {
345 void (*cleanup)(void);
346 int (*readlock)(void);
347 void (*read_delay)(struct torture_random_state *rrsp,
348 struct rt_read_seg *rtrsp);
349 void (*readunlock)(int idx);
350 int (*readlock_held)(void);
351 unsigned long (*get_gp_seq)(void);
352 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
353 void (*deferred_free)(struct rcu_torture *p);
355 void (*exp_sync)(void);
356 unsigned long (*get_gp_state_exp)(void);
357 unsigned long (*start_gp_poll_exp)(void);
358 void (*start_gp_poll_exp_full)(struct rcu_gp_oldstate *rgosp);
359 bool (*poll_gp_state_exp)(unsigned long oldstate);
360 void (*cond_sync_exp)(unsigned long oldstate);
361 void (*cond_sync_exp_full)(struct rcu_gp_oldstate *rgosp);
362 unsigned long (*get_comp_state)(void);
363 void (*get_comp_state_full)(struct rcu_gp_oldstate *rgosp);
364 bool (*same_gp_state)(unsigned long oldstate1, unsigned long oldstate2);
365 bool (*same_gp_state_full)(struct rcu_gp_oldstate *rgosp1, struct rcu_gp_oldstate *rgosp2);
366 unsigned long (*get_gp_state)(void);
367 void (*get_gp_state_full)(struct rcu_gp_oldstate *rgosp);
368 unsigned long (*get_gp_completed)(void);
369 void (*get_gp_completed_full)(struct rcu_gp_oldstate *rgosp);
370 unsigned long (*start_gp_poll)(void);
371 void (*start_gp_poll_full)(struct rcu_gp_oldstate *rgosp);
372 bool (*poll_gp_state)(unsigned long oldstate);
373 bool (*poll_gp_state_full)(struct rcu_gp_oldstate *rgosp);
374 bool (*poll_need_2gp)(bool poll, bool poll_full);
375 void (*cond_sync)(unsigned long oldstate);
376 void (*cond_sync_full)(struct rcu_gp_oldstate *rgosp);
377 call_rcu_func_t call;
378 void (*cb_barrier)(void);
381 void (*gp_kthread_dbg)(void);
382 bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
383 int (*stall_dur)(void);
393 static struct rcu_torture_ops *cur_ops;
396 * Definitions for rcu torture testing.
399 static int torture_readlock_not_held(void)
401 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held();
404 static int rcu_torture_read_lock(void)
411 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
413 unsigned long started;
414 unsigned long completed;
415 const unsigned long shortdelay_us = 200;
416 unsigned long longdelay_ms = 300;
417 unsigned long long ts;
419 /* We want a short delay sometimes to make a reader delay the grace
420 * period, and we want a long delay occasionally to trigger
421 * force_quiescent_state. */
423 if (!atomic_read(&rcu_fwd_cb_nodelay) &&
424 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
425 started = cur_ops->get_gp_seq();
426 ts = rcu_trace_clock_local();
427 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
428 longdelay_ms = 5; /* Avoid triggering BH limits. */
429 mdelay(longdelay_ms);
430 rtrsp->rt_delay_ms = longdelay_ms;
431 completed = cur_ops->get_gp_seq();
432 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
435 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
436 udelay(shortdelay_us);
437 rtrsp->rt_delay_us = shortdelay_us;
439 if (!preempt_count() &&
440 !(torture_random(rrsp) % (nrealreaders * 500))) {
441 torture_preempt_schedule(); /* QS only if preemptible. */
442 rtrsp->rt_preempted = true;
446 static void rcu_torture_read_unlock(int idx)
452 * Update callback in the pipe. This should be invoked after a grace period.
455 rcu_torture_pipe_update_one(struct rcu_torture *rp)
458 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp);
461 WRITE_ONCE(rp->rtort_chkp, NULL);
462 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire().
464 i = READ_ONCE(rp->rtort_pipe_count);
465 if (i > RCU_TORTURE_PIPE_LEN)
466 i = RCU_TORTURE_PIPE_LEN;
467 atomic_inc(&rcu_torture_wcount[i]);
468 WRITE_ONCE(rp->rtort_pipe_count, i + 1);
469 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
470 rp->rtort_mbtest = 0;
477 * Update all callbacks in the pipe. Suitable for synchronous grace-period
481 rcu_torture_pipe_update(struct rcu_torture *old_rp)
483 struct rcu_torture *rp;
484 struct rcu_torture *rp1;
487 list_add(&old_rp->rtort_free, &rcu_torture_removed);
488 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
489 if (rcu_torture_pipe_update_one(rp)) {
490 list_del(&rp->rtort_free);
491 rcu_torture_free(rp);
497 rcu_torture_cb(struct rcu_head *p)
499 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
501 if (torture_must_stop_irq()) {
502 /* Test is ending, just drop callbacks on the floor. */
503 /* The next initialization will pick up the pieces. */
506 if (rcu_torture_pipe_update_one(rp))
507 rcu_torture_free(rp);
509 cur_ops->deferred_free(rp);
512 static unsigned long rcu_no_completed(void)
517 static void rcu_torture_deferred_free(struct rcu_torture *p)
519 call_rcu_hurry(&p->rtort_rcu, rcu_torture_cb);
522 static void rcu_sync_torture_init(void)
524 INIT_LIST_HEAD(&rcu_torture_removed);
527 static bool rcu_poll_need_2gp(bool poll, bool poll_full)
532 static struct rcu_torture_ops rcu_ops = {
534 .init = rcu_sync_torture_init,
535 .readlock = rcu_torture_read_lock,
536 .read_delay = rcu_read_delay,
537 .readunlock = rcu_torture_read_unlock,
538 .readlock_held = torture_readlock_not_held,
539 .get_gp_seq = rcu_get_gp_seq,
540 .gp_diff = rcu_seq_diff,
541 .deferred_free = rcu_torture_deferred_free,
542 .sync = synchronize_rcu,
543 .exp_sync = synchronize_rcu_expedited,
544 .same_gp_state = same_state_synchronize_rcu,
545 .same_gp_state_full = same_state_synchronize_rcu_full,
546 .get_comp_state = get_completed_synchronize_rcu,
547 .get_comp_state_full = get_completed_synchronize_rcu_full,
548 .get_gp_state = get_state_synchronize_rcu,
549 .get_gp_state_full = get_state_synchronize_rcu_full,
550 .get_gp_completed = get_completed_synchronize_rcu,
551 .get_gp_completed_full = get_completed_synchronize_rcu_full,
552 .start_gp_poll = start_poll_synchronize_rcu,
553 .start_gp_poll_full = start_poll_synchronize_rcu_full,
554 .poll_gp_state = poll_state_synchronize_rcu,
555 .poll_gp_state_full = poll_state_synchronize_rcu_full,
556 .poll_need_2gp = rcu_poll_need_2gp,
557 .cond_sync = cond_synchronize_rcu,
558 .cond_sync_full = cond_synchronize_rcu_full,
559 .get_gp_state_exp = get_state_synchronize_rcu,
560 .start_gp_poll_exp = start_poll_synchronize_rcu_expedited,
561 .start_gp_poll_exp_full = start_poll_synchronize_rcu_expedited_full,
562 .poll_gp_state_exp = poll_state_synchronize_rcu,
563 .cond_sync_exp = cond_synchronize_rcu_expedited,
564 .call = call_rcu_hurry,
565 .cb_barrier = rcu_barrier,
566 .fqs = rcu_force_quiescent_state,
568 .gp_kthread_dbg = show_rcu_gp_kthreads,
569 .check_boost_failed = rcu_check_boost_fail,
570 .stall_dur = rcu_jiffies_till_stall_check,
572 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
573 .extendables = RCUTORTURE_MAX_EXTEND,
578 * Don't even think about trying any of these in real life!!!
579 * The names includes "busted", and they really means it!
580 * The only purpose of these functions is to provide a buggy RCU
581 * implementation to make sure that rcutorture correctly emits
582 * buggy-RCU error messages.
584 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
586 /* This is a deliberate bug for testing purposes only! */
587 rcu_torture_cb(&p->rtort_rcu);
590 static void synchronize_rcu_busted(void)
592 /* This is a deliberate bug for testing purposes only! */
596 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
598 /* This is a deliberate bug for testing purposes only! */
602 static struct rcu_torture_ops rcu_busted_ops = {
603 .ttype = INVALID_RCU_FLAVOR,
604 .init = rcu_sync_torture_init,
605 .readlock = rcu_torture_read_lock,
606 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
607 .readunlock = rcu_torture_read_unlock,
608 .readlock_held = torture_readlock_not_held,
609 .get_gp_seq = rcu_no_completed,
610 .deferred_free = rcu_busted_torture_deferred_free,
611 .sync = synchronize_rcu_busted,
612 .exp_sync = synchronize_rcu_busted,
613 .call = call_rcu_busted,
622 * Definitions for srcu torture testing.
625 DEFINE_STATIC_SRCU(srcu_ctl);
626 static struct srcu_struct srcu_ctld;
627 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
628 static struct rcu_torture_ops srcud_ops;
630 static int srcu_torture_read_lock(void)
632 if (cur_ops == &srcud_ops)
633 return srcu_read_lock_nmisafe(srcu_ctlp);
635 return srcu_read_lock(srcu_ctlp);
639 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
642 const long uspertick = 1000000 / HZ;
643 const long longdelay = 10;
645 /* We want there to be long-running readers, but not all the time. */
647 delay = torture_random(rrsp) %
648 (nrealreaders * 2 * longdelay * uspertick);
649 if (!delay && in_task()) {
650 schedule_timeout_interruptible(longdelay);
651 rtrsp->rt_delay_jiffies = longdelay;
653 rcu_read_delay(rrsp, rtrsp);
657 static void srcu_torture_read_unlock(int idx)
659 if (cur_ops == &srcud_ops)
660 srcu_read_unlock_nmisafe(srcu_ctlp, idx);
662 srcu_read_unlock(srcu_ctlp, idx);
665 static int torture_srcu_read_lock_held(void)
667 return srcu_read_lock_held(srcu_ctlp);
670 static unsigned long srcu_torture_completed(void)
672 return srcu_batches_completed(srcu_ctlp);
675 static void srcu_torture_deferred_free(struct rcu_torture *rp)
677 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
680 static void srcu_torture_synchronize(void)
682 synchronize_srcu(srcu_ctlp);
685 static unsigned long srcu_torture_get_gp_state(void)
687 return get_state_synchronize_srcu(srcu_ctlp);
690 static unsigned long srcu_torture_start_gp_poll(void)
692 return start_poll_synchronize_srcu(srcu_ctlp);
695 static bool srcu_torture_poll_gp_state(unsigned long oldstate)
697 return poll_state_synchronize_srcu(srcu_ctlp, oldstate);
700 static void srcu_torture_call(struct rcu_head *head,
703 call_srcu(srcu_ctlp, head, func);
706 static void srcu_torture_barrier(void)
708 srcu_barrier(srcu_ctlp);
711 static void srcu_torture_stats(void)
713 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
716 static void srcu_torture_synchronize_expedited(void)
718 synchronize_srcu_expedited(srcu_ctlp);
721 static struct rcu_torture_ops srcu_ops = {
722 .ttype = SRCU_FLAVOR,
723 .init = rcu_sync_torture_init,
724 .readlock = srcu_torture_read_lock,
725 .read_delay = srcu_read_delay,
726 .readunlock = srcu_torture_read_unlock,
727 .readlock_held = torture_srcu_read_lock_held,
728 .get_gp_seq = srcu_torture_completed,
729 .deferred_free = srcu_torture_deferred_free,
730 .sync = srcu_torture_synchronize,
731 .exp_sync = srcu_torture_synchronize_expedited,
732 .get_gp_state = srcu_torture_get_gp_state,
733 .start_gp_poll = srcu_torture_start_gp_poll,
734 .poll_gp_state = srcu_torture_poll_gp_state,
735 .call = srcu_torture_call,
736 .cb_barrier = srcu_torture_barrier,
737 .stats = srcu_torture_stats,
738 .cbflood_max = 50000,
740 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
744 static void srcu_torture_init(void)
746 rcu_sync_torture_init();
747 WARN_ON(init_srcu_struct(&srcu_ctld));
748 srcu_ctlp = &srcu_ctld;
751 static void srcu_torture_cleanup(void)
753 cleanup_srcu_struct(&srcu_ctld);
754 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
757 /* As above, but dynamically allocated. */
758 static struct rcu_torture_ops srcud_ops = {
759 .ttype = SRCU_FLAVOR,
760 .init = srcu_torture_init,
761 .cleanup = srcu_torture_cleanup,
762 .readlock = srcu_torture_read_lock,
763 .read_delay = srcu_read_delay,
764 .readunlock = srcu_torture_read_unlock,
765 .readlock_held = torture_srcu_read_lock_held,
766 .get_gp_seq = srcu_torture_completed,
767 .deferred_free = srcu_torture_deferred_free,
768 .sync = srcu_torture_synchronize,
769 .exp_sync = srcu_torture_synchronize_expedited,
770 .get_gp_state = srcu_torture_get_gp_state,
771 .start_gp_poll = srcu_torture_start_gp_poll,
772 .poll_gp_state = srcu_torture_poll_gp_state,
773 .call = srcu_torture_call,
774 .cb_barrier = srcu_torture_barrier,
775 .stats = srcu_torture_stats,
776 .cbflood_max = 50000,
778 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
782 /* As above, but broken due to inappropriate reader extension. */
783 static struct rcu_torture_ops busted_srcud_ops = {
784 .ttype = SRCU_FLAVOR,
785 .init = srcu_torture_init,
786 .cleanup = srcu_torture_cleanup,
787 .readlock = srcu_torture_read_lock,
788 .read_delay = rcu_read_delay,
789 .readunlock = srcu_torture_read_unlock,
790 .readlock_held = torture_srcu_read_lock_held,
791 .get_gp_seq = srcu_torture_completed,
792 .deferred_free = srcu_torture_deferred_free,
793 .sync = srcu_torture_synchronize,
794 .exp_sync = srcu_torture_synchronize_expedited,
795 .call = srcu_torture_call,
796 .cb_barrier = srcu_torture_barrier,
797 .stats = srcu_torture_stats,
799 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
800 .extendables = RCUTORTURE_MAX_EXTEND,
801 .name = "busted_srcud"
805 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
806 * This implementation does not necessarily work well with CPU hotplug.
809 static void synchronize_rcu_trivial(void)
813 for_each_online_cpu(cpu) {
814 torture_sched_setaffinity(current->pid, cpumask_of(cpu));
815 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
819 static int rcu_torture_read_lock_trivial(void)
825 static void rcu_torture_read_unlock_trivial(int idx)
830 static struct rcu_torture_ops trivial_ops = {
831 .ttype = RCU_TRIVIAL_FLAVOR,
832 .init = rcu_sync_torture_init,
833 .readlock = rcu_torture_read_lock_trivial,
834 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
835 .readunlock = rcu_torture_read_unlock_trivial,
836 .readlock_held = torture_readlock_not_held,
837 .get_gp_seq = rcu_no_completed,
838 .sync = synchronize_rcu_trivial,
839 .exp_sync = synchronize_rcu_trivial,
846 #ifdef CONFIG_TASKS_RCU
849 * Definitions for RCU-tasks torture testing.
852 static int tasks_torture_read_lock(void)
857 static void tasks_torture_read_unlock(int idx)
861 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
863 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
866 static void synchronize_rcu_mult_test(void)
868 synchronize_rcu_mult(call_rcu_tasks, call_rcu_hurry);
871 static struct rcu_torture_ops tasks_ops = {
872 .ttype = RCU_TASKS_FLAVOR,
873 .init = rcu_sync_torture_init,
874 .readlock = tasks_torture_read_lock,
875 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
876 .readunlock = tasks_torture_read_unlock,
877 .get_gp_seq = rcu_no_completed,
878 .deferred_free = rcu_tasks_torture_deferred_free,
879 .sync = synchronize_rcu_tasks,
880 .exp_sync = synchronize_rcu_mult_test,
881 .call = call_rcu_tasks,
882 .cb_barrier = rcu_barrier_tasks,
883 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread,
891 #define TASKS_OPS &tasks_ops,
893 #else // #ifdef CONFIG_TASKS_RCU
897 #endif // #else #ifdef CONFIG_TASKS_RCU
900 #ifdef CONFIG_TASKS_RUDE_RCU
903 * Definitions for rude RCU-tasks torture testing.
906 static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p)
908 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb);
911 static struct rcu_torture_ops tasks_rude_ops = {
912 .ttype = RCU_TASKS_RUDE_FLAVOR,
913 .init = rcu_sync_torture_init,
914 .readlock = rcu_torture_read_lock_trivial,
915 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
916 .readunlock = rcu_torture_read_unlock_trivial,
917 .get_gp_seq = rcu_no_completed,
918 .deferred_free = rcu_tasks_rude_torture_deferred_free,
919 .sync = synchronize_rcu_tasks_rude,
920 .exp_sync = synchronize_rcu_tasks_rude,
921 .call = call_rcu_tasks_rude,
922 .cb_barrier = rcu_barrier_tasks_rude,
923 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread,
924 .cbflood_max = 50000,
931 #define TASKS_RUDE_OPS &tasks_rude_ops,
933 #else // #ifdef CONFIG_TASKS_RUDE_RCU
935 #define TASKS_RUDE_OPS
937 #endif // #else #ifdef CONFIG_TASKS_RUDE_RCU
940 #ifdef CONFIG_TASKS_TRACE_RCU
943 * Definitions for tracing RCU-tasks torture testing.
946 static int tasks_tracing_torture_read_lock(void)
948 rcu_read_lock_trace();
952 static void tasks_tracing_torture_read_unlock(int idx)
954 rcu_read_unlock_trace();
957 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
959 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
962 static struct rcu_torture_ops tasks_tracing_ops = {
963 .ttype = RCU_TASKS_TRACING_FLAVOR,
964 .init = rcu_sync_torture_init,
965 .readlock = tasks_tracing_torture_read_lock,
966 .read_delay = srcu_read_delay, /* just reuse srcu's version. */
967 .readunlock = tasks_tracing_torture_read_unlock,
968 .readlock_held = rcu_read_lock_trace_held,
969 .get_gp_seq = rcu_no_completed,
970 .deferred_free = rcu_tasks_tracing_torture_deferred_free,
971 .sync = synchronize_rcu_tasks_trace,
972 .exp_sync = synchronize_rcu_tasks_trace,
973 .call = call_rcu_tasks_trace,
974 .cb_barrier = rcu_barrier_tasks_trace,
975 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread,
976 .cbflood_max = 50000,
981 .name = "tasks-tracing"
984 #define TASKS_TRACING_OPS &tasks_tracing_ops,
986 #else // #ifdef CONFIG_TASKS_TRACE_RCU
988 #define TASKS_TRACING_OPS
990 #endif // #else #ifdef CONFIG_TASKS_TRACE_RCU
993 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
995 if (!cur_ops->gp_diff)
997 return cur_ops->gp_diff(new, old);
1001 * RCU torture priority-boost testing. Runs one real-time thread per
1002 * CPU for moderate bursts, repeatedly starting grace periods and waiting
1003 * for them to complete. If a given grace period takes too long, we assume
1004 * that priority inversion has occurred.
1007 static int old_rt_runtime = -1;
1009 static void rcu_torture_disable_rt_throttle(void)
1012 * Disable RT throttling so that rcutorture's boost threads don't get
1013 * throttled. Only possible if rcutorture is built-in otherwise the
1014 * user should manually do this by setting the sched_rt_period_us and
1015 * sched_rt_runtime sysctls.
1017 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
1020 old_rt_runtime = sysctl_sched_rt_runtime;
1021 sysctl_sched_rt_runtime = -1;
1024 static void rcu_torture_enable_rt_throttle(void)
1026 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
1029 sysctl_sched_rt_runtime = old_rt_runtime;
1030 old_rt_runtime = -1;
1033 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start)
1036 static int dbg_done;
1037 unsigned long end = jiffies;
1040 static unsigned long last_persist;
1042 unsigned long mininterval = test_boost_duration * HZ - HZ / 2;
1044 if (end - *start > mininterval) {
1045 // Recheck after checking time to avoid false positives.
1046 smp_mb(); // Time check before grace-period check.
1047 if (cur_ops->poll_gp_state(gp_state))
1048 return false; // passed, though perhaps just barely
1049 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) {
1050 // At most one persisted message per boost test.
1052 lp = READ_ONCE(last_persist);
1053 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp)
1054 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu);
1055 return false; // passed on a technicality
1057 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
1058 n_rcu_torture_boost_failure++;
1059 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) {
1060 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n",
1061 current->rt_priority, gp_state, end - *start);
1062 cur_ops->gp_kthread_dbg();
1063 // Recheck after print to flag grace period ending during splat.
1064 gp_done = cur_ops->poll_gp_state(gp_state);
1065 pr_info("Boost inversion: GP %lu %s.\n", gp_state,
1066 gp_done ? "ended already" : "still pending");
1070 return true; // failed
1071 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) {
1075 return false; // passed
1078 static int rcu_torture_boost(void *arg)
1080 unsigned long endtime;
1081 unsigned long gp_state;
1082 unsigned long gp_state_time;
1083 unsigned long oldstarttime;
1085 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
1087 /* Set real-time priority. */
1088 sched_set_fifo_low(current);
1090 /* Each pass through the following loop does one boost-test cycle. */
1092 bool failed = false; // Test failed already in this test interval
1093 bool gp_initiated = false;
1095 if (kthread_should_stop())
1098 /* Wait for the next test interval. */
1099 oldstarttime = READ_ONCE(boost_starttime);
1100 while (time_before(jiffies, oldstarttime)) {
1101 schedule_timeout_interruptible(oldstarttime - jiffies);
1102 if (stutter_wait("rcu_torture_boost"))
1103 sched_set_fifo_low(current);
1104 if (torture_must_stop())
1108 // Do one boost-test interval.
1109 endtime = oldstarttime + test_boost_duration * HZ;
1110 while (time_before(jiffies, endtime)) {
1111 // Has current GP gone too long?
1112 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1113 failed = rcu_torture_boost_failed(gp_state, &gp_state_time);
1114 // If we don't have a grace period in flight, start one.
1115 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) {
1116 gp_state = cur_ops->start_gp_poll();
1117 gp_initiated = true;
1118 gp_state_time = jiffies;
1120 if (stutter_wait("rcu_torture_boost")) {
1121 sched_set_fifo_low(current);
1122 // If the grace period already ended,
1123 // we don't know when that happened, so
1125 if (cur_ops->poll_gp_state(gp_state))
1126 gp_initiated = false;
1128 if (torture_must_stop())
1132 // In case the grace period extended beyond the end of the loop.
1133 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1134 rcu_torture_boost_failed(gp_state, &gp_state_time);
1137 * Set the start time of the next test interval.
1138 * Yes, this is vulnerable to long delays, but such
1139 * delays simply cause a false negative for the next
1140 * interval. Besides, we are running at RT priority,
1141 * so delays should be relatively rare.
1143 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) {
1144 if (mutex_trylock(&boost_mutex)) {
1145 if (oldstarttime == boost_starttime) {
1146 WRITE_ONCE(boost_starttime,
1147 jiffies + test_boost_interval * HZ);
1148 n_rcu_torture_boosts++;
1150 mutex_unlock(&boost_mutex);
1153 schedule_timeout_uninterruptible(HZ / 20);
1156 /* Go do the stutter. */
1157 checkwait: if (stutter_wait("rcu_torture_boost"))
1158 sched_set_fifo_low(current);
1159 } while (!torture_must_stop());
1161 /* Clean up and exit. */
1162 while (!kthread_should_stop()) {
1163 torture_shutdown_absorb("rcu_torture_boost");
1164 schedule_timeout_uninterruptible(HZ / 20);
1166 torture_kthread_stopping("rcu_torture_boost");
1171 * RCU torture force-quiescent-state kthread. Repeatedly induces
1172 * bursts of calls to force_quiescent_state(), increasing the probability
1173 * of occurrence of some important types of race conditions.
1176 rcu_torture_fqs(void *arg)
1178 unsigned long fqs_resume_time;
1179 int fqs_burst_remaining;
1180 int oldnice = task_nice(current);
1182 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
1184 fqs_resume_time = jiffies + fqs_stutter * HZ;
1185 while (time_before(jiffies, fqs_resume_time) &&
1186 !kthread_should_stop()) {
1187 schedule_timeout_interruptible(HZ / 20);
1189 fqs_burst_remaining = fqs_duration;
1190 while (fqs_burst_remaining > 0 &&
1191 !kthread_should_stop()) {
1193 udelay(fqs_holdoff);
1194 fqs_burst_remaining -= fqs_holdoff;
1196 if (stutter_wait("rcu_torture_fqs"))
1197 sched_set_normal(current, oldnice);
1198 } while (!torture_must_stop());
1199 torture_kthread_stopping("rcu_torture_fqs");
1203 // Used by writers to randomly choose from the available grace-period primitives.
1204 static int synctype[ARRAY_SIZE(rcu_torture_writer_state_names)] = { };
1205 static int nsynctypes;
1208 * Determine which grace-period primitives are available.
1210 static void rcu_torture_write_types(void)
1212 bool gp_cond1 = gp_cond, gp_cond_exp1 = gp_cond_exp, gp_cond_full1 = gp_cond_full;
1213 bool gp_cond_exp_full1 = gp_cond_exp_full, gp_exp1 = gp_exp, gp_poll_exp1 = gp_poll_exp;
1214 bool gp_poll_exp_full1 = gp_poll_exp_full, gp_normal1 = gp_normal, gp_poll1 = gp_poll;
1215 bool gp_poll_full1 = gp_poll_full, gp_sync1 = gp_sync;
1217 /* Initialize synctype[] array. If none set, take default. */
1221 !gp_cond_exp_full1 &&
1224 !gp_poll_exp_full1 &&
1230 gp_cond_exp1 = true;
1231 gp_cond_full1 = true;
1232 gp_cond_exp_full1 = true;
1234 gp_poll_exp1 = true;
1235 gp_poll_exp_full1 = true;
1238 gp_poll_full1 = true;
1241 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) {
1242 synctype[nsynctypes++] = RTWS_COND_GET;
1243 pr_info("%s: Testing conditional GPs.\n", __func__);
1244 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) {
1245 pr_alert("%s: gp_cond without primitives.\n", __func__);
1247 if (gp_cond_exp1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp) {
1248 synctype[nsynctypes++] = RTWS_COND_GET_EXP;
1249 pr_info("%s: Testing conditional expedited GPs.\n", __func__);
1250 } else if (gp_cond_exp && (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp)) {
1251 pr_alert("%s: gp_cond_exp without primitives.\n", __func__);
1253 if (gp_cond_full1 && cur_ops->get_gp_state && cur_ops->cond_sync_full) {
1254 synctype[nsynctypes++] = RTWS_COND_GET_FULL;
1255 pr_info("%s: Testing conditional full-state GPs.\n", __func__);
1256 } else if (gp_cond_full && (!cur_ops->get_gp_state || !cur_ops->cond_sync_full)) {
1257 pr_alert("%s: gp_cond_full without primitives.\n", __func__);
1259 if (gp_cond_exp_full1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp_full) {
1260 synctype[nsynctypes++] = RTWS_COND_GET_EXP_FULL;
1261 pr_info("%s: Testing conditional full-state expedited GPs.\n", __func__);
1262 } else if (gp_cond_exp_full &&
1263 (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp_full)) {
1264 pr_alert("%s: gp_cond_exp_full without primitives.\n", __func__);
1266 if (gp_exp1 && cur_ops->exp_sync) {
1267 synctype[nsynctypes++] = RTWS_EXP_SYNC;
1268 pr_info("%s: Testing expedited GPs.\n", __func__);
1269 } else if (gp_exp && !cur_ops->exp_sync) {
1270 pr_alert("%s: gp_exp without primitives.\n", __func__);
1272 if (gp_normal1 && cur_ops->deferred_free) {
1273 synctype[nsynctypes++] = RTWS_DEF_FREE;
1274 pr_info("%s: Testing asynchronous GPs.\n", __func__);
1275 } else if (gp_normal && !cur_ops->deferred_free) {
1276 pr_alert("%s: gp_normal without primitives.\n", __func__);
1278 if (gp_poll1 && cur_ops->get_comp_state && cur_ops->same_gp_state &&
1279 cur_ops->start_gp_poll && cur_ops->poll_gp_state) {
1280 synctype[nsynctypes++] = RTWS_POLL_GET;
1281 pr_info("%s: Testing polling GPs.\n", __func__);
1282 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) {
1283 pr_alert("%s: gp_poll without primitives.\n", __func__);
1285 if (gp_poll_full1 && cur_ops->get_comp_state_full && cur_ops->same_gp_state_full
1286 && cur_ops->start_gp_poll_full && cur_ops->poll_gp_state_full) {
1287 synctype[nsynctypes++] = RTWS_POLL_GET_FULL;
1288 pr_info("%s: Testing polling full-state GPs.\n", __func__);
1289 } else if (gp_poll_full && (!cur_ops->start_gp_poll_full || !cur_ops->poll_gp_state_full)) {
1290 pr_alert("%s: gp_poll_full without primitives.\n", __func__);
1292 if (gp_poll_exp1 && cur_ops->start_gp_poll_exp && cur_ops->poll_gp_state_exp) {
1293 synctype[nsynctypes++] = RTWS_POLL_GET_EXP;
1294 pr_info("%s: Testing polling expedited GPs.\n", __func__);
1295 } else if (gp_poll_exp && (!cur_ops->start_gp_poll_exp || !cur_ops->poll_gp_state_exp)) {
1296 pr_alert("%s: gp_poll_exp without primitives.\n", __func__);
1298 if (gp_poll_exp_full1 && cur_ops->start_gp_poll_exp_full && cur_ops->poll_gp_state_full) {
1299 synctype[nsynctypes++] = RTWS_POLL_GET_EXP_FULL;
1300 pr_info("%s: Testing polling full-state expedited GPs.\n", __func__);
1301 } else if (gp_poll_exp_full &&
1302 (!cur_ops->start_gp_poll_exp_full || !cur_ops->poll_gp_state_full)) {
1303 pr_alert("%s: gp_poll_exp_full without primitives.\n", __func__);
1305 if (gp_sync1 && cur_ops->sync) {
1306 synctype[nsynctypes++] = RTWS_SYNC;
1307 pr_info("%s: Testing normal GPs.\n", __func__);
1308 } else if (gp_sync && !cur_ops->sync) {
1309 pr_alert("%s: gp_sync without primitives.\n", __func__);
1314 * Do the specified rcu_torture_writer() synchronous grace period,
1315 * while also testing out the polled APIs. Note well that the single-CPU
1316 * grace-period optimizations must be accounted for.
1318 static void do_rtws_sync(struct torture_random_state *trsp, void (*sync)(void))
1320 unsigned long cookie;
1321 struct rcu_gp_oldstate cookie_full;
1324 unsigned long r = torture_random(trsp);
1326 dopoll = cur_ops->get_gp_state && cur_ops->poll_gp_state && !(r & 0x300);
1327 dopoll_full = cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full && !(r & 0xc00);
1328 if (dopoll || dopoll_full)
1331 cookie = cur_ops->get_gp_state();
1333 cur_ops->get_gp_state_full(&cookie_full);
1334 if (cur_ops->poll_need_2gp && cur_ops->poll_need_2gp(dopoll, dopoll_full))
1337 WARN_ONCE(dopoll && !cur_ops->poll_gp_state(cookie),
1338 "%s: Cookie check 3 failed %pS() online %*pbl.",
1339 __func__, sync, cpumask_pr_args(cpu_online_mask));
1340 WARN_ONCE(dopoll_full && !cur_ops->poll_gp_state_full(&cookie_full),
1341 "%s: Cookie check 4 failed %pS() online %*pbl",
1342 __func__, sync, cpumask_pr_args(cpu_online_mask));
1343 if (dopoll || dopoll_full)
1348 * RCU torture writer kthread. Repeatedly substitutes a new structure
1349 * for that pointed to by rcu_torture_current, freeing the old structure
1350 * after a series of grace periods (the "pipeline").
1353 rcu_torture_writer(void *arg)
1356 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
1357 unsigned long cookie;
1358 struct rcu_gp_oldstate cookie_full;
1360 unsigned long gp_snap;
1361 unsigned long gp_snap1;
1362 struct rcu_gp_oldstate gp_snap_full;
1363 struct rcu_gp_oldstate gp_snap1_full;
1366 int oldnice = task_nice(current);
1367 struct rcu_gp_oldstate rgo[NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE];
1368 struct rcu_torture *rp;
1369 struct rcu_torture *old_rp;
1370 static DEFINE_TORTURE_RANDOM(rand);
1371 bool stutter_waited;
1372 unsigned long ulo[NUM_ACTIVE_RCU_POLL_OLDSTATE];
1374 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
1376 pr_alert("%s" TORTURE_FLAG
1377 " GP expediting controlled from boot/sysfs for %s.\n",
1378 torture_type, cur_ops->name);
1379 if (WARN_ONCE(nsynctypes == 0,
1380 "%s: No update-side primitives.\n", __func__)) {
1382 * No updates primitives, so don't try updating.
1383 * The resulting test won't be testing much, hence the
1384 * above WARN_ONCE().
1386 rcu_torture_writer_state = RTWS_STOPPING;
1387 torture_kthread_stopping("rcu_torture_writer");
1392 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1393 torture_hrtimeout_us(500, 1000, &rand);
1394 rp = rcu_torture_alloc();
1397 rp->rtort_pipe_count = 0;
1398 rcu_torture_writer_state = RTWS_DELAY;
1399 udelay(torture_random(&rand) & 0x3ff);
1400 rcu_torture_writer_state = RTWS_REPLACE;
1401 old_rp = rcu_dereference_check(rcu_torture_current,
1402 current == writer_task);
1403 rp->rtort_mbtest = 1;
1404 rcu_assign_pointer(rcu_torture_current, rp);
1405 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1407 i = old_rp->rtort_pipe_count;
1408 if (i > RCU_TORTURE_PIPE_LEN)
1409 i = RCU_TORTURE_PIPE_LEN;
1410 atomic_inc(&rcu_torture_wcount[i]);
1411 WRITE_ONCE(old_rp->rtort_pipe_count,
1412 old_rp->rtort_pipe_count + 1);
1414 // Make sure readers block polled grace periods.
1415 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
1416 idx = cur_ops->readlock();
1417 cookie = cur_ops->get_gp_state();
1418 WARN_ONCE(cur_ops->poll_gp_state(cookie),
1419 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n",
1421 rcu_torture_writer_state_getname(),
1422 rcu_torture_writer_state,
1423 cookie, cur_ops->get_gp_state());
1424 if (cur_ops->get_gp_completed) {
1425 cookie = cur_ops->get_gp_completed();
1426 WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie));
1428 cur_ops->readunlock(idx);
1430 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) {
1431 idx = cur_ops->readlock();
1432 cur_ops->get_gp_state_full(&cookie_full);
1433 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
1434 "%s: Cookie check 5 failed %s(%d) online %*pbl\n",
1436 rcu_torture_writer_state_getname(),
1437 rcu_torture_writer_state,
1438 cpumask_pr_args(cpu_online_mask));
1439 if (cur_ops->get_gp_completed_full) {
1440 cur_ops->get_gp_completed_full(&cookie_full);
1441 WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full));
1443 cur_ops->readunlock(idx);
1445 switch (synctype[torture_random(&rand) % nsynctypes]) {
1447 rcu_torture_writer_state = RTWS_DEF_FREE;
1448 cur_ops->deferred_free(old_rp);
1451 rcu_torture_writer_state = RTWS_EXP_SYNC;
1452 do_rtws_sync(&rand, cur_ops->exp_sync);
1453 rcu_torture_pipe_update(old_rp);
1456 rcu_torture_writer_state = RTWS_COND_GET;
1457 gp_snap = cur_ops->get_gp_state();
1458 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1459 rcu_torture_writer_state = RTWS_COND_SYNC;
1460 cur_ops->cond_sync(gp_snap);
1461 rcu_torture_pipe_update(old_rp);
1463 case RTWS_COND_GET_EXP:
1464 rcu_torture_writer_state = RTWS_COND_GET_EXP;
1465 gp_snap = cur_ops->get_gp_state_exp();
1466 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1467 rcu_torture_writer_state = RTWS_COND_SYNC_EXP;
1468 cur_ops->cond_sync_exp(gp_snap);
1469 rcu_torture_pipe_update(old_rp);
1471 case RTWS_COND_GET_FULL:
1472 rcu_torture_writer_state = RTWS_COND_GET_FULL;
1473 cur_ops->get_gp_state_full(&gp_snap_full);
1474 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1475 rcu_torture_writer_state = RTWS_COND_SYNC_FULL;
1476 cur_ops->cond_sync_full(&gp_snap_full);
1477 rcu_torture_pipe_update(old_rp);
1479 case RTWS_COND_GET_EXP_FULL:
1480 rcu_torture_writer_state = RTWS_COND_GET_EXP_FULL;
1481 cur_ops->get_gp_state_full(&gp_snap_full);
1482 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1483 rcu_torture_writer_state = RTWS_COND_SYNC_EXP_FULL;
1484 cur_ops->cond_sync_exp_full(&gp_snap_full);
1485 rcu_torture_pipe_update(old_rp);
1488 rcu_torture_writer_state = RTWS_POLL_GET;
1489 for (i = 0; i < ARRAY_SIZE(ulo); i++)
1490 ulo[i] = cur_ops->get_comp_state();
1491 gp_snap = cur_ops->start_gp_poll();
1492 rcu_torture_writer_state = RTWS_POLL_WAIT;
1493 while (!cur_ops->poll_gp_state(gp_snap)) {
1494 gp_snap1 = cur_ops->get_gp_state();
1495 for (i = 0; i < ARRAY_SIZE(ulo); i++)
1496 if (cur_ops->poll_gp_state(ulo[i]) ||
1497 cur_ops->same_gp_state(ulo[i], gp_snap1)) {
1501 WARN_ON_ONCE(i >= ARRAY_SIZE(ulo));
1502 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1505 rcu_torture_pipe_update(old_rp);
1507 case RTWS_POLL_GET_FULL:
1508 rcu_torture_writer_state = RTWS_POLL_GET_FULL;
1509 for (i = 0; i < ARRAY_SIZE(rgo); i++)
1510 cur_ops->get_comp_state_full(&rgo[i]);
1511 cur_ops->start_gp_poll_full(&gp_snap_full);
1512 rcu_torture_writer_state = RTWS_POLL_WAIT_FULL;
1513 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1514 cur_ops->get_gp_state_full(&gp_snap1_full);
1515 for (i = 0; i < ARRAY_SIZE(rgo); i++)
1516 if (cur_ops->poll_gp_state_full(&rgo[i]) ||
1517 cur_ops->same_gp_state_full(&rgo[i],
1519 rgo[i] = gp_snap1_full;
1522 WARN_ON_ONCE(i >= ARRAY_SIZE(rgo));
1523 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1526 rcu_torture_pipe_update(old_rp);
1528 case RTWS_POLL_GET_EXP:
1529 rcu_torture_writer_state = RTWS_POLL_GET_EXP;
1530 gp_snap = cur_ops->start_gp_poll_exp();
1531 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP;
1532 while (!cur_ops->poll_gp_state_exp(gp_snap))
1533 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1535 rcu_torture_pipe_update(old_rp);
1537 case RTWS_POLL_GET_EXP_FULL:
1538 rcu_torture_writer_state = RTWS_POLL_GET_EXP_FULL;
1539 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1540 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP_FULL;
1541 while (!cur_ops->poll_gp_state_full(&gp_snap_full))
1542 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1544 rcu_torture_pipe_update(old_rp);
1547 rcu_torture_writer_state = RTWS_SYNC;
1548 do_rtws_sync(&rand, cur_ops->sync);
1549 rcu_torture_pipe_update(old_rp);
1556 WRITE_ONCE(rcu_torture_current_version,
1557 rcu_torture_current_version + 1);
1558 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1560 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1561 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1562 if (expediting >= 0)
1565 rcu_unexpedite_gp();
1566 if (++expediting > 3)
1567 expediting = -expediting;
1568 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1569 can_expedite = !rcu_gp_is_expedited() &&
1570 !rcu_gp_is_normal();
1572 rcu_torture_writer_state = RTWS_STUTTER;
1573 boot_ended = rcu_inkernel_boot_has_ended();
1574 stutter_waited = stutter_wait("rcu_torture_writer");
1575 if (stutter_waited &&
1576 !atomic_read(&rcu_fwd_cb_nodelay) &&
1577 !cur_ops->slow_gps &&
1578 !torture_must_stop() &&
1580 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1581 if (list_empty(&rcu_tortures[i].rtort_free) &&
1582 rcu_access_pointer(rcu_torture_current) !=
1585 show_rcu_gp_kthreads();
1586 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1587 rcu_ftrace_dump(DUMP_ALL);
1590 sched_set_normal(current, oldnice);
1591 } while (!torture_must_stop());
1592 rcu_torture_current = NULL; // Let stats task know that we are done.
1593 /* Reset expediting back to unexpedited. */
1595 expediting = -expediting;
1596 while (can_expedite && expediting++ < 0)
1597 rcu_unexpedite_gp();
1598 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1600 pr_alert("%s" TORTURE_FLAG
1601 " Dynamic grace-period expediting was disabled.\n",
1603 rcu_torture_writer_state = RTWS_STOPPING;
1604 torture_kthread_stopping("rcu_torture_writer");
1609 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1610 * delay between calls.
1613 rcu_torture_fakewriter(void *arg)
1615 unsigned long gp_snap;
1616 struct rcu_gp_oldstate gp_snap_full;
1617 DEFINE_TORTURE_RANDOM(rand);
1619 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1620 set_user_nice(current, MAX_NICE);
1622 if (WARN_ONCE(nsynctypes == 0,
1623 "%s: No update-side primitives.\n", __func__)) {
1625 * No updates primitives, so don't try updating.
1626 * The resulting test won't be testing much, hence the
1627 * above WARN_ONCE().
1629 torture_kthread_stopping("rcu_torture_fakewriter");
1634 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand);
1635 if (cur_ops->cb_barrier != NULL &&
1636 torture_random(&rand) % (nfakewriters * 8) == 0) {
1637 cur_ops->cb_barrier();
1639 switch (synctype[torture_random(&rand) % nsynctypes]) {
1643 cur_ops->exp_sync();
1646 gp_snap = cur_ops->get_gp_state();
1647 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1648 cur_ops->cond_sync(gp_snap);
1650 case RTWS_COND_GET_EXP:
1651 gp_snap = cur_ops->get_gp_state_exp();
1652 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1653 cur_ops->cond_sync_exp(gp_snap);
1655 case RTWS_COND_GET_FULL:
1656 cur_ops->get_gp_state_full(&gp_snap_full);
1657 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1658 cur_ops->cond_sync_full(&gp_snap_full);
1660 case RTWS_COND_GET_EXP_FULL:
1661 cur_ops->get_gp_state_full(&gp_snap_full);
1662 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1663 cur_ops->cond_sync_exp_full(&gp_snap_full);
1666 gp_snap = cur_ops->start_gp_poll();
1667 while (!cur_ops->poll_gp_state(gp_snap)) {
1668 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1672 case RTWS_POLL_GET_FULL:
1673 cur_ops->start_gp_poll_full(&gp_snap_full);
1674 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1675 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1679 case RTWS_POLL_GET_EXP:
1680 gp_snap = cur_ops->start_gp_poll_exp();
1681 while (!cur_ops->poll_gp_state_exp(gp_snap)) {
1682 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1686 case RTWS_POLL_GET_EXP_FULL:
1687 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1688 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1689 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1701 stutter_wait("rcu_torture_fakewriter");
1702 } while (!torture_must_stop());
1704 torture_kthread_stopping("rcu_torture_fakewriter");
1708 static void rcu_torture_timer_cb(struct rcu_head *rhp)
1713 // Set up and carry out testing of RCU's global memory ordering
1714 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp,
1715 struct torture_random_state *trsp)
1717 unsigned long loops;
1718 int noc = torture_num_online_cpus();
1721 struct rcu_torture_reader_check *rtrcp; // Me.
1722 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking.
1723 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked.
1724 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me.
1727 return; // Don't try this from timer handlers.
1729 // Increment my counter.
1730 rtrcp = &rcu_torture_reader_mbchk[myid];
1731 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1);
1733 // Attempt to assign someone else some checking work.
1734 rdrchked = torture_random(trsp) % nrealreaders;
1735 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1736 rdrchker = torture_random(trsp) % nrealreaders;
1737 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker];
1738 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker &&
1739 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below.
1740 !READ_ONCE(rtp->rtort_chkp) &&
1741 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below.
1742 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops);
1743 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0);
1744 rtrcp->rtc_chkrdr = rdrchked;
1745 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends.
1746 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) ||
1747 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp))
1748 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out.
1751 // If assigned some completed work, do it!
1752 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner);
1753 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready))
1754 return; // No work or work not yet ready.
1755 rdrchked = rtrcp_assigner->rtc_chkrdr;
1756 if (WARN_ON_ONCE(rdrchked < 0))
1758 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1759 loops = READ_ONCE(rtrcp_chked->rtc_myloops);
1760 atomic_inc(&n_rcu_torture_mbchk_tries);
1761 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops))
1762 atomic_inc(&n_rcu_torture_mbchk_fail);
1763 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2;
1764 rtrcp_assigner->rtc_ready = 0;
1765 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work.
1766 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign.
1770 * Do one extension of an RCU read-side critical section using the
1771 * current reader state in readstate (set to zero for initial entry
1772 * to extended critical section), set the new state as specified by
1773 * newstate (set to zero for final exit from extended critical section),
1774 * and random-number-generator state in trsp. If this is neither the
1775 * beginning or end of the critical section and if there was actually a
1776 * change, do a ->read_delay().
1778 static void rcutorture_one_extend(int *readstate, int newstate,
1779 struct torture_random_state *trsp,
1780 struct rt_read_seg *rtrsp)
1782 unsigned long flags;
1785 int idxold1 = *readstate;
1786 int idxold2 = idxold1;
1787 int statesnew = ~*readstate & newstate;
1788 int statesold = *readstate & ~newstate;
1790 WARN_ON_ONCE(idxold2 < 0);
1791 WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
1792 rtrsp->rt_readstate = newstate;
1794 /* First, put new protection in place to avoid critical-section gap. */
1795 if (statesnew & RCUTORTURE_RDR_BH)
1797 if (statesnew & RCUTORTURE_RDR_RBH)
1799 if (statesnew & RCUTORTURE_RDR_IRQ)
1800 local_irq_disable();
1801 if (statesnew & RCUTORTURE_RDR_PREEMPT)
1803 if (statesnew & RCUTORTURE_RDR_SCHED)
1804 rcu_read_lock_sched();
1805 if (statesnew & RCUTORTURE_RDR_RCU_1)
1806 idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1;
1807 if (statesnew & RCUTORTURE_RDR_RCU_2)
1808 idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2;
1811 * Next, remove old protection, in decreasing order of strength
1812 * to avoid unlock paths that aren't safe in the stronger
1813 * context. Namely: BH can not be enabled with disabled interrupts.
1814 * Additionally PREEMPT_RT requires that BH is enabled in preemptible
1817 if (statesold & RCUTORTURE_RDR_IRQ)
1819 if (statesold & RCUTORTURE_RDR_PREEMPT)
1821 if (statesold & RCUTORTURE_RDR_SCHED)
1822 rcu_read_unlock_sched();
1823 if (statesold & RCUTORTURE_RDR_BH)
1825 if (statesold & RCUTORTURE_RDR_RBH)
1826 rcu_read_unlock_bh();
1827 if (statesold & RCUTORTURE_RDR_RCU_2) {
1828 cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1);
1829 WARN_ON_ONCE(idxnew2 != -1);
1832 if (statesold & RCUTORTURE_RDR_RCU_1) {
1835 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff);
1837 raw_spin_lock_irqsave(¤t->pi_lock, flags);
1838 cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1);
1839 WARN_ON_ONCE(idxnew1 != -1);
1842 raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
1845 /* Delay if neither beginning nor end and there was a change. */
1846 if ((statesnew || statesold) && *readstate && newstate)
1847 cur_ops->read_delay(trsp, rtrsp);
1849 /* Update the reader state. */
1851 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1;
1852 WARN_ON_ONCE(idxnew1 < 0);
1853 if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1))
1854 pr_info("Unexpected idxnew1 value of %#x\n", idxnew1);
1856 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2;
1857 WARN_ON_ONCE(idxnew2 < 0);
1858 WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
1859 *readstate = idxnew1 | idxnew2 | newstate;
1860 WARN_ON_ONCE(*readstate < 0);
1861 if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1))
1862 pr_info("Unexpected idxnew2 value of %#x\n", idxnew2);
1865 /* Return the biggest extendables mask given current RCU and boot parameters. */
1866 static int rcutorture_extend_mask_max(void)
1870 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1871 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1872 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2;
1876 /* Return a random protection state mask, but with at least one bit set. */
1878 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1880 int mask = rcutorture_extend_mask_max();
1881 unsigned long randmask1 = torture_random(trsp);
1882 unsigned long randmask2 = randmask1 >> 3;
1883 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
1884 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
1885 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1887 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1);
1888 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
1889 if (!(randmask1 & 0x7))
1890 mask = mask & randmask2;
1892 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1894 // Can't have nested RCU reader without outer RCU reader.
1895 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) {
1896 if (oldmask & RCUTORTURE_RDR_RCU_1)
1897 mask &= ~RCUTORTURE_RDR_RCU_2;
1899 mask |= RCUTORTURE_RDR_RCU_1;
1903 * Can't enable bh w/irq disabled.
1905 if (mask & RCUTORTURE_RDR_IRQ)
1906 mask |= oldmask & bhs;
1909 * Ideally these sequences would be detected in debug builds
1910 * (regardless of RT), but until then don't stop testing
1913 if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
1914 /* Can't modify BH in atomic context */
1915 if (oldmask & preempts_irq)
1917 if ((oldmask | mask) & preempts_irq)
1918 mask |= oldmask & bhs;
1921 return mask ?: RCUTORTURE_RDR_RCU_1;
1925 * Do a randomly selected number of extensions of an existing RCU read-side
1928 static struct rt_read_seg *
1929 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1930 struct rt_read_seg *rtrsp)
1934 int mask = rcutorture_extend_mask_max();
1936 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
1937 if (!((mask - 1) & mask))
1938 return rtrsp; /* Current RCU reader not extendable. */
1939 /* Bias towards larger numbers of loops. */
1940 i = torture_random(trsp);
1941 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
1942 for (j = 0; j < i; j++) {
1943 mask = rcutorture_extend_mask(*readstate, trsp);
1944 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
1950 * Do one read-side critical section, returning false if there was
1951 * no data to read. Can be invoked both from process context and
1952 * from a timer handler.
1954 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
1956 bool checkpolling = !(torture_random(trsp) & 0xfff);
1957 unsigned long cookie;
1958 struct rcu_gp_oldstate cookie_full;
1960 unsigned long started;
1961 unsigned long completed;
1963 struct rcu_torture *p;
1966 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
1967 struct rt_read_seg *rtrsp = &rtseg[0];
1968 struct rt_read_seg *rtrsp1;
1969 unsigned long long ts;
1971 WARN_ON_ONCE(!rcu_is_watching());
1972 newstate = rcutorture_extend_mask(readstate, trsp);
1973 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
1975 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
1976 cookie = cur_ops->get_gp_state();
1977 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
1978 cur_ops->get_gp_state_full(&cookie_full);
1980 started = cur_ops->get_gp_seq();
1981 ts = rcu_trace_clock_local();
1982 p = rcu_dereference_check(rcu_torture_current,
1983 !cur_ops->readlock_held || cur_ops->readlock_held());
1985 /* Wait for rcu_torture_writer to get underway */
1986 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1989 if (p->rtort_mbtest == 0)
1990 atomic_inc(&n_rcu_torture_mberror);
1991 rcu_torture_reader_do_mbchk(myid, p, trsp);
1992 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
1994 pipe_count = READ_ONCE(p->rtort_pipe_count);
1995 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1996 /* Should not happen, but... */
1997 pipe_count = RCU_TORTURE_PIPE_LEN;
1999 completed = cur_ops->get_gp_seq();
2000 if (pipe_count > 1) {
2001 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
2002 ts, started, completed);
2003 rcu_ftrace_dump(DUMP_ALL);
2005 __this_cpu_inc(rcu_torture_count[pipe_count]);
2006 completed = rcutorture_seq_diff(completed, started);
2007 if (completed > RCU_TORTURE_PIPE_LEN) {
2008 /* Should not happen, but... */
2009 completed = RCU_TORTURE_PIPE_LEN;
2011 __this_cpu_inc(rcu_torture_batch[completed]);
2014 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
2015 WARN_ONCE(cur_ops->poll_gp_state(cookie),
2016 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
2018 rcu_torture_writer_state_getname(),
2019 rcu_torture_writer_state,
2020 cookie, cur_ops->get_gp_state());
2021 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
2022 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
2023 "%s: Cookie check 6 failed %s(%d) online %*pbl\n",
2025 rcu_torture_writer_state_getname(),
2026 rcu_torture_writer_state,
2027 cpumask_pr_args(cpu_online_mask));
2029 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
2030 WARN_ON_ONCE(readstate);
2031 // This next splat is expected behavior if leakpointer, especially
2032 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
2033 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1);
2035 /* If error or close call, record the sequence of reader protections. */
2036 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
2038 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
2039 err_segs[i++] = *rtrsp1;
2046 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
2049 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
2050 * incrementing the corresponding element of the pipeline array. The
2051 * counter in the element should never be greater than 1, otherwise, the
2052 * RCU implementation is broken.
2054 static void rcu_torture_timer(struct timer_list *unused)
2056 atomic_long_inc(&n_rcu_torture_timers);
2057 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1);
2059 /* Test call_rcu() invocation from interrupt handler. */
2060 if (cur_ops->call) {
2061 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
2064 cur_ops->call(rhp, rcu_torture_timer_cb);
2069 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
2070 * incrementing the corresponding element of the pipeline array. The
2071 * counter in the element should never be greater than 1, otherwise, the
2072 * RCU implementation is broken.
2075 rcu_torture_reader(void *arg)
2077 unsigned long lastsleep = jiffies;
2078 long myid = (long)arg;
2079 int mynumonline = myid;
2080 DEFINE_TORTURE_RANDOM(rand);
2081 struct timer_list t;
2083 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
2084 set_user_nice(current, MAX_NICE);
2085 if (irqreader && cur_ops->irq_capable)
2086 timer_setup_on_stack(&t, rcu_torture_timer, 0);
2087 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2089 if (irqreader && cur_ops->irq_capable) {
2090 if (!timer_pending(&t))
2091 mod_timer(&t, jiffies + 1);
2093 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop())
2094 schedule_timeout_interruptible(HZ);
2095 if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
2096 torture_hrtimeout_us(500, 1000, &rand);
2097 lastsleep = jiffies + 10;
2099 while (torture_num_online_cpus() < mynumonline && !torture_must_stop())
2100 schedule_timeout_interruptible(HZ / 5);
2101 stutter_wait("rcu_torture_reader");
2102 } while (!torture_must_stop());
2103 if (irqreader && cur_ops->irq_capable) {
2105 destroy_timer_on_stack(&t);
2107 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2108 torture_kthread_stopping("rcu_torture_reader");
2113 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to
2114 * increase race probabilities and fuzzes the interval between toggling.
2116 static int rcu_nocb_toggle(void *arg)
2120 int oldnice = task_nice(current);
2122 DEFINE_TORTURE_RANDOM(rand);
2123 ktime_t toggle_delay;
2124 unsigned long toggle_fuzz;
2125 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle);
2127 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started");
2128 while (!rcu_inkernel_boot_has_ended())
2129 schedule_timeout_interruptible(HZ / 10);
2130 for_each_possible_cpu(cpu)
2132 WARN_ON(maxcpu < 0);
2133 if (toggle_interval > ULONG_MAX)
2134 toggle_fuzz = ULONG_MAX >> 3;
2136 toggle_fuzz = toggle_interval >> 3;
2137 if (toggle_fuzz <= 0)
2138 toggle_fuzz = NSEC_PER_USEC;
2140 r = torture_random(&rand);
2141 cpu = (r >> 1) % (maxcpu + 1);
2143 rcu_nocb_cpu_offload(cpu);
2144 atomic_long_inc(&n_nocb_offload);
2146 rcu_nocb_cpu_deoffload(cpu);
2147 atomic_long_inc(&n_nocb_deoffload);
2149 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval;
2150 set_current_state(TASK_INTERRUPTIBLE);
2151 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL);
2152 if (stutter_wait("rcu_nocb_toggle"))
2153 sched_set_normal(current, oldnice);
2154 } while (!torture_must_stop());
2155 torture_kthread_stopping("rcu_nocb_toggle");
2160 * Print torture statistics. Caller must ensure that there is only
2161 * one call to this function at a given time!!! This is normally
2162 * accomplished by relying on the module system to only have one copy
2163 * of the module loaded, and then by giving the rcu_torture_stats
2164 * kthread full control (or the init/cleanup functions when rcu_torture_stats
2165 * thread is not running).
2168 rcu_torture_stats_print(void)
2172 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2173 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2174 struct rcu_torture *rtcp;
2175 static unsigned long rtcv_snap = ULONG_MAX;
2176 static bool splatted;
2177 struct task_struct *wtp;
2179 for_each_possible_cpu(cpu) {
2180 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2181 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
2182 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
2185 for (i = RCU_TORTURE_PIPE_LEN; i >= 0; i--) {
2186 if (pipesummary[i] != 0)
2190 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2191 rtcp = rcu_access_pointer(rcu_torture_current);
2192 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
2194 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
2195 rcu_torture_current_version,
2196 list_empty(&rcu_torture_freelist),
2197 atomic_read(&n_rcu_torture_alloc),
2198 atomic_read(&n_rcu_torture_alloc_fail),
2199 atomic_read(&n_rcu_torture_free));
2200 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld ",
2201 atomic_read(&n_rcu_torture_mberror),
2202 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries),
2203 n_rcu_torture_barrier_error,
2204 n_rcu_torture_boost_ktrerror);
2205 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
2206 n_rcu_torture_boost_failure,
2207 n_rcu_torture_boosts,
2208 atomic_long_read(&n_rcu_torture_timers));
2209 torture_onoff_stats();
2210 pr_cont("barrier: %ld/%ld:%ld ",
2211 data_race(n_barrier_successes),
2212 data_race(n_barrier_attempts),
2213 data_race(n_rcu_torture_barrier_error));
2214 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic.
2215 pr_cont("nocb-toggles: %ld:%ld\n",
2216 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload));
2218 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2219 if (atomic_read(&n_rcu_torture_mberror) ||
2220 atomic_read(&n_rcu_torture_mbchk_fail) ||
2221 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
2222 n_rcu_torture_boost_failure || i > 1) {
2223 pr_cont("%s", "!!! ");
2224 atomic_inc(&n_rcu_torture_error);
2225 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
2226 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail));
2227 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
2228 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
2229 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
2230 WARN_ON_ONCE(i > 1); // Too-short grace period
2232 pr_cont("Reader Pipe: ");
2233 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2234 pr_cont(" %ld", pipesummary[i]);
2237 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2238 pr_cont("Reader Batch: ");
2239 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2240 pr_cont(" %ld", batchsummary[i]);
2243 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2244 pr_cont("Free-Block Circulation: ");
2245 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2246 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
2252 if (rtcv_snap == rcu_torture_current_version &&
2253 rcu_access_pointer(rcu_torture_current) &&
2254 !rcu_stall_is_suppressed()) {
2255 int __maybe_unused flags = 0;
2256 unsigned long __maybe_unused gp_seq = 0;
2258 rcutorture_get_gp_data(cur_ops->ttype,
2260 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
2262 wtp = READ_ONCE(writer_task);
2263 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n",
2264 rcu_torture_writer_state_getname(),
2265 rcu_torture_writer_state, gp_seq, flags,
2266 wtp == NULL ? ~0U : wtp->__state,
2267 wtp == NULL ? -1 : (int)task_cpu(wtp));
2268 if (!splatted && wtp) {
2269 sched_show_task(wtp);
2272 if (cur_ops->gp_kthread_dbg)
2273 cur_ops->gp_kthread_dbg();
2274 rcu_ftrace_dump(DUMP_ALL);
2276 rtcv_snap = rcu_torture_current_version;
2280 * Periodically prints torture statistics, if periodic statistics printing
2281 * was specified via the stat_interval module parameter.
2284 rcu_torture_stats(void *arg)
2286 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
2288 schedule_timeout_interruptible(stat_interval * HZ);
2289 rcu_torture_stats_print();
2290 torture_shutdown_absorb("rcu_torture_stats");
2291 } while (!torture_must_stop());
2292 torture_kthread_stopping("rcu_torture_stats");
2296 /* Test mem_dump_obj() and friends. */
2297 static void rcu_torture_mem_dump_obj(void)
2299 struct rcu_head *rhp;
2300 struct kmem_cache *kcp;
2303 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
2304 if (WARN_ON_ONCE(!kcp))
2306 rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
2307 if (WARN_ON_ONCE(!rhp)) {
2308 kmem_cache_destroy(kcp);
2311 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
2312 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
2313 mem_dump_obj(ZERO_SIZE_PTR);
2314 pr_alert("mem_dump_obj(NULL):");
2316 pr_alert("mem_dump_obj(%px):", &rhp);
2318 pr_alert("mem_dump_obj(%px):", rhp);
2320 pr_alert("mem_dump_obj(%px):", &rhp->func);
2321 mem_dump_obj(&rhp->func);
2322 pr_alert("mem_dump_obj(%px):", &z);
2324 kmem_cache_free(kcp, rhp);
2325 kmem_cache_destroy(kcp);
2326 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
2327 if (WARN_ON_ONCE(!rhp))
2329 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2330 pr_alert("mem_dump_obj(kmalloc %px):", rhp);
2332 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
2333 mem_dump_obj(&rhp->func);
2335 rhp = vmalloc(4096);
2336 if (WARN_ON_ONCE(!rhp))
2338 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2339 pr_alert("mem_dump_obj(vmalloc %px):", rhp);
2341 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
2342 mem_dump_obj(&rhp->func);
2347 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
2349 pr_alert("%s" TORTURE_FLAG
2350 "--- %s: nreaders=%d nfakewriters=%d "
2351 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
2352 "shuffle_interval=%d stutter=%d irqreader=%d "
2353 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
2354 "test_boost=%d/%d test_boost_interval=%d "
2355 "test_boost_duration=%d shutdown_secs=%d "
2356 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
2357 "stall_cpu_block=%d "
2359 "onoff_interval=%d onoff_holdoff=%d "
2360 "read_exit_delay=%d read_exit_burst=%d "
2361 "nocbs_nthreads=%d nocbs_toggle=%d "
2363 torture_type, tag, nrealreaders, nfakewriters,
2364 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
2365 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
2366 test_boost, cur_ops->can_boost,
2367 test_boost_interval, test_boost_duration, shutdown_secs,
2368 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
2371 onoff_interval, onoff_holdoff,
2372 read_exit_delay, read_exit_burst,
2373 nocbs_nthreads, nocbs_toggle,
2377 static int rcutorture_booster_cleanup(unsigned int cpu)
2379 struct task_struct *t;
2381 if (boost_tasks[cpu] == NULL)
2383 mutex_lock(&boost_mutex);
2384 t = boost_tasks[cpu];
2385 boost_tasks[cpu] = NULL;
2386 rcu_torture_enable_rt_throttle();
2387 mutex_unlock(&boost_mutex);
2389 /* This must be outside of the mutex, otherwise deadlock! */
2390 torture_stop_kthread(rcu_torture_boost, t);
2394 static int rcutorture_booster_init(unsigned int cpu)
2398 if (boost_tasks[cpu] != NULL)
2399 return 0; /* Already created, nothing more to do. */
2401 // Testing RCU priority boosting requires rcutorture do
2402 // some serious abuse. Counter this by running ksoftirqd
2403 // at higher priority.
2404 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) {
2405 struct sched_param sp;
2406 struct task_struct *t;
2408 t = per_cpu(ksoftirqd, cpu);
2410 sp.sched_priority = 2;
2411 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
2414 /* Don't allow time recalculation while creating a new task. */
2415 mutex_lock(&boost_mutex);
2416 rcu_torture_disable_rt_throttle();
2417 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
2418 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL,
2419 cpu, "rcu_torture_boost_%u");
2420 if (IS_ERR(boost_tasks[cpu])) {
2421 retval = PTR_ERR(boost_tasks[cpu]);
2422 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
2423 n_rcu_torture_boost_ktrerror++;
2424 boost_tasks[cpu] = NULL;
2425 mutex_unlock(&boost_mutex);
2428 mutex_unlock(&boost_mutex);
2432 static int rcu_torture_stall_nf(struct notifier_block *nb, unsigned long v, void *ptr)
2434 pr_info("%s: v=%lu, duration=%lu.\n", __func__, v, (unsigned long)ptr);
2438 static struct notifier_block rcu_torture_stall_block = {
2439 .notifier_call = rcu_torture_stall_nf,
2443 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
2444 * induces a CPU stall for the time specified by stall_cpu.
2446 static int rcu_torture_stall(void *args)
2450 unsigned long stop_at;
2452 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
2453 ret = rcu_stall_chain_notifier_register(&rcu_torture_stall_block);
2455 pr_info("%s: rcu_stall_chain_notifier_register() returned %d, %sexpected.\n",
2456 __func__, ret, !IS_ENABLED(CONFIG_RCU_STALL_COMMON) ? "un" : "");
2457 if (stall_cpu_holdoff > 0) {
2458 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
2459 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
2460 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
2462 if (!kthread_should_stop() && stall_gp_kthread > 0) {
2463 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
2464 rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
2465 for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
2466 if (kthread_should_stop())
2468 schedule_timeout_uninterruptible(HZ);
2471 if (!kthread_should_stop() && stall_cpu > 0) {
2472 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
2473 stop_at = ktime_get_seconds() + stall_cpu;
2474 /* RCU CPU stall is expected behavior in following code. */
2475 idx = cur_ops->readlock();
2476 if (stall_cpu_irqsoff)
2477 local_irq_disable();
2478 else if (!stall_cpu_block)
2480 pr_alert("%s start on CPU %d.\n",
2481 __func__, raw_smp_processor_id());
2482 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
2484 if (stall_cpu_block) {
2485 #ifdef CONFIG_PREEMPTION
2488 schedule_timeout_uninterruptible(HZ);
2490 } else if (stall_no_softlockup) {
2491 touch_softlockup_watchdog();
2493 if (stall_cpu_irqsoff)
2495 else if (!stall_cpu_block)
2497 cur_ops->readunlock(idx);
2499 pr_alert("%s end.\n", __func__);
2501 ret = rcu_stall_chain_notifier_unregister(&rcu_torture_stall_block);
2503 pr_info("%s: rcu_stall_chain_notifier_unregister() returned %d.\n", __func__, ret);
2505 torture_shutdown_absorb("rcu_torture_stall");
2506 while (!kthread_should_stop())
2507 schedule_timeout_interruptible(10 * HZ);
2511 /* Spawn CPU-stall kthread, if stall_cpu specified. */
2512 static int __init rcu_torture_stall_init(void)
2514 if (stall_cpu <= 0 && stall_gp_kthread <= 0)
2516 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
2519 /* State structure for forward-progress self-propagating RCU callback. */
2520 struct fwd_cb_state {
2526 * Forward-progress self-propagating RCU callback function. Because
2527 * callbacks run from softirq, this function is an implicit RCU read-side
2530 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
2532 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
2534 if (READ_ONCE(fcsp->stop)) {
2535 WRITE_ONCE(fcsp->stop, 2);
2538 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
2541 /* State for continuous-flood RCU callbacks. */
2544 struct rcu_fwd_cb *rfc_next;
2545 struct rcu_fwd *rfc_rfp;
2549 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
2550 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
2551 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
2552 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
2553 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
2555 struct rcu_launder_hist {
2557 unsigned long launder_gp_seq;
2561 spinlock_t rcu_fwd_lock;
2562 struct rcu_fwd_cb *rcu_fwd_cb_head;
2563 struct rcu_fwd_cb **rcu_fwd_cb_tail;
2565 unsigned long rcu_fwd_startat;
2566 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
2567 unsigned long rcu_launder_gp_seq_start;
2571 static DEFINE_MUTEX(rcu_fwd_mutex);
2572 static struct rcu_fwd *rcu_fwds;
2573 static unsigned long rcu_fwd_seq;
2574 static atomic_long_t rcu_fwd_max_cbs;
2575 static bool rcu_fwd_emergency_stop;
2577 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
2580 unsigned long gps_old;
2584 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
2585 if (rfp->n_launders_hist[i].n_launders > 0)
2587 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):",
2588 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat);
2589 gps_old = rfp->rcu_launder_gp_seq_start;
2590 for (j = 0; j <= i; j++) {
2591 gps = rfp->n_launders_hist[j].launder_gp_seq;
2592 pr_cont(" %ds/%d: %ld:%ld",
2593 j + 1, FWD_CBS_HIST_DIV,
2594 rfp->n_launders_hist[j].n_launders,
2595 rcutorture_seq_diff(gps, gps_old));
2601 /* Callback function for continuous-flood RCU callbacks. */
2602 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
2604 unsigned long flags;
2606 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
2607 struct rcu_fwd_cb **rfcpp;
2608 struct rcu_fwd *rfp = rfcp->rfc_rfp;
2610 rfcp->rfc_next = NULL;
2612 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2613 rfcpp = rfp->rcu_fwd_cb_tail;
2614 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
2615 WRITE_ONCE(*rfcpp, rfcp);
2616 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
2617 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
2618 if (i >= ARRAY_SIZE(rfp->n_launders_hist))
2619 i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
2620 rfp->n_launders_hist[i].n_launders++;
2621 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
2622 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2625 // Give the scheduler a chance, even on nohz_full CPUs.
2626 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
2628 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
2629 // Real call_rcu() floods hit userspace, so emulate that.
2630 if (need_resched() || (iter & 0xfff))
2634 // No userspace emulation: CB invocation throttles call_rcu()
2639 * Free all callbacks on the rcu_fwd_cb_head list, either because the
2640 * test is over or because we hit an OOM event.
2642 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
2644 unsigned long flags;
2645 unsigned long freed = 0;
2646 struct rcu_fwd_cb *rfcp;
2649 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2650 rfcp = rfp->rcu_fwd_cb_head;
2652 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2655 rfp->rcu_fwd_cb_head = rfcp->rfc_next;
2656 if (!rfp->rcu_fwd_cb_head)
2657 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2658 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2661 rcu_torture_fwd_prog_cond_resched(freed);
2662 if (tick_nohz_full_enabled()) {
2663 local_irq_save(flags);
2664 rcu_momentary_dyntick_idle();
2665 local_irq_restore(flags);
2671 /* Carry out need_resched()/cond_resched() forward-progress testing. */
2672 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
2673 int *tested, int *tested_tries)
2677 struct fwd_cb_state fcs;
2682 bool selfpropcb = false;
2683 unsigned long stopat;
2684 static DEFINE_TORTURE_RANDOM(trs);
2686 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2688 return; // Cannot do need_resched() forward progress testing without ->sync.
2689 if (cur_ops->call && cur_ops->cb_barrier) {
2690 init_rcu_head_on_stack(&fcs.rh);
2694 /* Tight loop containing cond_resched(). */
2695 atomic_inc(&rcu_fwd_cb_nodelay);
2696 cur_ops->sync(); /* Later readers see above write. */
2698 WRITE_ONCE(fcs.stop, 0);
2699 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
2701 cver = READ_ONCE(rcu_torture_current_version);
2702 gps = cur_ops->get_gp_seq();
2703 sd = cur_ops->stall_dur() + 1;
2704 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
2705 dur = sd4 + torture_random(&trs) % (sd - sd4);
2706 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2707 stopat = rfp->rcu_fwd_startat + dur;
2708 while (time_before(jiffies, stopat) &&
2709 !shutdown_time_arrived() &&
2710 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2711 idx = cur_ops->readlock();
2713 cur_ops->readunlock(idx);
2714 if (!fwd_progress_need_resched || need_resched())
2718 if (!time_before(jiffies, stopat) &&
2719 !shutdown_time_arrived() &&
2720 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2722 cver = READ_ONCE(rcu_torture_current_version) - cver;
2723 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2724 WARN_ON(!cver && gps < 2);
2725 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__,
2726 rfp->rcu_fwd_id, dur, cver, gps);
2729 WRITE_ONCE(fcs.stop, 1);
2730 cur_ops->sync(); /* Wait for running CB to complete. */
2731 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2732 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
2736 WARN_ON(READ_ONCE(fcs.stop) != 2);
2737 destroy_rcu_head_on_stack(&fcs.rh);
2739 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
2740 atomic_dec(&rcu_fwd_cb_nodelay);
2743 /* Carry out call_rcu() forward-progress testing. */
2744 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
2747 unsigned long flags;
2751 long n_launders_cb_snap;
2755 struct rcu_fwd_cb *rfcp;
2756 struct rcu_fwd_cb *rfcpn;
2757 unsigned long stopat;
2758 unsigned long stoppedat;
2760 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2761 if (READ_ONCE(rcu_fwd_emergency_stop))
2762 return; /* Get out of the way quickly, no GP wait! */
2764 return; /* Can't do call_rcu() fwd prog without ->call. */
2766 /* Loop continuously posting RCU callbacks. */
2767 atomic_inc(&rcu_fwd_cb_nodelay);
2768 cur_ops->sync(); /* Later readers see above write. */
2769 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2770 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
2772 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
2776 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
2777 rfp->n_launders_hist[i].n_launders = 0;
2778 cver = READ_ONCE(rcu_torture_current_version);
2779 gps = cur_ops->get_gp_seq();
2780 rfp->rcu_launder_gp_seq_start = gps;
2781 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2782 while (time_before(jiffies, stopat) &&
2783 !shutdown_time_arrived() &&
2784 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2785 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
2788 rfcpn = READ_ONCE(rfcp->rfc_next);
2790 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
2791 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
2793 rfp->rcu_fwd_cb_head = rfcpn;
2796 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) {
2797 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
2798 if (WARN_ON_ONCE(!rfcp)) {
2799 schedule_timeout_interruptible(1);
2805 rfcp->rfc_rfp = rfp;
2810 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
2811 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
2812 if (tick_nohz_full_enabled()) {
2813 local_irq_save(flags);
2814 rcu_momentary_dyntick_idle();
2815 local_irq_restore(flags);
2818 stoppedat = jiffies;
2819 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
2820 cver = READ_ONCE(rcu_torture_current_version) - cver;
2821 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2822 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2823 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
2824 (void)rcu_torture_fwd_prog_cbfree(rfp);
2826 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
2827 !shutdown_time_arrived()) {
2828 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
2829 pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n",
2831 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
2832 n_launders + n_max_cbs - n_launders_cb_snap,
2833 n_launders, n_launders_sa,
2834 n_max_gps, n_max_cbs, cver, gps);
2835 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs);
2836 mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
2837 rcu_torture_fwd_cb_hist(rfp);
2838 mutex_unlock(&rcu_fwd_mutex);
2840 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
2841 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2842 atomic_dec(&rcu_fwd_cb_nodelay);
2847 * OOM notifier, but this only prints diagnostic information for the
2848 * current forward-progress test.
2850 static int rcutorture_oom_notify(struct notifier_block *self,
2851 unsigned long notused, void *nfreed)
2855 struct rcu_fwd *rfp;
2857 mutex_lock(&rcu_fwd_mutex);
2860 mutex_unlock(&rcu_fwd_mutex);
2863 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
2865 for (i = 0; i < fwd_progress; i++) {
2866 rcu_torture_fwd_cb_hist(&rfp[i]);
2867 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2);
2869 WRITE_ONCE(rcu_fwd_emergency_stop, true);
2870 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
2872 for (i = 0; i < fwd_progress; i++)
2873 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2874 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2875 cur_ops->cb_barrier();
2877 for (i = 0; i < fwd_progress; i++)
2878 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2879 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2880 cur_ops->cb_barrier();
2882 for (i = 0; i < fwd_progress; i++)
2883 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2884 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2885 smp_mb(); /* Frees before return to avoid redoing OOM. */
2886 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
2887 pr_info("%s returning after OOM processing.\n", __func__);
2888 mutex_unlock(&rcu_fwd_mutex);
2892 static struct notifier_block rcutorture_oom_nb = {
2893 .notifier_call = rcutorture_oom_notify
2896 /* Carry out grace-period forward-progress testing. */
2897 static int rcu_torture_fwd_prog(void *args)
2899 bool firsttime = true;
2901 int oldnice = task_nice(current);
2902 unsigned long oldseq = READ_ONCE(rcu_fwd_seq);
2903 struct rcu_fwd *rfp = args;
2905 int tested_tries = 0;
2907 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
2908 rcu_bind_current_to_nocb();
2909 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
2910 set_user_nice(current, MAX_NICE);
2912 if (!rfp->rcu_fwd_id) {
2913 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
2914 WRITE_ONCE(rcu_fwd_emergency_stop, false);
2916 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0);
2917 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs);
2920 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1);
2922 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop())
2923 schedule_timeout_interruptible(HZ / 20);
2924 oldseq = READ_ONCE(rcu_fwd_seq);
2926 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2927 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id)
2928 rcu_torture_fwd_prog_cr(rfp);
2929 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) &&
2930 (!IS_ENABLED(CONFIG_TINY_RCU) ||
2931 (rcu_inkernel_boot_has_ended() &&
2932 torture_num_online_cpus() > rfp->rcu_fwd_id)))
2933 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
2935 /* Avoid slow periods, better to test when busy. */
2936 if (stutter_wait("rcu_torture_fwd_prog"))
2937 sched_set_normal(current, oldnice);
2938 } while (!torture_must_stop());
2939 /* Short runs might not contain a valid forward-progress attempt. */
2940 if (!rfp->rcu_fwd_id) {
2941 WARN_ON(!tested && tested_tries >= 5);
2942 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
2944 torture_kthread_stopping("rcu_torture_fwd_prog");
2948 /* If forward-progress checking is requested and feasible, spawn the thread. */
2949 static int __init rcu_torture_fwd_prog_init(void)
2953 struct rcu_fwd *rfp;
2956 return 0; /* Not requested, so don't do it. */
2957 if (fwd_progress >= nr_cpu_ids) {
2958 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n");
2959 fwd_progress = nr_cpu_ids;
2960 } else if (fwd_progress < 0) {
2961 fwd_progress = nr_cpu_ids;
2963 if ((!cur_ops->sync && !cur_ops->call) ||
2964 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) ||
2965 cur_ops == &rcu_busted_ops) {
2966 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
2970 if (stall_cpu > 0) {
2971 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
2973 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST))
2974 return -EINVAL; /* In module, can fail back to user. */
2975 WARN_ON(1); /* Make sure rcutorture notices conflict. */
2978 if (fwd_progress_holdoff <= 0)
2979 fwd_progress_holdoff = 1;
2980 if (fwd_progress_div <= 0)
2981 fwd_progress_div = 4;
2982 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL);
2983 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL);
2984 if (!rfp || !fwd_prog_tasks) {
2986 kfree(fwd_prog_tasks);
2987 fwd_prog_tasks = NULL;
2991 for (i = 0; i < fwd_progress; i++) {
2992 spin_lock_init(&rfp[i].rcu_fwd_lock);
2993 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head;
2994 rfp[i].rcu_fwd_id = i;
2996 mutex_lock(&rcu_fwd_mutex);
2998 mutex_unlock(&rcu_fwd_mutex);
2999 register_oom_notifier(&rcutorture_oom_nb);
3000 for (i = 0; i < fwd_progress; i++) {
3001 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]);
3010 static void rcu_torture_fwd_prog_cleanup(void)
3013 struct rcu_fwd *rfp;
3015 if (!rcu_fwds || !fwd_prog_tasks)
3017 for (i = 0; i < fwd_progress; i++)
3018 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]);
3019 unregister_oom_notifier(&rcutorture_oom_nb);
3020 mutex_lock(&rcu_fwd_mutex);
3023 mutex_unlock(&rcu_fwd_mutex);
3025 kfree(fwd_prog_tasks);
3026 fwd_prog_tasks = NULL;
3029 /* Callback function for RCU barrier testing. */
3030 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
3032 atomic_inc(&barrier_cbs_invoked);
3035 /* IPI handler to get callback posted on desired CPU, if online. */
3036 static void rcu_torture_barrier1cb(void *rcu_void)
3038 struct rcu_head *rhp = rcu_void;
3040 cur_ops->call(rhp, rcu_torture_barrier_cbf);
3043 /* kthread function to register callbacks used to test RCU barriers. */
3044 static int rcu_torture_barrier_cbs(void *arg)
3046 long myid = (long)arg;
3047 bool lastphase = false;
3049 struct rcu_head rcu;
3051 init_rcu_head_on_stack(&rcu);
3052 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
3053 set_user_nice(current, MAX_NICE);
3055 wait_event(barrier_cbs_wq[myid],
3057 smp_load_acquire(&barrier_phase)) != lastphase ||
3058 torture_must_stop());
3059 lastphase = newphase;
3060 if (torture_must_stop())
3063 * The above smp_load_acquire() ensures barrier_phase load
3064 * is ordered before the following ->call().
3066 if (smp_call_function_single(myid, rcu_torture_barrier1cb,
3068 // IPI failed, so use direct call from current CPU.
3069 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
3071 if (atomic_dec_and_test(&barrier_cbs_count))
3072 wake_up(&barrier_wq);
3073 } while (!torture_must_stop());
3074 if (cur_ops->cb_barrier != NULL)
3075 cur_ops->cb_barrier();
3076 destroy_rcu_head_on_stack(&rcu);
3077 torture_kthread_stopping("rcu_torture_barrier_cbs");
3081 /* kthread function to drive and coordinate RCU barrier testing. */
3082 static int rcu_torture_barrier(void *arg)
3086 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
3088 atomic_set(&barrier_cbs_invoked, 0);
3089 atomic_set(&barrier_cbs_count, n_barrier_cbs);
3090 /* Ensure barrier_phase ordered after prior assignments. */
3091 smp_store_release(&barrier_phase, !barrier_phase);
3092 for (i = 0; i < n_barrier_cbs; i++)
3093 wake_up(&barrier_cbs_wq[i]);
3094 wait_event(barrier_wq,
3095 atomic_read(&barrier_cbs_count) == 0 ||
3096 torture_must_stop());
3097 if (torture_must_stop())
3099 n_barrier_attempts++;
3100 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
3101 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
3102 n_rcu_torture_barrier_error++;
3103 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
3104 atomic_read(&barrier_cbs_invoked),
3107 // Wait manually for the remaining callbacks
3110 if (WARN_ON(i++ > HZ))
3112 schedule_timeout_interruptible(1);
3113 cur_ops->cb_barrier();
3114 } while (atomic_read(&barrier_cbs_invoked) !=
3116 !torture_must_stop());
3117 smp_mb(); // Can't trust ordering if broken.
3118 if (!torture_must_stop())
3119 pr_err("Recovered: barrier_cbs_invoked = %d\n",
3120 atomic_read(&barrier_cbs_invoked));
3122 n_barrier_successes++;
3124 schedule_timeout_interruptible(HZ / 10);
3125 } while (!torture_must_stop());
3126 torture_kthread_stopping("rcu_torture_barrier");
3130 /* Initialize RCU barrier testing. */
3131 static int rcu_torture_barrier_init(void)
3136 if (n_barrier_cbs <= 0)
3138 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
3139 pr_alert("%s" TORTURE_FLAG
3140 " Call or barrier ops missing for %s,\n",
3141 torture_type, cur_ops->name);
3142 pr_alert("%s" TORTURE_FLAG
3143 " RCU barrier testing omitted from run.\n",
3147 atomic_set(&barrier_cbs_count, 0);
3148 atomic_set(&barrier_cbs_invoked, 0);
3150 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
3153 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
3154 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
3156 for (i = 0; i < n_barrier_cbs; i++) {
3157 init_waitqueue_head(&barrier_cbs_wq[i]);
3158 ret = torture_create_kthread(rcu_torture_barrier_cbs,
3160 barrier_cbs_tasks[i]);
3164 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
3167 /* Clean up after RCU barrier testing. */
3168 static void rcu_torture_barrier_cleanup(void)
3172 torture_stop_kthread(rcu_torture_barrier, barrier_task);
3173 if (barrier_cbs_tasks != NULL) {
3174 for (i = 0; i < n_barrier_cbs; i++)
3175 torture_stop_kthread(rcu_torture_barrier_cbs,
3176 barrier_cbs_tasks[i]);
3177 kfree(barrier_cbs_tasks);
3178 barrier_cbs_tasks = NULL;
3180 if (barrier_cbs_wq != NULL) {
3181 kfree(barrier_cbs_wq);
3182 barrier_cbs_wq = NULL;
3186 static bool rcu_torture_can_boost(void)
3188 static int boost_warn_once;
3191 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
3193 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)
3196 prio = rcu_get_gp_kthreads_prio();
3201 if (boost_warn_once == 1)
3204 pr_alert("%s: WARN: RCU kthread priority too low to test boosting. Skipping RCU boost test. Try passing rcutree.kthread_prio > 1 on the kernel command line.\n", KBUILD_MODNAME);
3205 boost_warn_once = 1;
3212 static bool read_exit_child_stop;
3213 static bool read_exit_child_stopped;
3214 static wait_queue_head_t read_exit_wq;
3216 // Child kthread which just does an rcutorture reader and exits.
3217 static int rcu_torture_read_exit_child(void *trsp_in)
3219 struct torture_random_state *trsp = trsp_in;
3221 set_user_nice(current, MAX_NICE);
3222 // Minimize time between reading and exiting.
3223 while (!kthread_should_stop())
3224 schedule_timeout_uninterruptible(HZ / 20);
3225 (void)rcu_torture_one_read(trsp, -1);
3229 // Parent kthread which creates and destroys read-exit child kthreads.
3230 static int rcu_torture_read_exit(void *unused)
3232 bool errexit = false;
3234 struct task_struct *tsp;
3235 DEFINE_TORTURE_RANDOM(trs);
3237 // Allocate and initialize.
3238 set_user_nice(current, MAX_NICE);
3239 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
3241 // Each pass through this loop does one read-exit episode.
3243 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
3244 for (i = 0; i < read_exit_burst; i++) {
3245 if (READ_ONCE(read_exit_child_stop))
3247 stutter_wait("rcu_torture_read_exit");
3249 tsp = kthread_run(rcu_torture_read_exit_child,
3250 &trs, "%s", "rcu_torture_read_exit_child");
3252 TOROUT_ERRSTRING("out of memory");
3260 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
3261 rcu_barrier(); // Wait for task_struct free, avoid OOM.
3263 for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++)
3264 schedule_timeout_uninterruptible(HZ);
3265 } while (!errexit && !READ_ONCE(read_exit_child_stop));
3267 // Clean up and exit.
3268 smp_store_release(&read_exit_child_stopped, true); // After reaping.
3269 smp_mb(); // Store before wakeup.
3270 wake_up(&read_exit_wq);
3271 while (!torture_must_stop())
3272 schedule_timeout_uninterruptible(HZ / 20);
3273 torture_kthread_stopping("rcu_torture_read_exit");
3277 static int rcu_torture_read_exit_init(void)
3279 if (read_exit_burst <= 0)
3281 init_waitqueue_head(&read_exit_wq);
3282 read_exit_child_stop = false;
3283 read_exit_child_stopped = false;
3284 return torture_create_kthread(rcu_torture_read_exit, NULL,
3288 static void rcu_torture_read_exit_cleanup(void)
3290 if (!read_exit_task)
3292 WRITE_ONCE(read_exit_child_stop, true);
3293 smp_mb(); // Above write before wait.
3294 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
3295 torture_stop_kthread(rcutorture_read_exit, read_exit_task);
3298 static void rcutorture_test_nmis(int n)
3300 #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3305 for (i = 0; i < n; i++) {
3307 cpu = smp_processor_id();
3309 if (dumpcpu >= nr_cpu_ids)
3311 pr_alert("%s: CPU %d invoking dump_cpu_task(%d)\n", __func__, cpu, dumpcpu);
3312 dump_cpu_task(dumpcpu);
3314 schedule_timeout_uninterruptible(15 * HZ);
3316 #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3317 WARN_ONCE(n, "Non-zero rcutorture.test_nmis=%d permitted only when rcutorture is built in.\n", test_nmis);
3318 #endif // #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3321 static enum cpuhp_state rcutor_hp;
3324 rcu_torture_cleanup(void)
3328 unsigned long gp_seq = 0;
3331 if (torture_cleanup_begin()) {
3332 if (cur_ops->cb_barrier != NULL) {
3333 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3334 cur_ops->cb_barrier();
3336 rcu_gp_slow_unregister(NULL);
3340 torture_cleanup_end();
3341 rcu_gp_slow_unregister(NULL);
3345 rcutorture_test_nmis(test_nmis);
3347 if (cur_ops->gp_kthread_dbg)
3348 cur_ops->gp_kthread_dbg();
3349 rcu_torture_read_exit_cleanup();
3350 rcu_torture_barrier_cleanup();
3351 rcu_torture_fwd_prog_cleanup();
3352 torture_stop_kthread(rcu_torture_stall, stall_task);
3353 torture_stop_kthread(rcu_torture_writer, writer_task);
3356 for (i = 0; i < nrealnocbers; i++)
3357 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]);
3363 for (i = 0; i < nrealreaders; i++)
3364 torture_stop_kthread(rcu_torture_reader,
3366 kfree(reader_tasks);
3367 reader_tasks = NULL;
3369 kfree(rcu_torture_reader_mbchk);
3370 rcu_torture_reader_mbchk = NULL;
3372 if (fakewriter_tasks) {
3373 for (i = 0; i < nfakewriters; i++)
3374 torture_stop_kthread(rcu_torture_fakewriter,
3375 fakewriter_tasks[i]);
3376 kfree(fakewriter_tasks);
3377 fakewriter_tasks = NULL;
3380 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
3381 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
3382 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n",
3383 cur_ops->name, (long)gp_seq, flags,
3384 rcutorture_seq_diff(gp_seq, start_gp_seq));
3385 torture_stop_kthread(rcu_torture_stats, stats_task);
3386 torture_stop_kthread(rcu_torture_fqs, fqs_task);
3387 if (rcu_torture_can_boost() && rcutor_hp >= 0)
3388 cpuhp_remove_state(rcutor_hp);
3391 * Wait for all RCU callbacks to fire, then do torture-type-specific
3392 * cleanup operations.
3394 if (cur_ops->cb_barrier != NULL) {
3395 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3396 cur_ops->cb_barrier();
3398 if (cur_ops->cleanup != NULL)
3401 rcu_torture_mem_dump_obj();
3403 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
3405 if (err_segs_recorded) {
3406 pr_alert("Failure/close-call rcutorture reader segments:\n");
3407 if (rt_read_nsegs == 0)
3408 pr_alert("\t: No segments recorded!!!\n");
3410 for (i = 0; i < rt_read_nsegs; i++) {
3411 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
3412 if (err_segs[i].rt_delay_jiffies != 0) {
3413 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
3414 err_segs[i].rt_delay_jiffies);
3417 if (err_segs[i].rt_delay_ms != 0) {
3418 pr_cont("%s%ldms", firsttime ? "" : "+",
3419 err_segs[i].rt_delay_ms);
3422 if (err_segs[i].rt_delay_us != 0) {
3423 pr_cont("%s%ldus", firsttime ? "" : "+",
3424 err_segs[i].rt_delay_us);
3428 err_segs[i].rt_preempted ? "preempted" : "");
3432 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
3433 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
3434 else if (torture_onoff_failures())
3435 rcu_torture_print_module_parms(cur_ops,
3436 "End of test: RCU_HOTPLUG");
3438 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
3439 torture_cleanup_end();
3440 rcu_gp_slow_unregister(&rcu_fwd_cb_nodelay);
3443 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
3444 static void rcu_torture_leak_cb(struct rcu_head *rhp)
3448 static void rcu_torture_err_cb(struct rcu_head *rhp)
3451 * This -might- happen due to race conditions, but is unlikely.
3452 * The scenario that leads to this happening is that the
3453 * first of the pair of duplicate callbacks is queued,
3454 * someone else starts a grace period that includes that
3455 * callback, then the second of the pair must wait for the
3456 * next grace period. Unlikely, but can happen. If it
3457 * does happen, the debug-objects subsystem won't have splatted.
3459 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
3461 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3464 * Verify that double-free causes debug-objects to complain, but only
3465 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
3466 * cannot be carried out.
3468 static void rcu_test_debug_objects(void)
3470 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
3471 struct rcu_head rh1;
3472 struct rcu_head rh2;
3473 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
3475 init_rcu_head_on_stack(&rh1);
3476 init_rcu_head_on_stack(&rh2);
3477 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
3479 /* Try to queue the rh2 pair of callbacks for the same grace period. */
3480 preempt_disable(); /* Prevent preemption from interrupting test. */
3481 rcu_read_lock(); /* Make it impossible to finish a grace period. */
3482 call_rcu_hurry(&rh1, rcu_torture_leak_cb); /* Start grace period. */
3483 local_irq_disable(); /* Make it harder to start a new grace period. */
3484 call_rcu_hurry(&rh2, rcu_torture_leak_cb);
3485 call_rcu_hurry(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
3487 call_rcu_hurry(rhp, rcu_torture_leak_cb);
3488 call_rcu_hurry(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
3494 /* Wait for them all to get done so we can safely return. */
3496 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
3497 destroy_rcu_head_on_stack(&rh1);
3498 destroy_rcu_head_on_stack(&rh2);
3500 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3501 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
3502 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3505 static void rcutorture_sync(void)
3507 static unsigned long n;
3509 if (cur_ops->sync && !(++n & 0xfff))
3513 static DEFINE_MUTEX(mut0);
3514 static DEFINE_MUTEX(mut1);
3515 static DEFINE_MUTEX(mut2);
3516 static DEFINE_MUTEX(mut3);
3517 static DEFINE_MUTEX(mut4);
3518 static DEFINE_MUTEX(mut5);
3519 static DEFINE_MUTEX(mut6);
3520 static DEFINE_MUTEX(mut7);
3521 static DEFINE_MUTEX(mut8);
3522 static DEFINE_MUTEX(mut9);
3524 static DECLARE_RWSEM(rwsem0);
3525 static DECLARE_RWSEM(rwsem1);
3526 static DECLARE_RWSEM(rwsem2);
3527 static DECLARE_RWSEM(rwsem3);
3528 static DECLARE_RWSEM(rwsem4);
3529 static DECLARE_RWSEM(rwsem5);
3530 static DECLARE_RWSEM(rwsem6);
3531 static DECLARE_RWSEM(rwsem7);
3532 static DECLARE_RWSEM(rwsem8);
3533 static DECLARE_RWSEM(rwsem9);
3535 DEFINE_STATIC_SRCU(srcu0);
3536 DEFINE_STATIC_SRCU(srcu1);
3537 DEFINE_STATIC_SRCU(srcu2);
3538 DEFINE_STATIC_SRCU(srcu3);
3539 DEFINE_STATIC_SRCU(srcu4);
3540 DEFINE_STATIC_SRCU(srcu5);
3541 DEFINE_STATIC_SRCU(srcu6);
3542 DEFINE_STATIC_SRCU(srcu7);
3543 DEFINE_STATIC_SRCU(srcu8);
3544 DEFINE_STATIC_SRCU(srcu9);
3546 static int srcu_lockdep_next(const char *f, const char *fl, const char *fs, const char *fu, int i,
3547 int cyclelen, int deadlock)
3552 j = deadlock ? 0 : -1;
3554 pr_info("%s: %s(%d), %s(%d), %s(%d)\n", f, fl, i, fs, j, fu, i);
3556 pr_info("%s: %s(%d), %s(%d)\n", f, fl, i, fu, i);
3560 // Test lockdep on SRCU-based deadlock scenarios.
3561 static void rcu_torture_init_srcu_lockdep(void)
3569 struct mutex *muts[] = { &mut0, &mut1, &mut2, &mut3, &mut4,
3570 &mut5, &mut6, &mut7, &mut8, &mut9 };
3571 struct rw_semaphore *rwsems[] = { &rwsem0, &rwsem1, &rwsem2, &rwsem3, &rwsem4,
3572 &rwsem5, &rwsem6, &rwsem7, &rwsem8, &rwsem9 };
3573 struct srcu_struct *srcus[] = { &srcu0, &srcu1, &srcu2, &srcu3, &srcu4,
3574 &srcu5, &srcu6, &srcu7, &srcu8, &srcu9 };
3577 if (!test_srcu_lockdep)
3580 deadlock = test_srcu_lockdep / 1000;
3581 testtype = (test_srcu_lockdep / 10) % 100;
3582 cyclelen = test_srcu_lockdep % 10;
3583 WARN_ON_ONCE(ARRAY_SIZE(muts) != ARRAY_SIZE(srcus));
3584 if (WARN_ONCE(deadlock != !!deadlock,
3585 "%s: test_srcu_lockdep=%d and deadlock digit %d must be zero or one.\n",
3586 __func__, test_srcu_lockdep, deadlock))
3588 if (WARN_ONCE(cyclelen <= 0,
3589 "%s: test_srcu_lockdep=%d and cycle-length digit %d must be greater than zero.\n",
3590 __func__, test_srcu_lockdep, cyclelen))
3595 if (testtype == 0) {
3596 pr_info("%s: test_srcu_lockdep = %05d: SRCU %d-way %sdeadlock.\n",
3597 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3598 if (deadlock && cyclelen == 1)
3599 pr_info("%s: Expect hang.\n", __func__);
3600 for (i = 0; i < cyclelen; i++) {
3601 j = srcu_lockdep_next(__func__, "srcu_read_lock", "synchronize_srcu",
3602 "srcu_read_unlock", i, cyclelen, deadlock);
3603 idx = srcu_read_lock(srcus[i]);
3605 synchronize_srcu(srcus[j]);
3606 srcu_read_unlock(srcus[i], idx);
3611 if (testtype == 1) {
3612 pr_info("%s: test_srcu_lockdep = %05d: SRCU/mutex %d-way %sdeadlock.\n",
3613 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3614 for (i = 0; i < cyclelen; i++) {
3615 pr_info("%s: srcu_read_lock(%d), mutex_lock(%d), mutex_unlock(%d), srcu_read_unlock(%d)\n",
3616 __func__, i, i, i, i);
3617 idx = srcu_read_lock(srcus[i]);
3618 mutex_lock(muts[i]);
3619 mutex_unlock(muts[i]);
3620 srcu_read_unlock(srcus[i], idx);
3622 j = srcu_lockdep_next(__func__, "mutex_lock", "synchronize_srcu",
3623 "mutex_unlock", i, cyclelen, deadlock);
3624 mutex_lock(muts[i]);
3626 synchronize_srcu(srcus[j]);
3627 mutex_unlock(muts[i]);
3632 if (testtype == 2) {
3633 pr_info("%s: test_srcu_lockdep = %05d: SRCU/rwsem %d-way %sdeadlock.\n",
3634 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3635 for (i = 0; i < cyclelen; i++) {
3636 pr_info("%s: srcu_read_lock(%d), down_read(%d), up_read(%d), srcu_read_unlock(%d)\n",
3637 __func__, i, i, i, i);
3638 idx = srcu_read_lock(srcus[i]);
3639 down_read(rwsems[i]);
3641 srcu_read_unlock(srcus[i], idx);
3643 j = srcu_lockdep_next(__func__, "down_write", "synchronize_srcu",
3644 "up_write", i, cyclelen, deadlock);
3645 down_write(rwsems[i]);
3647 synchronize_srcu(srcus[j]);
3648 up_write(rwsems[i]);
3653 #ifdef CONFIG_TASKS_TRACE_RCU
3654 if (testtype == 3) {
3655 pr_info("%s: test_srcu_lockdep = %05d: SRCU and Tasks Trace RCU %d-way %sdeadlock.\n",
3656 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3657 if (deadlock && cyclelen == 1)
3658 pr_info("%s: Expect hang.\n", __func__);
3659 for (i = 0; i < cyclelen; i++) {
3660 char *fl = i == 0 ? "rcu_read_lock_trace" : "srcu_read_lock";
3661 char *fs = i == cyclelen - 1 ? "synchronize_rcu_tasks_trace"
3662 : "synchronize_srcu";
3663 char *fu = i == 0 ? "rcu_read_unlock_trace" : "srcu_read_unlock";
3665 j = srcu_lockdep_next(__func__, fl, fs, fu, i, cyclelen, deadlock);
3667 rcu_read_lock_trace();
3669 idx = srcu_read_lock(srcus[i]);
3671 if (i == cyclelen - 1)
3672 synchronize_rcu_tasks_trace();
3674 synchronize_srcu(srcus[j]);
3677 rcu_read_unlock_trace();
3679 srcu_read_unlock(srcus[i], idx);
3683 #endif // #ifdef CONFIG_TASKS_TRACE_RCU
3686 pr_info("%s: test_srcu_lockdep = %05d does nothing.\n", __func__, test_srcu_lockdep);
3687 pr_info("%s: test_srcu_lockdep = DNNL.\n", __func__);
3688 pr_info("%s: D: Deadlock if nonzero.\n", __func__);
3689 pr_info("%s: NN: Test number, 0=SRCU, 1=SRCU/mutex, 2=SRCU/rwsem, 3=SRCU/Tasks Trace RCU.\n", __func__);
3690 pr_info("%s: L: Cycle length.\n", __func__);
3691 if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU))
3692 pr_info("%s: NN=3 disallowed because kernel is built with CONFIG_TASKS_TRACE_RCU=n\n", __func__);
3696 rcu_torture_init(void)
3702 unsigned long gp_seq = 0;
3703 static struct rcu_torture_ops *torture_ops[] = {
3704 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops,
3705 TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
3709 if (!torture_init_begin(torture_type, verbose))
3712 /* Process args and tell the world that the torturer is on the job. */
3713 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
3714 cur_ops = torture_ops[i];
3715 if (strcmp(torture_type, cur_ops->name) == 0)
3718 if (i == ARRAY_SIZE(torture_ops)) {
3719 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
3721 pr_alert("rcu-torture types:");
3722 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
3723 pr_cont(" %s", torture_ops[i]->name);
3729 if (cur_ops->fqs == NULL && fqs_duration != 0) {
3730 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
3733 if (nocbs_nthreads != 0 && (cur_ops != &rcu_ops ||
3734 !IS_ENABLED(CONFIG_RCU_NOCB_CPU))) {
3735 pr_alert("rcu-torture types: %s and CONFIG_RCU_NOCB_CPU=%d, nocb toggle disabled.\n",
3736 cur_ops->name, IS_ENABLED(CONFIG_RCU_NOCB_CPU));
3742 rcu_torture_init_srcu_lockdep();
3744 if (nreaders >= 0) {
3745 nrealreaders = nreaders;
3747 nrealreaders = num_online_cpus() - 2 - nreaders;
3748 if (nrealreaders <= 0)
3751 rcu_torture_print_module_parms(cur_ops, "Start of test");
3752 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
3753 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
3754 start_gp_seq = gp_seq;
3755 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n",
3756 cur_ops->name, (long)gp_seq, flags);
3758 /* Set up the freelist. */
3760 INIT_LIST_HEAD(&rcu_torture_freelist);
3761 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
3762 rcu_tortures[i].rtort_mbtest = 0;
3763 list_add_tail(&rcu_tortures[i].rtort_free,
3764 &rcu_torture_freelist);
3767 /* Initialize the statistics so that each run gets its own numbers. */
3769 rcu_torture_current = NULL;
3770 rcu_torture_current_version = 0;
3771 atomic_set(&n_rcu_torture_alloc, 0);
3772 atomic_set(&n_rcu_torture_alloc_fail, 0);
3773 atomic_set(&n_rcu_torture_free, 0);
3774 atomic_set(&n_rcu_torture_mberror, 0);
3775 atomic_set(&n_rcu_torture_mbchk_fail, 0);
3776 atomic_set(&n_rcu_torture_mbchk_tries, 0);
3777 atomic_set(&n_rcu_torture_error, 0);
3778 n_rcu_torture_barrier_error = 0;
3779 n_rcu_torture_boost_ktrerror = 0;
3780 n_rcu_torture_boost_failure = 0;
3781 n_rcu_torture_boosts = 0;
3782 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
3783 atomic_set(&rcu_torture_wcount[i], 0);
3784 for_each_possible_cpu(cpu) {
3785 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
3786 per_cpu(rcu_torture_count, cpu)[i] = 0;
3787 per_cpu(rcu_torture_batch, cpu)[i] = 0;
3790 err_segs_recorded = 0;
3793 /* Start up the kthreads. */
3795 rcu_torture_write_types();
3796 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
3798 if (torture_init_error(firsterr))
3800 if (nfakewriters > 0) {
3801 fakewriter_tasks = kcalloc(nfakewriters,
3802 sizeof(fakewriter_tasks[0]),
3804 if (fakewriter_tasks == NULL) {
3805 TOROUT_ERRSTRING("out of memory");
3810 for (i = 0; i < nfakewriters; i++) {
3811 firsterr = torture_create_kthread(rcu_torture_fakewriter,
3812 NULL, fakewriter_tasks[i]);
3813 if (torture_init_error(firsterr))
3816 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
3818 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk),
3820 if (!reader_tasks || !rcu_torture_reader_mbchk) {
3821 TOROUT_ERRSTRING("out of memory");
3825 for (i = 0; i < nrealreaders; i++) {
3826 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1;
3827 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
3829 if (torture_init_error(firsterr))
3832 nrealnocbers = nocbs_nthreads;
3833 if (WARN_ON(nrealnocbers < 0))
3835 if (WARN_ON(nocbs_toggle < 0))
3837 if (nrealnocbers > 0) {
3838 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL);
3839 if (nocb_tasks == NULL) {
3840 TOROUT_ERRSTRING("out of memory");
3847 for (i = 0; i < nrealnocbers; i++) {
3848 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]);
3849 if (torture_init_error(firsterr))
3852 if (stat_interval > 0) {
3853 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
3855 if (torture_init_error(firsterr))
3858 if (test_no_idle_hz && shuffle_interval > 0) {
3859 firsterr = torture_shuffle_init(shuffle_interval * HZ);
3860 if (torture_init_error(firsterr))
3868 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
3869 firsterr = torture_stutter_init(stutter * HZ, t);
3870 if (torture_init_error(firsterr))
3873 if (fqs_duration < 0)
3876 /* Create the fqs thread */
3877 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
3879 if (torture_init_error(firsterr))
3882 if (test_boost_interval < 1)
3883 test_boost_interval = 1;
3884 if (test_boost_duration < 2)
3885 test_boost_duration = 2;
3886 if (rcu_torture_can_boost()) {
3888 boost_starttime = jiffies + test_boost_interval * HZ;
3890 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
3891 rcutorture_booster_init,
3892 rcutorture_booster_cleanup);
3893 rcutor_hp = firsterr;
3894 if (torture_init_error(firsterr))
3897 shutdown_jiffies = jiffies + shutdown_secs * HZ;
3898 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
3899 if (torture_init_error(firsterr))
3901 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
3903 if (torture_init_error(firsterr))
3905 firsterr = rcu_torture_stall_init();
3906 if (torture_init_error(firsterr))
3908 firsterr = rcu_torture_fwd_prog_init();
3909 if (torture_init_error(firsterr))
3911 firsterr = rcu_torture_barrier_init();
3912 if (torture_init_error(firsterr))
3914 firsterr = rcu_torture_read_exit_init();
3915 if (torture_init_error(firsterr))
3918 rcu_test_debug_objects();
3920 rcu_gp_slow_register(&rcu_fwd_cb_nodelay);
3925 rcu_torture_cleanup();
3926 if (shutdown_secs) {
3927 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
3933 module_init(rcu_torture_init);
3934 module_exit(rcu_torture_cleanup);