1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Read-Copy Update module-based torture test facility
4 *
5 * Copyright (C) IBM Corporation, 2005, 2006
6 *
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 * Josh Triplett <josh@joshtriplett.org>
9 *
10 * See also: Documentation/RCU/torture.rst
11 */
12
13 #define pr_fmt(fmt) fmt
14
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/interrupt.h>
25 #include <linux/sched/signal.h>
26 #include <uapi/linux/sched/types.h>
27 #include <linux/atomic.h>
28 #include <linux/bitops.h>
29 #include <linux/completion.h>
30 #include <linux/moduleparam.h>
31 #include <linux/percpu.h>
32 #include <linux/notifier.h>
33 #include <linux/reboot.h>
34 #include <linux/freezer.h>
35 #include <linux/cpu.h>
36 #include <linux/delay.h>
37 #include <linux/stat.h>
38 #include <linux/srcu.h>
39 #include <linux/slab.h>
40 #include <linux/trace_clock.h>
41 #include <asm/byteorder.h>
42 #include <linux/torture.h>
43 #include <linux/vmalloc.h>
44 #include <linux/sched/debug.h>
45 #include <linux/sched/sysctl.h>
46 #include <linux/oom.h>
47 #include <linux/tick.h>
48 #include <linux/rcupdate_trace.h>
49 #include <linux/nmi.h>
50
51 #include "rcu.h"
52
53 MODULE_LICENSE("GPL");
54 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
55
56 /* Bits for ->extendables field, extendables param, and related definitions. */
57 #define RCUTORTURE_RDR_SHIFT_1 8 /* Put SRCU index in upper bits. */
58 #define RCUTORTURE_RDR_MASK_1 (1 << RCUTORTURE_RDR_SHIFT_1)
59 #define RCUTORTURE_RDR_SHIFT_2 9 /* Put SRCU index in upper bits. */
60 #define RCUTORTURE_RDR_MASK_2 (1 << RCUTORTURE_RDR_SHIFT_2)
61 #define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */
62 #define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */
63 #define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */
64 #define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */
65 #define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */
66 #define RCUTORTURE_RDR_RCU_1 0x20 /* ... entering another RCU reader. */
67 #define RCUTORTURE_RDR_RCU_2 0x40 /* ... entering another RCU reader. */
68 #define RCUTORTURE_RDR_NBITS 7 /* Number of bits defined above. */
69 #define RCUTORTURE_MAX_EXTEND \
70 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
71 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
72 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
73 /* Must be power of two minus one. */
74 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
75
76 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
77 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
78 torture_param(int, fqs_duration, 0, "Duration of fqs bursts (us), 0 to disable");
79 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
80 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
81 torture_param(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)");
82 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
83 torture_param(int, fwd_progress_holdoff, 60, "Time between forward-progress tests (s)");
84 torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched() behind need_resched()");
85 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
86 torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait primitives");
87 torture_param(bool, gp_cond_full, false, "Use conditional/async full-state GP wait primitives");
88 torture_param(bool, gp_cond_exp_full, false,
89 "Use conditional/async full-stateexpedited GP wait primitives");
90 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
91 torture_param(bool, gp_normal, false, "Use normal (non-expedited) GP wait primitives");
92 torture_param(bool, gp_poll, false, "Use polling GP wait primitives");
93 torture_param(bool, gp_poll_exp, false, "Use polling expedited GP wait primitives");
94 torture_param(bool, gp_poll_full, false, "Use polling full-state GP wait primitives");
95 torture_param(bool, gp_poll_exp_full, false, "Use polling full-state expedited GP wait primitives");
96 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
97 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
98 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers");
99 torture_param(int, n_barrier_cbs, 0, "# of callbacks/kthreads for barrier testing");
100 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
101 torture_param(int, nreaders, -1, "Number of RCU reader threads");
102 torture_param(int, object_debug, 0, "Enable debug-object double call_rcu() testing");
103 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
104 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (jiffies), 0=disable");
105 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable");
106 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
107 torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
108 torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
109 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
110 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
111 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
112 torture_param(int, stall_cpu_holdoff, 10, "Time to wait before starting stall (s).");
113 torture_param(bool, stall_no_softlockup, false, "Avoid softlockup warning during cpu stall.");
114 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
115 torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
116 torture_param(int, stall_gp_kthread, 0, "Grace-period kthread stall duration (s).");
117 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s");
118 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
119 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
120 torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds.");
121 torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds.");
122 torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs");
123 torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
124
125 static char *torture_type = "rcu";
126 module_param(torture_type, charp, 0444);
127 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
128
129 static int nrealnocbers;
130 static int nrealreaders;
131 static struct task_struct *writer_task;
132 static struct task_struct **fakewriter_tasks;
133 static struct task_struct **reader_tasks;
134 static struct task_struct **nocb_tasks;
135 static struct task_struct *stats_task;
136 static struct task_struct *fqs_task;
137 static struct task_struct *boost_tasks[NR_CPUS];
138 static struct task_struct *stall_task;
139 static struct task_struct **fwd_prog_tasks;
140 static struct task_struct **barrier_cbs_tasks;
141 static struct task_struct *barrier_task;
142 static struct task_struct *read_exit_task;
143
144 #define RCU_TORTURE_PIPE_LEN 10
145
146 // Mailbox-like structure to check RCU global memory ordering.
147 struct rcu_torture_reader_check {
148 unsigned long rtc_myloops;
149 int rtc_chkrdr;
150 unsigned long rtc_chkloops;
151 int rtc_ready;
152 struct rcu_torture_reader_check *rtc_assigner;
153 } ____cacheline_internodealigned_in_smp;
154
155 // Update-side data structure used to check RCU readers.
156 struct rcu_torture {
157 struct rcu_head rtort_rcu;
158 int rtort_pipe_count;
159 struct list_head rtort_free;
160 int rtort_mbtest;
161 struct rcu_torture_reader_check *rtort_chkp;
162 };
163
164 static LIST_HEAD(rcu_torture_freelist);
165 static struct rcu_torture __rcu *rcu_torture_current;
166 static unsigned long rcu_torture_current_version;
167 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
168 static DEFINE_SPINLOCK(rcu_torture_lock);
169 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
170 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
171 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
172 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk;
173 static atomic_t n_rcu_torture_alloc;
174 static atomic_t n_rcu_torture_alloc_fail;
175 static atomic_t n_rcu_torture_free;
176 static atomic_t n_rcu_torture_mberror;
177 static atomic_t n_rcu_torture_mbchk_fail;
178 static atomic_t n_rcu_torture_mbchk_tries;
179 static atomic_t n_rcu_torture_error;
180 static long n_rcu_torture_barrier_error;
181 static long n_rcu_torture_boost_ktrerror;
182 static long n_rcu_torture_boost_rterror;
183 static long n_rcu_torture_boost_failure;
184 static long n_rcu_torture_boosts;
185 static atomic_long_t n_rcu_torture_timers;
186 static long n_barrier_attempts;
187 static long n_barrier_successes; /* did rcu_barrier test succeed? */
188 static unsigned long n_read_exits;
189 static struct list_head rcu_torture_removed;
190 static unsigned long shutdown_jiffies;
191 static unsigned long start_gp_seq;
192 static atomic_long_t n_nocb_offload;
193 static atomic_long_t n_nocb_deoffload;
194
195 static int rcu_torture_writer_state;
196 #define RTWS_FIXED_DELAY 0
197 #define RTWS_DELAY 1
198 #define RTWS_REPLACE 2
199 #define RTWS_DEF_FREE 3
200 #define RTWS_EXP_SYNC 4
201 #define RTWS_COND_GET 5
202 #define RTWS_COND_GET_FULL 6
203 #define RTWS_COND_GET_EXP 7
204 #define RTWS_COND_GET_EXP_FULL 8
205 #define RTWS_COND_SYNC 9
206 #define RTWS_COND_SYNC_FULL 10
207 #define RTWS_COND_SYNC_EXP 11
208 #define RTWS_COND_SYNC_EXP_FULL 12
209 #define RTWS_POLL_GET 13
210 #define RTWS_POLL_GET_FULL 14
211 #define RTWS_POLL_GET_EXP 15
212 #define RTWS_POLL_GET_EXP_FULL 16
213 #define RTWS_POLL_WAIT 17
214 #define RTWS_POLL_WAIT_FULL 18
215 #define RTWS_POLL_WAIT_EXP 19
216 #define RTWS_POLL_WAIT_EXP_FULL 20
217 #define RTWS_SYNC 21
218 #define RTWS_STUTTER 22
219 #define RTWS_STOPPING 23
220 static const char * const rcu_torture_writer_state_names[] = {
221 "RTWS_FIXED_DELAY",
222 "RTWS_DELAY",
223 "RTWS_REPLACE",
224 "RTWS_DEF_FREE",
225 "RTWS_EXP_SYNC",
226 "RTWS_COND_GET",
227 "RTWS_COND_GET_FULL",
228 "RTWS_COND_GET_EXP",
229 "RTWS_COND_GET_EXP_FULL",
230 "RTWS_COND_SYNC",
231 "RTWS_COND_SYNC_FULL",
232 "RTWS_COND_SYNC_EXP",
233 "RTWS_COND_SYNC_EXP_FULL",
234 "RTWS_POLL_GET",
235 "RTWS_POLL_GET_FULL",
236 "RTWS_POLL_GET_EXP",
237 "RTWS_POLL_GET_EXP_FULL",
238 "RTWS_POLL_WAIT",
239 "RTWS_POLL_WAIT_FULL",
240 "RTWS_POLL_WAIT_EXP",
241 "RTWS_POLL_WAIT_EXP_FULL",
242 "RTWS_SYNC",
243 "RTWS_STUTTER",
244 "RTWS_STOPPING",
245 };
246
247 /* Record reader segment types and duration for first failing read. */
248 struct rt_read_seg {
249 int rt_readstate;
250 unsigned long rt_delay_jiffies;
251 unsigned long rt_delay_ms;
252 unsigned long rt_delay_us;
253 bool rt_preempted;
254 };
255 static int err_segs_recorded;
256 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
257 static int rt_read_nsegs;
258
rcu_torture_writer_state_getname(void)259 static const char *rcu_torture_writer_state_getname(void)
260 {
261 unsigned int i = READ_ONCE(rcu_torture_writer_state);
262
263 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
264 return "???";
265 return rcu_torture_writer_state_names[i];
266 }
267
268 #ifdef CONFIG_RCU_TRACE
rcu_trace_clock_local(void)269 static u64 notrace rcu_trace_clock_local(void)
270 {
271 u64 ts = trace_clock_local();
272
273 (void)do_div(ts, NSEC_PER_USEC);
274 return ts;
275 }
276 #else /* #ifdef CONFIG_RCU_TRACE */
rcu_trace_clock_local(void)277 static u64 notrace rcu_trace_clock_local(void)
278 {
279 return 0ULL;
280 }
281 #endif /* #else #ifdef CONFIG_RCU_TRACE */
282
283 /*
284 * Stop aggressive CPU-hog tests a bit before the end of the test in order
285 * to avoid interfering with test shutdown.
286 */
shutdown_time_arrived(void)287 static bool shutdown_time_arrived(void)
288 {
289 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
290 }
291
292 static unsigned long boost_starttime; /* jiffies of next boost test start. */
293 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
294 /* and boost task create/destroy. */
295 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
296 static bool barrier_phase; /* Test phase. */
297 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
298 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
299 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
300
301 static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
302
303 /*
304 * Allocate an element from the rcu_tortures pool.
305 */
306 static struct rcu_torture *
rcu_torture_alloc(void)307 rcu_torture_alloc(void)
308 {
309 struct list_head *p;
310
311 spin_lock_bh(&rcu_torture_lock);
312 if (list_empty(&rcu_torture_freelist)) {
313 atomic_inc(&n_rcu_torture_alloc_fail);
314 spin_unlock_bh(&rcu_torture_lock);
315 return NULL;
316 }
317 atomic_inc(&n_rcu_torture_alloc);
318 p = rcu_torture_freelist.next;
319 list_del_init(p);
320 spin_unlock_bh(&rcu_torture_lock);
321 return container_of(p, struct rcu_torture, rtort_free);
322 }
323
324 /*
325 * Free an element to the rcu_tortures pool.
326 */
327 static void
rcu_torture_free(struct rcu_torture * p)328 rcu_torture_free(struct rcu_torture *p)
329 {
330 atomic_inc(&n_rcu_torture_free);
331 spin_lock_bh(&rcu_torture_lock);
332 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
333 spin_unlock_bh(&rcu_torture_lock);
334 }
335
336 /*
337 * Operations vector for selecting different types of tests.
338 */
339
340 struct rcu_torture_ops {
341 int ttype;
342 void (*init)(void);
343 void (*cleanup)(void);
344 int (*readlock)(void);
345 void (*read_delay)(struct torture_random_state *rrsp,
346 struct rt_read_seg *rtrsp);
347 void (*readunlock)(int idx);
348 int (*readlock_held)(void);
349 unsigned long (*get_gp_seq)(void);
350 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
351 void (*deferred_free)(struct rcu_torture *p);
352 void (*sync)(void);
353 void (*exp_sync)(void);
354 unsigned long (*get_gp_state_exp)(void);
355 unsigned long (*start_gp_poll_exp)(void);
356 void (*start_gp_poll_exp_full)(struct rcu_gp_oldstate *rgosp);
357 bool (*poll_gp_state_exp)(unsigned long oldstate);
358 void (*cond_sync_exp)(unsigned long oldstate);
359 void (*cond_sync_exp_full)(struct rcu_gp_oldstate *rgosp);
360 unsigned long (*get_gp_state)(void);
361 void (*get_gp_state_full)(struct rcu_gp_oldstate *rgosp);
362 unsigned long (*get_gp_completed)(void);
363 void (*get_gp_completed_full)(struct rcu_gp_oldstate *rgosp);
364 unsigned long (*start_gp_poll)(void);
365 void (*start_gp_poll_full)(struct rcu_gp_oldstate *rgosp);
366 bool (*poll_gp_state)(unsigned long oldstate);
367 bool (*poll_gp_state_full)(struct rcu_gp_oldstate *rgosp);
368 bool (*poll_need_2gp)(bool poll, bool poll_full);
369 void (*cond_sync)(unsigned long oldstate);
370 void (*cond_sync_full)(struct rcu_gp_oldstate *rgosp);
371 call_rcu_func_t call;
372 void (*cb_barrier)(void);
373 void (*fqs)(void);
374 void (*stats)(void);
375 void (*gp_kthread_dbg)(void);
376 bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
377 int (*stall_dur)(void);
378 long cbflood_max;
379 int irq_capable;
380 int can_boost;
381 int extendables;
382 int slow_gps;
383 int no_pi_lock;
384 const char *name;
385 };
386
387 static struct rcu_torture_ops *cur_ops;
388
389 /*
390 * Definitions for rcu torture testing.
391 */
392
torture_readlock_not_held(void)393 static int torture_readlock_not_held(void)
394 {
395 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held();
396 }
397
rcu_torture_read_lock(void)398 static int rcu_torture_read_lock(void) __acquires(RCU)
399 {
400 rcu_read_lock();
401 return 0;
402 }
403
404 static void
rcu_read_delay(struct torture_random_state * rrsp,struct rt_read_seg * rtrsp)405 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
406 {
407 unsigned long started;
408 unsigned long completed;
409 const unsigned long shortdelay_us = 200;
410 unsigned long longdelay_ms = 300;
411 unsigned long long ts;
412
413 /* We want a short delay sometimes to make a reader delay the grace
414 * period, and we want a long delay occasionally to trigger
415 * force_quiescent_state. */
416
417 if (!atomic_read(&rcu_fwd_cb_nodelay) &&
418 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
419 started = cur_ops->get_gp_seq();
420 ts = rcu_trace_clock_local();
421 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
422 longdelay_ms = 5; /* Avoid triggering BH limits. */
423 mdelay(longdelay_ms);
424 rtrsp->rt_delay_ms = longdelay_ms;
425 completed = cur_ops->get_gp_seq();
426 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
427 started, completed);
428 }
429 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
430 udelay(shortdelay_us);
431 rtrsp->rt_delay_us = shortdelay_us;
432 }
433 if (!preempt_count() &&
434 !(torture_random(rrsp) % (nrealreaders * 500))) {
435 torture_preempt_schedule(); /* QS only if preemptible. */
436 rtrsp->rt_preempted = true;
437 }
438 }
439
rcu_torture_read_unlock(int idx)440 static void rcu_torture_read_unlock(int idx) __releases(RCU)
441 {
442 rcu_read_unlock();
443 }
444
445 /*
446 * Update callback in the pipe. This should be invoked after a grace period.
447 */
448 static bool
rcu_torture_pipe_update_one(struct rcu_torture * rp)449 rcu_torture_pipe_update_one(struct rcu_torture *rp)
450 {
451 int i;
452 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp);
453
454 if (rtrcp) {
455 WRITE_ONCE(rp->rtort_chkp, NULL);
456 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire().
457 }
458 i = READ_ONCE(rp->rtort_pipe_count);
459 if (i > RCU_TORTURE_PIPE_LEN)
460 i = RCU_TORTURE_PIPE_LEN;
461 atomic_inc(&rcu_torture_wcount[i]);
462 WRITE_ONCE(rp->rtort_pipe_count, i + 1);
463 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
464 rp->rtort_mbtest = 0;
465 return true;
466 }
467 return false;
468 }
469
470 /*
471 * Update all callbacks in the pipe. Suitable for synchronous grace-period
472 * primitives.
473 */
474 static void
rcu_torture_pipe_update(struct rcu_torture * old_rp)475 rcu_torture_pipe_update(struct rcu_torture *old_rp)
476 {
477 struct rcu_torture *rp;
478 struct rcu_torture *rp1;
479
480 if (old_rp)
481 list_add(&old_rp->rtort_free, &rcu_torture_removed);
482 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
483 if (rcu_torture_pipe_update_one(rp)) {
484 list_del(&rp->rtort_free);
485 rcu_torture_free(rp);
486 }
487 }
488 }
489
490 static void
rcu_torture_cb(struct rcu_head * p)491 rcu_torture_cb(struct rcu_head *p)
492 {
493 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
494
495 if (torture_must_stop_irq()) {
496 /* Test is ending, just drop callbacks on the floor. */
497 /* The next initialization will pick up the pieces. */
498 return;
499 }
500 if (rcu_torture_pipe_update_one(rp))
501 rcu_torture_free(rp);
502 else
503 cur_ops->deferred_free(rp);
504 }
505
rcu_no_completed(void)506 static unsigned long rcu_no_completed(void)
507 {
508 return 0;
509 }
510
rcu_torture_deferred_free(struct rcu_torture * p)511 static void rcu_torture_deferred_free(struct rcu_torture *p)
512 {
513 call_rcu(&p->rtort_rcu, rcu_torture_cb);
514 }
515
rcu_sync_torture_init(void)516 static void rcu_sync_torture_init(void)
517 {
518 INIT_LIST_HEAD(&rcu_torture_removed);
519 }
520
rcu_poll_need_2gp(bool poll,bool poll_full)521 static bool rcu_poll_need_2gp(bool poll, bool poll_full)
522 {
523 return poll;
524 }
525
526 static struct rcu_torture_ops rcu_ops = {
527 .ttype = RCU_FLAVOR,
528 .init = rcu_sync_torture_init,
529 .readlock = rcu_torture_read_lock,
530 .read_delay = rcu_read_delay,
531 .readunlock = rcu_torture_read_unlock,
532 .readlock_held = torture_readlock_not_held,
533 .get_gp_seq = rcu_get_gp_seq,
534 .gp_diff = rcu_seq_diff,
535 .deferred_free = rcu_torture_deferred_free,
536 .sync = synchronize_rcu,
537 .exp_sync = synchronize_rcu_expedited,
538 .get_gp_state = get_state_synchronize_rcu,
539 .get_gp_state_full = get_state_synchronize_rcu_full,
540 .get_gp_completed = get_completed_synchronize_rcu,
541 .get_gp_completed_full = get_completed_synchronize_rcu_full,
542 .start_gp_poll = start_poll_synchronize_rcu,
543 .start_gp_poll_full = start_poll_synchronize_rcu_full,
544 .poll_gp_state = poll_state_synchronize_rcu,
545 .poll_gp_state_full = poll_state_synchronize_rcu_full,
546 .poll_need_2gp = rcu_poll_need_2gp,
547 .cond_sync = cond_synchronize_rcu,
548 .cond_sync_full = cond_synchronize_rcu_full,
549 .get_gp_state_exp = get_state_synchronize_rcu,
550 .start_gp_poll_exp = start_poll_synchronize_rcu_expedited,
551 .start_gp_poll_exp_full = start_poll_synchronize_rcu_expedited_full,
552 .poll_gp_state_exp = poll_state_synchronize_rcu,
553 .cond_sync_exp = cond_synchronize_rcu_expedited,
554 .call = call_rcu,
555 .cb_barrier = rcu_barrier,
556 .fqs = rcu_force_quiescent_state,
557 .stats = NULL,
558 .gp_kthread_dbg = show_rcu_gp_kthreads,
559 .check_boost_failed = rcu_check_boost_fail,
560 .stall_dur = rcu_jiffies_till_stall_check,
561 .irq_capable = 1,
562 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
563 .extendables = RCUTORTURE_MAX_EXTEND,
564 .name = "rcu"
565 };
566
567 /*
568 * Don't even think about trying any of these in real life!!!
569 * The names includes "busted", and they really means it!
570 * The only purpose of these functions is to provide a buggy RCU
571 * implementation to make sure that rcutorture correctly emits
572 * buggy-RCU error messages.
573 */
rcu_busted_torture_deferred_free(struct rcu_torture * p)574 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
575 {
576 /* This is a deliberate bug for testing purposes only! */
577 rcu_torture_cb(&p->rtort_rcu);
578 }
579
synchronize_rcu_busted(void)580 static void synchronize_rcu_busted(void)
581 {
582 /* This is a deliberate bug for testing purposes only! */
583 }
584
585 static void
call_rcu_busted(struct rcu_head * head,rcu_callback_t func)586 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
587 {
588 /* This is a deliberate bug for testing purposes only! */
589 func(head);
590 }
591
592 static struct rcu_torture_ops rcu_busted_ops = {
593 .ttype = INVALID_RCU_FLAVOR,
594 .init = rcu_sync_torture_init,
595 .readlock = rcu_torture_read_lock,
596 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
597 .readunlock = rcu_torture_read_unlock,
598 .readlock_held = torture_readlock_not_held,
599 .get_gp_seq = rcu_no_completed,
600 .deferred_free = rcu_busted_torture_deferred_free,
601 .sync = synchronize_rcu_busted,
602 .exp_sync = synchronize_rcu_busted,
603 .call = call_rcu_busted,
604 .cb_barrier = NULL,
605 .fqs = NULL,
606 .stats = NULL,
607 .irq_capable = 1,
608 .name = "busted"
609 };
610
611 /*
612 * Definitions for srcu torture testing.
613 */
614
615 DEFINE_STATIC_SRCU(srcu_ctl);
616 static struct srcu_struct srcu_ctld;
617 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
618
srcu_torture_read_lock(void)619 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
620 {
621 return srcu_read_lock(srcu_ctlp);
622 }
623
624 static void
srcu_read_delay(struct torture_random_state * rrsp,struct rt_read_seg * rtrsp)625 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
626 {
627 long delay;
628 const long uspertick = 1000000 / HZ;
629 const long longdelay = 10;
630
631 /* We want there to be long-running readers, but not all the time. */
632
633 delay = torture_random(rrsp) %
634 (nrealreaders * 2 * longdelay * uspertick);
635 if (!delay && in_task()) {
636 schedule_timeout_interruptible(longdelay);
637 rtrsp->rt_delay_jiffies = longdelay;
638 } else {
639 rcu_read_delay(rrsp, rtrsp);
640 }
641 }
642
srcu_torture_read_unlock(int idx)643 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
644 {
645 srcu_read_unlock(srcu_ctlp, idx);
646 }
647
torture_srcu_read_lock_held(void)648 static int torture_srcu_read_lock_held(void)
649 {
650 return srcu_read_lock_held(srcu_ctlp);
651 }
652
srcu_torture_completed(void)653 static unsigned long srcu_torture_completed(void)
654 {
655 return srcu_batches_completed(srcu_ctlp);
656 }
657
srcu_torture_deferred_free(struct rcu_torture * rp)658 static void srcu_torture_deferred_free(struct rcu_torture *rp)
659 {
660 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
661 }
662
srcu_torture_synchronize(void)663 static void srcu_torture_synchronize(void)
664 {
665 synchronize_srcu(srcu_ctlp);
666 }
667
srcu_torture_get_gp_state(void)668 static unsigned long srcu_torture_get_gp_state(void)
669 {
670 return get_state_synchronize_srcu(srcu_ctlp);
671 }
672
srcu_torture_start_gp_poll(void)673 static unsigned long srcu_torture_start_gp_poll(void)
674 {
675 return start_poll_synchronize_srcu(srcu_ctlp);
676 }
677
srcu_torture_poll_gp_state(unsigned long oldstate)678 static bool srcu_torture_poll_gp_state(unsigned long oldstate)
679 {
680 return poll_state_synchronize_srcu(srcu_ctlp, oldstate);
681 }
682
srcu_torture_call(struct rcu_head * head,rcu_callback_t func)683 static void srcu_torture_call(struct rcu_head *head,
684 rcu_callback_t func)
685 {
686 call_srcu(srcu_ctlp, head, func);
687 }
688
srcu_torture_barrier(void)689 static void srcu_torture_barrier(void)
690 {
691 srcu_barrier(srcu_ctlp);
692 }
693
srcu_torture_stats(void)694 static void srcu_torture_stats(void)
695 {
696 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
697 }
698
srcu_torture_synchronize_expedited(void)699 static void srcu_torture_synchronize_expedited(void)
700 {
701 synchronize_srcu_expedited(srcu_ctlp);
702 }
703
704 static struct rcu_torture_ops srcu_ops = {
705 .ttype = SRCU_FLAVOR,
706 .init = rcu_sync_torture_init,
707 .readlock = srcu_torture_read_lock,
708 .read_delay = srcu_read_delay,
709 .readunlock = srcu_torture_read_unlock,
710 .readlock_held = torture_srcu_read_lock_held,
711 .get_gp_seq = srcu_torture_completed,
712 .deferred_free = srcu_torture_deferred_free,
713 .sync = srcu_torture_synchronize,
714 .exp_sync = srcu_torture_synchronize_expedited,
715 .get_gp_state = srcu_torture_get_gp_state,
716 .start_gp_poll = srcu_torture_start_gp_poll,
717 .poll_gp_state = srcu_torture_poll_gp_state,
718 .call = srcu_torture_call,
719 .cb_barrier = srcu_torture_barrier,
720 .stats = srcu_torture_stats,
721 .cbflood_max = 50000,
722 .irq_capable = 1,
723 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
724 .name = "srcu"
725 };
726
srcu_torture_init(void)727 static void srcu_torture_init(void)
728 {
729 rcu_sync_torture_init();
730 WARN_ON(init_srcu_struct(&srcu_ctld));
731 srcu_ctlp = &srcu_ctld;
732 }
733
srcu_torture_cleanup(void)734 static void srcu_torture_cleanup(void)
735 {
736 cleanup_srcu_struct(&srcu_ctld);
737 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
738 }
739
740 /* As above, but dynamically allocated. */
741 static struct rcu_torture_ops srcud_ops = {
742 .ttype = SRCU_FLAVOR,
743 .init = srcu_torture_init,
744 .cleanup = srcu_torture_cleanup,
745 .readlock = srcu_torture_read_lock,
746 .read_delay = srcu_read_delay,
747 .readunlock = srcu_torture_read_unlock,
748 .readlock_held = torture_srcu_read_lock_held,
749 .get_gp_seq = srcu_torture_completed,
750 .deferred_free = srcu_torture_deferred_free,
751 .sync = srcu_torture_synchronize,
752 .exp_sync = srcu_torture_synchronize_expedited,
753 .get_gp_state = srcu_torture_get_gp_state,
754 .start_gp_poll = srcu_torture_start_gp_poll,
755 .poll_gp_state = srcu_torture_poll_gp_state,
756 .call = srcu_torture_call,
757 .cb_barrier = srcu_torture_barrier,
758 .stats = srcu_torture_stats,
759 .cbflood_max = 50000,
760 .irq_capable = 1,
761 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
762 .name = "srcud"
763 };
764
765 /* As above, but broken due to inappropriate reader extension. */
766 static struct rcu_torture_ops busted_srcud_ops = {
767 .ttype = SRCU_FLAVOR,
768 .init = srcu_torture_init,
769 .cleanup = srcu_torture_cleanup,
770 .readlock = srcu_torture_read_lock,
771 .read_delay = rcu_read_delay,
772 .readunlock = srcu_torture_read_unlock,
773 .readlock_held = torture_srcu_read_lock_held,
774 .get_gp_seq = srcu_torture_completed,
775 .deferred_free = srcu_torture_deferred_free,
776 .sync = srcu_torture_synchronize,
777 .exp_sync = srcu_torture_synchronize_expedited,
778 .call = srcu_torture_call,
779 .cb_barrier = srcu_torture_barrier,
780 .stats = srcu_torture_stats,
781 .irq_capable = 1,
782 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
783 .extendables = RCUTORTURE_MAX_EXTEND,
784 .name = "busted_srcud"
785 };
786
787 /*
788 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
789 * This implementation does not necessarily work well with CPU hotplug.
790 */
791
synchronize_rcu_trivial(void)792 static void synchronize_rcu_trivial(void)
793 {
794 int cpu;
795
796 for_each_online_cpu(cpu) {
797 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu));
798 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
799 }
800 }
801
rcu_torture_read_lock_trivial(void)802 static int rcu_torture_read_lock_trivial(void) __acquires(RCU)
803 {
804 preempt_disable();
805 return 0;
806 }
807
rcu_torture_read_unlock_trivial(int idx)808 static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU)
809 {
810 preempt_enable();
811 }
812
813 static struct rcu_torture_ops trivial_ops = {
814 .ttype = RCU_TRIVIAL_FLAVOR,
815 .init = rcu_sync_torture_init,
816 .readlock = rcu_torture_read_lock_trivial,
817 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
818 .readunlock = rcu_torture_read_unlock_trivial,
819 .readlock_held = torture_readlock_not_held,
820 .get_gp_seq = rcu_no_completed,
821 .sync = synchronize_rcu_trivial,
822 .exp_sync = synchronize_rcu_trivial,
823 .fqs = NULL,
824 .stats = NULL,
825 .irq_capable = 1,
826 .name = "trivial"
827 };
828
829 #ifdef CONFIG_TASKS_RCU
830
831 /*
832 * Definitions for RCU-tasks torture testing.
833 */
834
tasks_torture_read_lock(void)835 static int tasks_torture_read_lock(void)
836 {
837 return 0;
838 }
839
tasks_torture_read_unlock(int idx)840 static void tasks_torture_read_unlock(int idx)
841 {
842 }
843
rcu_tasks_torture_deferred_free(struct rcu_torture * p)844 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
845 {
846 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
847 }
848
synchronize_rcu_mult_test(void)849 static void synchronize_rcu_mult_test(void)
850 {
851 synchronize_rcu_mult(call_rcu_tasks, call_rcu);
852 }
853
854 static struct rcu_torture_ops tasks_ops = {
855 .ttype = RCU_TASKS_FLAVOR,
856 .init = rcu_sync_torture_init,
857 .readlock = tasks_torture_read_lock,
858 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
859 .readunlock = tasks_torture_read_unlock,
860 .get_gp_seq = rcu_no_completed,
861 .deferred_free = rcu_tasks_torture_deferred_free,
862 .sync = synchronize_rcu_tasks,
863 .exp_sync = synchronize_rcu_mult_test,
864 .call = call_rcu_tasks,
865 .cb_barrier = rcu_barrier_tasks,
866 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread,
867 .fqs = NULL,
868 .stats = NULL,
869 .irq_capable = 1,
870 .slow_gps = 1,
871 .name = "tasks"
872 };
873
874 #define TASKS_OPS &tasks_ops,
875
876 #else // #ifdef CONFIG_TASKS_RCU
877
878 #define TASKS_OPS
879
880 #endif // #else #ifdef CONFIG_TASKS_RCU
881
882
883 #ifdef CONFIG_TASKS_RUDE_RCU
884
885 /*
886 * Definitions for rude RCU-tasks torture testing.
887 */
888
rcu_tasks_rude_torture_deferred_free(struct rcu_torture * p)889 static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p)
890 {
891 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb);
892 }
893
894 static struct rcu_torture_ops tasks_rude_ops = {
895 .ttype = RCU_TASKS_RUDE_FLAVOR,
896 .init = rcu_sync_torture_init,
897 .readlock = rcu_torture_read_lock_trivial,
898 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
899 .readunlock = rcu_torture_read_unlock_trivial,
900 .get_gp_seq = rcu_no_completed,
901 .deferred_free = rcu_tasks_rude_torture_deferred_free,
902 .sync = synchronize_rcu_tasks_rude,
903 .exp_sync = synchronize_rcu_tasks_rude,
904 .call = call_rcu_tasks_rude,
905 .cb_barrier = rcu_barrier_tasks_rude,
906 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread,
907 .cbflood_max = 50000,
908 .fqs = NULL,
909 .stats = NULL,
910 .irq_capable = 1,
911 .name = "tasks-rude"
912 };
913
914 #define TASKS_RUDE_OPS &tasks_rude_ops,
915
916 #else // #ifdef CONFIG_TASKS_RUDE_RCU
917
918 #define TASKS_RUDE_OPS
919
920 #endif // #else #ifdef CONFIG_TASKS_RUDE_RCU
921
922
923 #ifdef CONFIG_TASKS_TRACE_RCU
924
925 /*
926 * Definitions for tracing RCU-tasks torture testing.
927 */
928
tasks_tracing_torture_read_lock(void)929 static int tasks_tracing_torture_read_lock(void)
930 {
931 rcu_read_lock_trace();
932 return 0;
933 }
934
tasks_tracing_torture_read_unlock(int idx)935 static void tasks_tracing_torture_read_unlock(int idx)
936 {
937 rcu_read_unlock_trace();
938 }
939
rcu_tasks_tracing_torture_deferred_free(struct rcu_torture * p)940 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
941 {
942 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
943 }
944
945 static struct rcu_torture_ops tasks_tracing_ops = {
946 .ttype = RCU_TASKS_TRACING_FLAVOR,
947 .init = rcu_sync_torture_init,
948 .readlock = tasks_tracing_torture_read_lock,
949 .read_delay = srcu_read_delay, /* just reuse srcu's version. */
950 .readunlock = tasks_tracing_torture_read_unlock,
951 .readlock_held = rcu_read_lock_trace_held,
952 .get_gp_seq = rcu_no_completed,
953 .deferred_free = rcu_tasks_tracing_torture_deferred_free,
954 .sync = synchronize_rcu_tasks_trace,
955 .exp_sync = synchronize_rcu_tasks_trace,
956 .call = call_rcu_tasks_trace,
957 .cb_barrier = rcu_barrier_tasks_trace,
958 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread,
959 .cbflood_max = 50000,
960 .fqs = NULL,
961 .stats = NULL,
962 .irq_capable = 1,
963 .slow_gps = 1,
964 .name = "tasks-tracing"
965 };
966
967 #define TASKS_TRACING_OPS &tasks_tracing_ops,
968
969 #else // #ifdef CONFIG_TASKS_TRACE_RCU
970
971 #define TASKS_TRACING_OPS
972
973 #endif // #else #ifdef CONFIG_TASKS_TRACE_RCU
974
975
rcutorture_seq_diff(unsigned long new,unsigned long old)976 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
977 {
978 if (!cur_ops->gp_diff)
979 return new - old;
980 return cur_ops->gp_diff(new, old);
981 }
982
983 /*
984 * RCU torture priority-boost testing. Runs one real-time thread per
985 * CPU for moderate bursts, repeatedly starting grace periods and waiting
986 * for them to complete. If a given grace period takes too long, we assume
987 * that priority inversion has occurred.
988 */
989
990 static int old_rt_runtime = -1;
991
rcu_torture_disable_rt_throttle(void)992 static void rcu_torture_disable_rt_throttle(void)
993 {
994 /*
995 * Disable RT throttling so that rcutorture's boost threads don't get
996 * throttled. Only possible if rcutorture is built-in otherwise the
997 * user should manually do this by setting the sched_rt_period_us and
998 * sched_rt_runtime sysctls.
999 */
1000 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
1001 return;
1002
1003 old_rt_runtime = sysctl_sched_rt_runtime;
1004 sysctl_sched_rt_runtime = -1;
1005 }
1006
rcu_torture_enable_rt_throttle(void)1007 static void rcu_torture_enable_rt_throttle(void)
1008 {
1009 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
1010 return;
1011
1012 sysctl_sched_rt_runtime = old_rt_runtime;
1013 old_rt_runtime = -1;
1014 }
1015
rcu_torture_boost_failed(unsigned long gp_state,unsigned long * start)1016 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start)
1017 {
1018 int cpu;
1019 static int dbg_done;
1020 unsigned long end = jiffies;
1021 bool gp_done;
1022 unsigned long j;
1023 static unsigned long last_persist;
1024 unsigned long lp;
1025 unsigned long mininterval = test_boost_duration * HZ - HZ / 2;
1026
1027 if (end - *start > mininterval) {
1028 // Recheck after checking time to avoid false positives.
1029 smp_mb(); // Time check before grace-period check.
1030 if (cur_ops->poll_gp_state(gp_state))
1031 return false; // passed, though perhaps just barely
1032 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) {
1033 // At most one persisted message per boost test.
1034 j = jiffies;
1035 lp = READ_ONCE(last_persist);
1036 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp)
1037 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu);
1038 return false; // passed on a technicality
1039 }
1040 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
1041 n_rcu_torture_boost_failure++;
1042 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) {
1043 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n",
1044 current->rt_priority, gp_state, end - *start);
1045 cur_ops->gp_kthread_dbg();
1046 // Recheck after print to flag grace period ending during splat.
1047 gp_done = cur_ops->poll_gp_state(gp_state);
1048 pr_info("Boost inversion: GP %lu %s.\n", gp_state,
1049 gp_done ? "ended already" : "still pending");
1050
1051 }
1052
1053 return true; // failed
1054 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) {
1055 *start = jiffies;
1056 }
1057
1058 return false; // passed
1059 }
1060
rcu_torture_boost(void * arg)1061 static int rcu_torture_boost(void *arg)
1062 {
1063 unsigned long endtime;
1064 unsigned long gp_state;
1065 unsigned long gp_state_time;
1066 unsigned long oldstarttime;
1067
1068 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
1069
1070 /* Set real-time priority. */
1071 sched_set_fifo_low(current);
1072
1073 /* Each pass through the following loop does one boost-test cycle. */
1074 do {
1075 bool failed = false; // Test failed already in this test interval
1076 bool gp_initiated = false;
1077
1078 if (kthread_should_stop())
1079 goto checkwait;
1080
1081 /* Wait for the next test interval. */
1082 oldstarttime = READ_ONCE(boost_starttime);
1083 while (time_before(jiffies, oldstarttime)) {
1084 schedule_timeout_interruptible(oldstarttime - jiffies);
1085 if (stutter_wait("rcu_torture_boost"))
1086 sched_set_fifo_low(current);
1087 if (torture_must_stop())
1088 goto checkwait;
1089 }
1090
1091 // Do one boost-test interval.
1092 endtime = oldstarttime + test_boost_duration * HZ;
1093 while (time_before(jiffies, endtime)) {
1094 // Has current GP gone too long?
1095 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1096 failed = rcu_torture_boost_failed(gp_state, &gp_state_time);
1097 // If we don't have a grace period in flight, start one.
1098 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) {
1099 gp_state = cur_ops->start_gp_poll();
1100 gp_initiated = true;
1101 gp_state_time = jiffies;
1102 }
1103 if (stutter_wait("rcu_torture_boost")) {
1104 sched_set_fifo_low(current);
1105 // If the grace period already ended,
1106 // we don't know when that happened, so
1107 // start over.
1108 if (cur_ops->poll_gp_state(gp_state))
1109 gp_initiated = false;
1110 }
1111 if (torture_must_stop())
1112 goto checkwait;
1113 }
1114
1115 // In case the grace period extended beyond the end of the loop.
1116 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1117 rcu_torture_boost_failed(gp_state, &gp_state_time);
1118
1119 /*
1120 * Set the start time of the next test interval.
1121 * Yes, this is vulnerable to long delays, but such
1122 * delays simply cause a false negative for the next
1123 * interval. Besides, we are running at RT priority,
1124 * so delays should be relatively rare.
1125 */
1126 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) {
1127 if (mutex_trylock(&boost_mutex)) {
1128 if (oldstarttime == boost_starttime) {
1129 WRITE_ONCE(boost_starttime,
1130 jiffies + test_boost_interval * HZ);
1131 n_rcu_torture_boosts++;
1132 }
1133 mutex_unlock(&boost_mutex);
1134 break;
1135 }
1136 schedule_timeout_uninterruptible(1);
1137 }
1138
1139 /* Go do the stutter. */
1140 checkwait: if (stutter_wait("rcu_torture_boost"))
1141 sched_set_fifo_low(current);
1142 } while (!torture_must_stop());
1143
1144 /* Clean up and exit. */
1145 while (!kthread_should_stop()) {
1146 torture_shutdown_absorb("rcu_torture_boost");
1147 schedule_timeout_uninterruptible(1);
1148 }
1149 torture_kthread_stopping("rcu_torture_boost");
1150 return 0;
1151 }
1152
1153 /*
1154 * RCU torture force-quiescent-state kthread. Repeatedly induces
1155 * bursts of calls to force_quiescent_state(), increasing the probability
1156 * of occurrence of some important types of race conditions.
1157 */
1158 static int
rcu_torture_fqs(void * arg)1159 rcu_torture_fqs(void *arg)
1160 {
1161 unsigned long fqs_resume_time;
1162 int fqs_burst_remaining;
1163 int oldnice = task_nice(current);
1164
1165 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
1166 do {
1167 fqs_resume_time = jiffies + fqs_stutter * HZ;
1168 while (time_before(jiffies, fqs_resume_time) &&
1169 !kthread_should_stop()) {
1170 schedule_timeout_interruptible(1);
1171 }
1172 fqs_burst_remaining = fqs_duration;
1173 while (fqs_burst_remaining > 0 &&
1174 !kthread_should_stop()) {
1175 cur_ops->fqs();
1176 udelay(fqs_holdoff);
1177 fqs_burst_remaining -= fqs_holdoff;
1178 }
1179 if (stutter_wait("rcu_torture_fqs"))
1180 sched_set_normal(current, oldnice);
1181 } while (!torture_must_stop());
1182 torture_kthread_stopping("rcu_torture_fqs");
1183 return 0;
1184 }
1185
1186 // Used by writers to randomly choose from the available grace-period primitives.
1187 static int synctype[ARRAY_SIZE(rcu_torture_writer_state_names)] = { };
1188 static int nsynctypes;
1189
1190 /*
1191 * Determine which grace-period primitives are available.
1192 */
rcu_torture_write_types(void)1193 static void rcu_torture_write_types(void)
1194 {
1195 bool gp_cond1 = gp_cond, gp_cond_exp1 = gp_cond_exp, gp_cond_full1 = gp_cond_full;
1196 bool gp_cond_exp_full1 = gp_cond_exp_full, gp_exp1 = gp_exp, gp_poll_exp1 = gp_poll_exp;
1197 bool gp_poll_exp_full1 = gp_poll_exp_full, gp_normal1 = gp_normal, gp_poll1 = gp_poll;
1198 bool gp_poll_full1 = gp_poll_full, gp_sync1 = gp_sync;
1199
1200 /* Initialize synctype[] array. If none set, take default. */
1201 if (!gp_cond1 &&
1202 !gp_cond_exp1 &&
1203 !gp_cond_full1 &&
1204 !gp_cond_exp_full1 &&
1205 !gp_exp1 &&
1206 !gp_poll_exp1 &&
1207 !gp_poll_exp_full1 &&
1208 !gp_normal1 &&
1209 !gp_poll1 &&
1210 !gp_poll_full1 &&
1211 !gp_sync1) {
1212 gp_cond1 = true;
1213 gp_cond_exp1 = true;
1214 gp_cond_full1 = true;
1215 gp_cond_exp_full1 = true;
1216 gp_exp1 = true;
1217 gp_poll_exp1 = true;
1218 gp_poll_exp_full1 = true;
1219 gp_normal1 = true;
1220 gp_poll1 = true;
1221 gp_poll_full1 = true;
1222 gp_sync1 = true;
1223 }
1224 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) {
1225 synctype[nsynctypes++] = RTWS_COND_GET;
1226 pr_info("%s: Testing conditional GPs.\n", __func__);
1227 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) {
1228 pr_alert("%s: gp_cond without primitives.\n", __func__);
1229 }
1230 if (gp_cond_exp1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp) {
1231 synctype[nsynctypes++] = RTWS_COND_GET_EXP;
1232 pr_info("%s: Testing conditional expedited GPs.\n", __func__);
1233 } else if (gp_cond_exp && (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp)) {
1234 pr_alert("%s: gp_cond_exp without primitives.\n", __func__);
1235 }
1236 if (gp_cond_full1 && cur_ops->get_gp_state && cur_ops->cond_sync_full) {
1237 synctype[nsynctypes++] = RTWS_COND_GET_FULL;
1238 pr_info("%s: Testing conditional full-state GPs.\n", __func__);
1239 } else if (gp_cond_full && (!cur_ops->get_gp_state || !cur_ops->cond_sync_full)) {
1240 pr_alert("%s: gp_cond_full without primitives.\n", __func__);
1241 }
1242 if (gp_cond_exp_full1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp_full) {
1243 synctype[nsynctypes++] = RTWS_COND_GET_EXP_FULL;
1244 pr_info("%s: Testing conditional full-state expedited GPs.\n", __func__);
1245 } else if (gp_cond_exp_full &&
1246 (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp_full)) {
1247 pr_alert("%s: gp_cond_exp_full without primitives.\n", __func__);
1248 }
1249 if (gp_exp1 && cur_ops->exp_sync) {
1250 synctype[nsynctypes++] = RTWS_EXP_SYNC;
1251 pr_info("%s: Testing expedited GPs.\n", __func__);
1252 } else if (gp_exp && !cur_ops->exp_sync) {
1253 pr_alert("%s: gp_exp without primitives.\n", __func__);
1254 }
1255 if (gp_normal1 && cur_ops->deferred_free) {
1256 synctype[nsynctypes++] = RTWS_DEF_FREE;
1257 pr_info("%s: Testing asynchronous GPs.\n", __func__);
1258 } else if (gp_normal && !cur_ops->deferred_free) {
1259 pr_alert("%s: gp_normal without primitives.\n", __func__);
1260 }
1261 if (gp_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) {
1262 synctype[nsynctypes++] = RTWS_POLL_GET;
1263 pr_info("%s: Testing polling GPs.\n", __func__);
1264 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) {
1265 pr_alert("%s: gp_poll without primitives.\n", __func__);
1266 }
1267 if (gp_poll_full1 && cur_ops->start_gp_poll_full && cur_ops->poll_gp_state_full) {
1268 synctype[nsynctypes++] = RTWS_POLL_GET_FULL;
1269 pr_info("%s: Testing polling full-state GPs.\n", __func__);
1270 } else if (gp_poll_full && (!cur_ops->start_gp_poll_full || !cur_ops->poll_gp_state_full)) {
1271 pr_alert("%s: gp_poll_full without primitives.\n", __func__);
1272 }
1273 if (gp_poll_exp1 && cur_ops->start_gp_poll_exp && cur_ops->poll_gp_state_exp) {
1274 synctype[nsynctypes++] = RTWS_POLL_GET_EXP;
1275 pr_info("%s: Testing polling expedited GPs.\n", __func__);
1276 } else if (gp_poll_exp && (!cur_ops->start_gp_poll_exp || !cur_ops->poll_gp_state_exp)) {
1277 pr_alert("%s: gp_poll_exp without primitives.\n", __func__);
1278 }
1279 if (gp_poll_exp_full1 && cur_ops->start_gp_poll_exp_full && cur_ops->poll_gp_state_full) {
1280 synctype[nsynctypes++] = RTWS_POLL_GET_EXP_FULL;
1281 pr_info("%s: Testing polling full-state expedited GPs.\n", __func__);
1282 } else if (gp_poll_exp_full &&
1283 (!cur_ops->start_gp_poll_exp_full || !cur_ops->poll_gp_state_full)) {
1284 pr_alert("%s: gp_poll_exp_full without primitives.\n", __func__);
1285 }
1286 if (gp_sync1 && cur_ops->sync) {
1287 synctype[nsynctypes++] = RTWS_SYNC;
1288 pr_info("%s: Testing normal GPs.\n", __func__);
1289 } else if (gp_sync && !cur_ops->sync) {
1290 pr_alert("%s: gp_sync without primitives.\n", __func__);
1291 }
1292 }
1293
1294 /*
1295 * Do the specified rcu_torture_writer() synchronous grace period,
1296 * while also testing out the polled APIs. Note well that the single-CPU
1297 * grace-period optimizations must be accounted for.
1298 */
do_rtws_sync(struct torture_random_state * trsp,void (* sync)(void))1299 static void do_rtws_sync(struct torture_random_state *trsp, void (*sync)(void))
1300 {
1301 unsigned long cookie;
1302 struct rcu_gp_oldstate cookie_full;
1303 bool dopoll;
1304 bool dopoll_full;
1305 unsigned long r = torture_random(trsp);
1306
1307 dopoll = cur_ops->get_gp_state && cur_ops->poll_gp_state && !(r & 0x300);
1308 dopoll_full = cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full && !(r & 0xc00);
1309 if (dopoll || dopoll_full)
1310 cpus_read_lock();
1311 if (dopoll)
1312 cookie = cur_ops->get_gp_state();
1313 if (dopoll_full)
1314 cur_ops->get_gp_state_full(&cookie_full);
1315 if (cur_ops->poll_need_2gp && cur_ops->poll_need_2gp(dopoll, dopoll_full))
1316 sync();
1317 sync();
1318 WARN_ONCE(dopoll && !cur_ops->poll_gp_state(cookie),
1319 "%s: Cookie check 3 failed %pS() online %*pbl.",
1320 __func__, sync, cpumask_pr_args(cpu_online_mask));
1321 WARN_ONCE(dopoll_full && !cur_ops->poll_gp_state_full(&cookie_full),
1322 "%s: Cookie check 4 failed %pS() online %*pbl",
1323 __func__, sync, cpumask_pr_args(cpu_online_mask));
1324 if (dopoll || dopoll_full)
1325 cpus_read_unlock();
1326 }
1327
1328 /*
1329 * RCU torture writer kthread. Repeatedly substitutes a new structure
1330 * for that pointed to by rcu_torture_current, freeing the old structure
1331 * after a series of grace periods (the "pipeline").
1332 */
1333 static int
rcu_torture_writer(void * arg)1334 rcu_torture_writer(void *arg)
1335 {
1336 bool boot_ended;
1337 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
1338 unsigned long cookie;
1339 struct rcu_gp_oldstate cookie_full;
1340 int expediting = 0;
1341 unsigned long gp_snap;
1342 struct rcu_gp_oldstate gp_snap_full;
1343 int i;
1344 int idx;
1345 int oldnice = task_nice(current);
1346 struct rcu_torture *rp;
1347 struct rcu_torture *old_rp;
1348 static DEFINE_TORTURE_RANDOM(rand);
1349 bool stutter_waited;
1350
1351 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
1352 if (!can_expedite)
1353 pr_alert("%s" TORTURE_FLAG
1354 " GP expediting controlled from boot/sysfs for %s.\n",
1355 torture_type, cur_ops->name);
1356 if (WARN_ONCE(nsynctypes == 0,
1357 "%s: No update-side primitives.\n", __func__)) {
1358 /*
1359 * No updates primitives, so don't try updating.
1360 * The resulting test won't be testing much, hence the
1361 * above WARN_ONCE().
1362 */
1363 rcu_torture_writer_state = RTWS_STOPPING;
1364 torture_kthread_stopping("rcu_torture_writer");
1365 return 0;
1366 }
1367
1368 do {
1369 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1370 torture_hrtimeout_us(500, 1000, &rand);
1371 rp = rcu_torture_alloc();
1372 if (rp == NULL)
1373 continue;
1374 rp->rtort_pipe_count = 0;
1375 rcu_torture_writer_state = RTWS_DELAY;
1376 udelay(torture_random(&rand) & 0x3ff);
1377 rcu_torture_writer_state = RTWS_REPLACE;
1378 old_rp = rcu_dereference_check(rcu_torture_current,
1379 current == writer_task);
1380 rp->rtort_mbtest = 1;
1381 rcu_assign_pointer(rcu_torture_current, rp);
1382 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1383 if (old_rp) {
1384 i = old_rp->rtort_pipe_count;
1385 if (i > RCU_TORTURE_PIPE_LEN)
1386 i = RCU_TORTURE_PIPE_LEN;
1387 atomic_inc(&rcu_torture_wcount[i]);
1388 WRITE_ONCE(old_rp->rtort_pipe_count,
1389 old_rp->rtort_pipe_count + 1);
1390
1391 // Make sure readers block polled grace periods.
1392 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
1393 idx = cur_ops->readlock();
1394 cookie = cur_ops->get_gp_state();
1395 WARN_ONCE(cur_ops->poll_gp_state(cookie),
1396 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n",
1397 __func__,
1398 rcu_torture_writer_state_getname(),
1399 rcu_torture_writer_state,
1400 cookie, cur_ops->get_gp_state());
1401 if (cur_ops->get_gp_completed) {
1402 cookie = cur_ops->get_gp_completed();
1403 WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie));
1404 }
1405 cur_ops->readunlock(idx);
1406 }
1407 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) {
1408 idx = cur_ops->readlock();
1409 cur_ops->get_gp_state_full(&cookie_full);
1410 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
1411 "%s: Cookie check 5 failed %s(%d) online %*pbl\n",
1412 __func__,
1413 rcu_torture_writer_state_getname(),
1414 rcu_torture_writer_state,
1415 cpumask_pr_args(cpu_online_mask));
1416 if (cur_ops->get_gp_completed_full) {
1417 cur_ops->get_gp_completed_full(&cookie_full);
1418 WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full));
1419 }
1420 cur_ops->readunlock(idx);
1421 }
1422 switch (synctype[torture_random(&rand) % nsynctypes]) {
1423 case RTWS_DEF_FREE:
1424 rcu_torture_writer_state = RTWS_DEF_FREE;
1425 cur_ops->deferred_free(old_rp);
1426 break;
1427 case RTWS_EXP_SYNC:
1428 rcu_torture_writer_state = RTWS_EXP_SYNC;
1429 do_rtws_sync(&rand, cur_ops->exp_sync);
1430 rcu_torture_pipe_update(old_rp);
1431 break;
1432 case RTWS_COND_GET:
1433 rcu_torture_writer_state = RTWS_COND_GET;
1434 gp_snap = cur_ops->get_gp_state();
1435 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1436 rcu_torture_writer_state = RTWS_COND_SYNC;
1437 cur_ops->cond_sync(gp_snap);
1438 rcu_torture_pipe_update(old_rp);
1439 break;
1440 case RTWS_COND_GET_EXP:
1441 rcu_torture_writer_state = RTWS_COND_GET_EXP;
1442 gp_snap = cur_ops->get_gp_state_exp();
1443 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1444 rcu_torture_writer_state = RTWS_COND_SYNC_EXP;
1445 cur_ops->cond_sync_exp(gp_snap);
1446 rcu_torture_pipe_update(old_rp);
1447 break;
1448 case RTWS_COND_GET_FULL:
1449 rcu_torture_writer_state = RTWS_COND_GET_FULL;
1450 cur_ops->get_gp_state_full(&gp_snap_full);
1451 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1452 rcu_torture_writer_state = RTWS_COND_SYNC_FULL;
1453 cur_ops->cond_sync_full(&gp_snap_full);
1454 rcu_torture_pipe_update(old_rp);
1455 break;
1456 case RTWS_COND_GET_EXP_FULL:
1457 rcu_torture_writer_state = RTWS_COND_GET_EXP_FULL;
1458 cur_ops->get_gp_state_full(&gp_snap_full);
1459 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1460 rcu_torture_writer_state = RTWS_COND_SYNC_EXP_FULL;
1461 cur_ops->cond_sync_exp_full(&gp_snap_full);
1462 rcu_torture_pipe_update(old_rp);
1463 break;
1464 case RTWS_POLL_GET:
1465 rcu_torture_writer_state = RTWS_POLL_GET;
1466 gp_snap = cur_ops->start_gp_poll();
1467 rcu_torture_writer_state = RTWS_POLL_WAIT;
1468 while (!cur_ops->poll_gp_state(gp_snap))
1469 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1470 &rand);
1471 rcu_torture_pipe_update(old_rp);
1472 break;
1473 case RTWS_POLL_GET_FULL:
1474 rcu_torture_writer_state = RTWS_POLL_GET_FULL;
1475 cur_ops->start_gp_poll_full(&gp_snap_full);
1476 rcu_torture_writer_state = RTWS_POLL_WAIT_FULL;
1477 while (!cur_ops->poll_gp_state_full(&gp_snap_full))
1478 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1479 &rand);
1480 rcu_torture_pipe_update(old_rp);
1481 break;
1482 case RTWS_POLL_GET_EXP:
1483 rcu_torture_writer_state = RTWS_POLL_GET_EXP;
1484 gp_snap = cur_ops->start_gp_poll_exp();
1485 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP;
1486 while (!cur_ops->poll_gp_state_exp(gp_snap))
1487 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1488 &rand);
1489 rcu_torture_pipe_update(old_rp);
1490 break;
1491 case RTWS_POLL_GET_EXP_FULL:
1492 rcu_torture_writer_state = RTWS_POLL_GET_EXP_FULL;
1493 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1494 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP_FULL;
1495 while (!cur_ops->poll_gp_state_full(&gp_snap_full))
1496 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1497 &rand);
1498 rcu_torture_pipe_update(old_rp);
1499 break;
1500 case RTWS_SYNC:
1501 rcu_torture_writer_state = RTWS_SYNC;
1502 do_rtws_sync(&rand, cur_ops->sync);
1503 rcu_torture_pipe_update(old_rp);
1504 break;
1505 default:
1506 WARN_ON_ONCE(1);
1507 break;
1508 }
1509 }
1510 WRITE_ONCE(rcu_torture_current_version,
1511 rcu_torture_current_version + 1);
1512 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1513 if (can_expedite &&
1514 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1515 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1516 if (expediting >= 0)
1517 rcu_expedite_gp();
1518 else
1519 rcu_unexpedite_gp();
1520 if (++expediting > 3)
1521 expediting = -expediting;
1522 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1523 can_expedite = !rcu_gp_is_expedited() &&
1524 !rcu_gp_is_normal();
1525 }
1526 rcu_torture_writer_state = RTWS_STUTTER;
1527 boot_ended = rcu_inkernel_boot_has_ended();
1528 stutter_waited = stutter_wait("rcu_torture_writer");
1529 if (stutter_waited &&
1530 !atomic_read(&rcu_fwd_cb_nodelay) &&
1531 !cur_ops->slow_gps &&
1532 !torture_must_stop() &&
1533 boot_ended)
1534 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1535 if (list_empty(&rcu_tortures[i].rtort_free) &&
1536 rcu_access_pointer(rcu_torture_current) !=
1537 &rcu_tortures[i]) {
1538 tracing_off();
1539 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1540 rcu_ftrace_dump(DUMP_ALL);
1541 }
1542 if (stutter_waited)
1543 sched_set_normal(current, oldnice);
1544 } while (!torture_must_stop());
1545 rcu_torture_current = NULL; // Let stats task know that we are done.
1546 /* Reset expediting back to unexpedited. */
1547 if (expediting > 0)
1548 expediting = -expediting;
1549 while (can_expedite && expediting++ < 0)
1550 rcu_unexpedite_gp();
1551 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1552 if (!can_expedite)
1553 pr_alert("%s" TORTURE_FLAG
1554 " Dynamic grace-period expediting was disabled.\n",
1555 torture_type);
1556 rcu_torture_writer_state = RTWS_STOPPING;
1557 torture_kthread_stopping("rcu_torture_writer");
1558 return 0;
1559 }
1560
1561 /*
1562 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1563 * delay between calls.
1564 */
1565 static int
rcu_torture_fakewriter(void * arg)1566 rcu_torture_fakewriter(void *arg)
1567 {
1568 unsigned long gp_snap;
1569 struct rcu_gp_oldstate gp_snap_full;
1570 DEFINE_TORTURE_RANDOM(rand);
1571
1572 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1573 set_user_nice(current, MAX_NICE);
1574
1575 if (WARN_ONCE(nsynctypes == 0,
1576 "%s: No update-side primitives.\n", __func__)) {
1577 /*
1578 * No updates primitives, so don't try updating.
1579 * The resulting test won't be testing much, hence the
1580 * above WARN_ONCE().
1581 */
1582 torture_kthread_stopping("rcu_torture_fakewriter");
1583 return 0;
1584 }
1585
1586 do {
1587 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand);
1588 if (cur_ops->cb_barrier != NULL &&
1589 torture_random(&rand) % (nfakewriters * 8) == 0) {
1590 cur_ops->cb_barrier();
1591 } else {
1592 switch (synctype[torture_random(&rand) % nsynctypes]) {
1593 case RTWS_DEF_FREE:
1594 break;
1595 case RTWS_EXP_SYNC:
1596 cur_ops->exp_sync();
1597 break;
1598 case RTWS_COND_GET:
1599 gp_snap = cur_ops->get_gp_state();
1600 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1601 cur_ops->cond_sync(gp_snap);
1602 break;
1603 case RTWS_COND_GET_EXP:
1604 gp_snap = cur_ops->get_gp_state_exp();
1605 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1606 cur_ops->cond_sync_exp(gp_snap);
1607 break;
1608 case RTWS_COND_GET_FULL:
1609 cur_ops->get_gp_state_full(&gp_snap_full);
1610 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1611 cur_ops->cond_sync_full(&gp_snap_full);
1612 break;
1613 case RTWS_COND_GET_EXP_FULL:
1614 cur_ops->get_gp_state_full(&gp_snap_full);
1615 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1616 cur_ops->cond_sync_exp_full(&gp_snap_full);
1617 break;
1618 case RTWS_POLL_GET:
1619 gp_snap = cur_ops->start_gp_poll();
1620 while (!cur_ops->poll_gp_state(gp_snap)) {
1621 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1622 &rand);
1623 }
1624 break;
1625 case RTWS_POLL_GET_FULL:
1626 cur_ops->start_gp_poll_full(&gp_snap_full);
1627 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1628 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1629 &rand);
1630 }
1631 break;
1632 case RTWS_POLL_GET_EXP:
1633 gp_snap = cur_ops->start_gp_poll_exp();
1634 while (!cur_ops->poll_gp_state_exp(gp_snap)) {
1635 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1636 &rand);
1637 }
1638 break;
1639 case RTWS_POLL_GET_EXP_FULL:
1640 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1641 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1642 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1643 &rand);
1644 }
1645 break;
1646 case RTWS_SYNC:
1647 cur_ops->sync();
1648 break;
1649 default:
1650 WARN_ON_ONCE(1);
1651 break;
1652 }
1653 }
1654 stutter_wait("rcu_torture_fakewriter");
1655 } while (!torture_must_stop());
1656
1657 torture_kthread_stopping("rcu_torture_fakewriter");
1658 return 0;
1659 }
1660
rcu_torture_timer_cb(struct rcu_head * rhp)1661 static void rcu_torture_timer_cb(struct rcu_head *rhp)
1662 {
1663 kfree(rhp);
1664 }
1665
1666 // Set up and carry out testing of RCU's global memory ordering
rcu_torture_reader_do_mbchk(long myid,struct rcu_torture * rtp,struct torture_random_state * trsp)1667 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp,
1668 struct torture_random_state *trsp)
1669 {
1670 unsigned long loops;
1671 int noc = torture_num_online_cpus();
1672 int rdrchked;
1673 int rdrchker;
1674 struct rcu_torture_reader_check *rtrcp; // Me.
1675 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking.
1676 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked.
1677 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me.
1678
1679 if (myid < 0)
1680 return; // Don't try this from timer handlers.
1681
1682 // Increment my counter.
1683 rtrcp = &rcu_torture_reader_mbchk[myid];
1684 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1);
1685
1686 // Attempt to assign someone else some checking work.
1687 rdrchked = torture_random(trsp) % nrealreaders;
1688 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1689 rdrchker = torture_random(trsp) % nrealreaders;
1690 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker];
1691 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker &&
1692 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below.
1693 !READ_ONCE(rtp->rtort_chkp) &&
1694 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below.
1695 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops);
1696 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0);
1697 rtrcp->rtc_chkrdr = rdrchked;
1698 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends.
1699 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) ||
1700 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp))
1701 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out.
1702 }
1703
1704 // If assigned some completed work, do it!
1705 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner);
1706 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready))
1707 return; // No work or work not yet ready.
1708 rdrchked = rtrcp_assigner->rtc_chkrdr;
1709 if (WARN_ON_ONCE(rdrchked < 0))
1710 return;
1711 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1712 loops = READ_ONCE(rtrcp_chked->rtc_myloops);
1713 atomic_inc(&n_rcu_torture_mbchk_tries);
1714 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops))
1715 atomic_inc(&n_rcu_torture_mbchk_fail);
1716 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2;
1717 rtrcp_assigner->rtc_ready = 0;
1718 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work.
1719 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign.
1720 }
1721
1722 /*
1723 * Do one extension of an RCU read-side critical section using the
1724 * current reader state in readstate (set to zero for initial entry
1725 * to extended critical section), set the new state as specified by
1726 * newstate (set to zero for final exit from extended critical section),
1727 * and random-number-generator state in trsp. If this is neither the
1728 * beginning or end of the critical section and if there was actually a
1729 * change, do a ->read_delay().
1730 */
rcutorture_one_extend(int * readstate,int newstate,struct torture_random_state * trsp,struct rt_read_seg * rtrsp)1731 static void rcutorture_one_extend(int *readstate, int newstate,
1732 struct torture_random_state *trsp,
1733 struct rt_read_seg *rtrsp)
1734 {
1735 unsigned long flags;
1736 int idxnew1 = -1;
1737 int idxnew2 = -1;
1738 int idxold1 = *readstate;
1739 int idxold2 = idxold1;
1740 int statesnew = ~*readstate & newstate;
1741 int statesold = *readstate & ~newstate;
1742
1743 WARN_ON_ONCE(idxold2 < 0);
1744 WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
1745 rtrsp->rt_readstate = newstate;
1746
1747 /* First, put new protection in place to avoid critical-section gap. */
1748 if (statesnew & RCUTORTURE_RDR_BH)
1749 local_bh_disable();
1750 if (statesnew & RCUTORTURE_RDR_RBH)
1751 rcu_read_lock_bh();
1752 if (statesnew & RCUTORTURE_RDR_IRQ)
1753 local_irq_disable();
1754 if (statesnew & RCUTORTURE_RDR_PREEMPT)
1755 preempt_disable();
1756 if (statesnew & RCUTORTURE_RDR_SCHED)
1757 rcu_read_lock_sched();
1758 if (statesnew & RCUTORTURE_RDR_RCU_1)
1759 idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1;
1760 if (statesnew & RCUTORTURE_RDR_RCU_2)
1761 idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2;
1762
1763 /*
1764 * Next, remove old protection, in decreasing order of strength
1765 * to avoid unlock paths that aren't safe in the stronger
1766 * context. Namely: BH can not be enabled with disabled interrupts.
1767 * Additionally PREEMPT_RT requires that BH is enabled in preemptible
1768 * context.
1769 */
1770 if (statesold & RCUTORTURE_RDR_IRQ)
1771 local_irq_enable();
1772 if (statesold & RCUTORTURE_RDR_PREEMPT)
1773 preempt_enable();
1774 if (statesold & RCUTORTURE_RDR_SCHED)
1775 rcu_read_unlock_sched();
1776 if (statesold & RCUTORTURE_RDR_BH)
1777 local_bh_enable();
1778 if (statesold & RCUTORTURE_RDR_RBH)
1779 rcu_read_unlock_bh();
1780 if (statesold & RCUTORTURE_RDR_RCU_2) {
1781 cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1);
1782 WARN_ON_ONCE(idxnew2 != -1);
1783 idxold2 = 0;
1784 }
1785 if (statesold & RCUTORTURE_RDR_RCU_1) {
1786 bool lockit;
1787
1788 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff);
1789 if (lockit)
1790 raw_spin_lock_irqsave(¤t->pi_lock, flags);
1791 cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1);
1792 WARN_ON_ONCE(idxnew1 != -1);
1793 idxold1 = 0;
1794 if (lockit)
1795 raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
1796 }
1797
1798 /* Delay if neither beginning nor end and there was a change. */
1799 if ((statesnew || statesold) && *readstate && newstate)
1800 cur_ops->read_delay(trsp, rtrsp);
1801
1802 /* Update the reader state. */
1803 if (idxnew1 == -1)
1804 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1;
1805 WARN_ON_ONCE(idxnew1 < 0);
1806 if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1))
1807 pr_info("Unexpected idxnew1 value of %#x\n", idxnew1);
1808 if (idxnew2 == -1)
1809 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2;
1810 WARN_ON_ONCE(idxnew2 < 0);
1811 WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
1812 *readstate = idxnew1 | idxnew2 | newstate;
1813 WARN_ON_ONCE(*readstate < 0);
1814 if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1))
1815 pr_info("Unexpected idxnew2 value of %#x\n", idxnew2);
1816 }
1817
1818 /* Return the biggest extendables mask given current RCU and boot parameters. */
rcutorture_extend_mask_max(void)1819 static int rcutorture_extend_mask_max(void)
1820 {
1821 int mask;
1822
1823 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1824 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1825 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2;
1826 return mask;
1827 }
1828
1829 /* Return a random protection state mask, but with at least one bit set. */
1830 static int
rcutorture_extend_mask(int oldmask,struct torture_random_state * trsp)1831 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1832 {
1833 int mask = rcutorture_extend_mask_max();
1834 unsigned long randmask1 = torture_random(trsp) >> 8;
1835 unsigned long randmask2 = randmask1 >> 3;
1836 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
1837 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
1838 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1839
1840 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1);
1841 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
1842 if (!(randmask1 & 0x7))
1843 mask = mask & randmask2;
1844 else
1845 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1846
1847 // Can't have nested RCU reader without outer RCU reader.
1848 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) {
1849 if (oldmask & RCUTORTURE_RDR_RCU_1)
1850 mask &= ~RCUTORTURE_RDR_RCU_2;
1851 else
1852 mask |= RCUTORTURE_RDR_RCU_1;
1853 }
1854
1855 /*
1856 * Can't enable bh w/irq disabled.
1857 */
1858 if (mask & RCUTORTURE_RDR_IRQ)
1859 mask |= oldmask & bhs;
1860
1861 /*
1862 * Ideally these sequences would be detected in debug builds
1863 * (regardless of RT), but until then don't stop testing
1864 * them on non-RT.
1865 */
1866 if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
1867 /* Can't modify BH in atomic context */
1868 if (oldmask & preempts_irq)
1869 mask &= ~bhs;
1870 if ((oldmask | mask) & preempts_irq)
1871 mask |= oldmask & bhs;
1872 }
1873
1874 return mask ?: RCUTORTURE_RDR_RCU_1;
1875 }
1876
1877 /*
1878 * Do a randomly selected number of extensions of an existing RCU read-side
1879 * critical section.
1880 */
1881 static struct rt_read_seg *
rcutorture_loop_extend(int * readstate,struct torture_random_state * trsp,struct rt_read_seg * rtrsp)1882 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1883 struct rt_read_seg *rtrsp)
1884 {
1885 int i;
1886 int j;
1887 int mask = rcutorture_extend_mask_max();
1888
1889 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
1890 if (!((mask - 1) & mask))
1891 return rtrsp; /* Current RCU reader not extendable. */
1892 /* Bias towards larger numbers of loops. */
1893 i = (torture_random(trsp) >> 3);
1894 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
1895 for (j = 0; j < i; j++) {
1896 mask = rcutorture_extend_mask(*readstate, trsp);
1897 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
1898 }
1899 return &rtrsp[j];
1900 }
1901
1902 /*
1903 * Do one read-side critical section, returning false if there was
1904 * no data to read. Can be invoked both from process context and
1905 * from a timer handler.
1906 */
rcu_torture_one_read(struct torture_random_state * trsp,long myid)1907 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
1908 {
1909 bool checkpolling = !(torture_random(trsp) & 0xfff);
1910 unsigned long cookie;
1911 struct rcu_gp_oldstate cookie_full;
1912 int i;
1913 unsigned long started;
1914 unsigned long completed;
1915 int newstate;
1916 struct rcu_torture *p;
1917 int pipe_count;
1918 int readstate = 0;
1919 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
1920 struct rt_read_seg *rtrsp = &rtseg[0];
1921 struct rt_read_seg *rtrsp1;
1922 unsigned long long ts;
1923
1924 WARN_ON_ONCE(!rcu_is_watching());
1925 newstate = rcutorture_extend_mask(readstate, trsp);
1926 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
1927 if (checkpolling) {
1928 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
1929 cookie = cur_ops->get_gp_state();
1930 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
1931 cur_ops->get_gp_state_full(&cookie_full);
1932 }
1933 started = cur_ops->get_gp_seq();
1934 ts = rcu_trace_clock_local();
1935 p = rcu_dereference_check(rcu_torture_current,
1936 !cur_ops->readlock_held || cur_ops->readlock_held());
1937 if (p == NULL) {
1938 /* Wait for rcu_torture_writer to get underway */
1939 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1940 return false;
1941 }
1942 if (p->rtort_mbtest == 0)
1943 atomic_inc(&n_rcu_torture_mberror);
1944 rcu_torture_reader_do_mbchk(myid, p, trsp);
1945 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
1946 preempt_disable();
1947 pipe_count = READ_ONCE(p->rtort_pipe_count);
1948 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1949 /* Should not happen, but... */
1950 pipe_count = RCU_TORTURE_PIPE_LEN;
1951 }
1952 completed = cur_ops->get_gp_seq();
1953 if (pipe_count > 1) {
1954 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1955 ts, started, completed);
1956 rcu_ftrace_dump(DUMP_ALL);
1957 }
1958 __this_cpu_inc(rcu_torture_count[pipe_count]);
1959 completed = rcutorture_seq_diff(completed, started);
1960 if (completed > RCU_TORTURE_PIPE_LEN) {
1961 /* Should not happen, but... */
1962 completed = RCU_TORTURE_PIPE_LEN;
1963 }
1964 __this_cpu_inc(rcu_torture_batch[completed]);
1965 preempt_enable();
1966 if (checkpolling) {
1967 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
1968 WARN_ONCE(cur_ops->poll_gp_state(cookie),
1969 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
1970 __func__,
1971 rcu_torture_writer_state_getname(),
1972 rcu_torture_writer_state,
1973 cookie, cur_ops->get_gp_state());
1974 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
1975 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
1976 "%s: Cookie check 6 failed %s(%d) online %*pbl\n",
1977 __func__,
1978 rcu_torture_writer_state_getname(),
1979 rcu_torture_writer_state,
1980 cpumask_pr_args(cpu_online_mask));
1981 }
1982 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1983 WARN_ON_ONCE(readstate);
1984 // This next splat is expected behavior if leakpointer, especially
1985 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
1986 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1);
1987
1988 /* If error or close call, record the sequence of reader protections. */
1989 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
1990 i = 0;
1991 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
1992 err_segs[i++] = *rtrsp1;
1993 rt_read_nsegs = i;
1994 }
1995
1996 return true;
1997 }
1998
1999 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
2000
2001 /*
2002 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
2003 * incrementing the corresponding element of the pipeline array. The
2004 * counter in the element should never be greater than 1, otherwise, the
2005 * RCU implementation is broken.
2006 */
rcu_torture_timer(struct timer_list * unused)2007 static void rcu_torture_timer(struct timer_list *unused)
2008 {
2009 atomic_long_inc(&n_rcu_torture_timers);
2010 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1);
2011
2012 /* Test call_rcu() invocation from interrupt handler. */
2013 if (cur_ops->call) {
2014 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
2015
2016 if (rhp)
2017 cur_ops->call(rhp, rcu_torture_timer_cb);
2018 }
2019 }
2020
2021 /*
2022 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
2023 * incrementing the corresponding element of the pipeline array. The
2024 * counter in the element should never be greater than 1, otherwise, the
2025 * RCU implementation is broken.
2026 */
2027 static int
rcu_torture_reader(void * arg)2028 rcu_torture_reader(void *arg)
2029 {
2030 unsigned long lastsleep = jiffies;
2031 long myid = (long)arg;
2032 int mynumonline = myid;
2033 DEFINE_TORTURE_RANDOM(rand);
2034 struct timer_list t;
2035
2036 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
2037 set_user_nice(current, MAX_NICE);
2038 if (irqreader && cur_ops->irq_capable)
2039 timer_setup_on_stack(&t, rcu_torture_timer, 0);
2040 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2041 do {
2042 if (irqreader && cur_ops->irq_capable) {
2043 if (!timer_pending(&t))
2044 mod_timer(&t, jiffies + 1);
2045 }
2046 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop())
2047 schedule_timeout_interruptible(HZ);
2048 if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
2049 torture_hrtimeout_us(500, 1000, &rand);
2050 lastsleep = jiffies + 10;
2051 }
2052 while (torture_num_online_cpus() < mynumonline && !torture_must_stop())
2053 schedule_timeout_interruptible(HZ / 5);
2054 stutter_wait("rcu_torture_reader");
2055 } while (!torture_must_stop());
2056 if (irqreader && cur_ops->irq_capable) {
2057 del_timer_sync(&t);
2058 destroy_timer_on_stack(&t);
2059 }
2060 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2061 torture_kthread_stopping("rcu_torture_reader");
2062 return 0;
2063 }
2064
2065 /*
2066 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to
2067 * increase race probabilities and fuzzes the interval between toggling.
2068 */
rcu_nocb_toggle(void * arg)2069 static int rcu_nocb_toggle(void *arg)
2070 {
2071 int cpu;
2072 int maxcpu = -1;
2073 int oldnice = task_nice(current);
2074 long r;
2075 DEFINE_TORTURE_RANDOM(rand);
2076 ktime_t toggle_delay;
2077 unsigned long toggle_fuzz;
2078 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle);
2079
2080 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started");
2081 while (!rcu_inkernel_boot_has_ended())
2082 schedule_timeout_interruptible(HZ / 10);
2083 for_each_online_cpu(cpu)
2084 maxcpu = cpu;
2085 WARN_ON(maxcpu < 0);
2086 if (toggle_interval > ULONG_MAX)
2087 toggle_fuzz = ULONG_MAX >> 3;
2088 else
2089 toggle_fuzz = toggle_interval >> 3;
2090 if (toggle_fuzz <= 0)
2091 toggle_fuzz = NSEC_PER_USEC;
2092 do {
2093 r = torture_random(&rand);
2094 cpu = (r >> 4) % (maxcpu + 1);
2095 if (r & 0x1) {
2096 rcu_nocb_cpu_offload(cpu);
2097 atomic_long_inc(&n_nocb_offload);
2098 } else {
2099 rcu_nocb_cpu_deoffload(cpu);
2100 atomic_long_inc(&n_nocb_deoffload);
2101 }
2102 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval;
2103 set_current_state(TASK_INTERRUPTIBLE);
2104 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL);
2105 if (stutter_wait("rcu_nocb_toggle"))
2106 sched_set_normal(current, oldnice);
2107 } while (!torture_must_stop());
2108 torture_kthread_stopping("rcu_nocb_toggle");
2109 return 0;
2110 }
2111
2112 /*
2113 * Print torture statistics. Caller must ensure that there is only
2114 * one call to this function at a given time!!! This is normally
2115 * accomplished by relying on the module system to only have one copy
2116 * of the module loaded, and then by giving the rcu_torture_stats
2117 * kthread full control (or the init/cleanup functions when rcu_torture_stats
2118 * thread is not running).
2119 */
2120 static void
rcu_torture_stats_print(void)2121 rcu_torture_stats_print(void)
2122 {
2123 int cpu;
2124 int i;
2125 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2126 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2127 struct rcu_torture *rtcp;
2128 static unsigned long rtcv_snap = ULONG_MAX;
2129 static bool splatted;
2130 struct task_struct *wtp;
2131
2132 for_each_possible_cpu(cpu) {
2133 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2134 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
2135 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
2136 }
2137 }
2138 for (i = RCU_TORTURE_PIPE_LEN; i >= 0; i--) {
2139 if (pipesummary[i] != 0)
2140 break;
2141 }
2142
2143 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2144 rtcp = rcu_access_pointer(rcu_torture_current);
2145 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
2146 rtcp,
2147 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
2148 rcu_torture_current_version,
2149 list_empty(&rcu_torture_freelist),
2150 atomic_read(&n_rcu_torture_alloc),
2151 atomic_read(&n_rcu_torture_alloc_fail),
2152 atomic_read(&n_rcu_torture_free));
2153 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ",
2154 atomic_read(&n_rcu_torture_mberror),
2155 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries),
2156 n_rcu_torture_barrier_error,
2157 n_rcu_torture_boost_ktrerror,
2158 n_rcu_torture_boost_rterror);
2159 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
2160 n_rcu_torture_boost_failure,
2161 n_rcu_torture_boosts,
2162 atomic_long_read(&n_rcu_torture_timers));
2163 torture_onoff_stats();
2164 pr_cont("barrier: %ld/%ld:%ld ",
2165 data_race(n_barrier_successes),
2166 data_race(n_barrier_attempts),
2167 data_race(n_rcu_torture_barrier_error));
2168 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic.
2169 pr_cont("nocb-toggles: %ld:%ld\n",
2170 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload));
2171
2172 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2173 if (atomic_read(&n_rcu_torture_mberror) ||
2174 atomic_read(&n_rcu_torture_mbchk_fail) ||
2175 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
2176 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure ||
2177 i > 1) {
2178 pr_cont("%s", "!!! ");
2179 atomic_inc(&n_rcu_torture_error);
2180 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
2181 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail));
2182 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
2183 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
2184 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio
2185 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
2186 WARN_ON_ONCE(i > 1); // Too-short grace period
2187 }
2188 pr_cont("Reader Pipe: ");
2189 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2190 pr_cont(" %ld", pipesummary[i]);
2191 pr_cont("\n");
2192
2193 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2194 pr_cont("Reader Batch: ");
2195 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2196 pr_cont(" %ld", batchsummary[i]);
2197 pr_cont("\n");
2198
2199 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2200 pr_cont("Free-Block Circulation: ");
2201 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2202 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
2203 }
2204 pr_cont("\n");
2205
2206 if (cur_ops->stats)
2207 cur_ops->stats();
2208 if (rtcv_snap == rcu_torture_current_version &&
2209 rcu_access_pointer(rcu_torture_current) &&
2210 !rcu_stall_is_suppressed()) {
2211 int __maybe_unused flags = 0;
2212 unsigned long __maybe_unused gp_seq = 0;
2213
2214 rcutorture_get_gp_data(cur_ops->ttype,
2215 &flags, &gp_seq);
2216 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
2217 &flags, &gp_seq);
2218 wtp = READ_ONCE(writer_task);
2219 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n",
2220 rcu_torture_writer_state_getname(),
2221 rcu_torture_writer_state, gp_seq, flags,
2222 wtp == NULL ? ~0U : wtp->__state,
2223 wtp == NULL ? -1 : (int)task_cpu(wtp));
2224 if (!splatted && wtp) {
2225 sched_show_task(wtp);
2226 splatted = true;
2227 }
2228 if (cur_ops->gp_kthread_dbg)
2229 cur_ops->gp_kthread_dbg();
2230 rcu_ftrace_dump(DUMP_ALL);
2231 }
2232 rtcv_snap = rcu_torture_current_version;
2233 }
2234
2235 /*
2236 * Periodically prints torture statistics, if periodic statistics printing
2237 * was specified via the stat_interval module parameter.
2238 */
2239 static int
rcu_torture_stats(void * arg)2240 rcu_torture_stats(void *arg)
2241 {
2242 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
2243 do {
2244 schedule_timeout_interruptible(stat_interval * HZ);
2245 rcu_torture_stats_print();
2246 torture_shutdown_absorb("rcu_torture_stats");
2247 } while (!torture_must_stop());
2248 torture_kthread_stopping("rcu_torture_stats");
2249 return 0;
2250 }
2251
2252 /* Test mem_dump_obj() and friends. */
rcu_torture_mem_dump_obj(void)2253 static void rcu_torture_mem_dump_obj(void)
2254 {
2255 struct rcu_head *rhp;
2256 struct kmem_cache *kcp;
2257 static int z;
2258
2259 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
2260 if (WARN_ON_ONCE(!kcp))
2261 return;
2262 rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
2263 if (WARN_ON_ONCE(!rhp)) {
2264 kmem_cache_destroy(kcp);
2265 return;
2266 }
2267 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
2268 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
2269 mem_dump_obj(ZERO_SIZE_PTR);
2270 pr_alert("mem_dump_obj(NULL):");
2271 mem_dump_obj(NULL);
2272 pr_alert("mem_dump_obj(%px):", &rhp);
2273 mem_dump_obj(&rhp);
2274 pr_alert("mem_dump_obj(%px):", rhp);
2275 mem_dump_obj(rhp);
2276 pr_alert("mem_dump_obj(%px):", &rhp->func);
2277 mem_dump_obj(&rhp->func);
2278 pr_alert("mem_dump_obj(%px):", &z);
2279 mem_dump_obj(&z);
2280 kmem_cache_free(kcp, rhp);
2281 kmem_cache_destroy(kcp);
2282 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
2283 if (WARN_ON_ONCE(!rhp))
2284 return;
2285 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2286 pr_alert("mem_dump_obj(kmalloc %px):", rhp);
2287 mem_dump_obj(rhp);
2288 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
2289 mem_dump_obj(&rhp->func);
2290 kfree(rhp);
2291 rhp = vmalloc(4096);
2292 if (WARN_ON_ONCE(!rhp))
2293 return;
2294 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2295 pr_alert("mem_dump_obj(vmalloc %px):", rhp);
2296 mem_dump_obj(rhp);
2297 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
2298 mem_dump_obj(&rhp->func);
2299 vfree(rhp);
2300 }
2301
2302 static void
rcu_torture_print_module_parms(struct rcu_torture_ops * cur_ops,const char * tag)2303 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
2304 {
2305 pr_alert("%s" TORTURE_FLAG
2306 "--- %s: nreaders=%d nfakewriters=%d "
2307 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
2308 "shuffle_interval=%d stutter=%d irqreader=%d "
2309 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
2310 "test_boost=%d/%d test_boost_interval=%d "
2311 "test_boost_duration=%d shutdown_secs=%d "
2312 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
2313 "stall_cpu_block=%d "
2314 "n_barrier_cbs=%d "
2315 "onoff_interval=%d onoff_holdoff=%d "
2316 "read_exit_delay=%d read_exit_burst=%d "
2317 "nocbs_nthreads=%d nocbs_toggle=%d\n",
2318 torture_type, tag, nrealreaders, nfakewriters,
2319 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
2320 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
2321 test_boost, cur_ops->can_boost,
2322 test_boost_interval, test_boost_duration, shutdown_secs,
2323 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
2324 stall_cpu_block,
2325 n_barrier_cbs,
2326 onoff_interval, onoff_holdoff,
2327 read_exit_delay, read_exit_burst,
2328 nocbs_nthreads, nocbs_toggle);
2329 }
2330
rcutorture_booster_cleanup(unsigned int cpu)2331 static int rcutorture_booster_cleanup(unsigned int cpu)
2332 {
2333 struct task_struct *t;
2334
2335 if (boost_tasks[cpu] == NULL)
2336 return 0;
2337 mutex_lock(&boost_mutex);
2338 t = boost_tasks[cpu];
2339 boost_tasks[cpu] = NULL;
2340 rcu_torture_enable_rt_throttle();
2341 mutex_unlock(&boost_mutex);
2342
2343 /* This must be outside of the mutex, otherwise deadlock! */
2344 torture_stop_kthread(rcu_torture_boost, t);
2345 return 0;
2346 }
2347
rcutorture_booster_init(unsigned int cpu)2348 static int rcutorture_booster_init(unsigned int cpu)
2349 {
2350 int retval;
2351
2352 if (boost_tasks[cpu] != NULL)
2353 return 0; /* Already created, nothing more to do. */
2354
2355 // Testing RCU priority boosting requires rcutorture do
2356 // some serious abuse. Counter this by running ksoftirqd
2357 // at higher priority.
2358 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) {
2359 struct sched_param sp;
2360 struct task_struct *t;
2361
2362 t = per_cpu(ksoftirqd, cpu);
2363 WARN_ON_ONCE(!t);
2364 sp.sched_priority = 2;
2365 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
2366 }
2367
2368 /* Don't allow time recalculation while creating a new task. */
2369 mutex_lock(&boost_mutex);
2370 rcu_torture_disable_rt_throttle();
2371 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
2372 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL,
2373 cpu, "rcu_torture_boost_%u");
2374 if (IS_ERR(boost_tasks[cpu])) {
2375 retval = PTR_ERR(boost_tasks[cpu]);
2376 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
2377 n_rcu_torture_boost_ktrerror++;
2378 boost_tasks[cpu] = NULL;
2379 mutex_unlock(&boost_mutex);
2380 return retval;
2381 }
2382 mutex_unlock(&boost_mutex);
2383 return 0;
2384 }
2385
2386 /*
2387 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
2388 * induces a CPU stall for the time specified by stall_cpu.
2389 */
rcu_torture_stall(void * args)2390 static int rcu_torture_stall(void *args)
2391 {
2392 int idx;
2393 unsigned long stop_at;
2394
2395 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
2396 if (stall_cpu_holdoff > 0) {
2397 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
2398 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
2399 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
2400 }
2401 if (!kthread_should_stop() && stall_gp_kthread > 0) {
2402 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
2403 rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
2404 for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
2405 if (kthread_should_stop())
2406 break;
2407 schedule_timeout_uninterruptible(HZ);
2408 }
2409 }
2410 if (!kthread_should_stop() && stall_cpu > 0) {
2411 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
2412 stop_at = ktime_get_seconds() + stall_cpu;
2413 /* RCU CPU stall is expected behavior in following code. */
2414 idx = cur_ops->readlock();
2415 if (stall_cpu_irqsoff)
2416 local_irq_disable();
2417 else if (!stall_cpu_block)
2418 preempt_disable();
2419 pr_alert("%s start on CPU %d.\n",
2420 __func__, raw_smp_processor_id());
2421 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
2422 stop_at))
2423 if (stall_cpu_block) {
2424 #ifdef CONFIG_PREEMPTION
2425 preempt_schedule();
2426 #else
2427 schedule_timeout_uninterruptible(HZ);
2428 #endif
2429 } else if (stall_no_softlockup) {
2430 touch_softlockup_watchdog();
2431 }
2432 if (stall_cpu_irqsoff)
2433 local_irq_enable();
2434 else if (!stall_cpu_block)
2435 preempt_enable();
2436 cur_ops->readunlock(idx);
2437 }
2438 pr_alert("%s end.\n", __func__);
2439 torture_shutdown_absorb("rcu_torture_stall");
2440 while (!kthread_should_stop())
2441 schedule_timeout_interruptible(10 * HZ);
2442 return 0;
2443 }
2444
2445 /* Spawn CPU-stall kthread, if stall_cpu specified. */
rcu_torture_stall_init(void)2446 static int __init rcu_torture_stall_init(void)
2447 {
2448 if (stall_cpu <= 0 && stall_gp_kthread <= 0)
2449 return 0;
2450 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
2451 }
2452
2453 /* State structure for forward-progress self-propagating RCU callback. */
2454 struct fwd_cb_state {
2455 struct rcu_head rh;
2456 int stop;
2457 };
2458
2459 /*
2460 * Forward-progress self-propagating RCU callback function. Because
2461 * callbacks run from softirq, this function is an implicit RCU read-side
2462 * critical section.
2463 */
rcu_torture_fwd_prog_cb(struct rcu_head * rhp)2464 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
2465 {
2466 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
2467
2468 if (READ_ONCE(fcsp->stop)) {
2469 WRITE_ONCE(fcsp->stop, 2);
2470 return;
2471 }
2472 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
2473 }
2474
2475 /* State for continuous-flood RCU callbacks. */
2476 struct rcu_fwd_cb {
2477 struct rcu_head rh;
2478 struct rcu_fwd_cb *rfc_next;
2479 struct rcu_fwd *rfc_rfp;
2480 int rfc_gps;
2481 };
2482
2483 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
2484 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
2485 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
2486 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
2487 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
2488
2489 struct rcu_launder_hist {
2490 long n_launders;
2491 unsigned long launder_gp_seq;
2492 };
2493
2494 struct rcu_fwd {
2495 spinlock_t rcu_fwd_lock;
2496 struct rcu_fwd_cb *rcu_fwd_cb_head;
2497 struct rcu_fwd_cb **rcu_fwd_cb_tail;
2498 long n_launders_cb;
2499 unsigned long rcu_fwd_startat;
2500 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
2501 unsigned long rcu_launder_gp_seq_start;
2502 int rcu_fwd_id;
2503 };
2504
2505 static DEFINE_MUTEX(rcu_fwd_mutex);
2506 static struct rcu_fwd *rcu_fwds;
2507 static unsigned long rcu_fwd_seq;
2508 static atomic_long_t rcu_fwd_max_cbs;
2509 static bool rcu_fwd_emergency_stop;
2510
rcu_torture_fwd_cb_hist(struct rcu_fwd * rfp)2511 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
2512 {
2513 unsigned long gps;
2514 unsigned long gps_old;
2515 int i;
2516 int j;
2517
2518 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
2519 if (rfp->n_launders_hist[i].n_launders > 0)
2520 break;
2521 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):",
2522 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat);
2523 gps_old = rfp->rcu_launder_gp_seq_start;
2524 for (j = 0; j <= i; j++) {
2525 gps = rfp->n_launders_hist[j].launder_gp_seq;
2526 pr_cont(" %ds/%d: %ld:%ld",
2527 j + 1, FWD_CBS_HIST_DIV,
2528 rfp->n_launders_hist[j].n_launders,
2529 rcutorture_seq_diff(gps, gps_old));
2530 gps_old = gps;
2531 }
2532 pr_cont("\n");
2533 }
2534
2535 /* Callback function for continuous-flood RCU callbacks. */
rcu_torture_fwd_cb_cr(struct rcu_head * rhp)2536 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
2537 {
2538 unsigned long flags;
2539 int i;
2540 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
2541 struct rcu_fwd_cb **rfcpp;
2542 struct rcu_fwd *rfp = rfcp->rfc_rfp;
2543
2544 rfcp->rfc_next = NULL;
2545 rfcp->rfc_gps++;
2546 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2547 rfcpp = rfp->rcu_fwd_cb_tail;
2548 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
2549 WRITE_ONCE(*rfcpp, rfcp);
2550 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
2551 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
2552 if (i >= ARRAY_SIZE(rfp->n_launders_hist))
2553 i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
2554 rfp->n_launders_hist[i].n_launders++;
2555 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
2556 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2557 }
2558
2559 // Give the scheduler a chance, even on nohz_full CPUs.
rcu_torture_fwd_prog_cond_resched(unsigned long iter)2560 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
2561 {
2562 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
2563 // Real call_rcu() floods hit userspace, so emulate that.
2564 if (need_resched() || (iter & 0xfff))
2565 schedule();
2566 return;
2567 }
2568 // No userspace emulation: CB invocation throttles call_rcu()
2569 cond_resched();
2570 }
2571
2572 /*
2573 * Free all callbacks on the rcu_fwd_cb_head list, either because the
2574 * test is over or because we hit an OOM event.
2575 */
rcu_torture_fwd_prog_cbfree(struct rcu_fwd * rfp)2576 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
2577 {
2578 unsigned long flags;
2579 unsigned long freed = 0;
2580 struct rcu_fwd_cb *rfcp;
2581
2582 for (;;) {
2583 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2584 rfcp = rfp->rcu_fwd_cb_head;
2585 if (!rfcp) {
2586 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2587 break;
2588 }
2589 rfp->rcu_fwd_cb_head = rfcp->rfc_next;
2590 if (!rfp->rcu_fwd_cb_head)
2591 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2592 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2593 kfree(rfcp);
2594 freed++;
2595 rcu_torture_fwd_prog_cond_resched(freed);
2596 if (tick_nohz_full_enabled()) {
2597 local_irq_save(flags);
2598 rcu_momentary_dyntick_idle();
2599 local_irq_restore(flags);
2600 }
2601 }
2602 return freed;
2603 }
2604
2605 /* Carry out need_resched()/cond_resched() forward-progress testing. */
rcu_torture_fwd_prog_nr(struct rcu_fwd * rfp,int * tested,int * tested_tries)2606 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
2607 int *tested, int *tested_tries)
2608 {
2609 unsigned long cver;
2610 unsigned long dur;
2611 struct fwd_cb_state fcs;
2612 unsigned long gps;
2613 int idx;
2614 int sd;
2615 int sd4;
2616 bool selfpropcb = false;
2617 unsigned long stopat;
2618 static DEFINE_TORTURE_RANDOM(trs);
2619
2620 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2621 if (!cur_ops->sync)
2622 return; // Cannot do need_resched() forward progress testing without ->sync.
2623 if (cur_ops->call && cur_ops->cb_barrier) {
2624 init_rcu_head_on_stack(&fcs.rh);
2625 selfpropcb = true;
2626 }
2627
2628 /* Tight loop containing cond_resched(). */
2629 atomic_inc(&rcu_fwd_cb_nodelay);
2630 cur_ops->sync(); /* Later readers see above write. */
2631 if (selfpropcb) {
2632 WRITE_ONCE(fcs.stop, 0);
2633 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
2634 }
2635 cver = READ_ONCE(rcu_torture_current_version);
2636 gps = cur_ops->get_gp_seq();
2637 sd = cur_ops->stall_dur() + 1;
2638 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
2639 dur = sd4 + torture_random(&trs) % (sd - sd4);
2640 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2641 stopat = rfp->rcu_fwd_startat + dur;
2642 while (time_before(jiffies, stopat) &&
2643 !shutdown_time_arrived() &&
2644 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2645 idx = cur_ops->readlock();
2646 udelay(10);
2647 cur_ops->readunlock(idx);
2648 if (!fwd_progress_need_resched || need_resched())
2649 cond_resched();
2650 }
2651 (*tested_tries)++;
2652 if (!time_before(jiffies, stopat) &&
2653 !shutdown_time_arrived() &&
2654 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2655 (*tested)++;
2656 cver = READ_ONCE(rcu_torture_current_version) - cver;
2657 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2658 WARN_ON(!cver && gps < 2);
2659 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__,
2660 rfp->rcu_fwd_id, dur, cver, gps);
2661 }
2662 if (selfpropcb) {
2663 WRITE_ONCE(fcs.stop, 1);
2664 cur_ops->sync(); /* Wait for running CB to complete. */
2665 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2666 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
2667 }
2668
2669 if (selfpropcb) {
2670 WARN_ON(READ_ONCE(fcs.stop) != 2);
2671 destroy_rcu_head_on_stack(&fcs.rh);
2672 }
2673 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
2674 atomic_dec(&rcu_fwd_cb_nodelay);
2675 }
2676
2677 /* Carry out call_rcu() forward-progress testing. */
rcu_torture_fwd_prog_cr(struct rcu_fwd * rfp)2678 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
2679 {
2680 unsigned long cver;
2681 unsigned long flags;
2682 unsigned long gps;
2683 int i;
2684 long n_launders;
2685 long n_launders_cb_snap;
2686 long n_launders_sa;
2687 long n_max_cbs;
2688 long n_max_gps;
2689 struct rcu_fwd_cb *rfcp;
2690 struct rcu_fwd_cb *rfcpn;
2691 unsigned long stopat;
2692 unsigned long stoppedat;
2693
2694 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2695 if (READ_ONCE(rcu_fwd_emergency_stop))
2696 return; /* Get out of the way quickly, no GP wait! */
2697 if (!cur_ops->call)
2698 return; /* Can't do call_rcu() fwd prog without ->call. */
2699
2700 /* Loop continuously posting RCU callbacks. */
2701 atomic_inc(&rcu_fwd_cb_nodelay);
2702 cur_ops->sync(); /* Later readers see above write. */
2703 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2704 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
2705 n_launders = 0;
2706 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
2707 n_launders_sa = 0;
2708 n_max_cbs = 0;
2709 n_max_gps = 0;
2710 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
2711 rfp->n_launders_hist[i].n_launders = 0;
2712 cver = READ_ONCE(rcu_torture_current_version);
2713 gps = cur_ops->get_gp_seq();
2714 rfp->rcu_launder_gp_seq_start = gps;
2715 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2716 while (time_before(jiffies, stopat) &&
2717 !shutdown_time_arrived() &&
2718 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2719 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
2720 rfcpn = NULL;
2721 if (rfcp)
2722 rfcpn = READ_ONCE(rfcp->rfc_next);
2723 if (rfcpn) {
2724 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
2725 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
2726 break;
2727 rfp->rcu_fwd_cb_head = rfcpn;
2728 n_launders++;
2729 n_launders_sa++;
2730 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) {
2731 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
2732 if (WARN_ON_ONCE(!rfcp)) {
2733 schedule_timeout_interruptible(1);
2734 continue;
2735 }
2736 n_max_cbs++;
2737 n_launders_sa = 0;
2738 rfcp->rfc_gps = 0;
2739 rfcp->rfc_rfp = rfp;
2740 } else {
2741 rfcp = NULL;
2742 }
2743 if (rfcp)
2744 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
2745 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
2746 if (tick_nohz_full_enabled()) {
2747 local_irq_save(flags);
2748 rcu_momentary_dyntick_idle();
2749 local_irq_restore(flags);
2750 }
2751 }
2752 stoppedat = jiffies;
2753 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
2754 cver = READ_ONCE(rcu_torture_current_version) - cver;
2755 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2756 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2757 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
2758 (void)rcu_torture_fwd_prog_cbfree(rfp);
2759
2760 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
2761 !shutdown_time_arrived()) {
2762 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
2763 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",
2764 __func__,
2765 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
2766 n_launders + n_max_cbs - n_launders_cb_snap,
2767 n_launders, n_launders_sa,
2768 n_max_gps, n_max_cbs, cver, gps);
2769 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs);
2770 mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
2771 rcu_torture_fwd_cb_hist(rfp);
2772 mutex_unlock(&rcu_fwd_mutex);
2773 }
2774 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
2775 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2776 atomic_dec(&rcu_fwd_cb_nodelay);
2777 }
2778
2779
2780 /*
2781 * OOM notifier, but this only prints diagnostic information for the
2782 * current forward-progress test.
2783 */
rcutorture_oom_notify(struct notifier_block * self,unsigned long notused,void * nfreed)2784 static int rcutorture_oom_notify(struct notifier_block *self,
2785 unsigned long notused, void *nfreed)
2786 {
2787 int i;
2788 long ncbs;
2789 struct rcu_fwd *rfp;
2790
2791 mutex_lock(&rcu_fwd_mutex);
2792 rfp = rcu_fwds;
2793 if (!rfp) {
2794 mutex_unlock(&rcu_fwd_mutex);
2795 return NOTIFY_OK;
2796 }
2797 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
2798 __func__);
2799 for (i = 0; i < fwd_progress; i++) {
2800 rcu_torture_fwd_cb_hist(&rfp[i]);
2801 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2);
2802 }
2803 WRITE_ONCE(rcu_fwd_emergency_stop, true);
2804 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
2805 ncbs = 0;
2806 for (i = 0; i < fwd_progress; i++)
2807 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2808 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2809 cur_ops->cb_barrier();
2810 ncbs = 0;
2811 for (i = 0; i < fwd_progress; i++)
2812 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2813 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2814 cur_ops->cb_barrier();
2815 ncbs = 0;
2816 for (i = 0; i < fwd_progress; i++)
2817 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2818 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2819 smp_mb(); /* Frees before return to avoid redoing OOM. */
2820 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
2821 pr_info("%s returning after OOM processing.\n", __func__);
2822 mutex_unlock(&rcu_fwd_mutex);
2823 return NOTIFY_OK;
2824 }
2825
2826 static struct notifier_block rcutorture_oom_nb = {
2827 .notifier_call = rcutorture_oom_notify
2828 };
2829
2830 /* Carry out grace-period forward-progress testing. */
rcu_torture_fwd_prog(void * args)2831 static int rcu_torture_fwd_prog(void *args)
2832 {
2833 bool firsttime = true;
2834 long max_cbs;
2835 int oldnice = task_nice(current);
2836 unsigned long oldseq = READ_ONCE(rcu_fwd_seq);
2837 struct rcu_fwd *rfp = args;
2838 int tested = 0;
2839 int tested_tries = 0;
2840
2841 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
2842 rcu_bind_current_to_nocb();
2843 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
2844 set_user_nice(current, MAX_NICE);
2845 do {
2846 if (!rfp->rcu_fwd_id) {
2847 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
2848 WRITE_ONCE(rcu_fwd_emergency_stop, false);
2849 if (!firsttime) {
2850 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0);
2851 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs);
2852 }
2853 firsttime = false;
2854 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1);
2855 } else {
2856 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop())
2857 schedule_timeout_interruptible(1);
2858 oldseq = READ_ONCE(rcu_fwd_seq);
2859 }
2860 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2861 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id)
2862 rcu_torture_fwd_prog_cr(rfp);
2863 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) &&
2864 (!IS_ENABLED(CONFIG_TINY_RCU) ||
2865 (rcu_inkernel_boot_has_ended() &&
2866 torture_num_online_cpus() > rfp->rcu_fwd_id)))
2867 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
2868
2869 /* Avoid slow periods, better to test when busy. */
2870 if (stutter_wait("rcu_torture_fwd_prog"))
2871 sched_set_normal(current, oldnice);
2872 } while (!torture_must_stop());
2873 /* Short runs might not contain a valid forward-progress attempt. */
2874 if (!rfp->rcu_fwd_id) {
2875 WARN_ON(!tested && tested_tries >= 5);
2876 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
2877 }
2878 torture_kthread_stopping("rcu_torture_fwd_prog");
2879 return 0;
2880 }
2881
2882 /* If forward-progress checking is requested and feasible, spawn the thread. */
rcu_torture_fwd_prog_init(void)2883 static int __init rcu_torture_fwd_prog_init(void)
2884 {
2885 int i;
2886 int ret = 0;
2887 struct rcu_fwd *rfp;
2888
2889 if (!fwd_progress)
2890 return 0; /* Not requested, so don't do it. */
2891 if (fwd_progress >= nr_cpu_ids) {
2892 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n");
2893 fwd_progress = nr_cpu_ids;
2894 } else if (fwd_progress < 0) {
2895 fwd_progress = nr_cpu_ids;
2896 }
2897 if ((!cur_ops->sync && !cur_ops->call) ||
2898 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) ||
2899 cur_ops == &rcu_busted_ops) {
2900 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
2901 fwd_progress = 0;
2902 return 0;
2903 }
2904 if (stall_cpu > 0) {
2905 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
2906 fwd_progress = 0;
2907 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST))
2908 return -EINVAL; /* In module, can fail back to user. */
2909 WARN_ON(1); /* Make sure rcutorture notices conflict. */
2910 return 0;
2911 }
2912 if (fwd_progress_holdoff <= 0)
2913 fwd_progress_holdoff = 1;
2914 if (fwd_progress_div <= 0)
2915 fwd_progress_div = 4;
2916 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL);
2917 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL);
2918 if (!rfp || !fwd_prog_tasks) {
2919 kfree(rfp);
2920 kfree(fwd_prog_tasks);
2921 fwd_prog_tasks = NULL;
2922 fwd_progress = 0;
2923 return -ENOMEM;
2924 }
2925 for (i = 0; i < fwd_progress; i++) {
2926 spin_lock_init(&rfp[i].rcu_fwd_lock);
2927 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head;
2928 rfp[i].rcu_fwd_id = i;
2929 }
2930 mutex_lock(&rcu_fwd_mutex);
2931 rcu_fwds = rfp;
2932 mutex_unlock(&rcu_fwd_mutex);
2933 register_oom_notifier(&rcutorture_oom_nb);
2934 for (i = 0; i < fwd_progress; i++) {
2935 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]);
2936 if (ret) {
2937 fwd_progress = i;
2938 return ret;
2939 }
2940 }
2941 return 0;
2942 }
2943
rcu_torture_fwd_prog_cleanup(void)2944 static void rcu_torture_fwd_prog_cleanup(void)
2945 {
2946 int i;
2947 struct rcu_fwd *rfp;
2948
2949 if (!rcu_fwds || !fwd_prog_tasks)
2950 return;
2951 for (i = 0; i < fwd_progress; i++)
2952 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]);
2953 unregister_oom_notifier(&rcutorture_oom_nb);
2954 mutex_lock(&rcu_fwd_mutex);
2955 rfp = rcu_fwds;
2956 rcu_fwds = NULL;
2957 mutex_unlock(&rcu_fwd_mutex);
2958 kfree(rfp);
2959 kfree(fwd_prog_tasks);
2960 fwd_prog_tasks = NULL;
2961 }
2962
2963 /* Callback function for RCU barrier testing. */
rcu_torture_barrier_cbf(struct rcu_head * rcu)2964 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
2965 {
2966 atomic_inc(&barrier_cbs_invoked);
2967 }
2968
2969 /* IPI handler to get callback posted on desired CPU, if online. */
rcu_torture_barrier1cb(void * rcu_void)2970 static void rcu_torture_barrier1cb(void *rcu_void)
2971 {
2972 struct rcu_head *rhp = rcu_void;
2973
2974 cur_ops->call(rhp, rcu_torture_barrier_cbf);
2975 }
2976
2977 /* kthread function to register callbacks used to test RCU barriers. */
rcu_torture_barrier_cbs(void * arg)2978 static int rcu_torture_barrier_cbs(void *arg)
2979 {
2980 long myid = (long)arg;
2981 bool lastphase = false;
2982 bool newphase;
2983 struct rcu_head rcu;
2984
2985 init_rcu_head_on_stack(&rcu);
2986 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
2987 set_user_nice(current, MAX_NICE);
2988 do {
2989 wait_event(barrier_cbs_wq[myid],
2990 (newphase =
2991 smp_load_acquire(&barrier_phase)) != lastphase ||
2992 torture_must_stop());
2993 lastphase = newphase;
2994 if (torture_must_stop())
2995 break;
2996 /*
2997 * The above smp_load_acquire() ensures barrier_phase load
2998 * is ordered before the following ->call().
2999 */
3000 if (smp_call_function_single(myid, rcu_torture_barrier1cb,
3001 &rcu, 1)) {
3002 // IPI failed, so use direct call from current CPU.
3003 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
3004 }
3005 if (atomic_dec_and_test(&barrier_cbs_count))
3006 wake_up(&barrier_wq);
3007 } while (!torture_must_stop());
3008 if (cur_ops->cb_barrier != NULL)
3009 cur_ops->cb_barrier();
3010 destroy_rcu_head_on_stack(&rcu);
3011 torture_kthread_stopping("rcu_torture_barrier_cbs");
3012 return 0;
3013 }
3014
3015 /* kthread function to drive and coordinate RCU barrier testing. */
rcu_torture_barrier(void * arg)3016 static int rcu_torture_barrier(void *arg)
3017 {
3018 int i;
3019
3020 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
3021 do {
3022 atomic_set(&barrier_cbs_invoked, 0);
3023 atomic_set(&barrier_cbs_count, n_barrier_cbs);
3024 /* Ensure barrier_phase ordered after prior assignments. */
3025 smp_store_release(&barrier_phase, !barrier_phase);
3026 for (i = 0; i < n_barrier_cbs; i++)
3027 wake_up(&barrier_cbs_wq[i]);
3028 wait_event(barrier_wq,
3029 atomic_read(&barrier_cbs_count) == 0 ||
3030 torture_must_stop());
3031 if (torture_must_stop())
3032 break;
3033 n_barrier_attempts++;
3034 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
3035 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
3036 n_rcu_torture_barrier_error++;
3037 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
3038 atomic_read(&barrier_cbs_invoked),
3039 n_barrier_cbs);
3040 WARN_ON(1);
3041 // Wait manually for the remaining callbacks
3042 i = 0;
3043 do {
3044 if (WARN_ON(i++ > HZ))
3045 i = INT_MIN;
3046 schedule_timeout_interruptible(1);
3047 cur_ops->cb_barrier();
3048 } while (atomic_read(&barrier_cbs_invoked) !=
3049 n_barrier_cbs &&
3050 !torture_must_stop());
3051 smp_mb(); // Can't trust ordering if broken.
3052 if (!torture_must_stop())
3053 pr_err("Recovered: barrier_cbs_invoked = %d\n",
3054 atomic_read(&barrier_cbs_invoked));
3055 } else {
3056 n_barrier_successes++;
3057 }
3058 schedule_timeout_interruptible(HZ / 10);
3059 } while (!torture_must_stop());
3060 torture_kthread_stopping("rcu_torture_barrier");
3061 return 0;
3062 }
3063
3064 /* Initialize RCU barrier testing. */
rcu_torture_barrier_init(void)3065 static int rcu_torture_barrier_init(void)
3066 {
3067 int i;
3068 int ret;
3069
3070 if (n_barrier_cbs <= 0)
3071 return 0;
3072 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
3073 pr_alert("%s" TORTURE_FLAG
3074 " Call or barrier ops missing for %s,\n",
3075 torture_type, cur_ops->name);
3076 pr_alert("%s" TORTURE_FLAG
3077 " RCU barrier testing omitted from run.\n",
3078 torture_type);
3079 return 0;
3080 }
3081 atomic_set(&barrier_cbs_count, 0);
3082 atomic_set(&barrier_cbs_invoked, 0);
3083 barrier_cbs_tasks =
3084 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
3085 GFP_KERNEL);
3086 barrier_cbs_wq =
3087 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
3088 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
3089 return -ENOMEM;
3090 for (i = 0; i < n_barrier_cbs; i++) {
3091 init_waitqueue_head(&barrier_cbs_wq[i]);
3092 ret = torture_create_kthread(rcu_torture_barrier_cbs,
3093 (void *)(long)i,
3094 barrier_cbs_tasks[i]);
3095 if (ret)
3096 return ret;
3097 }
3098 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
3099 }
3100
3101 /* Clean up after RCU barrier testing. */
rcu_torture_barrier_cleanup(void)3102 static void rcu_torture_barrier_cleanup(void)
3103 {
3104 int i;
3105
3106 torture_stop_kthread(rcu_torture_barrier, barrier_task);
3107 if (barrier_cbs_tasks != NULL) {
3108 for (i = 0; i < n_barrier_cbs; i++)
3109 torture_stop_kthread(rcu_torture_barrier_cbs,
3110 barrier_cbs_tasks[i]);
3111 kfree(barrier_cbs_tasks);
3112 barrier_cbs_tasks = NULL;
3113 }
3114 if (barrier_cbs_wq != NULL) {
3115 kfree(barrier_cbs_wq);
3116 barrier_cbs_wq = NULL;
3117 }
3118 }
3119
rcu_torture_can_boost(void)3120 static bool rcu_torture_can_boost(void)
3121 {
3122 static int boost_warn_once;
3123 int prio;
3124
3125 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
3126 return false;
3127 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)
3128 return false;
3129
3130 prio = rcu_get_gp_kthreads_prio();
3131 if (!prio)
3132 return false;
3133
3134 if (prio < 2) {
3135 if (boost_warn_once == 1)
3136 return false;
3137
3138 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);
3139 boost_warn_once = 1;
3140 return false;
3141 }
3142
3143 return true;
3144 }
3145
3146 static bool read_exit_child_stop;
3147 static bool read_exit_child_stopped;
3148 static wait_queue_head_t read_exit_wq;
3149
3150 // Child kthread which just does an rcutorture reader and exits.
rcu_torture_read_exit_child(void * trsp_in)3151 static int rcu_torture_read_exit_child(void *trsp_in)
3152 {
3153 struct torture_random_state *trsp = trsp_in;
3154
3155 set_user_nice(current, MAX_NICE);
3156 // Minimize time between reading and exiting.
3157 while (!kthread_should_stop())
3158 schedule_timeout_uninterruptible(1);
3159 (void)rcu_torture_one_read(trsp, -1);
3160 return 0;
3161 }
3162
3163 // Parent kthread which creates and destroys read-exit child kthreads.
rcu_torture_read_exit(void * unused)3164 static int rcu_torture_read_exit(void *unused)
3165 {
3166 bool errexit = false;
3167 int i;
3168 struct task_struct *tsp;
3169 DEFINE_TORTURE_RANDOM(trs);
3170
3171 // Allocate and initialize.
3172 set_user_nice(current, MAX_NICE);
3173 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
3174
3175 // Each pass through this loop does one read-exit episode.
3176 do {
3177 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
3178 for (i = 0; i < read_exit_burst; i++) {
3179 if (READ_ONCE(read_exit_child_stop))
3180 break;
3181 stutter_wait("rcu_torture_read_exit");
3182 // Spawn child.
3183 tsp = kthread_run(rcu_torture_read_exit_child,
3184 &trs, "%s", "rcu_torture_read_exit_child");
3185 if (IS_ERR(tsp)) {
3186 TOROUT_ERRSTRING("out of memory");
3187 errexit = true;
3188 break;
3189 }
3190 cond_resched();
3191 kthread_stop(tsp);
3192 n_read_exits++;
3193 }
3194 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
3195 rcu_barrier(); // Wait for task_struct free, avoid OOM.
3196 i = 0;
3197 for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++)
3198 schedule_timeout_uninterruptible(HZ);
3199 } while (!errexit && !READ_ONCE(read_exit_child_stop));
3200
3201 // Clean up and exit.
3202 smp_store_release(&read_exit_child_stopped, true); // After reaping.
3203 smp_mb(); // Store before wakeup.
3204 wake_up(&read_exit_wq);
3205 while (!torture_must_stop())
3206 schedule_timeout_uninterruptible(1);
3207 torture_kthread_stopping("rcu_torture_read_exit");
3208 return 0;
3209 }
3210
rcu_torture_read_exit_init(void)3211 static int rcu_torture_read_exit_init(void)
3212 {
3213 if (read_exit_burst <= 0)
3214 return 0;
3215 init_waitqueue_head(&read_exit_wq);
3216 read_exit_child_stop = false;
3217 read_exit_child_stopped = false;
3218 return torture_create_kthread(rcu_torture_read_exit, NULL,
3219 read_exit_task);
3220 }
3221
rcu_torture_read_exit_cleanup(void)3222 static void rcu_torture_read_exit_cleanup(void)
3223 {
3224 if (!read_exit_task)
3225 return;
3226 WRITE_ONCE(read_exit_child_stop, true);
3227 smp_mb(); // Above write before wait.
3228 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
3229 torture_stop_kthread(rcutorture_read_exit, read_exit_task);
3230 }
3231
3232 static enum cpuhp_state rcutor_hp;
3233
3234 static void
rcu_torture_cleanup(void)3235 rcu_torture_cleanup(void)
3236 {
3237 int firsttime;
3238 int flags = 0;
3239 unsigned long gp_seq = 0;
3240 int i;
3241
3242 if (torture_cleanup_begin()) {
3243 if (cur_ops->cb_barrier != NULL) {
3244 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3245 cur_ops->cb_barrier();
3246 }
3247 rcu_gp_slow_unregister(NULL);
3248 return;
3249 }
3250 if (!cur_ops) {
3251 torture_cleanup_end();
3252 rcu_gp_slow_unregister(NULL);
3253 return;
3254 }
3255
3256 if (cur_ops->gp_kthread_dbg)
3257 cur_ops->gp_kthread_dbg();
3258 rcu_torture_read_exit_cleanup();
3259 rcu_torture_barrier_cleanup();
3260 rcu_torture_fwd_prog_cleanup();
3261 torture_stop_kthread(rcu_torture_stall, stall_task);
3262 torture_stop_kthread(rcu_torture_writer, writer_task);
3263
3264 if (nocb_tasks) {
3265 for (i = 0; i < nrealnocbers; i++)
3266 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]);
3267 kfree(nocb_tasks);
3268 nocb_tasks = NULL;
3269 }
3270
3271 if (reader_tasks) {
3272 for (i = 0; i < nrealreaders; i++)
3273 torture_stop_kthread(rcu_torture_reader,
3274 reader_tasks[i]);
3275 kfree(reader_tasks);
3276 reader_tasks = NULL;
3277 }
3278 kfree(rcu_torture_reader_mbchk);
3279 rcu_torture_reader_mbchk = NULL;
3280
3281 if (fakewriter_tasks) {
3282 for (i = 0; i < nfakewriters; i++)
3283 torture_stop_kthread(rcu_torture_fakewriter,
3284 fakewriter_tasks[i]);
3285 kfree(fakewriter_tasks);
3286 fakewriter_tasks = NULL;
3287 }
3288
3289 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
3290 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
3291 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n",
3292 cur_ops->name, (long)gp_seq, flags,
3293 rcutorture_seq_diff(gp_seq, start_gp_seq));
3294 torture_stop_kthread(rcu_torture_stats, stats_task);
3295 torture_stop_kthread(rcu_torture_fqs, fqs_task);
3296 if (rcu_torture_can_boost() && rcutor_hp >= 0)
3297 cpuhp_remove_state(rcutor_hp);
3298
3299 /*
3300 * Wait for all RCU callbacks to fire, then do torture-type-specific
3301 * cleanup operations.
3302 */
3303 if (cur_ops->cb_barrier != NULL) {
3304 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3305 cur_ops->cb_barrier();
3306 }
3307 if (cur_ops->cleanup != NULL)
3308 cur_ops->cleanup();
3309
3310 rcu_torture_mem_dump_obj();
3311
3312 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
3313
3314 if (err_segs_recorded) {
3315 pr_alert("Failure/close-call rcutorture reader segments:\n");
3316 if (rt_read_nsegs == 0)
3317 pr_alert("\t: No segments recorded!!!\n");
3318 firsttime = 1;
3319 for (i = 0; i < rt_read_nsegs; i++) {
3320 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
3321 if (err_segs[i].rt_delay_jiffies != 0) {
3322 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
3323 err_segs[i].rt_delay_jiffies);
3324 firsttime = 0;
3325 }
3326 if (err_segs[i].rt_delay_ms != 0) {
3327 pr_cont("%s%ldms", firsttime ? "" : "+",
3328 err_segs[i].rt_delay_ms);
3329 firsttime = 0;
3330 }
3331 if (err_segs[i].rt_delay_us != 0) {
3332 pr_cont("%s%ldus", firsttime ? "" : "+",
3333 err_segs[i].rt_delay_us);
3334 firsttime = 0;
3335 }
3336 pr_cont("%s\n",
3337 err_segs[i].rt_preempted ? "preempted" : "");
3338
3339 }
3340 }
3341 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
3342 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
3343 else if (torture_onoff_failures())
3344 rcu_torture_print_module_parms(cur_ops,
3345 "End of test: RCU_HOTPLUG");
3346 else
3347 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
3348 torture_cleanup_end();
3349 rcu_gp_slow_unregister(&rcu_fwd_cb_nodelay);
3350 }
3351
3352 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
rcu_torture_leak_cb(struct rcu_head * rhp)3353 static void rcu_torture_leak_cb(struct rcu_head *rhp)
3354 {
3355 }
3356
rcu_torture_err_cb(struct rcu_head * rhp)3357 static void rcu_torture_err_cb(struct rcu_head *rhp)
3358 {
3359 /*
3360 * This -might- happen due to race conditions, but is unlikely.
3361 * The scenario that leads to this happening is that the
3362 * first of the pair of duplicate callbacks is queued,
3363 * someone else starts a grace period that includes that
3364 * callback, then the second of the pair must wait for the
3365 * next grace period. Unlikely, but can happen. If it
3366 * does happen, the debug-objects subsystem won't have splatted.
3367 */
3368 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
3369 }
3370 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3371
3372 /*
3373 * Verify that double-free causes debug-objects to complain, but only
3374 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
3375 * cannot be carried out.
3376 */
rcu_test_debug_objects(void)3377 static void rcu_test_debug_objects(void)
3378 {
3379 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
3380 struct rcu_head rh1;
3381 struct rcu_head rh2;
3382 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
3383
3384 init_rcu_head_on_stack(&rh1);
3385 init_rcu_head_on_stack(&rh2);
3386 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
3387
3388 /* Try to queue the rh2 pair of callbacks for the same grace period. */
3389 preempt_disable(); /* Prevent preemption from interrupting test. */
3390 rcu_read_lock(); /* Make it impossible to finish a grace period. */
3391 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
3392 local_irq_disable(); /* Make it harder to start a new grace period. */
3393 call_rcu(&rh2, rcu_torture_leak_cb);
3394 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
3395 if (rhp) {
3396 call_rcu(rhp, rcu_torture_leak_cb);
3397 call_rcu(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
3398 }
3399 local_irq_enable();
3400 rcu_read_unlock();
3401 preempt_enable();
3402
3403 /* Wait for them all to get done so we can safely return. */
3404 rcu_barrier();
3405 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
3406 destroy_rcu_head_on_stack(&rh1);
3407 destroy_rcu_head_on_stack(&rh2);
3408 kfree(rhp);
3409 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3410 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
3411 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3412 }
3413
rcutorture_sync(void)3414 static void rcutorture_sync(void)
3415 {
3416 static unsigned long n;
3417
3418 if (cur_ops->sync && !(++n & 0xfff))
3419 cur_ops->sync();
3420 }
3421
3422 static int __init
rcu_torture_init(void)3423 rcu_torture_init(void)
3424 {
3425 long i;
3426 int cpu;
3427 int firsterr = 0;
3428 int flags = 0;
3429 unsigned long gp_seq = 0;
3430 static struct rcu_torture_ops *torture_ops[] = {
3431 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops,
3432 TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
3433 &trivial_ops,
3434 };
3435
3436 if (!torture_init_begin(torture_type, verbose))
3437 return -EBUSY;
3438
3439 /* Process args and tell the world that the torturer is on the job. */
3440 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
3441 cur_ops = torture_ops[i];
3442 if (strcmp(torture_type, cur_ops->name) == 0)
3443 break;
3444 }
3445 if (i == ARRAY_SIZE(torture_ops)) {
3446 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
3447 torture_type);
3448 pr_alert("rcu-torture types:");
3449 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
3450 pr_cont(" %s", torture_ops[i]->name);
3451 pr_cont("\n");
3452 firsterr = -EINVAL;
3453 cur_ops = NULL;
3454 goto unwind;
3455 }
3456 if (cur_ops->fqs == NULL && fqs_duration != 0) {
3457 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
3458 fqs_duration = 0;
3459 }
3460 if (cur_ops->init)
3461 cur_ops->init();
3462
3463 if (nreaders >= 0) {
3464 nrealreaders = nreaders;
3465 } else {
3466 nrealreaders = num_online_cpus() - 2 - nreaders;
3467 if (nrealreaders <= 0)
3468 nrealreaders = 1;
3469 }
3470 rcu_torture_print_module_parms(cur_ops, "Start of test");
3471 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
3472 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
3473 start_gp_seq = gp_seq;
3474 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n",
3475 cur_ops->name, (long)gp_seq, flags);
3476
3477 /* Set up the freelist. */
3478
3479 INIT_LIST_HEAD(&rcu_torture_freelist);
3480 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
3481 rcu_tortures[i].rtort_mbtest = 0;
3482 list_add_tail(&rcu_tortures[i].rtort_free,
3483 &rcu_torture_freelist);
3484 }
3485
3486 /* Initialize the statistics so that each run gets its own numbers. */
3487
3488 rcu_torture_current = NULL;
3489 rcu_torture_current_version = 0;
3490 atomic_set(&n_rcu_torture_alloc, 0);
3491 atomic_set(&n_rcu_torture_alloc_fail, 0);
3492 atomic_set(&n_rcu_torture_free, 0);
3493 atomic_set(&n_rcu_torture_mberror, 0);
3494 atomic_set(&n_rcu_torture_mbchk_fail, 0);
3495 atomic_set(&n_rcu_torture_mbchk_tries, 0);
3496 atomic_set(&n_rcu_torture_error, 0);
3497 n_rcu_torture_barrier_error = 0;
3498 n_rcu_torture_boost_ktrerror = 0;
3499 n_rcu_torture_boost_rterror = 0;
3500 n_rcu_torture_boost_failure = 0;
3501 n_rcu_torture_boosts = 0;
3502 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
3503 atomic_set(&rcu_torture_wcount[i], 0);
3504 for_each_possible_cpu(cpu) {
3505 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
3506 per_cpu(rcu_torture_count, cpu)[i] = 0;
3507 per_cpu(rcu_torture_batch, cpu)[i] = 0;
3508 }
3509 }
3510 err_segs_recorded = 0;
3511 rt_read_nsegs = 0;
3512
3513 /* Start up the kthreads. */
3514
3515 rcu_torture_write_types();
3516 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
3517 writer_task);
3518 if (torture_init_error(firsterr))
3519 goto unwind;
3520 if (nfakewriters > 0) {
3521 fakewriter_tasks = kcalloc(nfakewriters,
3522 sizeof(fakewriter_tasks[0]),
3523 GFP_KERNEL);
3524 if (fakewriter_tasks == NULL) {
3525 TOROUT_ERRSTRING("out of memory");
3526 firsterr = -ENOMEM;
3527 goto unwind;
3528 }
3529 }
3530 for (i = 0; i < nfakewriters; i++) {
3531 firsterr = torture_create_kthread(rcu_torture_fakewriter,
3532 NULL, fakewriter_tasks[i]);
3533 if (torture_init_error(firsterr))
3534 goto unwind;
3535 }
3536 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
3537 GFP_KERNEL);
3538 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk),
3539 GFP_KERNEL);
3540 if (!reader_tasks || !rcu_torture_reader_mbchk) {
3541 TOROUT_ERRSTRING("out of memory");
3542 firsterr = -ENOMEM;
3543 goto unwind;
3544 }
3545 for (i = 0; i < nrealreaders; i++) {
3546 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1;
3547 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
3548 reader_tasks[i]);
3549 if (torture_init_error(firsterr))
3550 goto unwind;
3551 }
3552 nrealnocbers = nocbs_nthreads;
3553 if (WARN_ON(nrealnocbers < 0))
3554 nrealnocbers = 1;
3555 if (WARN_ON(nocbs_toggle < 0))
3556 nocbs_toggle = HZ;
3557 if (nrealnocbers > 0) {
3558 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL);
3559 if (nocb_tasks == NULL) {
3560 TOROUT_ERRSTRING("out of memory");
3561 firsterr = -ENOMEM;
3562 goto unwind;
3563 }
3564 } else {
3565 nocb_tasks = NULL;
3566 }
3567 for (i = 0; i < nrealnocbers; i++) {
3568 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]);
3569 if (torture_init_error(firsterr))
3570 goto unwind;
3571 }
3572 if (stat_interval > 0) {
3573 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
3574 stats_task);
3575 if (torture_init_error(firsterr))
3576 goto unwind;
3577 }
3578 if (test_no_idle_hz && shuffle_interval > 0) {
3579 firsterr = torture_shuffle_init(shuffle_interval * HZ);
3580 if (torture_init_error(firsterr))
3581 goto unwind;
3582 }
3583 if (stutter < 0)
3584 stutter = 0;
3585 if (stutter) {
3586 int t;
3587
3588 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
3589 firsterr = torture_stutter_init(stutter * HZ, t);
3590 if (torture_init_error(firsterr))
3591 goto unwind;
3592 }
3593 if (fqs_duration < 0)
3594 fqs_duration = 0;
3595 if (fqs_duration) {
3596 /* Create the fqs thread */
3597 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
3598 fqs_task);
3599 if (torture_init_error(firsterr))
3600 goto unwind;
3601 }
3602 if (test_boost_interval < 1)
3603 test_boost_interval = 1;
3604 if (test_boost_duration < 2)
3605 test_boost_duration = 2;
3606 if (rcu_torture_can_boost()) {
3607
3608 boost_starttime = jiffies + test_boost_interval * HZ;
3609
3610 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
3611 rcutorture_booster_init,
3612 rcutorture_booster_cleanup);
3613 rcutor_hp = firsterr;
3614 if (torture_init_error(firsterr))
3615 goto unwind;
3616 }
3617 shutdown_jiffies = jiffies + shutdown_secs * HZ;
3618 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
3619 if (torture_init_error(firsterr))
3620 goto unwind;
3621 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
3622 rcutorture_sync);
3623 if (torture_init_error(firsterr))
3624 goto unwind;
3625 firsterr = rcu_torture_stall_init();
3626 if (torture_init_error(firsterr))
3627 goto unwind;
3628 firsterr = rcu_torture_fwd_prog_init();
3629 if (torture_init_error(firsterr))
3630 goto unwind;
3631 firsterr = rcu_torture_barrier_init();
3632 if (torture_init_error(firsterr))
3633 goto unwind;
3634 firsterr = rcu_torture_read_exit_init();
3635 if (torture_init_error(firsterr))
3636 goto unwind;
3637 if (object_debug)
3638 rcu_test_debug_objects();
3639 torture_init_end();
3640 rcu_gp_slow_register(&rcu_fwd_cb_nodelay);
3641 return 0;
3642
3643 unwind:
3644 torture_init_end();
3645 rcu_torture_cleanup();
3646 if (shutdown_secs) {
3647 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
3648 kernel_power_off();
3649 }
3650 return firsterr;
3651 }
3652
3653 module_init(rcu_torture_init);
3654 module_exit(rcu_torture_cleanup);
3655