?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
drm/connector: hdmi: Fix memory leak in drm_display_mode_from_cea_vic()
[drm/drm-misc.git] / kernel / rcu / rcutorture.c
blobbb75dbf5c800cf72b94e6fad4624218ad5a94134
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/rcu_notifier.h>
25 #include <linux/interrupt.h>
26 #include <linux/sched/signal.h>
27 #include <uapi/linux/sched/types.h>
28 #include <linux/atomic.h>
29 #include <linux/bitops.h>
30 #include <linux/completion.h>
31 #include <linux/moduleparam.h>
32 #include <linux/percpu.h>
33 #include <linux/notifier.h>
34 #include <linux/reboot.h>
35 #include <linux/freezer.h>
36 #include <linux/cpu.h>
37 #include <linux/delay.h>
38 #include <linux/stat.h>
39 #include <linux/srcu.h>
40 #include <linux/slab.h>
41 #include <linux/trace_clock.h>
42 #include <asm/byteorder.h>
43 #include <linux/torture.h>
44 #include <linux/vmalloc.h>
45 #include <linux/sched/debug.h>
46 #include <linux/sched/sysctl.h>
47 #include <linux/oom.h>
48 #include <linux/tick.h>
49 #include <linux/rcupdate_trace.h>
50 #include <linux/nmi.h>
51
52 #include "rcu.h"
53
54 MODULE_DESCRIPTION("Read-Copy Update module-based torture test facility");
55 MODULE_LICENSE("GPL");
56 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
57
58 /* Bits for ->extendables field, extendables param, and related definitions. */
59 #define RCUTORTURE_RDR_SHIFT_1 8 /* Put SRCU index in upper bits. */
60 #define RCUTORTURE_RDR_MASK_1 (1 << RCUTORTURE_RDR_SHIFT_1)
61 #define RCUTORTURE_RDR_SHIFT_2 9 /* Put SRCU index in upper bits. */
62 #define RCUTORTURE_RDR_MASK_2 (1 << RCUTORTURE_RDR_SHIFT_2)
63 #define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */
64 #define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */
65 #define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */
66 #define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */
67 #define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */
68 #define RCUTORTURE_RDR_RCU_1 0x20 /* ... entering another RCU reader. */
69 #define RCUTORTURE_RDR_RCU_2 0x40 /* ... entering another RCU reader. */
70 #define RCUTORTURE_RDR_NBITS 7 /* Number of bits defined above. */
71 #define RCUTORTURE_MAX_EXTEND \
72 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
73 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
74 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
75 /* Must be power of two minus one. */
76 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
77
78 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
79 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
80 torture_param(int, fqs_duration, 0, "Duration of fqs bursts (us), 0 to disable");
81 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
82 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
83 torture_param(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)");
84 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
85 torture_param(int, fwd_progress_holdoff, 60, "Time between forward-progress tests (s)");
86 torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched() behind need_resched()");
87 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
88 torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait primitives");
89 torture_param(bool, gp_cond_full, false, "Use conditional/async full-state GP wait primitives");
90 torture_param(bool, gp_cond_exp_full, false,
91 "Use conditional/async full-stateexpedited GP wait primitives");
92 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
93 torture_param(bool, gp_normal, false, "Use normal (non-expedited) GP wait primitives");
94 torture_param(bool, gp_poll, false, "Use polling GP wait primitives");
95 torture_param(bool, gp_poll_exp, false, "Use polling expedited GP wait primitives");
96 torture_param(bool, gp_poll_full, false, "Use polling full-state GP wait primitives");
97 torture_param(bool, gp_poll_exp_full, false, "Use polling full-state expedited GP wait primitives");
98 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
99 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
100 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers");
101 torture_param(int, n_barrier_cbs, 0, "# of callbacks/kthreads for barrier testing");
102 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
103 torture_param(int, nreaders, -1, "Number of RCU reader threads");
104 torture_param(int, object_debug, 0, "Enable debug-object double call_rcu() testing");
105 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
106 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (jiffies), 0=disable");
107 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable");
108 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
109 torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
110 torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
111 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
112 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
113 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
114 torture_param(int, stall_cpu_holdoff, 10, "Time to wait before starting stall (s).");
115 torture_param(bool, stall_no_softlockup, false, "Avoid softlockup warning during cpu stall.");
116 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
117 torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
118 torture_param(int, stall_cpu_repeat, 0, "Number of additional stalls after the first one.");
119 torture_param(int, stall_gp_kthread, 0, "Grace-period kthread stall duration (s).");
120 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s");
121 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
122 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
123 torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds.");
124 torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds.");
125 torture_param(int, test_nmis, 0, "End-test NMI tests, 0 to disable.");
126 torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs");
127 torture_param(int, test_srcu_lockdep, 0, "Test specified SRCU deadlock scenario.");
128 torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
129
130 static char *torture_type = "rcu";
131 module_param(torture_type, charp, 0444);
132 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
133
134 static int nrealnocbers;
135 static int nrealreaders;
136 static struct task_struct *writer_task;
137 static struct task_struct **fakewriter_tasks;
138 static struct task_struct **reader_tasks;
139 static struct task_struct **nocb_tasks;
140 static struct task_struct *stats_task;
141 static struct task_struct *fqs_task;
142 static struct task_struct *boost_tasks[NR_CPUS];
143 static struct task_struct *stall_task;
144 static struct task_struct **fwd_prog_tasks;
145 static struct task_struct **barrier_cbs_tasks;
146 static struct task_struct *barrier_task;
147 static struct task_struct *read_exit_task;
148
149 #define RCU_TORTURE_PIPE_LEN 10
150
151 // Mailbox-like structure to check RCU global memory ordering.
152 struct rcu_torture_reader_check {
153 unsigned long rtc_myloops;
154 int rtc_chkrdr;
155 unsigned long rtc_chkloops;
156 int rtc_ready;
157 struct rcu_torture_reader_check *rtc_assigner;
158 } ____cacheline_internodealigned_in_smp;
159
160 // Update-side data structure used to check RCU readers.
161 struct rcu_torture {
162 struct rcu_head rtort_rcu;
163 int rtort_pipe_count;
164 struct list_head rtort_free;
165 int rtort_mbtest;
166 struct rcu_torture_reader_check *rtort_chkp;
167 };
168
169 static LIST_HEAD(rcu_torture_freelist);
170 static struct rcu_torture __rcu *rcu_torture_current;
171 static unsigned long rcu_torture_current_version;
172 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
173 static DEFINE_SPINLOCK(rcu_torture_lock);
174 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
175 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
176 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
177 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk;
178 static atomic_t n_rcu_torture_alloc;
179 static atomic_t n_rcu_torture_alloc_fail;
180 static atomic_t n_rcu_torture_free;
181 static atomic_t n_rcu_torture_mberror;
182 static atomic_t n_rcu_torture_mbchk_fail;
183 static atomic_t n_rcu_torture_mbchk_tries;
184 static atomic_t n_rcu_torture_error;
185 static long n_rcu_torture_barrier_error;
186 static long n_rcu_torture_boost_ktrerror;
187 static long n_rcu_torture_boost_failure;
188 static long n_rcu_torture_boosts;
189 static atomic_long_t n_rcu_torture_timers;
190 static long n_barrier_attempts;
191 static long n_barrier_successes; /* did rcu_barrier test succeed? */
192 static unsigned long n_read_exits;
193 static struct list_head rcu_torture_removed;
194 static unsigned long shutdown_jiffies;
195 static unsigned long start_gp_seq;
196 static atomic_long_t n_nocb_offload;
197 static atomic_long_t n_nocb_deoffload;
198
199 static int rcu_torture_writer_state;
200 #define RTWS_FIXED_DELAY 0
201 #define RTWS_DELAY 1
202 #define RTWS_REPLACE 2
203 #define RTWS_DEF_FREE 3
204 #define RTWS_EXP_SYNC 4
205 #define RTWS_COND_GET 5
206 #define RTWS_COND_GET_FULL 6
207 #define RTWS_COND_GET_EXP 7
208 #define RTWS_COND_GET_EXP_FULL 8
209 #define RTWS_COND_SYNC 9
210 #define RTWS_COND_SYNC_FULL 10
211 #define RTWS_COND_SYNC_EXP 11
212 #define RTWS_COND_SYNC_EXP_FULL 12
213 #define RTWS_POLL_GET 13
214 #define RTWS_POLL_GET_FULL 14
215 #define RTWS_POLL_GET_EXP 15
216 #define RTWS_POLL_GET_EXP_FULL 16
217 #define RTWS_POLL_WAIT 17
218 #define RTWS_POLL_WAIT_FULL 18
219 #define RTWS_POLL_WAIT_EXP 19
220 #define RTWS_POLL_WAIT_EXP_FULL 20
221 #define RTWS_SYNC 21
222 #define RTWS_STUTTER 22
223 #define RTWS_STOPPING 23
224 static const char * const rcu_torture_writer_state_names[] = {
225 "RTWS_FIXED_DELAY",
226 "RTWS_DELAY",
227 "RTWS_REPLACE",
228 "RTWS_DEF_FREE",
229 "RTWS_EXP_SYNC",
230 "RTWS_COND_GET",
231 "RTWS_COND_GET_FULL",
232 "RTWS_COND_GET_EXP",
233 "RTWS_COND_GET_EXP_FULL",
234 "RTWS_COND_SYNC",
235 "RTWS_COND_SYNC_FULL",
236 "RTWS_COND_SYNC_EXP",
237 "RTWS_COND_SYNC_EXP_FULL",
238 "RTWS_POLL_GET",
239 "RTWS_POLL_GET_FULL",
240 "RTWS_POLL_GET_EXP",
241 "RTWS_POLL_GET_EXP_FULL",
242 "RTWS_POLL_WAIT",
243 "RTWS_POLL_WAIT_FULL",
244 "RTWS_POLL_WAIT_EXP",
245 "RTWS_POLL_WAIT_EXP_FULL",
246 "RTWS_SYNC",
247 "RTWS_STUTTER",
248 "RTWS_STOPPING",
249 };
250
251 /* Record reader segment types and duration for first failing read. */
252 struct rt_read_seg {
253 int rt_readstate;
254 unsigned long rt_delay_jiffies;
255 unsigned long rt_delay_ms;
256 unsigned long rt_delay_us;
257 bool rt_preempted;
258 };
259 static int err_segs_recorded;
260 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
261 static int rt_read_nsegs;
262
263 static const char *rcu_torture_writer_state_getname(void)
264 {
265 unsigned int i = READ_ONCE(rcu_torture_writer_state);
266
267 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
268 return "???";
269 return rcu_torture_writer_state_names[i];
270 }
271
272 #ifdef CONFIG_RCU_TRACE
273 static u64 notrace rcu_trace_clock_local(void)
274 {
275 u64 ts = trace_clock_local();
276
277 (void)do_div(ts, NSEC_PER_USEC);
278 return ts;
279 }
280 #else /* #ifdef CONFIG_RCU_TRACE */
281 static u64 notrace rcu_trace_clock_local(void)
282 {
283 return 0ULL;
284 }
285 #endif /* #else #ifdef CONFIG_RCU_TRACE */
286
287 /*
288 * Stop aggressive CPU-hog tests a bit before the end of the test in order
289 * to avoid interfering with test shutdown.
290 */
291 static bool shutdown_time_arrived(void)
292 {
293 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
294 }
295
296 static unsigned long boost_starttime; /* jiffies of next boost test start. */
297 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
298 /* and boost task create/destroy. */
299 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
300 static bool barrier_phase; /* Test phase. */
301 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
302 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
303 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
304
305 static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
306
307 /*
308 * Allocate an element from the rcu_tortures pool.
309 */
310 static struct rcu_torture *
311 rcu_torture_alloc(void)
312 {
313 struct list_head *p;
314
315 spin_lock_bh(&rcu_torture_lock);
316 if (list_empty(&rcu_torture_freelist)) {
317 atomic_inc(&n_rcu_torture_alloc_fail);
318 spin_unlock_bh(&rcu_torture_lock);
319 return NULL;
320 }
321 atomic_inc(&n_rcu_torture_alloc);
322 p = rcu_torture_freelist.next;
323 list_del_init(p);
324 spin_unlock_bh(&rcu_torture_lock);
325 return container_of(p, struct rcu_torture, rtort_free);
326 }
327
328 /*
329 * Free an element to the rcu_tortures pool.
330 */
331 static void
332 rcu_torture_free(struct rcu_torture *p)
333 {
334 atomic_inc(&n_rcu_torture_free);
335 spin_lock_bh(&rcu_torture_lock);
336 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
337 spin_unlock_bh(&rcu_torture_lock);
338 }
339
340 /*
341 * Operations vector for selecting different types of tests.
342 */
343
344 struct rcu_torture_ops {
345 int ttype;
346 void (*init)(void);
347 void (*cleanup)(void);
348 int (*readlock)(void);
349 void (*read_delay)(struct torture_random_state *rrsp,
350 struct rt_read_seg *rtrsp);
351 void (*readunlock)(int idx);
352 int (*readlock_held)(void);
353 unsigned long (*get_gp_seq)(void);
354 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
355 void (*deferred_free)(struct rcu_torture *p);
356 void (*sync)(void);
357 void (*exp_sync)(void);
358 unsigned long (*get_gp_state_exp)(void);
359 unsigned long (*start_gp_poll_exp)(void);
360 void (*start_gp_poll_exp_full)(struct rcu_gp_oldstate *rgosp);
361 bool (*poll_gp_state_exp)(unsigned long oldstate);
362 void (*cond_sync_exp)(unsigned long oldstate);
363 void (*cond_sync_exp_full)(struct rcu_gp_oldstate *rgosp);
364 unsigned long (*get_comp_state)(void);
365 void (*get_comp_state_full)(struct rcu_gp_oldstate *rgosp);
366 bool (*same_gp_state)(unsigned long oldstate1, unsigned long oldstate2);
367 bool (*same_gp_state_full)(struct rcu_gp_oldstate *rgosp1, struct rcu_gp_oldstate *rgosp2);
368 unsigned long (*get_gp_state)(void);
369 void (*get_gp_state_full)(struct rcu_gp_oldstate *rgosp);
370 unsigned long (*start_gp_poll)(void);
371 void (*start_gp_poll_full)(struct rcu_gp_oldstate *rgosp);
372 bool (*poll_gp_state)(unsigned long oldstate);
373 bool (*poll_gp_state_full)(struct rcu_gp_oldstate *rgosp);
374 bool (*poll_need_2gp)(bool poll, bool poll_full);
375 void (*cond_sync)(unsigned long oldstate);
376 void (*cond_sync_full)(struct rcu_gp_oldstate *rgosp);
377 int poll_active;
378 int poll_active_full;
379 call_rcu_func_t call;
380 void (*cb_barrier)(void);
381 void (*fqs)(void);
382 void (*stats)(void);
383 void (*gp_kthread_dbg)(void);
384 bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
385 int (*stall_dur)(void);
386 void (*get_gp_data)(int *flags, unsigned long *gp_seq);
387 void (*gp_slow_register)(atomic_t *rgssp);
388 void (*gp_slow_unregister)(atomic_t *rgssp);
389 long cbflood_max;
390 int irq_capable;
391 int can_boost;
392 int extendables;
393 int slow_gps;
394 int no_pi_lock;
395 int debug_objects;
396 const char *name;
397 };
398
399 static struct rcu_torture_ops *cur_ops;
400
401 /*
402 * Definitions for rcu torture testing.
403 */
404
405 static int torture_readlock_not_held(void)
406 {
407 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held();
408 }
409
410 static int rcu_torture_read_lock(void)
411 {
412 rcu_read_lock();
413 return 0;
414 }
415
416 static void
417 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
418 {
419 unsigned long started;
420 unsigned long completed;
421 const unsigned long shortdelay_us = 200;
422 unsigned long longdelay_ms = 300;
423 unsigned long long ts;
424
425 /* We want a short delay sometimes to make a reader delay the grace
426 * period, and we want a long delay occasionally to trigger
427 * force_quiescent_state. */
428
429 if (!atomic_read(&rcu_fwd_cb_nodelay) &&
430 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
431 started = cur_ops->get_gp_seq();
432 ts = rcu_trace_clock_local();
433 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
434 longdelay_ms = 5; /* Avoid triggering BH limits. */
435 mdelay(longdelay_ms);
436 rtrsp->rt_delay_ms = longdelay_ms;
437 completed = cur_ops->get_gp_seq();
438 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
439 started, completed);
440 }
441 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
442 udelay(shortdelay_us);
443 rtrsp->rt_delay_us = shortdelay_us;
444 }
445 if (!preempt_count() &&
446 !(torture_random(rrsp) % (nrealreaders * 500))) {
447 torture_preempt_schedule(); /* QS only if preemptible. */
448 rtrsp->rt_preempted = true;
449 }
450 }
451
452 static void rcu_torture_read_unlock(int idx)
453 {
454 rcu_read_unlock();
455 }
456
457 /*
458 * Update callback in the pipe. This should be invoked after a grace period.
459 */
460 static bool
461 rcu_torture_pipe_update_one(struct rcu_torture *rp)
462 {
463 int i;
464 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp);
465
466 if (rtrcp) {
467 WRITE_ONCE(rp->rtort_chkp, NULL);
468 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire().
469 }
470 i = rp->rtort_pipe_count;
471 if (i > RCU_TORTURE_PIPE_LEN)
472 i = RCU_TORTURE_PIPE_LEN;
473 atomic_inc(&rcu_torture_wcount[i]);
474 WRITE_ONCE(rp->rtort_pipe_count, i + 1);
475 ASSERT_EXCLUSIVE_WRITER(rp->rtort_pipe_count);
476 if (i + 1 >= RCU_TORTURE_PIPE_LEN) {
477 rp->rtort_mbtest = 0;
478 return true;
479 }
480 return false;
481 }
482
483 /*
484 * Update all callbacks in the pipe. Suitable for synchronous grace-period
485 * primitives.
486 */
487 static void
488 rcu_torture_pipe_update(struct rcu_torture *old_rp)
489 {
490 struct rcu_torture *rp;
491 struct rcu_torture *rp1;
492
493 if (old_rp)
494 list_add(&old_rp->rtort_free, &rcu_torture_removed);
495 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
496 if (rcu_torture_pipe_update_one(rp)) {
497 list_del(&rp->rtort_free);
498 rcu_torture_free(rp);
499 }
500 }
501 }
502
503 static void
504 rcu_torture_cb(struct rcu_head *p)
505 {
506 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
507
508 if (torture_must_stop_irq()) {
509 /* Test is ending, just drop callbacks on the floor. */
510 /* The next initialization will pick up the pieces. */
511 return;
512 }
513 if (rcu_torture_pipe_update_one(rp))
514 rcu_torture_free(rp);
515 else
516 cur_ops->deferred_free(rp);
517 }
518
519 static unsigned long rcu_no_completed(void)
520 {
521 return 0;
522 }
523
524 static void rcu_torture_deferred_free(struct rcu_torture *p)
525 {
526 call_rcu_hurry(&p->rtort_rcu, rcu_torture_cb);
527 }
528
529 static void rcu_sync_torture_init(void)
530 {
531 INIT_LIST_HEAD(&rcu_torture_removed);
532 }
533
534 static bool rcu_poll_need_2gp(bool poll, bool poll_full)
535 {
536 return poll;
537 }
538
539 static struct rcu_torture_ops rcu_ops = {
540 .ttype = RCU_FLAVOR,
541 .init = rcu_sync_torture_init,
542 .readlock = rcu_torture_read_lock,
543 .read_delay = rcu_read_delay,
544 .readunlock = rcu_torture_read_unlock,
545 .readlock_held = torture_readlock_not_held,
546 .get_gp_seq = rcu_get_gp_seq,
547 .gp_diff = rcu_seq_diff,
548 .deferred_free = rcu_torture_deferred_free,
549 .sync = synchronize_rcu,
550 .exp_sync = synchronize_rcu_expedited,
551 .same_gp_state = same_state_synchronize_rcu,
552 .same_gp_state_full = same_state_synchronize_rcu_full,
553 .get_comp_state = get_completed_synchronize_rcu,
554 .get_comp_state_full = get_completed_synchronize_rcu_full,
555 .get_gp_state = get_state_synchronize_rcu,
556 .get_gp_state_full = get_state_synchronize_rcu_full,
557 .start_gp_poll = start_poll_synchronize_rcu,
558 .start_gp_poll_full = start_poll_synchronize_rcu_full,
559 .poll_gp_state = poll_state_synchronize_rcu,
560 .poll_gp_state_full = poll_state_synchronize_rcu_full,
561 .poll_need_2gp = rcu_poll_need_2gp,
562 .cond_sync = cond_synchronize_rcu,
563 .cond_sync_full = cond_synchronize_rcu_full,
564 .poll_active = NUM_ACTIVE_RCU_POLL_OLDSTATE,
565 .poll_active_full = NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE,
566 .get_gp_state_exp = get_state_synchronize_rcu,
567 .start_gp_poll_exp = start_poll_synchronize_rcu_expedited,
568 .start_gp_poll_exp_full = start_poll_synchronize_rcu_expedited_full,
569 .poll_gp_state_exp = poll_state_synchronize_rcu,
570 .cond_sync_exp = cond_synchronize_rcu_expedited,
571 .call = call_rcu_hurry,
572 .cb_barrier = rcu_barrier,
573 .fqs = rcu_force_quiescent_state,
574 .gp_kthread_dbg = show_rcu_gp_kthreads,
575 .check_boost_failed = rcu_check_boost_fail,
576 .stall_dur = rcu_jiffies_till_stall_check,
577 .get_gp_data = rcutorture_get_gp_data,
578 .gp_slow_register = rcu_gp_slow_register,
579 .gp_slow_unregister = rcu_gp_slow_unregister,
580 .irq_capable = 1,
581 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
582 .extendables = RCUTORTURE_MAX_EXTEND,
583 .debug_objects = 1,
584 .name = "rcu"
585 };
586
587 /*
588 * Don't even think about trying any of these in real life!!!
589 * The names includes "busted", and they really means it!
590 * The only purpose of these functions is to provide a buggy RCU
591 * implementation to make sure that rcutorture correctly emits
592 * buggy-RCU error messages.
593 */
594 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
595 {
596 /* This is a deliberate bug for testing purposes only! */
597 rcu_torture_cb(&p->rtort_rcu);
598 }
599
600 static void synchronize_rcu_busted(void)
601 {
602 /* This is a deliberate bug for testing purposes only! */
603 }
604
605 static void
606 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
607 {
608 /* This is a deliberate bug for testing purposes only! */
609 func(head);
610 }
611
612 static struct rcu_torture_ops rcu_busted_ops = {
613 .ttype = INVALID_RCU_FLAVOR,
614 .init = rcu_sync_torture_init,
615 .readlock = rcu_torture_read_lock,
616 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
617 .readunlock = rcu_torture_read_unlock,
618 .readlock_held = torture_readlock_not_held,
619 .get_gp_seq = rcu_no_completed,
620 .deferred_free = rcu_busted_torture_deferred_free,
621 .sync = synchronize_rcu_busted,
622 .exp_sync = synchronize_rcu_busted,
623 .call = call_rcu_busted,
624 .irq_capable = 1,
625 .name = "busted"
626 };
627
628 /*
629 * Definitions for srcu torture testing.
630 */
631
632 DEFINE_STATIC_SRCU(srcu_ctl);
633 static struct srcu_struct srcu_ctld;
634 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
635 static struct rcu_torture_ops srcud_ops;
636
637 static void srcu_get_gp_data(int *flags, unsigned long *gp_seq)
638 {
639 srcutorture_get_gp_data(srcu_ctlp, flags, gp_seq);
640 }
641
642 static int srcu_torture_read_lock(void)
643 {
644 if (cur_ops == &srcud_ops)
645 return srcu_read_lock_nmisafe(srcu_ctlp);
646 else
647 return srcu_read_lock(srcu_ctlp);
648 }
649
650 static void
651 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
652 {
653 long delay;
654 const long uspertick = 1000000 / HZ;
655 const long longdelay = 10;
656
657 /* We want there to be long-running readers, but not all the time. */
658
659 delay = torture_random(rrsp) %
660 (nrealreaders * 2 * longdelay * uspertick);
661 if (!delay && in_task()) {
662 schedule_timeout_interruptible(longdelay);
663 rtrsp->rt_delay_jiffies = longdelay;
664 } else {
665 rcu_read_delay(rrsp, rtrsp);
666 }
667 }
668
669 static void srcu_torture_read_unlock(int idx)
670 {
671 if (cur_ops == &srcud_ops)
672 srcu_read_unlock_nmisafe(srcu_ctlp, idx);
673 else
674 srcu_read_unlock(srcu_ctlp, idx);
675 }
676
677 static int torture_srcu_read_lock_held(void)
678 {
679 return srcu_read_lock_held(srcu_ctlp);
680 }
681
682 static unsigned long srcu_torture_completed(void)
683 {
684 return srcu_batches_completed(srcu_ctlp);
685 }
686
687 static void srcu_torture_deferred_free(struct rcu_torture *rp)
688 {
689 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
690 }
691
692 static void srcu_torture_synchronize(void)
693 {
694 synchronize_srcu(srcu_ctlp);
695 }
696
697 static unsigned long srcu_torture_get_gp_state(void)
698 {
699 return get_state_synchronize_srcu(srcu_ctlp);
700 }
701
702 static unsigned long srcu_torture_start_gp_poll(void)
703 {
704 return start_poll_synchronize_srcu(srcu_ctlp);
705 }
706
707 static bool srcu_torture_poll_gp_state(unsigned long oldstate)
708 {
709 return poll_state_synchronize_srcu(srcu_ctlp, oldstate);
710 }
711
712 static void srcu_torture_call(struct rcu_head *head,
713 rcu_callback_t func)
714 {
715 call_srcu(srcu_ctlp, head, func);
716 }
717
718 static void srcu_torture_barrier(void)
719 {
720 srcu_barrier(srcu_ctlp);
721 }
722
723 static void srcu_torture_stats(void)
724 {
725 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
726 }
727
728 static void srcu_torture_synchronize_expedited(void)
729 {
730 synchronize_srcu_expedited(srcu_ctlp);
731 }
732
733 static struct rcu_torture_ops srcu_ops = {
734 .ttype = SRCU_FLAVOR,
735 .init = rcu_sync_torture_init,
736 .readlock = srcu_torture_read_lock,
737 .read_delay = srcu_read_delay,
738 .readunlock = srcu_torture_read_unlock,
739 .readlock_held = torture_srcu_read_lock_held,
740 .get_gp_seq = srcu_torture_completed,
741 .deferred_free = srcu_torture_deferred_free,
742 .sync = srcu_torture_synchronize,
743 .exp_sync = srcu_torture_synchronize_expedited,
744 .same_gp_state = same_state_synchronize_srcu,
745 .get_comp_state = get_completed_synchronize_srcu,
746 .get_gp_state = srcu_torture_get_gp_state,
747 .start_gp_poll = srcu_torture_start_gp_poll,
748 .poll_gp_state = srcu_torture_poll_gp_state,
749 .poll_active = NUM_ACTIVE_SRCU_POLL_OLDSTATE,
750 .call = srcu_torture_call,
751 .cb_barrier = srcu_torture_barrier,
752 .stats = srcu_torture_stats,
753 .get_gp_data = srcu_get_gp_data,
754 .cbflood_max = 50000,
755 .irq_capable = 1,
756 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
757 .debug_objects = 1,
758 .name = "srcu"
759 };
760
761 static void srcu_torture_init(void)
762 {
763 rcu_sync_torture_init();
764 WARN_ON(init_srcu_struct(&srcu_ctld));
765 srcu_ctlp = &srcu_ctld;
766 }
767
768 static void srcu_torture_cleanup(void)
769 {
770 cleanup_srcu_struct(&srcu_ctld);
771 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
772 }
773
774 /* As above, but dynamically allocated. */
775 static struct rcu_torture_ops srcud_ops = {
776 .ttype = SRCU_FLAVOR,
777 .init = srcu_torture_init,
778 .cleanup = srcu_torture_cleanup,
779 .readlock = srcu_torture_read_lock,
780 .read_delay = srcu_read_delay,
781 .readunlock = srcu_torture_read_unlock,
782 .readlock_held = torture_srcu_read_lock_held,
783 .get_gp_seq = srcu_torture_completed,
784 .deferred_free = srcu_torture_deferred_free,
785 .sync = srcu_torture_synchronize,
786 .exp_sync = srcu_torture_synchronize_expedited,
787 .same_gp_state = same_state_synchronize_srcu,
788 .get_comp_state = get_completed_synchronize_srcu,
789 .get_gp_state = srcu_torture_get_gp_state,
790 .start_gp_poll = srcu_torture_start_gp_poll,
791 .poll_gp_state = srcu_torture_poll_gp_state,
792 .poll_active = NUM_ACTIVE_SRCU_POLL_OLDSTATE,
793 .call = srcu_torture_call,
794 .cb_barrier = srcu_torture_barrier,
795 .stats = srcu_torture_stats,
796 .get_gp_data = srcu_get_gp_data,
797 .cbflood_max = 50000,
798 .irq_capable = 1,
799 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
800 .debug_objects = 1,
801 .name = "srcud"
802 };
803
804 /* As above, but broken due to inappropriate reader extension. */
805 static struct rcu_torture_ops busted_srcud_ops = {
806 .ttype = SRCU_FLAVOR,
807 .init = srcu_torture_init,
808 .cleanup = srcu_torture_cleanup,
809 .readlock = srcu_torture_read_lock,
810 .read_delay = rcu_read_delay,
811 .readunlock = srcu_torture_read_unlock,
812 .readlock_held = torture_srcu_read_lock_held,
813 .get_gp_seq = srcu_torture_completed,
814 .deferred_free = srcu_torture_deferred_free,
815 .sync = srcu_torture_synchronize,
816 .exp_sync = srcu_torture_synchronize_expedited,
817 .call = srcu_torture_call,
818 .cb_barrier = srcu_torture_barrier,
819 .stats = srcu_torture_stats,
820 .irq_capable = 1,
821 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
822 .extendables = RCUTORTURE_MAX_EXTEND,
823 .name = "busted_srcud"
824 };
825
826 /*
827 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
828 * This implementation does not necessarily work well with CPU hotplug.
829 */
830
831 static void synchronize_rcu_trivial(void)
832 {
833 int cpu;
834
835 for_each_online_cpu(cpu) {
836 torture_sched_setaffinity(current->pid, cpumask_of(cpu));
837 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
838 }
839 }
840
841 static int rcu_torture_read_lock_trivial(void)
842 {
843 preempt_disable();
844 return 0;
845 }
846
847 static void rcu_torture_read_unlock_trivial(int idx)
848 {
849 preempt_enable();
850 }
851
852 static struct rcu_torture_ops trivial_ops = {
853 .ttype = RCU_TRIVIAL_FLAVOR,
854 .init = rcu_sync_torture_init,
855 .readlock = rcu_torture_read_lock_trivial,
856 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
857 .readunlock = rcu_torture_read_unlock_trivial,
858 .readlock_held = torture_readlock_not_held,
859 .get_gp_seq = rcu_no_completed,
860 .sync = synchronize_rcu_trivial,
861 .exp_sync = synchronize_rcu_trivial,
862 .irq_capable = 1,
863 .name = "trivial"
864 };
865
866 #ifdef CONFIG_TASKS_RCU
867
868 /*
869 * Definitions for RCU-tasks torture testing.
870 */
871
872 static int tasks_torture_read_lock(void)
873 {
874 return 0;
875 }
876
877 static void tasks_torture_read_unlock(int idx)
878 {
879 }
880
881 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
882 {
883 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
884 }
885
886 static void synchronize_rcu_mult_test(void)
887 {
888 synchronize_rcu_mult(call_rcu_tasks, call_rcu_hurry);
889 }
890
891 static struct rcu_torture_ops tasks_ops = {
892 .ttype = RCU_TASKS_FLAVOR,
893 .init = rcu_sync_torture_init,
894 .readlock = tasks_torture_read_lock,
895 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
896 .readunlock = tasks_torture_read_unlock,
897 .get_gp_seq = rcu_no_completed,
898 .deferred_free = rcu_tasks_torture_deferred_free,
899 .sync = synchronize_rcu_tasks,
900 .exp_sync = synchronize_rcu_mult_test,
901 .call = call_rcu_tasks,
902 .cb_barrier = rcu_barrier_tasks,
903 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread,
904 .get_gp_data = rcu_tasks_get_gp_data,
905 .irq_capable = 1,
906 .slow_gps = 1,
907 .name = "tasks"
908 };
909
910 #define TASKS_OPS &tasks_ops,
911
912 #else // #ifdef CONFIG_TASKS_RCU
913
914 #define TASKS_OPS
915
916 #endif // #else #ifdef CONFIG_TASKS_RCU
917
918
919 #ifdef CONFIG_TASKS_RUDE_RCU
920
921 /*
922 * Definitions for rude RCU-tasks torture testing.
923 */
924
925 static struct rcu_torture_ops tasks_rude_ops = {
926 .ttype = RCU_TASKS_RUDE_FLAVOR,
927 .init = rcu_sync_torture_init,
928 .readlock = rcu_torture_read_lock_trivial,
929 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
930 .readunlock = rcu_torture_read_unlock_trivial,
931 .get_gp_seq = rcu_no_completed,
932 .sync = synchronize_rcu_tasks_rude,
933 .exp_sync = synchronize_rcu_tasks_rude,
934 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread,
935 .get_gp_data = rcu_tasks_rude_get_gp_data,
936 .cbflood_max = 50000,
937 .irq_capable = 1,
938 .name = "tasks-rude"
939 };
940
941 #define TASKS_RUDE_OPS &tasks_rude_ops,
942
943 #else // #ifdef CONFIG_TASKS_RUDE_RCU
944
945 #define TASKS_RUDE_OPS
946
947 #endif // #else #ifdef CONFIG_TASKS_RUDE_RCU
948
949
950 #ifdef CONFIG_TASKS_TRACE_RCU
951
952 /*
953 * Definitions for tracing RCU-tasks torture testing.
954 */
955
956 static int tasks_tracing_torture_read_lock(void)
957 {
958 rcu_read_lock_trace();
959 return 0;
960 }
961
962 static void tasks_tracing_torture_read_unlock(int idx)
963 {
964 rcu_read_unlock_trace();
965 }
966
967 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
968 {
969 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
970 }
971
972 static struct rcu_torture_ops tasks_tracing_ops = {
973 .ttype = RCU_TASKS_TRACING_FLAVOR,
974 .init = rcu_sync_torture_init,
975 .readlock = tasks_tracing_torture_read_lock,
976 .read_delay = srcu_read_delay, /* just reuse srcu's version. */
977 .readunlock = tasks_tracing_torture_read_unlock,
978 .readlock_held = rcu_read_lock_trace_held,
979 .get_gp_seq = rcu_no_completed,
980 .deferred_free = rcu_tasks_tracing_torture_deferred_free,
981 .sync = synchronize_rcu_tasks_trace,
982 .exp_sync = synchronize_rcu_tasks_trace,
983 .call = call_rcu_tasks_trace,
984 .cb_barrier = rcu_barrier_tasks_trace,
985 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread,
986 .get_gp_data = rcu_tasks_trace_get_gp_data,
987 .cbflood_max = 50000,
988 .irq_capable = 1,
989 .slow_gps = 1,
990 .name = "tasks-tracing"
991 };
992
993 #define TASKS_TRACING_OPS &tasks_tracing_ops,
994
995 #else // #ifdef CONFIG_TASKS_TRACE_RCU
996
997 #define TASKS_TRACING_OPS
998
999 #endif // #else #ifdef CONFIG_TASKS_TRACE_RCU
1000
1001
1002 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
1003 {
1004 if (!cur_ops->gp_diff)
1005 return new - old;
1006 return cur_ops->gp_diff(new, old);
1007 }
1008
1009 /*
1010 * RCU torture priority-boost testing. Runs one real-time thread per
1011 * CPU for moderate bursts, repeatedly starting grace periods and waiting
1012 * for them to complete. If a given grace period takes too long, we assume
1013 * that priority inversion has occurred.
1014 */
1015
1016 static int old_rt_runtime = -1;
1017
1018 static void rcu_torture_disable_rt_throttle(void)
1019 {
1020 /*
1021 * Disable RT throttling so that rcutorture's boost threads don't get
1022 * throttled. Only possible if rcutorture is built-in otherwise the
1023 * user should manually do this by setting the sched_rt_period_us and
1024 * sched_rt_runtime sysctls.
1025 */
1026 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
1027 return;
1028
1029 old_rt_runtime = sysctl_sched_rt_runtime;
1030 sysctl_sched_rt_runtime = -1;
1031 }
1032
1033 static void rcu_torture_enable_rt_throttle(void)
1034 {
1035 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
1036 return;
1037
1038 sysctl_sched_rt_runtime = old_rt_runtime;
1039 old_rt_runtime = -1;
1040 }
1041
1042 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start)
1043 {
1044 int cpu;
1045 static int dbg_done;
1046 unsigned long end = jiffies;
1047 bool gp_done;
1048 unsigned long j;
1049 static unsigned long last_persist;
1050 unsigned long lp;
1051 unsigned long mininterval = test_boost_duration * HZ - HZ / 2;
1052
1053 if (end - *start > mininterval) {
1054 // Recheck after checking time to avoid false positives.
1055 smp_mb(); // Time check before grace-period check.
1056 if (cur_ops->poll_gp_state(gp_state))
1057 return false; // passed, though perhaps just barely
1058 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) {
1059 // At most one persisted message per boost test.
1060 j = jiffies;
1061 lp = READ_ONCE(last_persist);
1062 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp)
1063 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu);
1064 return false; // passed on a technicality
1065 }
1066 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
1067 n_rcu_torture_boost_failure++;
1068 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) {
1069 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n",
1070 current->rt_priority, gp_state, end - *start);
1071 cur_ops->gp_kthread_dbg();
1072 // Recheck after print to flag grace period ending during splat.
1073 gp_done = cur_ops->poll_gp_state(gp_state);
1074 pr_info("Boost inversion: GP %lu %s.\n", gp_state,
1075 gp_done ? "ended already" : "still pending");
1076
1077 }
1078
1079 return true; // failed
1080 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) {
1081 *start = jiffies;
1082 }
1083
1084 return false; // passed
1085 }
1086
1087 static int rcu_torture_boost(void *arg)
1088 {
1089 unsigned long endtime;
1090 unsigned long gp_state;
1091 unsigned long gp_state_time;
1092 unsigned long oldstarttime;
1093
1094 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
1095
1096 /* Set real-time priority. */
1097 sched_set_fifo_low(current);
1098
1099 /* Each pass through the following loop does one boost-test cycle. */
1100 do {
1101 bool failed = false; // Test failed already in this test interval
1102 bool gp_initiated = false;
1103
1104 if (kthread_should_stop())
1105 goto checkwait;
1106
1107 /* Wait for the next test interval. */
1108 oldstarttime = READ_ONCE(boost_starttime);
1109 while (time_before(jiffies, oldstarttime)) {
1110 schedule_timeout_interruptible(oldstarttime - jiffies);
1111 if (stutter_wait("rcu_torture_boost"))
1112 sched_set_fifo_low(current);
1113 if (torture_must_stop())
1114 goto checkwait;
1115 }
1116
1117 // Do one boost-test interval.
1118 endtime = oldstarttime + test_boost_duration * HZ;
1119 while (time_before(jiffies, endtime)) {
1120 // Has current GP gone too long?
1121 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1122 failed = rcu_torture_boost_failed(gp_state, &gp_state_time);
1123 // If we don't have a grace period in flight, start one.
1124 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) {
1125 gp_state = cur_ops->start_gp_poll();
1126 gp_initiated = true;
1127 gp_state_time = jiffies;
1128 }
1129 if (stutter_wait("rcu_torture_boost")) {
1130 sched_set_fifo_low(current);
1131 // If the grace period already ended,
1132 // we don't know when that happened, so
1133 // start over.
1134 if (cur_ops->poll_gp_state(gp_state))
1135 gp_initiated = false;
1136 }
1137 if (torture_must_stop())
1138 goto checkwait;
1139 }
1140
1141 // In case the grace period extended beyond the end of the loop.
1142 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1143 rcu_torture_boost_failed(gp_state, &gp_state_time);
1144
1145 /*
1146 * Set the start time of the next test interval.
1147 * Yes, this is vulnerable to long delays, but such
1148 * delays simply cause a false negative for the next
1149 * interval. Besides, we are running at RT priority,
1150 * so delays should be relatively rare.
1151 */
1152 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) {
1153 if (mutex_trylock(&boost_mutex)) {
1154 if (oldstarttime == boost_starttime) {
1155 WRITE_ONCE(boost_starttime,
1156 jiffies + test_boost_interval * HZ);
1157 n_rcu_torture_boosts++;
1158 }
1159 mutex_unlock(&boost_mutex);
1160 break;
1161 }
1162 schedule_timeout_uninterruptible(HZ / 20);
1163 }
1164
1165 /* Go do the stutter. */
1166 checkwait: if (stutter_wait("rcu_torture_boost"))
1167 sched_set_fifo_low(current);
1168 } while (!torture_must_stop());
1169
1170 /* Clean up and exit. */
1171 while (!kthread_should_stop()) {
1172 torture_shutdown_absorb("rcu_torture_boost");
1173 schedule_timeout_uninterruptible(HZ / 20);
1174 }
1175 torture_kthread_stopping("rcu_torture_boost");
1176 return 0;
1177 }
1178
1179 /*
1180 * RCU torture force-quiescent-state kthread. Repeatedly induces
1181 * bursts of calls to force_quiescent_state(), increasing the probability
1182 * of occurrence of some important types of race conditions.
1183 */
1184 static int
1185 rcu_torture_fqs(void *arg)
1186 {
1187 unsigned long fqs_resume_time;
1188 int fqs_burst_remaining;
1189 int oldnice = task_nice(current);
1190
1191 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
1192 do {
1193 fqs_resume_time = jiffies + fqs_stutter * HZ;
1194 while (time_before(jiffies, fqs_resume_time) &&
1195 !kthread_should_stop()) {
1196 schedule_timeout_interruptible(HZ / 20);
1197 }
1198 fqs_burst_remaining = fqs_duration;
1199 while (fqs_burst_remaining > 0 &&
1200 !kthread_should_stop()) {
1201 cur_ops->fqs();
1202 udelay(fqs_holdoff);
1203 fqs_burst_remaining -= fqs_holdoff;
1204 }
1205 if (stutter_wait("rcu_torture_fqs"))
1206 sched_set_normal(current, oldnice);
1207 } while (!torture_must_stop());
1208 torture_kthread_stopping("rcu_torture_fqs");
1209 return 0;
1210 }
1211
1212 // Used by writers to randomly choose from the available grace-period primitives.
1213 static int synctype[ARRAY_SIZE(rcu_torture_writer_state_names)] = { };
1214 static int nsynctypes;
1215
1216 /*
1217 * Determine which grace-period primitives are available.
1218 */
1219 static void rcu_torture_write_types(void)
1220 {
1221 bool gp_cond1 = gp_cond, gp_cond_exp1 = gp_cond_exp, gp_cond_full1 = gp_cond_full;
1222 bool gp_cond_exp_full1 = gp_cond_exp_full, gp_exp1 = gp_exp, gp_poll_exp1 = gp_poll_exp;
1223 bool gp_poll_exp_full1 = gp_poll_exp_full, gp_normal1 = gp_normal, gp_poll1 = gp_poll;
1224 bool gp_poll_full1 = gp_poll_full, gp_sync1 = gp_sync;
1225
1226 /* Initialize synctype[] array. If none set, take default. */
1227 if (!gp_cond1 &&
1228 !gp_cond_exp1 &&
1229 !gp_cond_full1 &&
1230 !gp_cond_exp_full1 &&
1231 !gp_exp1 &&
1232 !gp_poll_exp1 &&
1233 !gp_poll_exp_full1 &&
1234 !gp_normal1 &&
1235 !gp_poll1 &&
1236 !gp_poll_full1 &&
1237 !gp_sync1) {
1238 gp_cond1 = true;
1239 gp_cond_exp1 = true;
1240 gp_cond_full1 = true;
1241 gp_cond_exp_full1 = true;
1242 gp_exp1 = true;
1243 gp_poll_exp1 = true;
1244 gp_poll_exp_full1 = true;
1245 gp_normal1 = true;
1246 gp_poll1 = true;
1247 gp_poll_full1 = true;
1248 gp_sync1 = true;
1249 }
1250 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) {
1251 synctype[nsynctypes++] = RTWS_COND_GET;
1252 pr_info("%s: Testing conditional GPs.\n", __func__);
1253 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) {
1254 pr_alert("%s: gp_cond without primitives.\n", __func__);
1255 }
1256 if (gp_cond_exp1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp) {
1257 synctype[nsynctypes++] = RTWS_COND_GET_EXP;
1258 pr_info("%s: Testing conditional expedited GPs.\n", __func__);
1259 } else if (gp_cond_exp && (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp)) {
1260 pr_alert("%s: gp_cond_exp without primitives.\n", __func__);
1261 }
1262 if (gp_cond_full1 && cur_ops->get_gp_state && cur_ops->cond_sync_full) {
1263 synctype[nsynctypes++] = RTWS_COND_GET_FULL;
1264 pr_info("%s: Testing conditional full-state GPs.\n", __func__);
1265 } else if (gp_cond_full && (!cur_ops->get_gp_state || !cur_ops->cond_sync_full)) {
1266 pr_alert("%s: gp_cond_full without primitives.\n", __func__);
1267 }
1268 if (gp_cond_exp_full1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp_full) {
1269 synctype[nsynctypes++] = RTWS_COND_GET_EXP_FULL;
1270 pr_info("%s: Testing conditional full-state expedited GPs.\n", __func__);
1271 } else if (gp_cond_exp_full &&
1272 (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp_full)) {
1273 pr_alert("%s: gp_cond_exp_full without primitives.\n", __func__);
1274 }
1275 if (gp_exp1 && cur_ops->exp_sync) {
1276 synctype[nsynctypes++] = RTWS_EXP_SYNC;
1277 pr_info("%s: Testing expedited GPs.\n", __func__);
1278 } else if (gp_exp && !cur_ops->exp_sync) {
1279 pr_alert("%s: gp_exp without primitives.\n", __func__);
1280 }
1281 if (gp_normal1 && cur_ops->deferred_free) {
1282 synctype[nsynctypes++] = RTWS_DEF_FREE;
1283 pr_info("%s: Testing asynchronous GPs.\n", __func__);
1284 } else if (gp_normal && !cur_ops->deferred_free) {
1285 pr_alert("%s: gp_normal without primitives.\n", __func__);
1286 }
1287 if (gp_poll1 && cur_ops->get_comp_state && cur_ops->same_gp_state &&
1288 cur_ops->start_gp_poll && cur_ops->poll_gp_state) {
1289 synctype[nsynctypes++] = RTWS_POLL_GET;
1290 pr_info("%s: Testing polling GPs.\n", __func__);
1291 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) {
1292 pr_alert("%s: gp_poll without primitives.\n", __func__);
1293 }
1294 if (gp_poll_full1 && cur_ops->get_comp_state_full && cur_ops->same_gp_state_full
1295 && cur_ops->start_gp_poll_full && cur_ops->poll_gp_state_full) {
1296 synctype[nsynctypes++] = RTWS_POLL_GET_FULL;
1297 pr_info("%s: Testing polling full-state GPs.\n", __func__);
1298 } else if (gp_poll_full && (!cur_ops->start_gp_poll_full || !cur_ops->poll_gp_state_full)) {
1299 pr_alert("%s: gp_poll_full without primitives.\n", __func__);
1300 }
1301 if (gp_poll_exp1 && cur_ops->start_gp_poll_exp && cur_ops->poll_gp_state_exp) {
1302 synctype[nsynctypes++] = RTWS_POLL_GET_EXP;
1303 pr_info("%s: Testing polling expedited GPs.\n", __func__);
1304 } else if (gp_poll_exp && (!cur_ops->start_gp_poll_exp || !cur_ops->poll_gp_state_exp)) {
1305 pr_alert("%s: gp_poll_exp without primitives.\n", __func__);
1306 }
1307 if (gp_poll_exp_full1 && cur_ops->start_gp_poll_exp_full && cur_ops->poll_gp_state_full) {
1308 synctype[nsynctypes++] = RTWS_POLL_GET_EXP_FULL;
1309 pr_info("%s: Testing polling full-state expedited GPs.\n", __func__);
1310 } else if (gp_poll_exp_full &&
1311 (!cur_ops->start_gp_poll_exp_full || !cur_ops->poll_gp_state_full)) {
1312 pr_alert("%s: gp_poll_exp_full without primitives.\n", __func__);
1313 }
1314 if (gp_sync1 && cur_ops->sync) {
1315 synctype[nsynctypes++] = RTWS_SYNC;
1316 pr_info("%s: Testing normal GPs.\n", __func__);
1317 } else if (gp_sync && !cur_ops->sync) {
1318 pr_alert("%s: gp_sync without primitives.\n", __func__);
1319 }
1320 pr_alert("%s: Testing %d update types.\n", __func__, nsynctypes);
1321 }
1322
1323 /*
1324 * Do the specified rcu_torture_writer() synchronous grace period,
1325 * while also testing out the polled APIs. Note well that the single-CPU
1326 * grace-period optimizations must be accounted for.
1327 */
1328 static void do_rtws_sync(struct torture_random_state *trsp, void (*sync)(void))
1329 {
1330 unsigned long cookie;
1331 struct rcu_gp_oldstate cookie_full;
1332 bool dopoll;
1333 bool dopoll_full;
1334 unsigned long r = torture_random(trsp);
1335
1336 dopoll = cur_ops->get_gp_state && cur_ops->poll_gp_state && !(r & 0x300);
1337 dopoll_full = cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full && !(r & 0xc00);
1338 if (dopoll || dopoll_full)
1339 cpus_read_lock();
1340 if (dopoll)
1341 cookie = cur_ops->get_gp_state();
1342 if (dopoll_full)
1343 cur_ops->get_gp_state_full(&cookie_full);
1344 if (cur_ops->poll_need_2gp && cur_ops->poll_need_2gp(dopoll, dopoll_full))
1345 sync();
1346 sync();
1347 WARN_ONCE(dopoll && !cur_ops->poll_gp_state(cookie),
1348 "%s: Cookie check 3 failed %pS() online %*pbl.",
1349 __func__, sync, cpumask_pr_args(cpu_online_mask));
1350 WARN_ONCE(dopoll_full && !cur_ops->poll_gp_state_full(&cookie_full),
1351 "%s: Cookie check 4 failed %pS() online %*pbl",
1352 __func__, sync, cpumask_pr_args(cpu_online_mask));
1353 if (dopoll || dopoll_full)
1354 cpus_read_unlock();
1355 }
1356
1357 /*
1358 * RCU torture writer kthread. Repeatedly substitutes a new structure
1359 * for that pointed to by rcu_torture_current, freeing the old structure
1360 * after a series of grace periods (the "pipeline").
1361 */
1362 static int
1363 rcu_torture_writer(void *arg)
1364 {
1365 bool boot_ended;
1366 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
1367 unsigned long cookie;
1368 struct rcu_gp_oldstate cookie_full;
1369 int expediting = 0;
1370 unsigned long gp_snap;
1371 unsigned long gp_snap1;
1372 struct rcu_gp_oldstate gp_snap_full;
1373 struct rcu_gp_oldstate gp_snap1_full;
1374 int i;
1375 int idx;
1376 int oldnice = task_nice(current);
1377 struct rcu_gp_oldstate *rgo = NULL;
1378 int rgo_size = 0;
1379 struct rcu_torture *rp;
1380 struct rcu_torture *old_rp;
1381 static DEFINE_TORTURE_RANDOM(rand);
1382 unsigned long stallsdone = jiffies;
1383 bool stutter_waited;
1384 unsigned long *ulo = NULL;
1385 int ulo_size = 0;
1386
1387 // If a new stall test is added, this must be adjusted.
1388 if (stall_cpu_holdoff + stall_gp_kthread + stall_cpu)
1389 stallsdone += (stall_cpu_holdoff + stall_gp_kthread + stall_cpu + 60) *
1390 HZ * (stall_cpu_repeat + 1);
1391 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
1392 if (!can_expedite)
1393 pr_alert("%s" TORTURE_FLAG
1394 " GP expediting controlled from boot/sysfs for %s.\n",
1395 torture_type, cur_ops->name);
1396 if (WARN_ONCE(nsynctypes == 0,
1397 "%s: No update-side primitives.\n", __func__)) {
1398 /*
1399 * No updates primitives, so don't try updating.
1400 * The resulting test won't be testing much, hence the
1401 * above WARN_ONCE().
1402 */
1403 rcu_torture_writer_state = RTWS_STOPPING;
1404 torture_kthread_stopping("rcu_torture_writer");
1405 return 0;
1406 }
1407 if (cur_ops->poll_active > 0) {
1408 ulo = kzalloc(cur_ops->poll_active * sizeof(ulo[0]), GFP_KERNEL);
1409 if (!WARN_ON(!ulo))
1410 ulo_size = cur_ops->poll_active;
1411 }
1412 if (cur_ops->poll_active_full > 0) {
1413 rgo = kzalloc(cur_ops->poll_active_full * sizeof(rgo[0]), GFP_KERNEL);
1414 if (!WARN_ON(!rgo))
1415 rgo_size = cur_ops->poll_active_full;
1416 }
1417
1418 do {
1419 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1420 torture_hrtimeout_us(500, 1000, &rand);
1421 rp = rcu_torture_alloc();
1422 if (rp == NULL)
1423 continue;
1424 rp->rtort_pipe_count = 0;
1425 ASSERT_EXCLUSIVE_WRITER(rp->rtort_pipe_count);
1426 rcu_torture_writer_state = RTWS_DELAY;
1427 udelay(torture_random(&rand) & 0x3ff);
1428 rcu_torture_writer_state = RTWS_REPLACE;
1429 old_rp = rcu_dereference_check(rcu_torture_current,
1430 current == writer_task);
1431 rp->rtort_mbtest = 1;
1432 rcu_assign_pointer(rcu_torture_current, rp);
1433 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1434 if (old_rp) {
1435 i = old_rp->rtort_pipe_count;
1436 if (i > RCU_TORTURE_PIPE_LEN)
1437 i = RCU_TORTURE_PIPE_LEN;
1438 atomic_inc(&rcu_torture_wcount[i]);
1439 WRITE_ONCE(old_rp->rtort_pipe_count,
1440 old_rp->rtort_pipe_count + 1);
1441 ASSERT_EXCLUSIVE_WRITER(old_rp->rtort_pipe_count);
1442
1443 // Make sure readers block polled grace periods.
1444 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
1445 idx = cur_ops->readlock();
1446 cookie = cur_ops->get_gp_state();
1447 WARN_ONCE(cur_ops->poll_gp_state(cookie),
1448 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n",
1449 __func__,
1450 rcu_torture_writer_state_getname(),
1451 rcu_torture_writer_state,
1452 cookie, cur_ops->get_gp_state());
1453 if (cur_ops->get_comp_state) {
1454 cookie = cur_ops->get_comp_state();
1455 WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie));
1456 }
1457 cur_ops->readunlock(idx);
1458 }
1459 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) {
1460 idx = cur_ops->readlock();
1461 cur_ops->get_gp_state_full(&cookie_full);
1462 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
1463 "%s: Cookie check 5 failed %s(%d) online %*pbl\n",
1464 __func__,
1465 rcu_torture_writer_state_getname(),
1466 rcu_torture_writer_state,
1467 cpumask_pr_args(cpu_online_mask));
1468 if (cur_ops->get_comp_state_full) {
1469 cur_ops->get_comp_state_full(&cookie_full);
1470 WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full));
1471 }
1472 cur_ops->readunlock(idx);
1473 }
1474 switch (synctype[torture_random(&rand) % nsynctypes]) {
1475 case RTWS_DEF_FREE:
1476 rcu_torture_writer_state = RTWS_DEF_FREE;
1477 cur_ops->deferred_free(old_rp);
1478 break;
1479 case RTWS_EXP_SYNC:
1480 rcu_torture_writer_state = RTWS_EXP_SYNC;
1481 do_rtws_sync(&rand, cur_ops->exp_sync);
1482 rcu_torture_pipe_update(old_rp);
1483 break;
1484 case RTWS_COND_GET:
1485 rcu_torture_writer_state = RTWS_COND_GET;
1486 gp_snap = cur_ops->get_gp_state();
1487 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1488 rcu_torture_writer_state = RTWS_COND_SYNC;
1489 cur_ops->cond_sync(gp_snap);
1490 rcu_torture_pipe_update(old_rp);
1491 break;
1492 case RTWS_COND_GET_EXP:
1493 rcu_torture_writer_state = RTWS_COND_GET_EXP;
1494 gp_snap = cur_ops->get_gp_state_exp();
1495 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1496 rcu_torture_writer_state = RTWS_COND_SYNC_EXP;
1497 cur_ops->cond_sync_exp(gp_snap);
1498 rcu_torture_pipe_update(old_rp);
1499 break;
1500 case RTWS_COND_GET_FULL:
1501 rcu_torture_writer_state = RTWS_COND_GET_FULL;
1502 cur_ops->get_gp_state_full(&gp_snap_full);
1503 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1504 rcu_torture_writer_state = RTWS_COND_SYNC_FULL;
1505 cur_ops->cond_sync_full(&gp_snap_full);
1506 rcu_torture_pipe_update(old_rp);
1507 break;
1508 case RTWS_COND_GET_EXP_FULL:
1509 rcu_torture_writer_state = RTWS_COND_GET_EXP_FULL;
1510 cur_ops->get_gp_state_full(&gp_snap_full);
1511 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1512 rcu_torture_writer_state = RTWS_COND_SYNC_EXP_FULL;
1513 cur_ops->cond_sync_exp_full(&gp_snap_full);
1514 rcu_torture_pipe_update(old_rp);
1515 break;
1516 case RTWS_POLL_GET:
1517 rcu_torture_writer_state = RTWS_POLL_GET;
1518 for (i = 0; i < ulo_size; i++)
1519 ulo[i] = cur_ops->get_comp_state();
1520 gp_snap = cur_ops->start_gp_poll();
1521 rcu_torture_writer_state = RTWS_POLL_WAIT;
1522 while (!cur_ops->poll_gp_state(gp_snap)) {
1523 gp_snap1 = cur_ops->get_gp_state();
1524 for (i = 0; i < ulo_size; i++)
1525 if (cur_ops->poll_gp_state(ulo[i]) ||
1526 cur_ops->same_gp_state(ulo[i], gp_snap1)) {
1527 ulo[i] = gp_snap1;
1528 break;
1529 }
1530 WARN_ON_ONCE(ulo_size > 0 && i >= ulo_size);
1531 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1532 &rand);
1533 }
1534 rcu_torture_pipe_update(old_rp);
1535 break;
1536 case RTWS_POLL_GET_FULL:
1537 rcu_torture_writer_state = RTWS_POLL_GET_FULL;
1538 for (i = 0; i < rgo_size; i++)
1539 cur_ops->get_comp_state_full(&rgo[i]);
1540 cur_ops->start_gp_poll_full(&gp_snap_full);
1541 rcu_torture_writer_state = RTWS_POLL_WAIT_FULL;
1542 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1543 cur_ops->get_gp_state_full(&gp_snap1_full);
1544 for (i = 0; i < rgo_size; i++)
1545 if (cur_ops->poll_gp_state_full(&rgo[i]) ||
1546 cur_ops->same_gp_state_full(&rgo[i],
1547 &gp_snap1_full)) {
1548 rgo[i] = gp_snap1_full;
1549 break;
1550 }
1551 WARN_ON_ONCE(rgo_size > 0 && i >= rgo_size);
1552 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1553 &rand);
1554 }
1555 rcu_torture_pipe_update(old_rp);
1556 break;
1557 case RTWS_POLL_GET_EXP:
1558 rcu_torture_writer_state = RTWS_POLL_GET_EXP;
1559 gp_snap = cur_ops->start_gp_poll_exp();
1560 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP;
1561 while (!cur_ops->poll_gp_state_exp(gp_snap))
1562 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1563 &rand);
1564 rcu_torture_pipe_update(old_rp);
1565 break;
1566 case RTWS_POLL_GET_EXP_FULL:
1567 rcu_torture_writer_state = RTWS_POLL_GET_EXP_FULL;
1568 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1569 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP_FULL;
1570 while (!cur_ops->poll_gp_state_full(&gp_snap_full))
1571 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1572 &rand);
1573 rcu_torture_pipe_update(old_rp);
1574 break;
1575 case RTWS_SYNC:
1576 rcu_torture_writer_state = RTWS_SYNC;
1577 do_rtws_sync(&rand, cur_ops->sync);
1578 rcu_torture_pipe_update(old_rp);
1579 break;
1580 default:
1581 WARN_ON_ONCE(1);
1582 break;
1583 }
1584 }
1585 WRITE_ONCE(rcu_torture_current_version,
1586 rcu_torture_current_version + 1);
1587 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1588 if (can_expedite &&
1589 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1590 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1591 if (expediting >= 0)
1592 rcu_expedite_gp();
1593 else
1594 rcu_unexpedite_gp();
1595 if (++expediting > 3)
1596 expediting = -expediting;
1597 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1598 can_expedite = !rcu_gp_is_expedited() &&
1599 !rcu_gp_is_normal();
1600 }
1601 rcu_torture_writer_state = RTWS_STUTTER;
1602 boot_ended = rcu_inkernel_boot_has_ended();
1603 stutter_waited = stutter_wait("rcu_torture_writer");
1604 if (stutter_waited &&
1605 !atomic_read(&rcu_fwd_cb_nodelay) &&
1606 !cur_ops->slow_gps &&
1607 !torture_must_stop() &&
1608 boot_ended &&
1609 time_after(jiffies, stallsdone))
1610 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1611 if (list_empty(&rcu_tortures[i].rtort_free) &&
1612 rcu_access_pointer(rcu_torture_current) != &rcu_tortures[i]) {
1613 tracing_off();
1614 if (cur_ops->gp_kthread_dbg)
1615 cur_ops->gp_kthread_dbg();
1616 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1617 rcu_ftrace_dump(DUMP_ALL);
1618 }
1619 if (stutter_waited)
1620 sched_set_normal(current, oldnice);
1621 } while (!torture_must_stop());
1622 rcu_torture_current = NULL; // Let stats task know that we are done.
1623 /* Reset expediting back to unexpedited. */
1624 if (expediting > 0)
1625 expediting = -expediting;
1626 while (can_expedite && expediting++ < 0)
1627 rcu_unexpedite_gp();
1628 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1629 if (!can_expedite)
1630 pr_alert("%s" TORTURE_FLAG
1631 " Dynamic grace-period expediting was disabled.\n",
1632 torture_type);
1633 kfree(ulo);
1634 kfree(rgo);
1635 rcu_torture_writer_state = RTWS_STOPPING;
1636 torture_kthread_stopping("rcu_torture_writer");
1637 return 0;
1638 }
1639
1640 /*
1641 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1642 * delay between calls.
1643 */
1644 static int
1645 rcu_torture_fakewriter(void *arg)
1646 {
1647 unsigned long gp_snap;
1648 struct rcu_gp_oldstate gp_snap_full;
1649 DEFINE_TORTURE_RANDOM(rand);
1650
1651 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1652 set_user_nice(current, MAX_NICE);
1653
1654 if (WARN_ONCE(nsynctypes == 0,
1655 "%s: No update-side primitives.\n", __func__)) {
1656 /*
1657 * No updates primitives, so don't try updating.
1658 * The resulting test won't be testing much, hence the
1659 * above WARN_ONCE().
1660 */
1661 torture_kthread_stopping("rcu_torture_fakewriter");
1662 return 0;
1663 }
1664
1665 do {
1666 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand);
1667 if (cur_ops->cb_barrier != NULL &&
1668 torture_random(&rand) % (nfakewriters * 8) == 0) {
1669 cur_ops->cb_barrier();
1670 } else {
1671 switch (synctype[torture_random(&rand) % nsynctypes]) {
1672 case RTWS_DEF_FREE:
1673 break;
1674 case RTWS_EXP_SYNC:
1675 cur_ops->exp_sync();
1676 break;
1677 case RTWS_COND_GET:
1678 gp_snap = cur_ops->get_gp_state();
1679 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1680 cur_ops->cond_sync(gp_snap);
1681 break;
1682 case RTWS_COND_GET_EXP:
1683 gp_snap = cur_ops->get_gp_state_exp();
1684 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1685 cur_ops->cond_sync_exp(gp_snap);
1686 break;
1687 case RTWS_COND_GET_FULL:
1688 cur_ops->get_gp_state_full(&gp_snap_full);
1689 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1690 cur_ops->cond_sync_full(&gp_snap_full);
1691 break;
1692 case RTWS_COND_GET_EXP_FULL:
1693 cur_ops->get_gp_state_full(&gp_snap_full);
1694 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1695 cur_ops->cond_sync_exp_full(&gp_snap_full);
1696 break;
1697 case RTWS_POLL_GET:
1698 gp_snap = cur_ops->start_gp_poll();
1699 while (!cur_ops->poll_gp_state(gp_snap)) {
1700 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1701 &rand);
1702 }
1703 break;
1704 case RTWS_POLL_GET_FULL:
1705 cur_ops->start_gp_poll_full(&gp_snap_full);
1706 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1707 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1708 &rand);
1709 }
1710 break;
1711 case RTWS_POLL_GET_EXP:
1712 gp_snap = cur_ops->start_gp_poll_exp();
1713 while (!cur_ops->poll_gp_state_exp(gp_snap)) {
1714 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1715 &rand);
1716 }
1717 break;
1718 case RTWS_POLL_GET_EXP_FULL:
1719 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1720 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1721 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1722 &rand);
1723 }
1724 break;
1725 case RTWS_SYNC:
1726 cur_ops->sync();
1727 break;
1728 default:
1729 WARN_ON_ONCE(1);
1730 break;
1731 }
1732 }
1733 stutter_wait("rcu_torture_fakewriter");
1734 } while (!torture_must_stop());
1735
1736 torture_kthread_stopping("rcu_torture_fakewriter");
1737 return 0;
1738 }
1739
1740 static void rcu_torture_timer_cb(struct rcu_head *rhp)
1741 {
1742 kfree(rhp);
1743 }
1744
1745 // Set up and carry out testing of RCU's global memory ordering
1746 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp,
1747 struct torture_random_state *trsp)
1748 {
1749 unsigned long loops;
1750 int noc = torture_num_online_cpus();
1751 int rdrchked;
1752 int rdrchker;
1753 struct rcu_torture_reader_check *rtrcp; // Me.
1754 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking.
1755 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked.
1756 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me.
1757
1758 if (myid < 0)
1759 return; // Don't try this from timer handlers.
1760
1761 // Increment my counter.
1762 rtrcp = &rcu_torture_reader_mbchk[myid];
1763 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1);
1764
1765 // Attempt to assign someone else some checking work.
1766 rdrchked = torture_random(trsp) % nrealreaders;
1767 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1768 rdrchker = torture_random(trsp) % nrealreaders;
1769 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker];
1770 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker &&
1771 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below.
1772 !READ_ONCE(rtp->rtort_chkp) &&
1773 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below.
1774 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops);
1775 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0);
1776 rtrcp->rtc_chkrdr = rdrchked;
1777 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends.
1778 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) ||
1779 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp))
1780 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out.
1781 }
1782
1783 // If assigned some completed work, do it!
1784 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner);
1785 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready))
1786 return; // No work or work not yet ready.
1787 rdrchked = rtrcp_assigner->rtc_chkrdr;
1788 if (WARN_ON_ONCE(rdrchked < 0))
1789 return;
1790 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1791 loops = READ_ONCE(rtrcp_chked->rtc_myloops);
1792 atomic_inc(&n_rcu_torture_mbchk_tries);
1793 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops))
1794 atomic_inc(&n_rcu_torture_mbchk_fail);
1795 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2;
1796 rtrcp_assigner->rtc_ready = 0;
1797 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work.
1798 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign.
1799 }
1800
1801 /*
1802 * Do one extension of an RCU read-side critical section using the
1803 * current reader state in readstate (set to zero for initial entry
1804 * to extended critical section), set the new state as specified by
1805 * newstate (set to zero for final exit from extended critical section),
1806 * and random-number-generator state in trsp. If this is neither the
1807 * beginning or end of the critical section and if there was actually a
1808 * change, do a ->read_delay().
1809 */
1810 static void rcutorture_one_extend(int *readstate, int newstate,
1811 struct torture_random_state *trsp,
1812 struct rt_read_seg *rtrsp)
1813 {
1814 unsigned long flags;
1815 int idxnew1 = -1;
1816 int idxnew2 = -1;
1817 int idxold1 = *readstate;
1818 int idxold2 = idxold1;
1819 int statesnew = ~*readstate & newstate;
1820 int statesold = *readstate & ~newstate;
1821
1822 WARN_ON_ONCE(idxold2 < 0);
1823 WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
1824 rtrsp->rt_readstate = newstate;
1825
1826 /* First, put new protection in place to avoid critical-section gap. */
1827 if (statesnew & RCUTORTURE_RDR_BH)
1828 local_bh_disable();
1829 if (statesnew & RCUTORTURE_RDR_RBH)
1830 rcu_read_lock_bh();
1831 if (statesnew & RCUTORTURE_RDR_IRQ)
1832 local_irq_disable();
1833 if (statesnew & RCUTORTURE_RDR_PREEMPT)
1834 preempt_disable();
1835 if (statesnew & RCUTORTURE_RDR_SCHED)
1836 rcu_read_lock_sched();
1837 if (statesnew & RCUTORTURE_RDR_RCU_1)
1838 idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1;
1839 if (statesnew & RCUTORTURE_RDR_RCU_2)
1840 idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2;
1841
1842 /*
1843 * Next, remove old protection, in decreasing order of strength
1844 * to avoid unlock paths that aren't safe in the stronger
1845 * context. Namely: BH can not be enabled with disabled interrupts.
1846 * Additionally PREEMPT_RT requires that BH is enabled in preemptible
1847 * context.
1848 */
1849 if (statesold & RCUTORTURE_RDR_IRQ)
1850 local_irq_enable();
1851 if (statesold & RCUTORTURE_RDR_PREEMPT)
1852 preempt_enable();
1853 if (statesold & RCUTORTURE_RDR_SCHED)
1854 rcu_read_unlock_sched();
1855 if (statesold & RCUTORTURE_RDR_BH)
1856 local_bh_enable();
1857 if (statesold & RCUTORTURE_RDR_RBH)
1858 rcu_read_unlock_bh();
1859 if (statesold & RCUTORTURE_RDR_RCU_2) {
1860 cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1);
1861 WARN_ON_ONCE(idxnew2 != -1);
1862 idxold2 = 0;
1863 }
1864 if (statesold & RCUTORTURE_RDR_RCU_1) {
1865 bool lockit;
1866
1867 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff);
1868 if (lockit)
1869 raw_spin_lock_irqsave(&current->pi_lock, flags);
1870 cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1);
1871 WARN_ON_ONCE(idxnew1 != -1);
1872 idxold1 = 0;
1873 if (lockit)
1874 raw_spin_unlock_irqrestore(&current->pi_lock, flags);
1875 }
1876
1877 /* Delay if neither beginning nor end and there was a change. */
1878 if ((statesnew || statesold) && *readstate && newstate)
1879 cur_ops->read_delay(trsp, rtrsp);
1880
1881 /* Update the reader state. */
1882 if (idxnew1 == -1)
1883 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1;
1884 WARN_ON_ONCE(idxnew1 < 0);
1885 if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1))
1886 pr_info("Unexpected idxnew1 value of %#x\n", idxnew1);
1887 if (idxnew2 == -1)
1888 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2;
1889 WARN_ON_ONCE(idxnew2 < 0);
1890 WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
1891 *readstate = idxnew1 | idxnew2 | newstate;
1892 WARN_ON_ONCE(*readstate < 0);
1893 if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1))
1894 pr_info("Unexpected idxnew2 value of %#x\n", idxnew2);
1895 }
1896
1897 /* Return the biggest extendables mask given current RCU and boot parameters. */
1898 static int rcutorture_extend_mask_max(void)
1899 {
1900 int mask;
1901
1902 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1903 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1904 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2;
1905 return mask;
1906 }
1907
1908 /* Return a random protection state mask, but with at least one bit set. */
1909 static int
1910 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1911 {
1912 int mask = rcutorture_extend_mask_max();
1913 unsigned long randmask1 = torture_random(trsp);
1914 unsigned long randmask2 = randmask1 >> 3;
1915 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
1916 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
1917 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1918
1919 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1);
1920 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
1921 if (!(randmask1 & 0x7))
1922 mask = mask & randmask2;
1923 else
1924 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1925
1926 // Can't have nested RCU reader without outer RCU reader.
1927 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) {
1928 if (oldmask & RCUTORTURE_RDR_RCU_1)
1929 mask &= ~RCUTORTURE_RDR_RCU_2;
1930 else
1931 mask |= RCUTORTURE_RDR_RCU_1;
1932 }
1933
1934 /*
1935 * Can't enable bh w/irq disabled.
1936 */
1937 if (mask & RCUTORTURE_RDR_IRQ)
1938 mask |= oldmask & bhs;
1939
1940 /*
1941 * Ideally these sequences would be detected in debug builds
1942 * (regardless of RT), but until then don't stop testing
1943 * them on non-RT.
1944 */
1945 if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
1946 /* Can't modify BH in atomic context */
1947 if (oldmask & preempts_irq)
1948 mask &= ~bhs;
1949 if ((oldmask | mask) & preempts_irq)
1950 mask |= oldmask & bhs;
1951 }
1952
1953 return mask ?: RCUTORTURE_RDR_RCU_1;
1954 }
1955
1956 /*
1957 * Do a randomly selected number of extensions of an existing RCU read-side
1958 * critical section.
1959 */
1960 static struct rt_read_seg *
1961 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1962 struct rt_read_seg *rtrsp)
1963 {
1964 int i;
1965 int j;
1966 int mask = rcutorture_extend_mask_max();
1967
1968 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
1969 if (!((mask - 1) & mask))
1970 return rtrsp; /* Current RCU reader not extendable. */
1971 /* Bias towards larger numbers of loops. */
1972 i = torture_random(trsp);
1973 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
1974 for (j = 0; j < i; j++) {
1975 mask = rcutorture_extend_mask(*readstate, trsp);
1976 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
1977 }
1978 return &rtrsp[j];
1979 }
1980
1981 /*
1982 * Do one read-side critical section, returning false if there was
1983 * no data to read. Can be invoked both from process context and
1984 * from a timer handler.
1985 */
1986 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
1987 {
1988 bool checkpolling = !(torture_random(trsp) & 0xfff);
1989 unsigned long cookie;
1990 struct rcu_gp_oldstate cookie_full;
1991 int i;
1992 unsigned long started;
1993 unsigned long completed;
1994 int newstate;
1995 struct rcu_torture *p;
1996 int pipe_count;
1997 int readstate = 0;
1998 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
1999 struct rt_read_seg *rtrsp = &rtseg[0];
2000 struct rt_read_seg *rtrsp1;
2001 unsigned long long ts;
2002
2003 WARN_ON_ONCE(!rcu_is_watching());
2004 newstate = rcutorture_extend_mask(readstate, trsp);
2005 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
2006 if (checkpolling) {
2007 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
2008 cookie = cur_ops->get_gp_state();
2009 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
2010 cur_ops->get_gp_state_full(&cookie_full);
2011 }
2012 started = cur_ops->get_gp_seq();
2013 ts = rcu_trace_clock_local();
2014 p = rcu_dereference_check(rcu_torture_current,
2015 !cur_ops->readlock_held || cur_ops->readlock_held());
2016 if (p == NULL) {
2017 /* Wait for rcu_torture_writer to get underway */
2018 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
2019 return false;
2020 }
2021 if (p->rtort_mbtest == 0)
2022 atomic_inc(&n_rcu_torture_mberror);
2023 rcu_torture_reader_do_mbchk(myid, p, trsp);
2024 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
2025 preempt_disable();
2026 pipe_count = READ_ONCE(p->rtort_pipe_count);
2027 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
2028 // Should not happen in a correct RCU implementation,
2029 // happens quite often for torture_type=busted.
2030 pipe_count = RCU_TORTURE_PIPE_LEN;
2031 }
2032 completed = cur_ops->get_gp_seq();
2033 if (pipe_count > 1) {
2034 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
2035 ts, started, completed);
2036 rcu_ftrace_dump(DUMP_ALL);
2037 }
2038 __this_cpu_inc(rcu_torture_count[pipe_count]);
2039 completed = rcutorture_seq_diff(completed, started);
2040 if (completed > RCU_TORTURE_PIPE_LEN) {
2041 /* Should not happen, but... */
2042 completed = RCU_TORTURE_PIPE_LEN;
2043 }
2044 __this_cpu_inc(rcu_torture_batch[completed]);
2045 preempt_enable();
2046 if (checkpolling) {
2047 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
2048 WARN_ONCE(cur_ops->poll_gp_state(cookie),
2049 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
2050 __func__,
2051 rcu_torture_writer_state_getname(),
2052 rcu_torture_writer_state,
2053 cookie, cur_ops->get_gp_state());
2054 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
2055 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
2056 "%s: Cookie check 6 failed %s(%d) online %*pbl\n",
2057 __func__,
2058 rcu_torture_writer_state_getname(),
2059 rcu_torture_writer_state,
2060 cpumask_pr_args(cpu_online_mask));
2061 }
2062 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
2063 WARN_ON_ONCE(readstate);
2064 // This next splat is expected behavior if leakpointer, especially
2065 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
2066 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1);
2067
2068 /* If error or close call, record the sequence of reader protections. */
2069 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
2070 i = 0;
2071 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
2072 err_segs[i++] = *rtrsp1;
2073 rt_read_nsegs = i;
2074 }
2075
2076 return true;
2077 }
2078
2079 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
2080
2081 /*
2082 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
2083 * incrementing the corresponding element of the pipeline array. The
2084 * counter in the element should never be greater than 1, otherwise, the
2085 * RCU implementation is broken.
2086 */
2087 static void rcu_torture_timer(struct timer_list *unused)
2088 {
2089 atomic_long_inc(&n_rcu_torture_timers);
2090 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1);
2091
2092 /* Test call_rcu() invocation from interrupt handler. */
2093 if (cur_ops->call) {
2094 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
2095
2096 if (rhp)
2097 cur_ops->call(rhp, rcu_torture_timer_cb);
2098 }
2099 }
2100
2101 /*
2102 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
2103 * incrementing the corresponding element of the pipeline array. The
2104 * counter in the element should never be greater than 1, otherwise, the
2105 * RCU implementation is broken.
2106 */
2107 static int
2108 rcu_torture_reader(void *arg)
2109 {
2110 unsigned long lastsleep = jiffies;
2111 long myid = (long)arg;
2112 int mynumonline = myid;
2113 DEFINE_TORTURE_RANDOM(rand);
2114 struct timer_list t;
2115
2116 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
2117 set_user_nice(current, MAX_NICE);
2118 if (irqreader && cur_ops->irq_capable)
2119 timer_setup_on_stack(&t, rcu_torture_timer, 0);
2120 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2121 do {
2122 if (irqreader && cur_ops->irq_capable) {
2123 if (!timer_pending(&t))
2124 mod_timer(&t, jiffies + 1);
2125 }
2126 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop())
2127 schedule_timeout_interruptible(HZ);
2128 if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
2129 torture_hrtimeout_us(500, 1000, &rand);
2130 lastsleep = jiffies + 10;
2131 }
2132 while (torture_num_online_cpus() < mynumonline && !torture_must_stop())
2133 schedule_timeout_interruptible(HZ / 5);
2134 stutter_wait("rcu_torture_reader");
2135 } while (!torture_must_stop());
2136 if (irqreader && cur_ops->irq_capable) {
2137 del_timer_sync(&t);
2138 destroy_timer_on_stack(&t);
2139 }
2140 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2141 torture_kthread_stopping("rcu_torture_reader");
2142 return 0;
2143 }
2144
2145 /*
2146 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to
2147 * increase race probabilities and fuzzes the interval between toggling.
2148 */
2149 static int rcu_nocb_toggle(void *arg)
2150 {
2151 int cpu;
2152 int maxcpu = -1;
2153 int oldnice = task_nice(current);
2154 long r;
2155 DEFINE_TORTURE_RANDOM(rand);
2156 ktime_t toggle_delay;
2157 unsigned long toggle_fuzz;
2158 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle);
2159
2160 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started");
2161 while (!rcu_inkernel_boot_has_ended())
2162 schedule_timeout_interruptible(HZ / 10);
2163 for_each_possible_cpu(cpu)
2164 maxcpu = cpu;
2165 WARN_ON(maxcpu < 0);
2166 if (toggle_interval > ULONG_MAX)
2167 toggle_fuzz = ULONG_MAX >> 3;
2168 else
2169 toggle_fuzz = toggle_interval >> 3;
2170 if (toggle_fuzz <= 0)
2171 toggle_fuzz = NSEC_PER_USEC;
2172 do {
2173 r = torture_random(&rand);
2174 cpu = (r >> 1) % (maxcpu + 1);
2175 if (r & 0x1) {
2176 rcu_nocb_cpu_offload(cpu);
2177 atomic_long_inc(&n_nocb_offload);
2178 } else {
2179 rcu_nocb_cpu_deoffload(cpu);
2180 atomic_long_inc(&n_nocb_deoffload);
2181 }
2182 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval;
2183 set_current_state(TASK_INTERRUPTIBLE);
2184 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL);
2185 if (stutter_wait("rcu_nocb_toggle"))
2186 sched_set_normal(current, oldnice);
2187 } while (!torture_must_stop());
2188 torture_kthread_stopping("rcu_nocb_toggle");
2189 return 0;
2190 }
2191
2192 /*
2193 * Print torture statistics. Caller must ensure that there is only
2194 * one call to this function at a given time!!! This is normally
2195 * accomplished by relying on the module system to only have one copy
2196 * of the module loaded, and then by giving the rcu_torture_stats
2197 * kthread full control (or the init/cleanup functions when rcu_torture_stats
2198 * thread is not running).
2199 */
2200 static void
2201 rcu_torture_stats_print(void)
2202 {
2203 int cpu;
2204 int i;
2205 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2206 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2207 struct rcu_torture *rtcp;
2208 static unsigned long rtcv_snap = ULONG_MAX;
2209 static bool splatted;
2210 struct task_struct *wtp;
2211
2212 for_each_possible_cpu(cpu) {
2213 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2214 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
2215 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
2216 }
2217 }
2218 for (i = RCU_TORTURE_PIPE_LEN; i >= 0; i--) {
2219 if (pipesummary[i] != 0)
2220 break;
2221 }
2222
2223 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2224 rtcp = rcu_access_pointer(rcu_torture_current);
2225 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
2226 rtcp,
2227 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
2228 rcu_torture_current_version,
2229 list_empty(&rcu_torture_freelist),
2230 atomic_read(&n_rcu_torture_alloc),
2231 atomic_read(&n_rcu_torture_alloc_fail),
2232 atomic_read(&n_rcu_torture_free));
2233 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld ",
2234 atomic_read(&n_rcu_torture_mberror),
2235 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries),
2236 n_rcu_torture_barrier_error,
2237 n_rcu_torture_boost_ktrerror);
2238 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
2239 n_rcu_torture_boost_failure,
2240 n_rcu_torture_boosts,
2241 atomic_long_read(&n_rcu_torture_timers));
2242 torture_onoff_stats();
2243 pr_cont("barrier: %ld/%ld:%ld ",
2244 data_race(n_barrier_successes),
2245 data_race(n_barrier_attempts),
2246 data_race(n_rcu_torture_barrier_error));
2247 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic.
2248 pr_cont("nocb-toggles: %ld:%ld\n",
2249 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload));
2250
2251 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2252 if (atomic_read(&n_rcu_torture_mberror) ||
2253 atomic_read(&n_rcu_torture_mbchk_fail) ||
2254 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
2255 n_rcu_torture_boost_failure || i > 1) {
2256 pr_cont("%s", "!!! ");
2257 atomic_inc(&n_rcu_torture_error);
2258 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
2259 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail));
2260 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
2261 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
2262 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
2263 WARN_ON_ONCE(i > 1); // Too-short grace period
2264 }
2265 pr_cont("Reader Pipe: ");
2266 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2267 pr_cont(" %ld", pipesummary[i]);
2268 pr_cont("\n");
2269
2270 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2271 pr_cont("Reader Batch: ");
2272 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2273 pr_cont(" %ld", batchsummary[i]);
2274 pr_cont("\n");
2275
2276 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2277 pr_cont("Free-Block Circulation: ");
2278 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2279 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
2280 }
2281 pr_cont("\n");
2282
2283 if (cur_ops->stats)
2284 cur_ops->stats();
2285 if (rtcv_snap == rcu_torture_current_version &&
2286 rcu_access_pointer(rcu_torture_current) &&
2287 !rcu_stall_is_suppressed()) {
2288 int __maybe_unused flags = 0;
2289 unsigned long __maybe_unused gp_seq = 0;
2290
2291 if (cur_ops->get_gp_data)
2292 cur_ops->get_gp_data(&flags, &gp_seq);
2293 wtp = READ_ONCE(writer_task);
2294 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n",
2295 rcu_torture_writer_state_getname(),
2296 rcu_torture_writer_state, gp_seq, flags,
2297 wtp == NULL ? ~0U : wtp->__state,
2298 wtp == NULL ? -1 : (int)task_cpu(wtp));
2299 if (!splatted && wtp) {
2300 sched_show_task(wtp);
2301 splatted = true;
2302 }
2303 if (cur_ops->gp_kthread_dbg)
2304 cur_ops->gp_kthread_dbg();
2305 rcu_ftrace_dump(DUMP_ALL);
2306 }
2307 rtcv_snap = rcu_torture_current_version;
2308 }
2309
2310 /*
2311 * Periodically prints torture statistics, if periodic statistics printing
2312 * was specified via the stat_interval module parameter.
2313 */
2314 static int
2315 rcu_torture_stats(void *arg)
2316 {
2317 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
2318 do {
2319 schedule_timeout_interruptible(stat_interval * HZ);
2320 rcu_torture_stats_print();
2321 torture_shutdown_absorb("rcu_torture_stats");
2322 } while (!torture_must_stop());
2323 torture_kthread_stopping("rcu_torture_stats");
2324 return 0;
2325 }
2326
2327 /* Test mem_dump_obj() and friends. */
2328 static void rcu_torture_mem_dump_obj(void)
2329 {
2330 struct rcu_head *rhp;
2331 struct kmem_cache *kcp;
2332 static int z;
2333
2334 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
2335 if (WARN_ON_ONCE(!kcp))
2336 return;
2337 rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
2338 if (WARN_ON_ONCE(!rhp)) {
2339 kmem_cache_destroy(kcp);
2340 return;
2341 }
2342 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
2343 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
2344 mem_dump_obj(ZERO_SIZE_PTR);
2345 pr_alert("mem_dump_obj(NULL):");
2346 mem_dump_obj(NULL);
2347 pr_alert("mem_dump_obj(%px):", &rhp);
2348 mem_dump_obj(&rhp);
2349 pr_alert("mem_dump_obj(%px):", rhp);
2350 mem_dump_obj(rhp);
2351 pr_alert("mem_dump_obj(%px):", &rhp->func);
2352 mem_dump_obj(&rhp->func);
2353 pr_alert("mem_dump_obj(%px):", &z);
2354 mem_dump_obj(&z);
2355 kmem_cache_free(kcp, rhp);
2356 kmem_cache_destroy(kcp);
2357 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
2358 if (WARN_ON_ONCE(!rhp))
2359 return;
2360 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2361 pr_alert("mem_dump_obj(kmalloc %px):", rhp);
2362 mem_dump_obj(rhp);
2363 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
2364 mem_dump_obj(&rhp->func);
2365 kfree(rhp);
2366 rhp = vmalloc(4096);
2367 if (WARN_ON_ONCE(!rhp))
2368 return;
2369 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2370 pr_alert("mem_dump_obj(vmalloc %px):", rhp);
2371 mem_dump_obj(rhp);
2372 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
2373 mem_dump_obj(&rhp->func);
2374 vfree(rhp);
2375 }
2376
2377 static void
2378 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
2379 {
2380 pr_alert("%s" TORTURE_FLAG
2381 "--- %s: nreaders=%d nfakewriters=%d "
2382 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
2383 "shuffle_interval=%d stutter=%d irqreader=%d "
2384 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
2385 "test_boost=%d/%d test_boost_interval=%d "
2386 "test_boost_duration=%d shutdown_secs=%d "
2387 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
2388 "stall_cpu_block=%d stall_cpu_repeat=%d "
2389 "n_barrier_cbs=%d "
2390 "onoff_interval=%d onoff_holdoff=%d "
2391 "read_exit_delay=%d read_exit_burst=%d "
2392 "nocbs_nthreads=%d nocbs_toggle=%d "
2393 "test_nmis=%d\n",
2394 torture_type, tag, nrealreaders, nfakewriters,
2395 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
2396 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
2397 test_boost, cur_ops->can_boost,
2398 test_boost_interval, test_boost_duration, shutdown_secs,
2399 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
2400 stall_cpu_block, stall_cpu_repeat,
2401 n_barrier_cbs,
2402 onoff_interval, onoff_holdoff,
2403 read_exit_delay, read_exit_burst,
2404 nocbs_nthreads, nocbs_toggle,
2405 test_nmis);
2406 }
2407
2408 static int rcutorture_booster_cleanup(unsigned int cpu)
2409 {
2410 struct task_struct *t;
2411
2412 if (boost_tasks[cpu] == NULL)
2413 return 0;
2414 mutex_lock(&boost_mutex);
2415 t = boost_tasks[cpu];
2416 boost_tasks[cpu] = NULL;
2417 rcu_torture_enable_rt_throttle();
2418 mutex_unlock(&boost_mutex);
2419
2420 /* This must be outside of the mutex, otherwise deadlock! */
2421 torture_stop_kthread(rcu_torture_boost, t);
2422 return 0;
2423 }
2424
2425 static int rcutorture_booster_init(unsigned int cpu)
2426 {
2427 int retval;
2428
2429 if (boost_tasks[cpu] != NULL)
2430 return 0; /* Already created, nothing more to do. */
2431
2432 // Testing RCU priority boosting requires rcutorture do
2433 // some serious abuse. Counter this by running ksoftirqd
2434 // at higher priority.
2435 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) {
2436 struct sched_param sp;
2437 struct task_struct *t;
2438
2439 t = per_cpu(ksoftirqd, cpu);
2440 WARN_ON_ONCE(!t);
2441 sp.sched_priority = 2;
2442 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
2443 }
2444
2445 /* Don't allow time recalculation while creating a new task. */
2446 mutex_lock(&boost_mutex);
2447 rcu_torture_disable_rt_throttle();
2448 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
2449 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL,
2450 cpu, "rcu_torture_boost_%u");
2451 if (IS_ERR(boost_tasks[cpu])) {
2452 retval = PTR_ERR(boost_tasks[cpu]);
2453 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
2454 n_rcu_torture_boost_ktrerror++;
2455 boost_tasks[cpu] = NULL;
2456 mutex_unlock(&boost_mutex);
2457 return retval;
2458 }
2459 mutex_unlock(&boost_mutex);
2460 return 0;
2461 }
2462
2463 static int rcu_torture_stall_nf(struct notifier_block *nb, unsigned long v, void *ptr)
2464 {
2465 pr_info("%s: v=%lu, duration=%lu.\n", __func__, v, (unsigned long)ptr);
2466 return NOTIFY_OK;
2467 }
2468
2469 static struct notifier_block rcu_torture_stall_block = {
2470 .notifier_call = rcu_torture_stall_nf,
2471 };
2472
2473 /*
2474 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
2475 * induces a CPU stall for the time specified by stall_cpu. If a new
2476 * stall test is added, stallsdone in rcu_torture_writer() must be adjusted.
2477 */
2478 static void rcu_torture_stall_one(int rep, int irqsoff)
2479 {
2480 int idx;
2481 unsigned long stop_at;
2482
2483 if (stall_cpu_holdoff > 0) {
2484 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
2485 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
2486 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
2487 }
2488 if (!kthread_should_stop() && stall_gp_kthread > 0) {
2489 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
2490 rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
2491 for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
2492 if (kthread_should_stop())
2493 break;
2494 schedule_timeout_uninterruptible(HZ);
2495 }
2496 }
2497 if (!kthread_should_stop() && stall_cpu > 0) {
2498 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
2499 stop_at = ktime_get_seconds() + stall_cpu;
2500 /* RCU CPU stall is expected behavior in following code. */
2501 idx = cur_ops->readlock();
2502 if (irqsoff)
2503 local_irq_disable();
2504 else if (!stall_cpu_block)
2505 preempt_disable();
2506 pr_alert("%s start stall episode %d on CPU %d.\n",
2507 __func__, rep + 1, raw_smp_processor_id());
2508 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), stop_at) &&
2509 !kthread_should_stop())
2510 if (stall_cpu_block) {
2511 #ifdef CONFIG_PREEMPTION
2512 preempt_schedule();
2513 #else
2514 schedule_timeout_uninterruptible(HZ);
2515 #endif
2516 } else if (stall_no_softlockup) {
2517 touch_softlockup_watchdog();
2518 }
2519 if (irqsoff)
2520 local_irq_enable();
2521 else if (!stall_cpu_block)
2522 preempt_enable();
2523 cur_ops->readunlock(idx);
2524 }
2525 }
2526
2527 /*
2528 * CPU-stall kthread. Invokes rcu_torture_stall_one() once, and then as many
2529 * additional times as specified by the stall_cpu_repeat module parameter.
2530 * Note that stall_cpu_irqsoff is ignored on the second and subsequent
2531 * stall.
2532 */
2533 static int rcu_torture_stall(void *args)
2534 {
2535 int i;
2536 int repeat = stall_cpu_repeat;
2537 int ret;
2538
2539 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
2540 if (repeat < 0) {
2541 repeat = 0;
2542 WARN_ON_ONCE(IS_BUILTIN(CONFIG_RCU_TORTURE_TEST));
2543 }
2544 if (rcu_cpu_stall_notifiers) {
2545 ret = rcu_stall_chain_notifier_register(&rcu_torture_stall_block);
2546 if (ret)
2547 pr_info("%s: rcu_stall_chain_notifier_register() returned %d, %sexpected.\n",
2548 __func__, ret, !IS_ENABLED(CONFIG_RCU_STALL_COMMON) ? "un" : "");
2549 }
2550 for (i = 0; i <= repeat; i++) {
2551 if (kthread_should_stop())
2552 break;
2553 rcu_torture_stall_one(i, i == 0 ? stall_cpu_irqsoff : 0);
2554 }
2555 pr_alert("%s end.\n", __func__);
2556 if (rcu_cpu_stall_notifiers && !ret) {
2557 ret = rcu_stall_chain_notifier_unregister(&rcu_torture_stall_block);
2558 if (ret)
2559 pr_info("%s: rcu_stall_chain_notifier_unregister() returned %d.\n", __func__, ret);
2560 }
2561 torture_shutdown_absorb("rcu_torture_stall");
2562 while (!kthread_should_stop())
2563 schedule_timeout_interruptible(10 * HZ);
2564 return 0;
2565 }
2566
2567 /* Spawn CPU-stall kthread, if stall_cpu specified. */
2568 static int __init rcu_torture_stall_init(void)
2569 {
2570 if (stall_cpu <= 0 && stall_gp_kthread <= 0)
2571 return 0;
2572 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
2573 }
2574
2575 /* State structure for forward-progress self-propagating RCU callback. */
2576 struct fwd_cb_state {
2577 struct rcu_head rh;
2578 int stop;
2579 };
2580
2581 /*
2582 * Forward-progress self-propagating RCU callback function. Because
2583 * callbacks run from softirq, this function is an implicit RCU read-side
2584 * critical section.
2585 */
2586 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
2587 {
2588 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
2589
2590 if (READ_ONCE(fcsp->stop)) {
2591 WRITE_ONCE(fcsp->stop, 2);
2592 return;
2593 }
2594 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
2595 }
2596
2597 /* State for continuous-flood RCU callbacks. */
2598 struct rcu_fwd_cb {
2599 struct rcu_head rh;
2600 struct rcu_fwd_cb *rfc_next;
2601 struct rcu_fwd *rfc_rfp;
2602 int rfc_gps;
2603 };
2604
2605 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
2606 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
2607 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
2608 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
2609 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
2610
2611 struct rcu_launder_hist {
2612 long n_launders;
2613 unsigned long launder_gp_seq;
2614 };
2615
2616 struct rcu_fwd {
2617 spinlock_t rcu_fwd_lock;
2618 struct rcu_fwd_cb *rcu_fwd_cb_head;
2619 struct rcu_fwd_cb **rcu_fwd_cb_tail;
2620 long n_launders_cb;
2621 unsigned long rcu_fwd_startat;
2622 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
2623 unsigned long rcu_launder_gp_seq_start;
2624 int rcu_fwd_id;
2625 };
2626
2627 static DEFINE_MUTEX(rcu_fwd_mutex);
2628 static struct rcu_fwd *rcu_fwds;
2629 static unsigned long rcu_fwd_seq;
2630 static atomic_long_t rcu_fwd_max_cbs;
2631 static bool rcu_fwd_emergency_stop;
2632
2633 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
2634 {
2635 unsigned long gps;
2636 unsigned long gps_old;
2637 int i;
2638 int j;
2639
2640 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
2641 if (rfp->n_launders_hist[i].n_launders > 0)
2642 break;
2643 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):",
2644 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat);
2645 gps_old = rfp->rcu_launder_gp_seq_start;
2646 for (j = 0; j <= i; j++) {
2647 gps = rfp->n_launders_hist[j].launder_gp_seq;
2648 pr_cont(" %ds/%d: %ld:%ld",
2649 j + 1, FWD_CBS_HIST_DIV,
2650 rfp->n_launders_hist[j].n_launders,
2651 rcutorture_seq_diff(gps, gps_old));
2652 gps_old = gps;
2653 }
2654 pr_cont("\n");
2655 }
2656
2657 /* Callback function for continuous-flood RCU callbacks. */
2658 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
2659 {
2660 unsigned long flags;
2661 int i;
2662 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
2663 struct rcu_fwd_cb **rfcpp;
2664 struct rcu_fwd *rfp = rfcp->rfc_rfp;
2665
2666 rfcp->rfc_next = NULL;
2667 rfcp->rfc_gps++;
2668 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2669 rfcpp = rfp->rcu_fwd_cb_tail;
2670 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
2671 smp_store_release(rfcpp, rfcp);
2672 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
2673 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
2674 if (i >= ARRAY_SIZE(rfp->n_launders_hist))
2675 i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
2676 rfp->n_launders_hist[i].n_launders++;
2677 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
2678 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2679 }
2680
2681 // Give the scheduler a chance, even on nohz_full CPUs.
2682 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
2683 {
2684 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
2685 // Real call_rcu() floods hit userspace, so emulate that.
2686 if (need_resched() || (iter & 0xfff))
2687 schedule();
2688 return;
2689 }
2690 // No userspace emulation: CB invocation throttles call_rcu()
2691 cond_resched();
2692 }
2693
2694 /*
2695 * Free all callbacks on the rcu_fwd_cb_head list, either because the
2696 * test is over or because we hit an OOM event.
2697 */
2698 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
2699 {
2700 unsigned long flags;
2701 unsigned long freed = 0;
2702 struct rcu_fwd_cb *rfcp;
2703
2704 for (;;) {
2705 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2706 rfcp = rfp->rcu_fwd_cb_head;
2707 if (!rfcp) {
2708 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2709 break;
2710 }
2711 rfp->rcu_fwd_cb_head = rfcp->rfc_next;
2712 if (!rfp->rcu_fwd_cb_head)
2713 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2714 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2715 kfree(rfcp);
2716 freed++;
2717 rcu_torture_fwd_prog_cond_resched(freed);
2718 if (tick_nohz_full_enabled()) {
2719 local_irq_save(flags);
2720 rcu_momentary_eqs();
2721 local_irq_restore(flags);
2722 }
2723 }
2724 return freed;
2725 }
2726
2727 /* Carry out need_resched()/cond_resched() forward-progress testing. */
2728 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
2729 int *tested, int *tested_tries)
2730 {
2731 unsigned long cver;
2732 unsigned long dur;
2733 struct fwd_cb_state fcs;
2734 unsigned long gps;
2735 int idx;
2736 int sd;
2737 int sd4;
2738 bool selfpropcb = false;
2739 unsigned long stopat;
2740 static DEFINE_TORTURE_RANDOM(trs);
2741
2742 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2743 if (!cur_ops->sync)
2744 return; // Cannot do need_resched() forward progress testing without ->sync.
2745 if (cur_ops->call && cur_ops->cb_barrier) {
2746 init_rcu_head_on_stack(&fcs.rh);
2747 selfpropcb = true;
2748 }
2749
2750 /* Tight loop containing cond_resched(). */
2751 atomic_inc(&rcu_fwd_cb_nodelay);
2752 cur_ops->sync(); /* Later readers see above write. */
2753 if (selfpropcb) {
2754 WRITE_ONCE(fcs.stop, 0);
2755 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
2756 }
2757 cver = READ_ONCE(rcu_torture_current_version);
2758 gps = cur_ops->get_gp_seq();
2759 sd = cur_ops->stall_dur() + 1;
2760 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
2761 dur = sd4 + torture_random(&trs) % (sd - sd4);
2762 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2763 stopat = rfp->rcu_fwd_startat + dur;
2764 while (time_before(jiffies, stopat) &&
2765 !shutdown_time_arrived() &&
2766 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2767 idx = cur_ops->readlock();
2768 udelay(10);
2769 cur_ops->readunlock(idx);
2770 if (!fwd_progress_need_resched || need_resched())
2771 cond_resched();
2772 }
2773 (*tested_tries)++;
2774 if (!time_before(jiffies, stopat) &&
2775 !shutdown_time_arrived() &&
2776 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2777 (*tested)++;
2778 cver = READ_ONCE(rcu_torture_current_version) - cver;
2779 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2780 WARN_ON(!cver && gps < 2);
2781 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__,
2782 rfp->rcu_fwd_id, dur, cver, gps);
2783 }
2784 if (selfpropcb) {
2785 WRITE_ONCE(fcs.stop, 1);
2786 cur_ops->sync(); /* Wait for running CB to complete. */
2787 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2788 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
2789 }
2790
2791 if (selfpropcb) {
2792 WARN_ON(READ_ONCE(fcs.stop) != 2);
2793 destroy_rcu_head_on_stack(&fcs.rh);
2794 }
2795 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
2796 atomic_dec(&rcu_fwd_cb_nodelay);
2797 }
2798
2799 /* Carry out call_rcu() forward-progress testing. */
2800 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
2801 {
2802 unsigned long cver;
2803 unsigned long flags;
2804 unsigned long gps;
2805 int i;
2806 long n_launders;
2807 long n_launders_cb_snap;
2808 long n_launders_sa;
2809 long n_max_cbs;
2810 long n_max_gps;
2811 struct rcu_fwd_cb *rfcp;
2812 struct rcu_fwd_cb *rfcpn;
2813 unsigned long stopat;
2814 unsigned long stoppedat;
2815
2816 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2817 if (READ_ONCE(rcu_fwd_emergency_stop))
2818 return; /* Get out of the way quickly, no GP wait! */
2819 if (!cur_ops->call)
2820 return; /* Can't do call_rcu() fwd prog without ->call. */
2821
2822 /* Loop continuously posting RCU callbacks. */
2823 atomic_inc(&rcu_fwd_cb_nodelay);
2824 cur_ops->sync(); /* Later readers see above write. */
2825 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2826 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
2827 n_launders = 0;
2828 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
2829 n_launders_sa = 0;
2830 n_max_cbs = 0;
2831 n_max_gps = 0;
2832 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
2833 rfp->n_launders_hist[i].n_launders = 0;
2834 cver = READ_ONCE(rcu_torture_current_version);
2835 gps = cur_ops->get_gp_seq();
2836 rfp->rcu_launder_gp_seq_start = gps;
2837 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2838 while (time_before(jiffies, stopat) &&
2839 !shutdown_time_arrived() &&
2840 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2841 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
2842 rfcpn = NULL;
2843 if (rfcp)
2844 rfcpn = READ_ONCE(rfcp->rfc_next);
2845 if (rfcpn) {
2846 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
2847 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
2848 break;
2849 rfp->rcu_fwd_cb_head = rfcpn;
2850 n_launders++;
2851 n_launders_sa++;
2852 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) {
2853 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
2854 if (WARN_ON_ONCE(!rfcp)) {
2855 schedule_timeout_interruptible(1);
2856 continue;
2857 }
2858 n_max_cbs++;
2859 n_launders_sa = 0;
2860 rfcp->rfc_gps = 0;
2861 rfcp->rfc_rfp = rfp;
2862 } else {
2863 rfcp = NULL;
2864 }
2865 if (rfcp)
2866 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
2867 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
2868 if (tick_nohz_full_enabled()) {
2869 local_irq_save(flags);
2870 rcu_momentary_eqs();
2871 local_irq_restore(flags);
2872 }
2873 }
2874 stoppedat = jiffies;
2875 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
2876 cver = READ_ONCE(rcu_torture_current_version) - cver;
2877 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2878 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2879 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
2880 (void)rcu_torture_fwd_prog_cbfree(rfp);
2881
2882 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
2883 !shutdown_time_arrived()) {
2884 if (WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED) && cur_ops->gp_kthread_dbg)
2885 cur_ops->gp_kthread_dbg();
2886 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 #online %u\n",
2887 __func__,
2888 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
2889 n_launders + n_max_cbs - n_launders_cb_snap,
2890 n_launders, n_launders_sa,
2891 n_max_gps, n_max_cbs, cver, gps, num_online_cpus());
2892 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs);
2893 mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
2894 rcu_torture_fwd_cb_hist(rfp);
2895 mutex_unlock(&rcu_fwd_mutex);
2896 }
2897 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
2898 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2899 atomic_dec(&rcu_fwd_cb_nodelay);
2900 }
2901
2902
2903 /*
2904 * OOM notifier, but this only prints diagnostic information for the
2905 * current forward-progress test.
2906 */
2907 static int rcutorture_oom_notify(struct notifier_block *self,
2908 unsigned long notused, void *nfreed)
2909 {
2910 int i;
2911 long ncbs;
2912 struct rcu_fwd *rfp;
2913
2914 mutex_lock(&rcu_fwd_mutex);
2915 rfp = rcu_fwds;
2916 if (!rfp) {
2917 mutex_unlock(&rcu_fwd_mutex);
2918 return NOTIFY_OK;
2919 }
2920 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
2921 __func__);
2922 for (i = 0; i < fwd_progress; i++) {
2923 rcu_torture_fwd_cb_hist(&rfp[i]);
2924 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2);
2925 }
2926 WRITE_ONCE(rcu_fwd_emergency_stop, true);
2927 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
2928 ncbs = 0;
2929 for (i = 0; i < fwd_progress; i++)
2930 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2931 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2932 cur_ops->cb_barrier();
2933 ncbs = 0;
2934 for (i = 0; i < fwd_progress; i++)
2935 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2936 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2937 cur_ops->cb_barrier();
2938 ncbs = 0;
2939 for (i = 0; i < fwd_progress; i++)
2940 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2941 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2942 smp_mb(); /* Frees before return to avoid redoing OOM. */
2943 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
2944 pr_info("%s returning after OOM processing.\n", __func__);
2945 mutex_unlock(&rcu_fwd_mutex);
2946 return NOTIFY_OK;
2947 }
2948
2949 static struct notifier_block rcutorture_oom_nb = {
2950 .notifier_call = rcutorture_oom_notify
2951 };
2952
2953 /* Carry out grace-period forward-progress testing. */
2954 static int rcu_torture_fwd_prog(void *args)
2955 {
2956 bool firsttime = true;
2957 long max_cbs;
2958 int oldnice = task_nice(current);
2959 unsigned long oldseq = READ_ONCE(rcu_fwd_seq);
2960 struct rcu_fwd *rfp = args;
2961 int tested = 0;
2962 int tested_tries = 0;
2963
2964 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
2965 rcu_bind_current_to_nocb();
2966 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
2967 set_user_nice(current, MAX_NICE);
2968 do {
2969 if (!rfp->rcu_fwd_id) {
2970 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
2971 WRITE_ONCE(rcu_fwd_emergency_stop, false);
2972 if (!firsttime) {
2973 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0);
2974 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs);
2975 }
2976 firsttime = false;
2977 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1);
2978 } else {
2979 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop())
2980 schedule_timeout_interruptible(HZ / 20);
2981 oldseq = READ_ONCE(rcu_fwd_seq);
2982 }
2983 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2984 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id)
2985 rcu_torture_fwd_prog_cr(rfp);
2986 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) &&
2987 (!IS_ENABLED(CONFIG_TINY_RCU) ||
2988 (rcu_inkernel_boot_has_ended() &&
2989 torture_num_online_cpus() > rfp->rcu_fwd_id)))
2990 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
2991
2992 /* Avoid slow periods, better to test when busy. */
2993 if (stutter_wait("rcu_torture_fwd_prog"))
2994 sched_set_normal(current, oldnice);
2995 } while (!torture_must_stop());
2996 /* Short runs might not contain a valid forward-progress attempt. */
2997 if (!rfp->rcu_fwd_id) {
2998 WARN_ON(!tested && tested_tries >= 5);
2999 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
3000 }
3001 torture_kthread_stopping("rcu_torture_fwd_prog");
3002 return 0;
3003 }
3004
3005 /* If forward-progress checking is requested and feasible, spawn the thread. */
3006 static int __init rcu_torture_fwd_prog_init(void)
3007 {
3008 int i;
3009 int ret = 0;
3010 struct rcu_fwd *rfp;
3011
3012 if (!fwd_progress)
3013 return 0; /* Not requested, so don't do it. */
3014 if (fwd_progress >= nr_cpu_ids) {
3015 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n");
3016 fwd_progress = nr_cpu_ids;
3017 } else if (fwd_progress < 0) {
3018 fwd_progress = nr_cpu_ids;
3019 }
3020 if ((!cur_ops->sync && !cur_ops->call) ||
3021 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) ||
3022 cur_ops == &rcu_busted_ops) {
3023 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
3024 fwd_progress = 0;
3025 return 0;
3026 }
3027 if (stall_cpu > 0) {
3028 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
3029 fwd_progress = 0;
3030 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST))
3031 return -EINVAL; /* In module, can fail back to user. */
3032 WARN_ON(1); /* Make sure rcutorture notices conflict. */
3033 return 0;
3034 }
3035 if (fwd_progress_holdoff <= 0)
3036 fwd_progress_holdoff = 1;
3037 if (fwd_progress_div <= 0)
3038 fwd_progress_div = 4;
3039 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL);
3040 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL);
3041 if (!rfp || !fwd_prog_tasks) {
3042 kfree(rfp);
3043 kfree(fwd_prog_tasks);
3044 fwd_prog_tasks = NULL;
3045 fwd_progress = 0;
3046 return -ENOMEM;
3047 }
3048 for (i = 0; i < fwd_progress; i++) {
3049 spin_lock_init(&rfp[i].rcu_fwd_lock);
3050 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head;
3051 rfp[i].rcu_fwd_id = i;
3052 }
3053 mutex_lock(&rcu_fwd_mutex);
3054 rcu_fwds = rfp;
3055 mutex_unlock(&rcu_fwd_mutex);
3056 register_oom_notifier(&rcutorture_oom_nb);
3057 for (i = 0; i < fwd_progress; i++) {
3058 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]);
3059 if (ret) {
3060 fwd_progress = i;
3061 return ret;
3062 }
3063 }
3064 return 0;
3065 }
3066
3067 static void rcu_torture_fwd_prog_cleanup(void)
3068 {
3069 int i;
3070 struct rcu_fwd *rfp;
3071
3072 if (!rcu_fwds || !fwd_prog_tasks)
3073 return;
3074 for (i = 0; i < fwd_progress; i++)
3075 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]);
3076 unregister_oom_notifier(&rcutorture_oom_nb);
3077 mutex_lock(&rcu_fwd_mutex);
3078 rfp = rcu_fwds;
3079 rcu_fwds = NULL;
3080 mutex_unlock(&rcu_fwd_mutex);
3081 kfree(rfp);
3082 kfree(fwd_prog_tasks);
3083 fwd_prog_tasks = NULL;
3084 }
3085
3086 /* Callback function for RCU barrier testing. */
3087 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
3088 {
3089 atomic_inc(&barrier_cbs_invoked);
3090 }
3091
3092 /* IPI handler to get callback posted on desired CPU, if online. */
3093 static int rcu_torture_barrier1cb(void *rcu_void)
3094 {
3095 struct rcu_head *rhp = rcu_void;
3096
3097 cur_ops->call(rhp, rcu_torture_barrier_cbf);
3098 return 0;
3099 }
3100
3101 /* kthread function to register callbacks used to test RCU barriers. */
3102 static int rcu_torture_barrier_cbs(void *arg)
3103 {
3104 long myid = (long)arg;
3105 bool lastphase = false;
3106 bool newphase;
3107 struct rcu_head rcu;
3108
3109 init_rcu_head_on_stack(&rcu);
3110 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
3111 set_user_nice(current, MAX_NICE);
3112 do {
3113 wait_event(barrier_cbs_wq[myid],
3114 (newphase =
3115 smp_load_acquire(&barrier_phase)) != lastphase ||
3116 torture_must_stop());
3117 lastphase = newphase;
3118 if (torture_must_stop())
3119 break;
3120 /*
3121 * The above smp_load_acquire() ensures barrier_phase load
3122 * is ordered before the following ->call().
3123 */
3124 if (smp_call_on_cpu(myid, rcu_torture_barrier1cb, &rcu, 1))
3125 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
3126
3127 if (atomic_dec_and_test(&barrier_cbs_count))
3128 wake_up(&barrier_wq);
3129 } while (!torture_must_stop());
3130 if (cur_ops->cb_barrier != NULL)
3131 cur_ops->cb_barrier();
3132 destroy_rcu_head_on_stack(&rcu);
3133 torture_kthread_stopping("rcu_torture_barrier_cbs");
3134 return 0;
3135 }
3136
3137 /* kthread function to drive and coordinate RCU barrier testing. */
3138 static int rcu_torture_barrier(void *arg)
3139 {
3140 int i;
3141
3142 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
3143 do {
3144 atomic_set(&barrier_cbs_invoked, 0);
3145 atomic_set(&barrier_cbs_count, n_barrier_cbs);
3146 /* Ensure barrier_phase ordered after prior assignments. */
3147 smp_store_release(&barrier_phase, !barrier_phase);
3148 for (i = 0; i < n_barrier_cbs; i++)
3149 wake_up(&barrier_cbs_wq[i]);
3150 wait_event(barrier_wq,
3151 atomic_read(&barrier_cbs_count) == 0 ||
3152 torture_must_stop());
3153 if (torture_must_stop())
3154 break;
3155 n_barrier_attempts++;
3156 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
3157 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
3158 n_rcu_torture_barrier_error++;
3159 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
3160 atomic_read(&barrier_cbs_invoked),
3161 n_barrier_cbs);
3162 WARN_ON(1);
3163 // Wait manually for the remaining callbacks
3164 i = 0;
3165 do {
3166 if (WARN_ON(i++ > HZ))
3167 i = INT_MIN;
3168 schedule_timeout_interruptible(1);
3169 cur_ops->cb_barrier();
3170 } while (atomic_read(&barrier_cbs_invoked) !=
3171 n_barrier_cbs &&
3172 !torture_must_stop());
3173 smp_mb(); // Can't trust ordering if broken.
3174 if (!torture_must_stop())
3175 pr_err("Recovered: barrier_cbs_invoked = %d\n",
3176 atomic_read(&barrier_cbs_invoked));
3177 } else {
3178 n_barrier_successes++;
3179 }
3180 schedule_timeout_interruptible(HZ / 10);
3181 } while (!torture_must_stop());
3182 torture_kthread_stopping("rcu_torture_barrier");
3183 return 0;
3184 }
3185
3186 /* Initialize RCU barrier testing. */
3187 static int rcu_torture_barrier_init(void)
3188 {
3189 int i;
3190 int ret;
3191
3192 if (n_barrier_cbs <= 0)
3193 return 0;
3194 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
3195 pr_alert("%s" TORTURE_FLAG
3196 " Call or barrier ops missing for %s,\n",
3197 torture_type, cur_ops->name);
3198 pr_alert("%s" TORTURE_FLAG
3199 " RCU barrier testing omitted from run.\n",
3200 torture_type);
3201 return 0;
3202 }
3203 atomic_set(&barrier_cbs_count, 0);
3204 atomic_set(&barrier_cbs_invoked, 0);
3205 barrier_cbs_tasks =
3206 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
3207 GFP_KERNEL);
3208 barrier_cbs_wq =
3209 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
3210 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
3211 return -ENOMEM;
3212 for (i = 0; i < n_barrier_cbs; i++) {
3213 init_waitqueue_head(&barrier_cbs_wq[i]);
3214 ret = torture_create_kthread(rcu_torture_barrier_cbs,
3215 (void *)(long)i,
3216 barrier_cbs_tasks[i]);
3217 if (ret)
3218 return ret;
3219 }
3220 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
3221 }
3222
3223 /* Clean up after RCU barrier testing. */
3224 static void rcu_torture_barrier_cleanup(void)
3225 {
3226 int i;
3227
3228 torture_stop_kthread(rcu_torture_barrier, barrier_task);
3229 if (barrier_cbs_tasks != NULL) {
3230 for (i = 0; i < n_barrier_cbs; i++)
3231 torture_stop_kthread(rcu_torture_barrier_cbs,
3232 barrier_cbs_tasks[i]);
3233 kfree(barrier_cbs_tasks);
3234 barrier_cbs_tasks = NULL;
3235 }
3236 if (barrier_cbs_wq != NULL) {
3237 kfree(barrier_cbs_wq);
3238 barrier_cbs_wq = NULL;
3239 }
3240 }
3241
3242 static bool rcu_torture_can_boost(void)
3243 {
3244 static int boost_warn_once;
3245 int prio;
3246
3247 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
3248 return false;
3249 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)
3250 return false;
3251
3252 prio = rcu_get_gp_kthreads_prio();
3253 if (!prio)
3254 return false;
3255
3256 if (prio < 2) {
3257 if (boost_warn_once == 1)
3258 return false;
3259
3260 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);
3261 boost_warn_once = 1;
3262 return false;
3263 }
3264
3265 return true;
3266 }
3267
3268 static bool read_exit_child_stop;
3269 static bool read_exit_child_stopped;
3270 static wait_queue_head_t read_exit_wq;
3271
3272 // Child kthread which just does an rcutorture reader and exits.
3273 static int rcu_torture_read_exit_child(void *trsp_in)
3274 {
3275 struct torture_random_state *trsp = trsp_in;
3276
3277 set_user_nice(current, MAX_NICE);
3278 // Minimize time between reading and exiting.
3279 while (!kthread_should_stop())
3280 schedule_timeout_uninterruptible(HZ / 20);
3281 (void)rcu_torture_one_read(trsp, -1);
3282 return 0;
3283 }
3284
3285 // Parent kthread which creates and destroys read-exit child kthreads.
3286 static int rcu_torture_read_exit(void *unused)
3287 {
3288 bool errexit = false;
3289 int i;
3290 struct task_struct *tsp;
3291 DEFINE_TORTURE_RANDOM(trs);
3292
3293 // Allocate and initialize.
3294 set_user_nice(current, MAX_NICE);
3295 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
3296
3297 // Each pass through this loop does one read-exit episode.
3298 do {
3299 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
3300 for (i = 0; i < read_exit_burst; i++) {
3301 if (READ_ONCE(read_exit_child_stop))
3302 break;
3303 stutter_wait("rcu_torture_read_exit");
3304 // Spawn child.
3305 tsp = kthread_run(rcu_torture_read_exit_child,
3306 &trs, "%s", "rcu_torture_read_exit_child");
3307 if (IS_ERR(tsp)) {
3308 TOROUT_ERRSTRING("out of memory");
3309 errexit = true;
3310 break;
3311 }
3312 cond_resched();
3313 kthread_stop(tsp);
3314 n_read_exits++;
3315 }
3316 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
3317 rcu_barrier(); // Wait for task_struct free, avoid OOM.
3318 i = 0;
3319 for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++)
3320 schedule_timeout_uninterruptible(HZ);
3321 } while (!errexit && !READ_ONCE(read_exit_child_stop));
3322
3323 // Clean up and exit.
3324 smp_store_release(&read_exit_child_stopped, true); // After reaping.
3325 smp_mb(); // Store before wakeup.
3326 wake_up(&read_exit_wq);
3327 while (!torture_must_stop())
3328 schedule_timeout_uninterruptible(HZ / 20);
3329 torture_kthread_stopping("rcu_torture_read_exit");
3330 return 0;
3331 }
3332
3333 static int rcu_torture_read_exit_init(void)
3334 {
3335 if (read_exit_burst <= 0)
3336 return 0;
3337 init_waitqueue_head(&read_exit_wq);
3338 read_exit_child_stop = false;
3339 read_exit_child_stopped = false;
3340 return torture_create_kthread(rcu_torture_read_exit, NULL,
3341 read_exit_task);
3342 }
3343
3344 static void rcu_torture_read_exit_cleanup(void)
3345 {
3346 if (!read_exit_task)
3347 return;
3348 WRITE_ONCE(read_exit_child_stop, true);
3349 smp_mb(); // Above write before wait.
3350 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
3351 torture_stop_kthread(rcutorture_read_exit, read_exit_task);
3352 }
3353
3354 static void rcutorture_test_nmis(int n)
3355 {
3356 #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3357 int cpu;
3358 int dumpcpu;
3359 int i;
3360
3361 for (i = 0; i < n; i++) {
3362 preempt_disable();
3363 cpu = smp_processor_id();
3364 dumpcpu = cpu + 1;
3365 if (dumpcpu >= nr_cpu_ids)
3366 dumpcpu = 0;
3367 pr_alert("%s: CPU %d invoking dump_cpu_task(%d)\n", __func__, cpu, dumpcpu);
3368 dump_cpu_task(dumpcpu);
3369 preempt_enable();
3370 schedule_timeout_uninterruptible(15 * HZ);
3371 }
3372 #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3373 WARN_ONCE(n, "Non-zero rcutorture.test_nmis=%d permitted only when rcutorture is built in.\n", test_nmis);
3374 #endif // #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3375 }
3376
3377 static enum cpuhp_state rcutor_hp;
3378
3379 static void
3380 rcu_torture_cleanup(void)
3381 {
3382 int firsttime;
3383 int flags = 0;
3384 unsigned long gp_seq = 0;
3385 int i;
3386
3387 if (torture_cleanup_begin()) {
3388 if (cur_ops->cb_barrier != NULL) {
3389 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3390 cur_ops->cb_barrier();
3391 }
3392 if (cur_ops->gp_slow_unregister)
3393 cur_ops->gp_slow_unregister(NULL);
3394 return;
3395 }
3396 if (!cur_ops) {
3397 torture_cleanup_end();
3398 return;
3399 }
3400
3401 rcutorture_test_nmis(test_nmis);
3402
3403 if (cur_ops->gp_kthread_dbg)
3404 cur_ops->gp_kthread_dbg();
3405 rcu_torture_read_exit_cleanup();
3406 rcu_torture_barrier_cleanup();
3407 rcu_torture_fwd_prog_cleanup();
3408 torture_stop_kthread(rcu_torture_stall, stall_task);
3409 torture_stop_kthread(rcu_torture_writer, writer_task);
3410
3411 if (nocb_tasks) {
3412 for (i = 0; i < nrealnocbers; i++)
3413 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]);
3414 kfree(nocb_tasks);
3415 nocb_tasks = NULL;
3416 }
3417
3418 if (reader_tasks) {
3419 for (i = 0; i < nrealreaders; i++)
3420 torture_stop_kthread(rcu_torture_reader,
3421 reader_tasks[i]);
3422 kfree(reader_tasks);
3423 reader_tasks = NULL;
3424 }
3425 kfree(rcu_torture_reader_mbchk);
3426 rcu_torture_reader_mbchk = NULL;
3427
3428 if (fakewriter_tasks) {
3429 for (i = 0; i < nfakewriters; i++)
3430 torture_stop_kthread(rcu_torture_fakewriter,
3431 fakewriter_tasks[i]);
3432 kfree(fakewriter_tasks);
3433 fakewriter_tasks = NULL;
3434 }
3435
3436 if (cur_ops->get_gp_data)
3437 cur_ops->get_gp_data(&flags, &gp_seq);
3438 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n",
3439 cur_ops->name, (long)gp_seq, flags,
3440 rcutorture_seq_diff(gp_seq, start_gp_seq));
3441 torture_stop_kthread(rcu_torture_stats, stats_task);
3442 torture_stop_kthread(rcu_torture_fqs, fqs_task);
3443 if (rcu_torture_can_boost() && rcutor_hp >= 0)
3444 cpuhp_remove_state(rcutor_hp);
3445
3446 /*
3447 * Wait for all RCU callbacks to fire, then do torture-type-specific
3448 * cleanup operations.
3449 */
3450 if (cur_ops->cb_barrier != NULL) {
3451 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3452 cur_ops->cb_barrier();
3453 }
3454 if (cur_ops->cleanup != NULL)
3455 cur_ops->cleanup();
3456
3457 rcu_torture_mem_dump_obj();
3458
3459 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
3460
3461 if (err_segs_recorded) {
3462 pr_alert("Failure/close-call rcutorture reader segments:\n");
3463 if (rt_read_nsegs == 0)
3464 pr_alert("\t: No segments recorded!!!\n");
3465 firsttime = 1;
3466 for (i = 0; i < rt_read_nsegs; i++) {
3467 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
3468 if (err_segs[i].rt_delay_jiffies != 0) {
3469 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
3470 err_segs[i].rt_delay_jiffies);
3471 firsttime = 0;
3472 }
3473 if (err_segs[i].rt_delay_ms != 0) {
3474 pr_cont("%s%ldms", firsttime ? "" : "+",
3475 err_segs[i].rt_delay_ms);
3476 firsttime = 0;
3477 }
3478 if (err_segs[i].rt_delay_us != 0) {
3479 pr_cont("%s%ldus", firsttime ? "" : "+",
3480 err_segs[i].rt_delay_us);
3481 firsttime = 0;
3482 }
3483 pr_cont("%s\n",
3484 err_segs[i].rt_preempted ? "preempted" : "");
3485
3486 }
3487 }
3488 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
3489 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
3490 else if (torture_onoff_failures())
3491 rcu_torture_print_module_parms(cur_ops,
3492 "End of test: RCU_HOTPLUG");
3493 else
3494 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
3495 torture_cleanup_end();
3496 if (cur_ops->gp_slow_unregister)
3497 cur_ops->gp_slow_unregister(NULL);
3498 }
3499
3500 static void rcu_torture_leak_cb(struct rcu_head *rhp)
3501 {
3502 }
3503
3504 static void rcu_torture_err_cb(struct rcu_head *rhp)
3505 {
3506 /*
3507 * This -might- happen due to race conditions, but is unlikely.
3508 * The scenario that leads to this happening is that the
3509 * first of the pair of duplicate callbacks is queued,
3510 * someone else starts a grace period that includes that
3511 * callback, then the second of the pair must wait for the
3512 * next grace period. Unlikely, but can happen. If it
3513 * does happen, the debug-objects subsystem won't have splatted.
3514 */
3515 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
3516 }
3517
3518 /*
3519 * Verify that double-free causes debug-objects to complain, but only
3520 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
3521 * cannot be carried out.
3522 */
3523 static void rcu_test_debug_objects(void)
3524 {
3525 struct rcu_head rh1;
3526 struct rcu_head rh2;
3527 int idx;
3528
3529 if (!IS_ENABLED(CONFIG_DEBUG_OBJECTS_RCU_HEAD)) {
3530 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_%s()\n",
3531 KBUILD_MODNAME, cur_ops->name);
3532 return;
3533 }
3534
3535 if (WARN_ON_ONCE(cur_ops->debug_objects &&
3536 (!cur_ops->call || !cur_ops->cb_barrier)))
3537 return;
3538
3539 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
3540
3541 init_rcu_head_on_stack(&rh1);
3542 init_rcu_head_on_stack(&rh2);
3543 pr_alert("%s: WARN: Duplicate call_%s() test starting.\n", KBUILD_MODNAME, cur_ops->name);
3544
3545 /* Try to queue the rh2 pair of callbacks for the same grace period. */
3546 idx = cur_ops->readlock(); /* Make it impossible to finish a grace period. */
3547 cur_ops->call(&rh1, rcu_torture_leak_cb); /* Start grace period. */
3548 cur_ops->call(&rh2, rcu_torture_leak_cb);
3549 cur_ops->call(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
3550 if (rhp) {
3551 cur_ops->call(rhp, rcu_torture_leak_cb);
3552 cur_ops->call(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
3553 }
3554 cur_ops->readunlock(idx);
3555
3556 /* Wait for them all to get done so we can safely return. */
3557 cur_ops->cb_barrier();
3558 pr_alert("%s: WARN: Duplicate call_%s() test complete.\n", KBUILD_MODNAME, cur_ops->name);
3559 destroy_rcu_head_on_stack(&rh1);
3560 destroy_rcu_head_on_stack(&rh2);
3561 kfree(rhp);
3562 }
3563
3564 static void rcutorture_sync(void)
3565 {
3566 static unsigned long n;
3567
3568 if (cur_ops->sync && !(++n & 0xfff))
3569 cur_ops->sync();
3570 }
3571
3572 static DEFINE_MUTEX(mut0);
3573 static DEFINE_MUTEX(mut1);
3574 static DEFINE_MUTEX(mut2);
3575 static DEFINE_MUTEX(mut3);
3576 static DEFINE_MUTEX(mut4);
3577 static DEFINE_MUTEX(mut5);
3578 static DEFINE_MUTEX(mut6);
3579 static DEFINE_MUTEX(mut7);
3580 static DEFINE_MUTEX(mut8);
3581 static DEFINE_MUTEX(mut9);
3582
3583 static DECLARE_RWSEM(rwsem0);
3584 static DECLARE_RWSEM(rwsem1);
3585 static DECLARE_RWSEM(rwsem2);
3586 static DECLARE_RWSEM(rwsem3);
3587 static DECLARE_RWSEM(rwsem4);
3588 static DECLARE_RWSEM(rwsem5);
3589 static DECLARE_RWSEM(rwsem6);
3590 static DECLARE_RWSEM(rwsem7);
3591 static DECLARE_RWSEM(rwsem8);
3592 static DECLARE_RWSEM(rwsem9);
3593
3594 DEFINE_STATIC_SRCU(srcu0);
3595 DEFINE_STATIC_SRCU(srcu1);
3596 DEFINE_STATIC_SRCU(srcu2);
3597 DEFINE_STATIC_SRCU(srcu3);
3598 DEFINE_STATIC_SRCU(srcu4);
3599 DEFINE_STATIC_SRCU(srcu5);
3600 DEFINE_STATIC_SRCU(srcu6);
3601 DEFINE_STATIC_SRCU(srcu7);
3602 DEFINE_STATIC_SRCU(srcu8);
3603 DEFINE_STATIC_SRCU(srcu9);
3604
3605 static int srcu_lockdep_next(const char *f, const char *fl, const char *fs, const char *fu, int i,
3606 int cyclelen, int deadlock)
3607 {
3608 int j = i + 1;
3609
3610 if (j >= cyclelen)
3611 j = deadlock ? 0 : -1;
3612 if (j >= 0)
3613 pr_info("%s: %s(%d), %s(%d), %s(%d)\n", f, fl, i, fs, j, fu, i);
3614 else
3615 pr_info("%s: %s(%d), %s(%d)\n", f, fl, i, fu, i);
3616 return j;
3617 }
3618
3619 // Test lockdep on SRCU-based deadlock scenarios.
3620 static void rcu_torture_init_srcu_lockdep(void)
3621 {
3622 int cyclelen;
3623 int deadlock;
3624 bool err = false;
3625 int i;
3626 int j;
3627 int idx;
3628 struct mutex *muts[] = { &mut0, &mut1, &mut2, &mut3, &mut4,
3629 &mut5, &mut6, &mut7, &mut8, &mut9 };
3630 struct rw_semaphore *rwsems[] = { &rwsem0, &rwsem1, &rwsem2, &rwsem3, &rwsem4,
3631 &rwsem5, &rwsem6, &rwsem7, &rwsem8, &rwsem9 };
3632 struct srcu_struct *srcus[] = { &srcu0, &srcu1, &srcu2, &srcu3, &srcu4,
3633 &srcu5, &srcu6, &srcu7, &srcu8, &srcu9 };
3634 int testtype;
3635
3636 if (!test_srcu_lockdep)
3637 return;
3638
3639 deadlock = test_srcu_lockdep / 1000;
3640 testtype = (test_srcu_lockdep / 10) % 100;
3641 cyclelen = test_srcu_lockdep % 10;
3642 WARN_ON_ONCE(ARRAY_SIZE(muts) != ARRAY_SIZE(srcus));
3643 if (WARN_ONCE(deadlock != !!deadlock,
3644 "%s: test_srcu_lockdep=%d and deadlock digit %d must be zero or one.\n",
3645 __func__, test_srcu_lockdep, deadlock))
3646 err = true;
3647 if (WARN_ONCE(cyclelen <= 0,
3648 "%s: test_srcu_lockdep=%d and cycle-length digit %d must be greater than zero.\n",
3649 __func__, test_srcu_lockdep, cyclelen))
3650 err = true;
3651 if (err)
3652 goto err_out;
3653
3654 if (testtype == 0) {
3655 pr_info("%s: test_srcu_lockdep = %05d: SRCU %d-way %sdeadlock.\n",
3656 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3657 if (deadlock && cyclelen == 1)
3658 pr_info("%s: Expect hang.\n", __func__);
3659 for (i = 0; i < cyclelen; i++) {
3660 j = srcu_lockdep_next(__func__, "srcu_read_lock", "synchronize_srcu",
3661 "srcu_read_unlock", i, cyclelen, deadlock);
3662 idx = srcu_read_lock(srcus[i]);
3663 if (j >= 0)
3664 synchronize_srcu(srcus[j]);
3665 srcu_read_unlock(srcus[i], idx);
3666 }
3667 return;
3668 }
3669
3670 if (testtype == 1) {
3671 pr_info("%s: test_srcu_lockdep = %05d: SRCU/mutex %d-way %sdeadlock.\n",
3672 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3673 for (i = 0; i < cyclelen; i++) {
3674 pr_info("%s: srcu_read_lock(%d), mutex_lock(%d), mutex_unlock(%d), srcu_read_unlock(%d)\n",
3675 __func__, i, i, i, i);
3676 idx = srcu_read_lock(srcus[i]);
3677 mutex_lock(muts[i]);
3678 mutex_unlock(muts[i]);
3679 srcu_read_unlock(srcus[i], idx);
3680
3681 j = srcu_lockdep_next(__func__, "mutex_lock", "synchronize_srcu",
3682 "mutex_unlock", i, cyclelen, deadlock);
3683 mutex_lock(muts[i]);
3684 if (j >= 0)
3685 synchronize_srcu(srcus[j]);
3686 mutex_unlock(muts[i]);
3687 }
3688 return;
3689 }
3690
3691 if (testtype == 2) {
3692 pr_info("%s: test_srcu_lockdep = %05d: SRCU/rwsem %d-way %sdeadlock.\n",
3693 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3694 for (i = 0; i < cyclelen; i++) {
3695 pr_info("%s: srcu_read_lock(%d), down_read(%d), up_read(%d), srcu_read_unlock(%d)\n",
3696 __func__, i, i, i, i);
3697 idx = srcu_read_lock(srcus[i]);
3698 down_read(rwsems[i]);
3699 up_read(rwsems[i]);
3700 srcu_read_unlock(srcus[i], idx);
3701
3702 j = srcu_lockdep_next(__func__, "down_write", "synchronize_srcu",
3703 "up_write", i, cyclelen, deadlock);
3704 down_write(rwsems[i]);
3705 if (j >= 0)
3706 synchronize_srcu(srcus[j]);
3707 up_write(rwsems[i]);
3708 }
3709 return;
3710 }
3711
3712 #ifdef CONFIG_TASKS_TRACE_RCU
3713 if (testtype == 3) {
3714 pr_info("%s: test_srcu_lockdep = %05d: SRCU and Tasks Trace RCU %d-way %sdeadlock.\n",
3715 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3716 if (deadlock && cyclelen == 1)
3717 pr_info("%s: Expect hang.\n", __func__);
3718 for (i = 0; i < cyclelen; i++) {
3719 char *fl = i == 0 ? "rcu_read_lock_trace" : "srcu_read_lock";
3720 char *fs = i == cyclelen - 1 ? "synchronize_rcu_tasks_trace"
3721 : "synchronize_srcu";
3722 char *fu = i == 0 ? "rcu_read_unlock_trace" : "srcu_read_unlock";
3723
3724 j = srcu_lockdep_next(__func__, fl, fs, fu, i, cyclelen, deadlock);
3725 if (i == 0)
3726 rcu_read_lock_trace();
3727 else
3728 idx = srcu_read_lock(srcus[i]);
3729 if (j >= 0) {
3730 if (i == cyclelen - 1)
3731 synchronize_rcu_tasks_trace();
3732 else
3733 synchronize_srcu(srcus[j]);
3734 }
3735 if (i == 0)
3736 rcu_read_unlock_trace();
3737 else
3738 srcu_read_unlock(srcus[i], idx);
3739 }
3740 return;
3741 }
3742 #endif // #ifdef CONFIG_TASKS_TRACE_RCU
3743
3744 err_out:
3745 pr_info("%s: test_srcu_lockdep = %05d does nothing.\n", __func__, test_srcu_lockdep);
3746 pr_info("%s: test_srcu_lockdep = DNNL.\n", __func__);
3747 pr_info("%s: D: Deadlock if nonzero.\n", __func__);
3748 pr_info("%s: NN: Test number, 0=SRCU, 1=SRCU/mutex, 2=SRCU/rwsem, 3=SRCU/Tasks Trace RCU.\n", __func__);
3749 pr_info("%s: L: Cycle length.\n", __func__);
3750 if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU))
3751 pr_info("%s: NN=3 disallowed because kernel is built with CONFIG_TASKS_TRACE_RCU=n\n", __func__);
3752 }
3753
3754 static int __init
3755 rcu_torture_init(void)
3756 {
3757 long i;
3758 int cpu;
3759 int firsterr = 0;
3760 int flags = 0;
3761 unsigned long gp_seq = 0;
3762 static struct rcu_torture_ops *torture_ops[] = {
3763 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops,
3764 TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
3765 &trivial_ops,
3766 };
3767
3768 if (!torture_init_begin(torture_type, verbose))
3769 return -EBUSY;
3770
3771 /* Process args and tell the world that the torturer is on the job. */
3772 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
3773 cur_ops = torture_ops[i];
3774 if (strcmp(torture_type, cur_ops->name) == 0)
3775 break;
3776 }
3777 if (i == ARRAY_SIZE(torture_ops)) {
3778 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
3779 torture_type);
3780 pr_alert("rcu-torture types:");
3781 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
3782 pr_cont(" %s", torture_ops[i]->name);
3783 pr_cont("\n");
3784 firsterr = -EINVAL;
3785 cur_ops = NULL;
3786 goto unwind;
3787 }
3788 if (cur_ops->fqs == NULL && fqs_duration != 0) {
3789 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
3790 fqs_duration = 0;
3791 }
3792 if (nocbs_nthreads != 0 && (cur_ops != &rcu_ops ||
3793 !IS_ENABLED(CONFIG_RCU_NOCB_CPU))) {
3794 pr_alert("rcu-torture types: %s and CONFIG_RCU_NOCB_CPU=%d, nocb toggle disabled.\n",
3795 cur_ops->name, IS_ENABLED(CONFIG_RCU_NOCB_CPU));
3796 nocbs_nthreads = 0;
3797 }
3798 if (cur_ops->init)
3799 cur_ops->init();
3800
3801 rcu_torture_init_srcu_lockdep();
3802
3803 if (nreaders >= 0) {
3804 nrealreaders = nreaders;
3805 } else {
3806 nrealreaders = num_online_cpus() - 2 - nreaders;
3807 if (nrealreaders <= 0)
3808 nrealreaders = 1;
3809 }
3810 rcu_torture_print_module_parms(cur_ops, "Start of test");
3811 if (cur_ops->get_gp_data)
3812 cur_ops->get_gp_data(&flags, &gp_seq);
3813 start_gp_seq = gp_seq;
3814 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n",
3815 cur_ops->name, (long)gp_seq, flags);
3816
3817 /* Set up the freelist. */
3818
3819 INIT_LIST_HEAD(&rcu_torture_freelist);
3820 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
3821 rcu_tortures[i].rtort_mbtest = 0;
3822 list_add_tail(&rcu_tortures[i].rtort_free,
3823 &rcu_torture_freelist);
3824 }
3825
3826 /* Initialize the statistics so that each run gets its own numbers. */
3827
3828 rcu_torture_current = NULL;
3829 rcu_torture_current_version = 0;
3830 atomic_set(&n_rcu_torture_alloc, 0);
3831 atomic_set(&n_rcu_torture_alloc_fail, 0);
3832 atomic_set(&n_rcu_torture_free, 0);
3833 atomic_set(&n_rcu_torture_mberror, 0);
3834 atomic_set(&n_rcu_torture_mbchk_fail, 0);
3835 atomic_set(&n_rcu_torture_mbchk_tries, 0);
3836 atomic_set(&n_rcu_torture_error, 0);
3837 n_rcu_torture_barrier_error = 0;
3838 n_rcu_torture_boost_ktrerror = 0;
3839 n_rcu_torture_boost_failure = 0;
3840 n_rcu_torture_boosts = 0;
3841 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
3842 atomic_set(&rcu_torture_wcount[i], 0);
3843 for_each_possible_cpu(cpu) {
3844 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
3845 per_cpu(rcu_torture_count, cpu)[i] = 0;
3846 per_cpu(rcu_torture_batch, cpu)[i] = 0;
3847 }
3848 }
3849 err_segs_recorded = 0;
3850 rt_read_nsegs = 0;
3851
3852 /* Start up the kthreads. */
3853
3854 rcu_torture_write_types();
3855 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
3856 writer_task);
3857 if (torture_init_error(firsterr))
3858 goto unwind;
3859 if (nfakewriters > 0) {
3860 fakewriter_tasks = kcalloc(nfakewriters,
3861 sizeof(fakewriter_tasks[0]),
3862 GFP_KERNEL);
3863 if (fakewriter_tasks == NULL) {
3864 TOROUT_ERRSTRING("out of memory");
3865 firsterr = -ENOMEM;
3866 goto unwind;
3867 }
3868 }
3869 for (i = 0; i < nfakewriters; i++) {
3870 firsterr = torture_create_kthread(rcu_torture_fakewriter,
3871 NULL, fakewriter_tasks[i]);
3872 if (torture_init_error(firsterr))
3873 goto unwind;
3874 }
3875 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
3876 GFP_KERNEL);
3877 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk),
3878 GFP_KERNEL);
3879 if (!reader_tasks || !rcu_torture_reader_mbchk) {
3880 TOROUT_ERRSTRING("out of memory");
3881 firsterr = -ENOMEM;
3882 goto unwind;
3883 }
3884 for (i = 0; i < nrealreaders; i++) {
3885 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1;
3886 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
3887 reader_tasks[i]);
3888 if (torture_init_error(firsterr))
3889 goto unwind;
3890 }
3891 nrealnocbers = nocbs_nthreads;
3892 if (WARN_ON(nrealnocbers < 0))
3893 nrealnocbers = 1;
3894 if (WARN_ON(nocbs_toggle < 0))
3895 nocbs_toggle = HZ;
3896 if (nrealnocbers > 0) {
3897 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL);
3898 if (nocb_tasks == NULL) {
3899 TOROUT_ERRSTRING("out of memory");
3900 firsterr = -ENOMEM;
3901 goto unwind;
3902 }
3903 } else {
3904 nocb_tasks = NULL;
3905 }
3906 for (i = 0; i < nrealnocbers; i++) {
3907 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]);
3908 if (torture_init_error(firsterr))
3909 goto unwind;
3910 }
3911 if (stat_interval > 0) {
3912 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
3913 stats_task);
3914 if (torture_init_error(firsterr))
3915 goto unwind;
3916 }
3917 if (test_no_idle_hz && shuffle_interval > 0) {
3918 firsterr = torture_shuffle_init(shuffle_interval * HZ);
3919 if (torture_init_error(firsterr))
3920 goto unwind;
3921 }
3922 if (stutter < 0)
3923 stutter = 0;
3924 if (stutter) {
3925 int t;
3926
3927 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
3928 firsterr = torture_stutter_init(stutter * HZ, t);
3929 if (torture_init_error(firsterr))
3930 goto unwind;
3931 }
3932 if (fqs_duration < 0)
3933 fqs_duration = 0;
3934 if (fqs_holdoff < 0)
3935 fqs_holdoff = 0;
3936 if (fqs_duration && fqs_holdoff) {
3937 /* Create the fqs thread */
3938 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
3939 fqs_task);
3940 if (torture_init_error(firsterr))
3941 goto unwind;
3942 }
3943 if (test_boost_interval < 1)
3944 test_boost_interval = 1;
3945 if (test_boost_duration < 2)
3946 test_boost_duration = 2;
3947 if (rcu_torture_can_boost()) {
3948
3949 boost_starttime = jiffies + test_boost_interval * HZ;
3950
3951 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
3952 rcutorture_booster_init,
3953 rcutorture_booster_cleanup);
3954 rcutor_hp = firsterr;
3955 if (torture_init_error(firsterr))
3956 goto unwind;
3957 }
3958 shutdown_jiffies = jiffies + shutdown_secs * HZ;
3959 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
3960 if (torture_init_error(firsterr))
3961 goto unwind;
3962 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
3963 rcutorture_sync);
3964 if (torture_init_error(firsterr))
3965 goto unwind;
3966 firsterr = rcu_torture_stall_init();
3967 if (torture_init_error(firsterr))
3968 goto unwind;
3969 firsterr = rcu_torture_fwd_prog_init();
3970 if (torture_init_error(firsterr))
3971 goto unwind;
3972 firsterr = rcu_torture_barrier_init();
3973 if (torture_init_error(firsterr))
3974 goto unwind;
3975 firsterr = rcu_torture_read_exit_init();
3976 if (torture_init_error(firsterr))
3977 goto unwind;
3978 if (object_debug)
3979 rcu_test_debug_objects();
3980 torture_init_end();
3981 if (cur_ops->gp_slow_register && !WARN_ON_ONCE(!cur_ops->gp_slow_unregister))
3982 cur_ops->gp_slow_register(&rcu_fwd_cb_nodelay);
3983 return 0;
3984
3985 unwind:
3986 torture_init_end();
3987 rcu_torture_cleanup();
3988 if (shutdown_secs) {
3989 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
3990 kernel_power_off();
3991 }
3992 return firsterr;
3993 }
3994
3995 module_init(rcu_torture_init);
3996 module_exit(rcu_torture_cleanup);
Kernel DRM miscellaneous fixes and cross-tree changes