?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
drm/rockchip: vop2: Support 32x8 superblock afbc
[drm/drm-misc.git] / kernel / rcu / rcutorture.c
blob612d276903352f04bf5ea678b2e090aa73a3e6ff
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 (0xff << RCUTORTURE_RDR_SHIFT_1)
61 #define RCUTORTURE_RDR_SHIFT_2 16 /* Put SRCU index in upper bits. */
62 #define RCUTORTURE_RDR_MASK_2 (0xff << 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_ALLBITS \
75 (RCUTORTURE_MAX_EXTEND | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2 | \
76 RCUTORTURE_RDR_MASK_1 | RCUTORTURE_RDR_MASK_2)
77 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
78 /* Must be power of two minus one. */
79 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
80
81 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
82 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
83 torture_param(int, fqs_duration, 0, "Duration of fqs bursts (us), 0 to disable");
84 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
85 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
86 torture_param(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)");
87 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
88 torture_param(int, fwd_progress_holdoff, 60, "Time between forward-progress tests (s)");
89 torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched() behind need_resched()");
90 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
91 torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait primitives");
92 torture_param(bool, gp_cond_full, false, "Use conditional/async full-state GP wait primitives");
93 torture_param(bool, gp_cond_exp_full, false,
94 "Use conditional/async full-stateexpedited GP wait primitives");
95 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
96 torture_param(bool, gp_normal, false, "Use normal (non-expedited) GP wait primitives");
97 torture_param(bool, gp_poll, false, "Use polling GP wait primitives");
98 torture_param(bool, gp_poll_exp, false, "Use polling expedited GP wait primitives");
99 torture_param(bool, gp_poll_full, false, "Use polling full-state GP wait primitives");
100 torture_param(bool, gp_poll_exp_full, false, "Use polling full-state expedited GP wait primitives");
101 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
102 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
103 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers");
104 torture_param(int, n_barrier_cbs, 0, "# of callbacks/kthreads for barrier testing");
105 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
106 torture_param(int, nreaders, -1, "Number of RCU reader threads");
107 torture_param(int, object_debug, 0, "Enable debug-object double call_rcu() testing");
108 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
109 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (jiffies), 0=disable");
110 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable");
111 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
112 torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
113 torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
114 torture_param(int, reader_flavor, 0x1, "Reader flavors to use, one per bit.");
115 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
116 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
117 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
118 torture_param(int, stall_cpu_holdoff, 10, "Time to wait before starting stall (s).");
119 torture_param(bool, stall_no_softlockup, false, "Avoid softlockup warning during cpu stall.");
120 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
121 torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
122 torture_param(int, stall_cpu_repeat, 0, "Number of additional stalls after the first one.");
123 torture_param(int, stall_gp_kthread, 0, "Grace-period kthread stall duration (s).");
124 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s");
125 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
126 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
127 torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds.");
128 torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds.");
129 torture_param(int, test_nmis, 0, "End-test NMI tests, 0 to disable.");
130 torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs");
131 torture_param(int, test_srcu_lockdep, 0, "Test specified SRCU deadlock scenario.");
132 torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
133
134 static char *torture_type = "rcu";
135 module_param(torture_type, charp, 0444);
136 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
137
138 static int nrealnocbers;
139 static int nrealreaders;
140 static struct task_struct *writer_task;
141 static struct task_struct **fakewriter_tasks;
142 static struct task_struct **reader_tasks;
143 static struct task_struct **nocb_tasks;
144 static struct task_struct *stats_task;
145 static struct task_struct *fqs_task;
146 static struct task_struct *boost_tasks[NR_CPUS];
147 static struct task_struct *stall_task;
148 static struct task_struct **fwd_prog_tasks;
149 static struct task_struct **barrier_cbs_tasks;
150 static struct task_struct *barrier_task;
151 static struct task_struct *read_exit_task;
152
153 #define RCU_TORTURE_PIPE_LEN 10
154
155 // Mailbox-like structure to check RCU global memory ordering.
156 struct rcu_torture_reader_check {
157 unsigned long rtc_myloops;
158 int rtc_chkrdr;
159 unsigned long rtc_chkloops;
160 int rtc_ready;
161 struct rcu_torture_reader_check *rtc_assigner;
162 } ____cacheline_internodealigned_in_smp;
163
164 // Update-side data structure used to check RCU readers.
165 struct rcu_torture {
166 struct rcu_head rtort_rcu;
167 int rtort_pipe_count;
168 struct list_head rtort_free;
169 int rtort_mbtest;
170 struct rcu_torture_reader_check *rtort_chkp;
171 };
172
173 static LIST_HEAD(rcu_torture_freelist);
174 static struct rcu_torture __rcu *rcu_torture_current;
175 static unsigned long rcu_torture_current_version;
176 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
177 static DEFINE_SPINLOCK(rcu_torture_lock);
178 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
179 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
180 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
181 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk;
182 static atomic_t n_rcu_torture_alloc;
183 static atomic_t n_rcu_torture_alloc_fail;
184 static atomic_t n_rcu_torture_free;
185 static atomic_t n_rcu_torture_mberror;
186 static atomic_t n_rcu_torture_mbchk_fail;
187 static atomic_t n_rcu_torture_mbchk_tries;
188 static atomic_t n_rcu_torture_error;
189 static long n_rcu_torture_barrier_error;
190 static long n_rcu_torture_boost_ktrerror;
191 static long n_rcu_torture_boost_failure;
192 static long n_rcu_torture_boosts;
193 static atomic_long_t n_rcu_torture_timers;
194 static long n_barrier_attempts;
195 static long n_barrier_successes; /* did rcu_barrier test succeed? */
196 static unsigned long n_read_exits;
197 static struct list_head rcu_torture_removed;
198 static unsigned long shutdown_jiffies;
199 static unsigned long start_gp_seq;
200 static atomic_long_t n_nocb_offload;
201 static atomic_long_t n_nocb_deoffload;
202
203 static int rcu_torture_writer_state;
204 #define RTWS_FIXED_DELAY 0
205 #define RTWS_DELAY 1
206 #define RTWS_REPLACE 2
207 #define RTWS_DEF_FREE 3
208 #define RTWS_EXP_SYNC 4
209 #define RTWS_COND_GET 5
210 #define RTWS_COND_GET_FULL 6
211 #define RTWS_COND_GET_EXP 7
212 #define RTWS_COND_GET_EXP_FULL 8
213 #define RTWS_COND_SYNC 9
214 #define RTWS_COND_SYNC_FULL 10
215 #define RTWS_COND_SYNC_EXP 11
216 #define RTWS_COND_SYNC_EXP_FULL 12
217 #define RTWS_POLL_GET 13
218 #define RTWS_POLL_GET_FULL 14
219 #define RTWS_POLL_GET_EXP 15
220 #define RTWS_POLL_GET_EXP_FULL 16
221 #define RTWS_POLL_WAIT 17
222 #define RTWS_POLL_WAIT_FULL 18
223 #define RTWS_POLL_WAIT_EXP 19
224 #define RTWS_POLL_WAIT_EXP_FULL 20
225 #define RTWS_SYNC 21
226 #define RTWS_STUTTER 22
227 #define RTWS_STOPPING 23
228 static const char * const rcu_torture_writer_state_names[] = {
229 "RTWS_FIXED_DELAY",
230 "RTWS_DELAY",
231 "RTWS_REPLACE",
232 "RTWS_DEF_FREE",
233 "RTWS_EXP_SYNC",
234 "RTWS_COND_GET",
235 "RTWS_COND_GET_FULL",
236 "RTWS_COND_GET_EXP",
237 "RTWS_COND_GET_EXP_FULL",
238 "RTWS_COND_SYNC",
239 "RTWS_COND_SYNC_FULL",
240 "RTWS_COND_SYNC_EXP",
241 "RTWS_COND_SYNC_EXP_FULL",
242 "RTWS_POLL_GET",
243 "RTWS_POLL_GET_FULL",
244 "RTWS_POLL_GET_EXP",
245 "RTWS_POLL_GET_EXP_FULL",
246 "RTWS_POLL_WAIT",
247 "RTWS_POLL_WAIT_FULL",
248 "RTWS_POLL_WAIT_EXP",
249 "RTWS_POLL_WAIT_EXP_FULL",
250 "RTWS_SYNC",
251 "RTWS_STUTTER",
252 "RTWS_STOPPING",
253 };
254
255 /* Record reader segment types and duration for first failing read. */
256 struct rt_read_seg {
257 int rt_readstate;
258 unsigned long rt_delay_jiffies;
259 unsigned long rt_delay_ms;
260 unsigned long rt_delay_us;
261 bool rt_preempted;
262 };
263 static int err_segs_recorded;
264 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
265 static int rt_read_nsegs;
266
267 static const char *rcu_torture_writer_state_getname(void)
268 {
269 unsigned int i = READ_ONCE(rcu_torture_writer_state);
270
271 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
272 return "???";
273 return rcu_torture_writer_state_names[i];
274 }
275
276 #ifdef CONFIG_RCU_TRACE
277 static u64 notrace rcu_trace_clock_local(void)
278 {
279 u64 ts = trace_clock_local();
280
281 (void)do_div(ts, NSEC_PER_USEC);
282 return ts;
283 }
284 #else /* #ifdef CONFIG_RCU_TRACE */
285 static u64 notrace rcu_trace_clock_local(void)
286 {
287 return 0ULL;
288 }
289 #endif /* #else #ifdef CONFIG_RCU_TRACE */
290
291 /*
292 * Stop aggressive CPU-hog tests a bit before the end of the test in order
293 * to avoid interfering with test shutdown.
294 */
295 static bool shutdown_time_arrived(void)
296 {
297 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
298 }
299
300 static unsigned long boost_starttime; /* jiffies of next boost test start. */
301 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
302 /* and boost task create/destroy. */
303 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
304 static bool barrier_phase; /* Test phase. */
305 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
306 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
307 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
308
309 static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
310
311 /*
312 * Allocate an element from the rcu_tortures pool.
313 */
314 static struct rcu_torture *
315 rcu_torture_alloc(void)
316 {
317 struct list_head *p;
318
319 spin_lock_bh(&rcu_torture_lock);
320 if (list_empty(&rcu_torture_freelist)) {
321 atomic_inc(&n_rcu_torture_alloc_fail);
322 spin_unlock_bh(&rcu_torture_lock);
323 return NULL;
324 }
325 atomic_inc(&n_rcu_torture_alloc);
326 p = rcu_torture_freelist.next;
327 list_del_init(p);
328 spin_unlock_bh(&rcu_torture_lock);
329 return container_of(p, struct rcu_torture, rtort_free);
330 }
331
332 /*
333 * Free an element to the rcu_tortures pool.
334 */
335 static void
336 rcu_torture_free(struct rcu_torture *p)
337 {
338 atomic_inc(&n_rcu_torture_free);
339 spin_lock_bh(&rcu_torture_lock);
340 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
341 spin_unlock_bh(&rcu_torture_lock);
342 }
343
344 /*
345 * Operations vector for selecting different types of tests.
346 */
347
348 struct rcu_torture_ops {
349 int ttype;
350 void (*init)(void);
351 void (*cleanup)(void);
352 int (*readlock)(void);
353 void (*read_delay)(struct torture_random_state *rrsp,
354 struct rt_read_seg *rtrsp);
355 void (*readunlock)(int idx);
356 int (*readlock_held)(void);
357 unsigned long (*get_gp_seq)(void);
358 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
359 void (*deferred_free)(struct rcu_torture *p);
360 void (*sync)(void);
361 void (*exp_sync)(void);
362 unsigned long (*get_gp_state_exp)(void);
363 unsigned long (*start_gp_poll_exp)(void);
364 void (*start_gp_poll_exp_full)(struct rcu_gp_oldstate *rgosp);
365 bool (*poll_gp_state_exp)(unsigned long oldstate);
366 void (*cond_sync_exp)(unsigned long oldstate);
367 void (*cond_sync_exp_full)(struct rcu_gp_oldstate *rgosp);
368 unsigned long (*get_comp_state)(void);
369 void (*get_comp_state_full)(struct rcu_gp_oldstate *rgosp);
370 bool (*same_gp_state)(unsigned long oldstate1, unsigned long oldstate2);
371 bool (*same_gp_state_full)(struct rcu_gp_oldstate *rgosp1, struct rcu_gp_oldstate *rgosp2);
372 unsigned long (*get_gp_state)(void);
373 void (*get_gp_state_full)(struct rcu_gp_oldstate *rgosp);
374 unsigned long (*start_gp_poll)(void);
375 void (*start_gp_poll_full)(struct rcu_gp_oldstate *rgosp);
376 bool (*poll_gp_state)(unsigned long oldstate);
377 bool (*poll_gp_state_full)(struct rcu_gp_oldstate *rgosp);
378 bool (*poll_need_2gp)(bool poll, bool poll_full);
379 void (*cond_sync)(unsigned long oldstate);
380 void (*cond_sync_full)(struct rcu_gp_oldstate *rgosp);
381 int poll_active;
382 int poll_active_full;
383 call_rcu_func_t call;
384 void (*cb_barrier)(void);
385 void (*fqs)(void);
386 void (*stats)(void);
387 void (*gp_kthread_dbg)(void);
388 bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
389 int (*stall_dur)(void);
390 void (*get_gp_data)(int *flags, unsigned long *gp_seq);
391 void (*gp_slow_register)(atomic_t *rgssp);
392 void (*gp_slow_unregister)(atomic_t *rgssp);
393 long cbflood_max;
394 int irq_capable;
395 int can_boost;
396 int extendables;
397 int slow_gps;
398 int no_pi_lock;
399 int debug_objects;
400 int start_poll_irqsoff;
401 const char *name;
402 };
403
404 static struct rcu_torture_ops *cur_ops;
405
406 /*
407 * Definitions for rcu torture testing.
408 */
409
410 static int torture_readlock_not_held(void)
411 {
412 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held();
413 }
414
415 static int rcu_torture_read_lock(void)
416 {
417 rcu_read_lock();
418 return 0;
419 }
420
421 static void
422 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
423 {
424 unsigned long started;
425 unsigned long completed;
426 const unsigned long shortdelay_us = 200;
427 unsigned long longdelay_ms = 300;
428 unsigned long long ts;
429
430 /* We want a short delay sometimes to make a reader delay the grace
431 * period, and we want a long delay occasionally to trigger
432 * force_quiescent_state. */
433
434 if (!atomic_read(&rcu_fwd_cb_nodelay) &&
435 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
436 started = cur_ops->get_gp_seq();
437 ts = rcu_trace_clock_local();
438 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
439 longdelay_ms = 5; /* Avoid triggering BH limits. */
440 mdelay(longdelay_ms);
441 rtrsp->rt_delay_ms = longdelay_ms;
442 completed = cur_ops->get_gp_seq();
443 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
444 started, completed);
445 }
446 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
447 udelay(shortdelay_us);
448 rtrsp->rt_delay_us = shortdelay_us;
449 }
450 if (!preempt_count() &&
451 !(torture_random(rrsp) % (nrealreaders * 500))) {
452 torture_preempt_schedule(); /* QS only if preemptible. */
453 rtrsp->rt_preempted = true;
454 }
455 }
456
457 static void rcu_torture_read_unlock(int idx)
458 {
459 rcu_read_unlock();
460 }
461
462 /*
463 * Update callback in the pipe. This should be invoked after a grace period.
464 */
465 static bool
466 rcu_torture_pipe_update_one(struct rcu_torture *rp)
467 {
468 int i;
469 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp);
470
471 if (rtrcp) {
472 WRITE_ONCE(rp->rtort_chkp, NULL);
473 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire().
474 }
475 i = rp->rtort_pipe_count;
476 if (i > RCU_TORTURE_PIPE_LEN)
477 i = RCU_TORTURE_PIPE_LEN;
478 atomic_inc(&rcu_torture_wcount[i]);
479 WRITE_ONCE(rp->rtort_pipe_count, i + 1);
480 ASSERT_EXCLUSIVE_WRITER(rp->rtort_pipe_count);
481 if (i + 1 >= RCU_TORTURE_PIPE_LEN) {
482 rp->rtort_mbtest = 0;
483 return true;
484 }
485 return false;
486 }
487
488 /*
489 * Update all callbacks in the pipe. Suitable for synchronous grace-period
490 * primitives.
491 */
492 static void
493 rcu_torture_pipe_update(struct rcu_torture *old_rp)
494 {
495 struct rcu_torture *rp;
496 struct rcu_torture *rp1;
497
498 if (old_rp)
499 list_add(&old_rp->rtort_free, &rcu_torture_removed);
500 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
501 if (rcu_torture_pipe_update_one(rp)) {
502 list_del(&rp->rtort_free);
503 rcu_torture_free(rp);
504 }
505 }
506 }
507
508 static void
509 rcu_torture_cb(struct rcu_head *p)
510 {
511 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
512
513 if (torture_must_stop_irq()) {
514 /* Test is ending, just drop callbacks on the floor. */
515 /* The next initialization will pick up the pieces. */
516 return;
517 }
518 if (rcu_torture_pipe_update_one(rp))
519 rcu_torture_free(rp);
520 else
521 cur_ops->deferred_free(rp);
522 }
523
524 static unsigned long rcu_no_completed(void)
525 {
526 return 0;
527 }
528
529 static void rcu_torture_deferred_free(struct rcu_torture *p)
530 {
531 call_rcu_hurry(&p->rtort_rcu, rcu_torture_cb);
532 }
533
534 static void rcu_sync_torture_init(void)
535 {
536 INIT_LIST_HEAD(&rcu_torture_removed);
537 }
538
539 static bool rcu_poll_need_2gp(bool poll, bool poll_full)
540 {
541 return poll;
542 }
543
544 static struct rcu_torture_ops rcu_ops = {
545 .ttype = RCU_FLAVOR,
546 .init = rcu_sync_torture_init,
547 .readlock = rcu_torture_read_lock,
548 .read_delay = rcu_read_delay,
549 .readunlock = rcu_torture_read_unlock,
550 .readlock_held = torture_readlock_not_held,
551 .get_gp_seq = rcu_get_gp_seq,
552 .gp_diff = rcu_seq_diff,
553 .deferred_free = rcu_torture_deferred_free,
554 .sync = synchronize_rcu,
555 .exp_sync = synchronize_rcu_expedited,
556 .same_gp_state = same_state_synchronize_rcu,
557 .same_gp_state_full = same_state_synchronize_rcu_full,
558 .get_comp_state = get_completed_synchronize_rcu,
559 .get_comp_state_full = get_completed_synchronize_rcu_full,
560 .get_gp_state = get_state_synchronize_rcu,
561 .get_gp_state_full = get_state_synchronize_rcu_full,
562 .start_gp_poll = start_poll_synchronize_rcu,
563 .start_gp_poll_full = start_poll_synchronize_rcu_full,
564 .poll_gp_state = poll_state_synchronize_rcu,
565 .poll_gp_state_full = poll_state_synchronize_rcu_full,
566 .poll_need_2gp = rcu_poll_need_2gp,
567 .cond_sync = cond_synchronize_rcu,
568 .cond_sync_full = cond_synchronize_rcu_full,
569 .poll_active = NUM_ACTIVE_RCU_POLL_OLDSTATE,
570 .poll_active_full = NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE,
571 .get_gp_state_exp = get_state_synchronize_rcu,
572 .start_gp_poll_exp = start_poll_synchronize_rcu_expedited,
573 .start_gp_poll_exp_full = start_poll_synchronize_rcu_expedited_full,
574 .poll_gp_state_exp = poll_state_synchronize_rcu,
575 .cond_sync_exp = cond_synchronize_rcu_expedited,
576 .call = call_rcu_hurry,
577 .cb_barrier = rcu_barrier,
578 .fqs = rcu_force_quiescent_state,
579 .gp_kthread_dbg = show_rcu_gp_kthreads,
580 .check_boost_failed = rcu_check_boost_fail,
581 .stall_dur = rcu_jiffies_till_stall_check,
582 .get_gp_data = rcutorture_get_gp_data,
583 .gp_slow_register = rcu_gp_slow_register,
584 .gp_slow_unregister = rcu_gp_slow_unregister,
585 .irq_capable = 1,
586 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
587 .extendables = RCUTORTURE_MAX_EXTEND,
588 .debug_objects = 1,
589 .start_poll_irqsoff = 1,
590 .name = "rcu"
591 };
592
593 /*
594 * Don't even think about trying any of these in real life!!!
595 * The names includes "busted", and they really means it!
596 * The only purpose of these functions is to provide a buggy RCU
597 * implementation to make sure that rcutorture correctly emits
598 * buggy-RCU error messages.
599 */
600 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
601 {
602 /* This is a deliberate bug for testing purposes only! */
603 rcu_torture_cb(&p->rtort_rcu);
604 }
605
606 static void synchronize_rcu_busted(void)
607 {
608 /* This is a deliberate bug for testing purposes only! */
609 }
610
611 static void
612 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
613 {
614 /* This is a deliberate bug for testing purposes only! */
615 func(head);
616 }
617
618 static struct rcu_torture_ops rcu_busted_ops = {
619 .ttype = INVALID_RCU_FLAVOR,
620 .init = rcu_sync_torture_init,
621 .readlock = rcu_torture_read_lock,
622 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
623 .readunlock = rcu_torture_read_unlock,
624 .readlock_held = torture_readlock_not_held,
625 .get_gp_seq = rcu_no_completed,
626 .deferred_free = rcu_busted_torture_deferred_free,
627 .sync = synchronize_rcu_busted,
628 .exp_sync = synchronize_rcu_busted,
629 .call = call_rcu_busted,
630 .irq_capable = 1,
631 .name = "busted"
632 };
633
634 /*
635 * Definitions for srcu torture testing.
636 */
637
638 DEFINE_STATIC_SRCU(srcu_ctl);
639 static struct srcu_struct srcu_ctld;
640 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
641 static struct rcu_torture_ops srcud_ops;
642
643 static void srcu_get_gp_data(int *flags, unsigned long *gp_seq)
644 {
645 srcutorture_get_gp_data(srcu_ctlp, flags, gp_seq);
646 }
647
648 static int srcu_torture_read_lock(void)
649 {
650 int idx;
651 int ret = 0;
652
653 if ((reader_flavor & 0x1) || !(reader_flavor & 0x7)) {
654 idx = srcu_read_lock(srcu_ctlp);
655 WARN_ON_ONCE(idx & ~0x1);
656 ret += idx;
657 }
658 if (reader_flavor & 0x2) {
659 idx = srcu_read_lock_nmisafe(srcu_ctlp);
660 WARN_ON_ONCE(idx & ~0x1);
661 ret += idx << 1;
662 }
663 if (reader_flavor & 0x4) {
664 idx = srcu_read_lock_lite(srcu_ctlp);
665 WARN_ON_ONCE(idx & ~0x1);
666 ret += idx << 2;
667 }
668 return ret;
669 }
670
671 static void
672 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
673 {
674 long delay;
675 const long uspertick = 1000000 / HZ;
676 const long longdelay = 10;
677
678 /* We want there to be long-running readers, but not all the time. */
679
680 delay = torture_random(rrsp) %
681 (nrealreaders * 2 * longdelay * uspertick);
682 if (!delay && in_task()) {
683 schedule_timeout_interruptible(longdelay);
684 rtrsp->rt_delay_jiffies = longdelay;
685 } else {
686 rcu_read_delay(rrsp, rtrsp);
687 }
688 }
689
690 static void srcu_torture_read_unlock(int idx)
691 {
692 WARN_ON_ONCE((reader_flavor && (idx & ~reader_flavor)) || (!reader_flavor && (idx & ~0x1)));
693 if (reader_flavor & 0x4)
694 srcu_read_unlock_lite(srcu_ctlp, (idx & 0x4) >> 2);
695 if (reader_flavor & 0x2)
696 srcu_read_unlock_nmisafe(srcu_ctlp, (idx & 0x2) >> 1);
697 if ((reader_flavor & 0x1) || !(reader_flavor & 0x7))
698 srcu_read_unlock(srcu_ctlp, idx & 0x1);
699 }
700
701 static int torture_srcu_read_lock_held(void)
702 {
703 return srcu_read_lock_held(srcu_ctlp);
704 }
705
706 static unsigned long srcu_torture_completed(void)
707 {
708 return srcu_batches_completed(srcu_ctlp);
709 }
710
711 static void srcu_torture_deferred_free(struct rcu_torture *rp)
712 {
713 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
714 }
715
716 static void srcu_torture_synchronize(void)
717 {
718 synchronize_srcu(srcu_ctlp);
719 }
720
721 static unsigned long srcu_torture_get_gp_state(void)
722 {
723 return get_state_synchronize_srcu(srcu_ctlp);
724 }
725
726 static unsigned long srcu_torture_start_gp_poll(void)
727 {
728 return start_poll_synchronize_srcu(srcu_ctlp);
729 }
730
731 static bool srcu_torture_poll_gp_state(unsigned long oldstate)
732 {
733 return poll_state_synchronize_srcu(srcu_ctlp, oldstate);
734 }
735
736 static void srcu_torture_call(struct rcu_head *head,
737 rcu_callback_t func)
738 {
739 call_srcu(srcu_ctlp, head, func);
740 }
741
742 static void srcu_torture_barrier(void)
743 {
744 srcu_barrier(srcu_ctlp);
745 }
746
747 static void srcu_torture_stats(void)
748 {
749 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
750 }
751
752 static void srcu_torture_synchronize_expedited(void)
753 {
754 synchronize_srcu_expedited(srcu_ctlp);
755 }
756
757 static struct rcu_torture_ops srcu_ops = {
758 .ttype = SRCU_FLAVOR,
759 .init = rcu_sync_torture_init,
760 .readlock = srcu_torture_read_lock,
761 .read_delay = srcu_read_delay,
762 .readunlock = srcu_torture_read_unlock,
763 .readlock_held = torture_srcu_read_lock_held,
764 .get_gp_seq = srcu_torture_completed,
765 .deferred_free = srcu_torture_deferred_free,
766 .sync = srcu_torture_synchronize,
767 .exp_sync = srcu_torture_synchronize_expedited,
768 .same_gp_state = same_state_synchronize_srcu,
769 .get_comp_state = get_completed_synchronize_srcu,
770 .get_gp_state = srcu_torture_get_gp_state,
771 .start_gp_poll = srcu_torture_start_gp_poll,
772 .poll_gp_state = srcu_torture_poll_gp_state,
773 .poll_active = NUM_ACTIVE_SRCU_POLL_OLDSTATE,
774 .call = srcu_torture_call,
775 .cb_barrier = srcu_torture_barrier,
776 .stats = srcu_torture_stats,
777 .get_gp_data = srcu_get_gp_data,
778 .cbflood_max = 50000,
779 .irq_capable = 1,
780 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
781 .debug_objects = 1,
782 .name = "srcu"
783 };
784
785 static void srcu_torture_init(void)
786 {
787 rcu_sync_torture_init();
788 WARN_ON(init_srcu_struct(&srcu_ctld));
789 srcu_ctlp = &srcu_ctld;
790 }
791
792 static void srcu_torture_cleanup(void)
793 {
794 cleanup_srcu_struct(&srcu_ctld);
795 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
796 }
797
798 /* As above, but dynamically allocated. */
799 static struct rcu_torture_ops srcud_ops = {
800 .ttype = SRCU_FLAVOR,
801 .init = srcu_torture_init,
802 .cleanup = srcu_torture_cleanup,
803 .readlock = srcu_torture_read_lock,
804 .read_delay = srcu_read_delay,
805 .readunlock = srcu_torture_read_unlock,
806 .readlock_held = torture_srcu_read_lock_held,
807 .get_gp_seq = srcu_torture_completed,
808 .deferred_free = srcu_torture_deferred_free,
809 .sync = srcu_torture_synchronize,
810 .exp_sync = srcu_torture_synchronize_expedited,
811 .same_gp_state = same_state_synchronize_srcu,
812 .get_comp_state = get_completed_synchronize_srcu,
813 .get_gp_state = srcu_torture_get_gp_state,
814 .start_gp_poll = srcu_torture_start_gp_poll,
815 .poll_gp_state = srcu_torture_poll_gp_state,
816 .poll_active = NUM_ACTIVE_SRCU_POLL_OLDSTATE,
817 .call = srcu_torture_call,
818 .cb_barrier = srcu_torture_barrier,
819 .stats = srcu_torture_stats,
820 .get_gp_data = srcu_get_gp_data,
821 .cbflood_max = 50000,
822 .irq_capable = 1,
823 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
824 .debug_objects = 1,
825 .name = "srcud"
826 };
827
828 /* As above, but broken due to inappropriate reader extension. */
829 static struct rcu_torture_ops busted_srcud_ops = {
830 .ttype = SRCU_FLAVOR,
831 .init = srcu_torture_init,
832 .cleanup = srcu_torture_cleanup,
833 .readlock = srcu_torture_read_lock,
834 .read_delay = rcu_read_delay,
835 .readunlock = srcu_torture_read_unlock,
836 .readlock_held = torture_srcu_read_lock_held,
837 .get_gp_seq = srcu_torture_completed,
838 .deferred_free = srcu_torture_deferred_free,
839 .sync = srcu_torture_synchronize,
840 .exp_sync = srcu_torture_synchronize_expedited,
841 .call = srcu_torture_call,
842 .cb_barrier = srcu_torture_barrier,
843 .stats = srcu_torture_stats,
844 .irq_capable = 1,
845 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
846 .extendables = RCUTORTURE_MAX_EXTEND,
847 .name = "busted_srcud"
848 };
849
850 /*
851 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
852 * This implementation does not necessarily work well with CPU hotplug.
853 */
854
855 static void synchronize_rcu_trivial(void)
856 {
857 int cpu;
858
859 for_each_online_cpu(cpu) {
860 torture_sched_setaffinity(current->pid, cpumask_of(cpu));
861 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
862 }
863 }
864
865 static int rcu_torture_read_lock_trivial(void)
866 {
867 preempt_disable();
868 return 0;
869 }
870
871 static void rcu_torture_read_unlock_trivial(int idx)
872 {
873 preempt_enable();
874 }
875
876 static struct rcu_torture_ops trivial_ops = {
877 .ttype = RCU_TRIVIAL_FLAVOR,
878 .init = rcu_sync_torture_init,
879 .readlock = rcu_torture_read_lock_trivial,
880 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
881 .readunlock = rcu_torture_read_unlock_trivial,
882 .readlock_held = torture_readlock_not_held,
883 .get_gp_seq = rcu_no_completed,
884 .sync = synchronize_rcu_trivial,
885 .exp_sync = synchronize_rcu_trivial,
886 .irq_capable = 1,
887 .name = "trivial"
888 };
889
890 #ifdef CONFIG_TASKS_RCU
891
892 /*
893 * Definitions for RCU-tasks torture testing.
894 */
895
896 static int tasks_torture_read_lock(void)
897 {
898 return 0;
899 }
900
901 static void tasks_torture_read_unlock(int idx)
902 {
903 }
904
905 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
906 {
907 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
908 }
909
910 static void synchronize_rcu_mult_test(void)
911 {
912 synchronize_rcu_mult(call_rcu_tasks, call_rcu_hurry);
913 }
914
915 static struct rcu_torture_ops tasks_ops = {
916 .ttype = RCU_TASKS_FLAVOR,
917 .init = rcu_sync_torture_init,
918 .readlock = tasks_torture_read_lock,
919 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
920 .readunlock = tasks_torture_read_unlock,
921 .get_gp_seq = rcu_no_completed,
922 .deferred_free = rcu_tasks_torture_deferred_free,
923 .sync = synchronize_rcu_tasks,
924 .exp_sync = synchronize_rcu_mult_test,
925 .call = call_rcu_tasks,
926 .cb_barrier = rcu_barrier_tasks,
927 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread,
928 .get_gp_data = rcu_tasks_get_gp_data,
929 .irq_capable = 1,
930 .slow_gps = 1,
931 .name = "tasks"
932 };
933
934 #define TASKS_OPS &tasks_ops,
935
936 #else // #ifdef CONFIG_TASKS_RCU
937
938 #define TASKS_OPS
939
940 #endif // #else #ifdef CONFIG_TASKS_RCU
941
942
943 #ifdef CONFIG_TASKS_RUDE_RCU
944
945 /*
946 * Definitions for rude RCU-tasks torture testing.
947 */
948
949 static struct rcu_torture_ops tasks_rude_ops = {
950 .ttype = RCU_TASKS_RUDE_FLAVOR,
951 .init = rcu_sync_torture_init,
952 .readlock = rcu_torture_read_lock_trivial,
953 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
954 .readunlock = rcu_torture_read_unlock_trivial,
955 .get_gp_seq = rcu_no_completed,
956 .sync = synchronize_rcu_tasks_rude,
957 .exp_sync = synchronize_rcu_tasks_rude,
958 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread,
959 .get_gp_data = rcu_tasks_rude_get_gp_data,
960 .cbflood_max = 50000,
961 .irq_capable = 1,
962 .name = "tasks-rude"
963 };
964
965 #define TASKS_RUDE_OPS &tasks_rude_ops,
966
967 #else // #ifdef CONFIG_TASKS_RUDE_RCU
968
969 #define TASKS_RUDE_OPS
970
971 #endif // #else #ifdef CONFIG_TASKS_RUDE_RCU
972
973
974 #ifdef CONFIG_TASKS_TRACE_RCU
975
976 /*
977 * Definitions for tracing RCU-tasks torture testing.
978 */
979
980 static int tasks_tracing_torture_read_lock(void)
981 {
982 rcu_read_lock_trace();
983 return 0;
984 }
985
986 static void tasks_tracing_torture_read_unlock(int idx)
987 {
988 rcu_read_unlock_trace();
989 }
990
991 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
992 {
993 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
994 }
995
996 static struct rcu_torture_ops tasks_tracing_ops = {
997 .ttype = RCU_TASKS_TRACING_FLAVOR,
998 .init = rcu_sync_torture_init,
999 .readlock = tasks_tracing_torture_read_lock,
1000 .read_delay = srcu_read_delay, /* just reuse srcu's version. */
1001 .readunlock = tasks_tracing_torture_read_unlock,
1002 .readlock_held = rcu_read_lock_trace_held,
1003 .get_gp_seq = rcu_no_completed,
1004 .deferred_free = rcu_tasks_tracing_torture_deferred_free,
1005 .sync = synchronize_rcu_tasks_trace,
1006 .exp_sync = synchronize_rcu_tasks_trace,
1007 .call = call_rcu_tasks_trace,
1008 .cb_barrier = rcu_barrier_tasks_trace,
1009 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread,
1010 .get_gp_data = rcu_tasks_trace_get_gp_data,
1011 .cbflood_max = 50000,
1012 .irq_capable = 1,
1013 .slow_gps = 1,
1014 .name = "tasks-tracing"
1015 };
1016
1017 #define TASKS_TRACING_OPS &tasks_tracing_ops,
1018
1019 #else // #ifdef CONFIG_TASKS_TRACE_RCU
1020
1021 #define TASKS_TRACING_OPS
1022
1023 #endif // #else #ifdef CONFIG_TASKS_TRACE_RCU
1024
1025
1026 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
1027 {
1028 if (!cur_ops->gp_diff)
1029 return new - old;
1030 return cur_ops->gp_diff(new, old);
1031 }
1032
1033 /*
1034 * RCU torture priority-boost testing. Runs one real-time thread per
1035 * CPU for moderate bursts, repeatedly starting grace periods and waiting
1036 * for them to complete. If a given grace period takes too long, we assume
1037 * that priority inversion has occurred.
1038 */
1039
1040 static int old_rt_runtime = -1;
1041
1042 static void rcu_torture_disable_rt_throttle(void)
1043 {
1044 /*
1045 * Disable RT throttling so that rcutorture's boost threads don't get
1046 * throttled. Only possible if rcutorture is built-in otherwise the
1047 * user should manually do this by setting the sched_rt_period_us and
1048 * sched_rt_runtime sysctls.
1049 */
1050 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
1051 return;
1052
1053 old_rt_runtime = sysctl_sched_rt_runtime;
1054 sysctl_sched_rt_runtime = -1;
1055 }
1056
1057 static void rcu_torture_enable_rt_throttle(void)
1058 {
1059 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
1060 return;
1061
1062 sysctl_sched_rt_runtime = old_rt_runtime;
1063 old_rt_runtime = -1;
1064 }
1065
1066 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start)
1067 {
1068 int cpu;
1069 static int dbg_done;
1070 unsigned long end = jiffies;
1071 bool gp_done;
1072 unsigned long j;
1073 static unsigned long last_persist;
1074 unsigned long lp;
1075 unsigned long mininterval = test_boost_duration * HZ - HZ / 2;
1076
1077 if (end - *start > mininterval) {
1078 // Recheck after checking time to avoid false positives.
1079 smp_mb(); // Time check before grace-period check.
1080 if (cur_ops->poll_gp_state(gp_state))
1081 return false; // passed, though perhaps just barely
1082 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) {
1083 // At most one persisted message per boost test.
1084 j = jiffies;
1085 lp = READ_ONCE(last_persist);
1086 if (time_after(j, lp + mininterval) &&
1087 cmpxchg(&last_persist, lp, j) == lp) {
1088 if (cpu < 0)
1089 pr_info("Boost inversion persisted: QS from all CPUs\n");
1090 else
1091 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu);
1092 }
1093 return false; // passed on a technicality
1094 }
1095 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
1096 n_rcu_torture_boost_failure++;
1097 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) {
1098 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n",
1099 current->rt_priority, gp_state, end - *start);
1100 cur_ops->gp_kthread_dbg();
1101 // Recheck after print to flag grace period ending during splat.
1102 gp_done = cur_ops->poll_gp_state(gp_state);
1103 pr_info("Boost inversion: GP %lu %s.\n", gp_state,
1104 gp_done ? "ended already" : "still pending");
1105
1106 }
1107
1108 return true; // failed
1109 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) {
1110 *start = jiffies;
1111 }
1112
1113 return false; // passed
1114 }
1115
1116 static int rcu_torture_boost(void *arg)
1117 {
1118 unsigned long endtime;
1119 unsigned long gp_state;
1120 unsigned long gp_state_time;
1121 unsigned long oldstarttime;
1122
1123 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
1124
1125 /* Set real-time priority. */
1126 sched_set_fifo_low(current);
1127
1128 /* Each pass through the following loop does one boost-test cycle. */
1129 do {
1130 bool failed = false; // Test failed already in this test interval
1131 bool gp_initiated = false;
1132
1133 if (kthread_should_stop())
1134 goto checkwait;
1135
1136 /* Wait for the next test interval. */
1137 oldstarttime = READ_ONCE(boost_starttime);
1138 while (time_before(jiffies, oldstarttime)) {
1139 schedule_timeout_interruptible(oldstarttime - jiffies);
1140 if (stutter_wait("rcu_torture_boost"))
1141 sched_set_fifo_low(current);
1142 if (torture_must_stop())
1143 goto checkwait;
1144 }
1145
1146 // Do one boost-test interval.
1147 endtime = oldstarttime + test_boost_duration * HZ;
1148 while (time_before(jiffies, endtime)) {
1149 // Has current GP gone too long?
1150 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1151 failed = rcu_torture_boost_failed(gp_state, &gp_state_time);
1152 // If we don't have a grace period in flight, start one.
1153 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) {
1154 gp_state = cur_ops->start_gp_poll();
1155 gp_initiated = true;
1156 gp_state_time = jiffies;
1157 }
1158 if (stutter_wait("rcu_torture_boost")) {
1159 sched_set_fifo_low(current);
1160 // If the grace period already ended,
1161 // we don't know when that happened, so
1162 // start over.
1163 if (cur_ops->poll_gp_state(gp_state))
1164 gp_initiated = false;
1165 }
1166 if (torture_must_stop())
1167 goto checkwait;
1168 }
1169
1170 // In case the grace period extended beyond the end of the loop.
1171 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1172 rcu_torture_boost_failed(gp_state, &gp_state_time);
1173
1174 /*
1175 * Set the start time of the next test interval.
1176 * Yes, this is vulnerable to long delays, but such
1177 * delays simply cause a false negative for the next
1178 * interval. Besides, we are running at RT priority,
1179 * so delays should be relatively rare.
1180 */
1181 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) {
1182 if (mutex_trylock(&boost_mutex)) {
1183 if (oldstarttime == boost_starttime) {
1184 WRITE_ONCE(boost_starttime,
1185 jiffies + test_boost_interval * HZ);
1186 n_rcu_torture_boosts++;
1187 }
1188 mutex_unlock(&boost_mutex);
1189 break;
1190 }
1191 schedule_timeout_uninterruptible(HZ / 20);
1192 }
1193
1194 /* Go do the stutter. */
1195 checkwait: if (stutter_wait("rcu_torture_boost"))
1196 sched_set_fifo_low(current);
1197 } while (!torture_must_stop());
1198
1199 /* Clean up and exit. */
1200 while (!kthread_should_stop()) {
1201 torture_shutdown_absorb("rcu_torture_boost");
1202 schedule_timeout_uninterruptible(HZ / 20);
1203 }
1204 torture_kthread_stopping("rcu_torture_boost");
1205 return 0;
1206 }
1207
1208 /*
1209 * RCU torture force-quiescent-state kthread. Repeatedly induces
1210 * bursts of calls to force_quiescent_state(), increasing the probability
1211 * of occurrence of some important types of race conditions.
1212 */
1213 static int
1214 rcu_torture_fqs(void *arg)
1215 {
1216 unsigned long fqs_resume_time;
1217 int fqs_burst_remaining;
1218 int oldnice = task_nice(current);
1219
1220 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
1221 do {
1222 fqs_resume_time = jiffies + fqs_stutter * HZ;
1223 while (time_before(jiffies, fqs_resume_time) &&
1224 !kthread_should_stop()) {
1225 schedule_timeout_interruptible(HZ / 20);
1226 }
1227 fqs_burst_remaining = fqs_duration;
1228 while (fqs_burst_remaining > 0 &&
1229 !kthread_should_stop()) {
1230 cur_ops->fqs();
1231 udelay(fqs_holdoff);
1232 fqs_burst_remaining -= fqs_holdoff;
1233 }
1234 if (stutter_wait("rcu_torture_fqs"))
1235 sched_set_normal(current, oldnice);
1236 } while (!torture_must_stop());
1237 torture_kthread_stopping("rcu_torture_fqs");
1238 return 0;
1239 }
1240
1241 // Used by writers to randomly choose from the available grace-period primitives.
1242 static int synctype[ARRAY_SIZE(rcu_torture_writer_state_names)] = { };
1243 static int nsynctypes;
1244
1245 /*
1246 * Determine which grace-period primitives are available.
1247 */
1248 static void rcu_torture_write_types(void)
1249 {
1250 bool gp_cond1 = gp_cond, gp_cond_exp1 = gp_cond_exp, gp_cond_full1 = gp_cond_full;
1251 bool gp_cond_exp_full1 = gp_cond_exp_full, gp_exp1 = gp_exp, gp_poll_exp1 = gp_poll_exp;
1252 bool gp_poll_exp_full1 = gp_poll_exp_full, gp_normal1 = gp_normal, gp_poll1 = gp_poll;
1253 bool gp_poll_full1 = gp_poll_full, gp_sync1 = gp_sync;
1254
1255 /* Initialize synctype[] array. If none set, take default. */
1256 if (!gp_cond1 &&
1257 !gp_cond_exp1 &&
1258 !gp_cond_full1 &&
1259 !gp_cond_exp_full1 &&
1260 !gp_exp1 &&
1261 !gp_poll_exp1 &&
1262 !gp_poll_exp_full1 &&
1263 !gp_normal1 &&
1264 !gp_poll1 &&
1265 !gp_poll_full1 &&
1266 !gp_sync1) {
1267 gp_cond1 = true;
1268 gp_cond_exp1 = true;
1269 gp_cond_full1 = true;
1270 gp_cond_exp_full1 = true;
1271 gp_exp1 = true;
1272 gp_poll_exp1 = true;
1273 gp_poll_exp_full1 = true;
1274 gp_normal1 = true;
1275 gp_poll1 = true;
1276 gp_poll_full1 = true;
1277 gp_sync1 = true;
1278 }
1279 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) {
1280 synctype[nsynctypes++] = RTWS_COND_GET;
1281 pr_info("%s: Testing conditional GPs.\n", __func__);
1282 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) {
1283 pr_alert("%s: gp_cond without primitives.\n", __func__);
1284 }
1285 if (gp_cond_exp1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp) {
1286 synctype[nsynctypes++] = RTWS_COND_GET_EXP;
1287 pr_info("%s: Testing conditional expedited GPs.\n", __func__);
1288 } else if (gp_cond_exp && (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp)) {
1289 pr_alert("%s: gp_cond_exp without primitives.\n", __func__);
1290 }
1291 if (gp_cond_full1 && cur_ops->get_gp_state && cur_ops->cond_sync_full) {
1292 synctype[nsynctypes++] = RTWS_COND_GET_FULL;
1293 pr_info("%s: Testing conditional full-state GPs.\n", __func__);
1294 } else if (gp_cond_full && (!cur_ops->get_gp_state || !cur_ops->cond_sync_full)) {
1295 pr_alert("%s: gp_cond_full without primitives.\n", __func__);
1296 }
1297 if (gp_cond_exp_full1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp_full) {
1298 synctype[nsynctypes++] = RTWS_COND_GET_EXP_FULL;
1299 pr_info("%s: Testing conditional full-state expedited GPs.\n", __func__);
1300 } else if (gp_cond_exp_full &&
1301 (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp_full)) {
1302 pr_alert("%s: gp_cond_exp_full without primitives.\n", __func__);
1303 }
1304 if (gp_exp1 && cur_ops->exp_sync) {
1305 synctype[nsynctypes++] = RTWS_EXP_SYNC;
1306 pr_info("%s: Testing expedited GPs.\n", __func__);
1307 } else if (gp_exp && !cur_ops->exp_sync) {
1308 pr_alert("%s: gp_exp without primitives.\n", __func__);
1309 }
1310 if (gp_normal1 && cur_ops->deferred_free) {
1311 synctype[nsynctypes++] = RTWS_DEF_FREE;
1312 pr_info("%s: Testing asynchronous GPs.\n", __func__);
1313 } else if (gp_normal && !cur_ops->deferred_free) {
1314 pr_alert("%s: gp_normal without primitives.\n", __func__);
1315 }
1316 if (gp_poll1 && cur_ops->get_comp_state && cur_ops->same_gp_state &&
1317 cur_ops->start_gp_poll && cur_ops->poll_gp_state) {
1318 synctype[nsynctypes++] = RTWS_POLL_GET;
1319 pr_info("%s: Testing polling GPs.\n", __func__);
1320 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) {
1321 pr_alert("%s: gp_poll without primitives.\n", __func__);
1322 }
1323 if (gp_poll_full1 && cur_ops->get_comp_state_full && cur_ops->same_gp_state_full
1324 && cur_ops->start_gp_poll_full && cur_ops->poll_gp_state_full) {
1325 synctype[nsynctypes++] = RTWS_POLL_GET_FULL;
1326 pr_info("%s: Testing polling full-state GPs.\n", __func__);
1327 } else if (gp_poll_full && (!cur_ops->start_gp_poll_full || !cur_ops->poll_gp_state_full)) {
1328 pr_alert("%s: gp_poll_full without primitives.\n", __func__);
1329 }
1330 if (gp_poll_exp1 && cur_ops->start_gp_poll_exp && cur_ops->poll_gp_state_exp) {
1331 synctype[nsynctypes++] = RTWS_POLL_GET_EXP;
1332 pr_info("%s: Testing polling expedited GPs.\n", __func__);
1333 } else if (gp_poll_exp && (!cur_ops->start_gp_poll_exp || !cur_ops->poll_gp_state_exp)) {
1334 pr_alert("%s: gp_poll_exp without primitives.\n", __func__);
1335 }
1336 if (gp_poll_exp_full1 && cur_ops->start_gp_poll_exp_full && cur_ops->poll_gp_state_full) {
1337 synctype[nsynctypes++] = RTWS_POLL_GET_EXP_FULL;
1338 pr_info("%s: Testing polling full-state expedited GPs.\n", __func__);
1339 } else if (gp_poll_exp_full &&
1340 (!cur_ops->start_gp_poll_exp_full || !cur_ops->poll_gp_state_full)) {
1341 pr_alert("%s: gp_poll_exp_full without primitives.\n", __func__);
1342 }
1343 if (gp_sync1 && cur_ops->sync) {
1344 synctype[nsynctypes++] = RTWS_SYNC;
1345 pr_info("%s: Testing normal GPs.\n", __func__);
1346 } else if (gp_sync && !cur_ops->sync) {
1347 pr_alert("%s: gp_sync without primitives.\n", __func__);
1348 }
1349 pr_alert("%s: Testing %d update types.\n", __func__, nsynctypes);
1350 }
1351
1352 /*
1353 * Do the specified rcu_torture_writer() synchronous grace period,
1354 * while also testing out the polled APIs. Note well that the single-CPU
1355 * grace-period optimizations must be accounted for.
1356 */
1357 static void do_rtws_sync(struct torture_random_state *trsp, void (*sync)(void))
1358 {
1359 unsigned long cookie;
1360 struct rcu_gp_oldstate cookie_full;
1361 bool dopoll;
1362 bool dopoll_full;
1363 unsigned long r = torture_random(trsp);
1364
1365 dopoll = cur_ops->get_gp_state && cur_ops->poll_gp_state && !(r & 0x300);
1366 dopoll_full = cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full && !(r & 0xc00);
1367 if (dopoll || dopoll_full)
1368 cpus_read_lock();
1369 if (dopoll)
1370 cookie = cur_ops->get_gp_state();
1371 if (dopoll_full)
1372 cur_ops->get_gp_state_full(&cookie_full);
1373 if (cur_ops->poll_need_2gp && cur_ops->poll_need_2gp(dopoll, dopoll_full))
1374 sync();
1375 sync();
1376 WARN_ONCE(dopoll && !cur_ops->poll_gp_state(cookie),
1377 "%s: Cookie check 3 failed %pS() online %*pbl.",
1378 __func__, sync, cpumask_pr_args(cpu_online_mask));
1379 WARN_ONCE(dopoll_full && !cur_ops->poll_gp_state_full(&cookie_full),
1380 "%s: Cookie check 4 failed %pS() online %*pbl",
1381 __func__, sync, cpumask_pr_args(cpu_online_mask));
1382 if (dopoll || dopoll_full)
1383 cpus_read_unlock();
1384 }
1385
1386 /*
1387 * RCU torture writer kthread. Repeatedly substitutes a new structure
1388 * for that pointed to by rcu_torture_current, freeing the old structure
1389 * after a series of grace periods (the "pipeline").
1390 */
1391 static int
1392 rcu_torture_writer(void *arg)
1393 {
1394 bool boot_ended;
1395 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
1396 unsigned long cookie;
1397 struct rcu_gp_oldstate cookie_full;
1398 int expediting = 0;
1399 unsigned long gp_snap;
1400 unsigned long gp_snap1;
1401 struct rcu_gp_oldstate gp_snap_full;
1402 struct rcu_gp_oldstate gp_snap1_full;
1403 int i;
1404 int idx;
1405 int oldnice = task_nice(current);
1406 struct rcu_gp_oldstate *rgo = NULL;
1407 int rgo_size = 0;
1408 struct rcu_torture *rp;
1409 struct rcu_torture *old_rp;
1410 static DEFINE_TORTURE_RANDOM(rand);
1411 unsigned long stallsdone = jiffies;
1412 bool stutter_waited;
1413 unsigned long *ulo = NULL;
1414 int ulo_size = 0;
1415
1416 // If a new stall test is added, this must be adjusted.
1417 if (stall_cpu_holdoff + stall_gp_kthread + stall_cpu)
1418 stallsdone += (stall_cpu_holdoff + stall_gp_kthread + stall_cpu + 60) *
1419 HZ * (stall_cpu_repeat + 1);
1420 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
1421 if (!can_expedite)
1422 pr_alert("%s" TORTURE_FLAG
1423 " GP expediting controlled from boot/sysfs for %s.\n",
1424 torture_type, cur_ops->name);
1425 if (WARN_ONCE(nsynctypes == 0,
1426 "%s: No update-side primitives.\n", __func__)) {
1427 /*
1428 * No updates primitives, so don't try updating.
1429 * The resulting test won't be testing much, hence the
1430 * above WARN_ONCE().
1431 */
1432 rcu_torture_writer_state = RTWS_STOPPING;
1433 torture_kthread_stopping("rcu_torture_writer");
1434 return 0;
1435 }
1436 if (cur_ops->poll_active > 0) {
1437 ulo = kzalloc(cur_ops->poll_active * sizeof(ulo[0]), GFP_KERNEL);
1438 if (!WARN_ON(!ulo))
1439 ulo_size = cur_ops->poll_active;
1440 }
1441 if (cur_ops->poll_active_full > 0) {
1442 rgo = kzalloc(cur_ops->poll_active_full * sizeof(rgo[0]), GFP_KERNEL);
1443 if (!WARN_ON(!rgo))
1444 rgo_size = cur_ops->poll_active_full;
1445 }
1446
1447 do {
1448 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1449 torture_hrtimeout_us(500, 1000, &rand);
1450 rp = rcu_torture_alloc();
1451 if (rp == NULL)
1452 continue;
1453 rp->rtort_pipe_count = 0;
1454 ASSERT_EXCLUSIVE_WRITER(rp->rtort_pipe_count);
1455 rcu_torture_writer_state = RTWS_DELAY;
1456 udelay(torture_random(&rand) & 0x3ff);
1457 rcu_torture_writer_state = RTWS_REPLACE;
1458 old_rp = rcu_dereference_check(rcu_torture_current,
1459 current == writer_task);
1460 rp->rtort_mbtest = 1;
1461 rcu_assign_pointer(rcu_torture_current, rp);
1462 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1463 if (old_rp) {
1464 i = old_rp->rtort_pipe_count;
1465 if (i > RCU_TORTURE_PIPE_LEN)
1466 i = RCU_TORTURE_PIPE_LEN;
1467 atomic_inc(&rcu_torture_wcount[i]);
1468 WRITE_ONCE(old_rp->rtort_pipe_count,
1469 old_rp->rtort_pipe_count + 1);
1470 ASSERT_EXCLUSIVE_WRITER(old_rp->rtort_pipe_count);
1471
1472 // Make sure readers block polled grace periods.
1473 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
1474 idx = cur_ops->readlock();
1475 cookie = cur_ops->get_gp_state();
1476 WARN_ONCE(cur_ops->poll_gp_state(cookie),
1477 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n",
1478 __func__,
1479 rcu_torture_writer_state_getname(),
1480 rcu_torture_writer_state,
1481 cookie, cur_ops->get_gp_state());
1482 if (cur_ops->get_comp_state) {
1483 cookie = cur_ops->get_comp_state();
1484 WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie));
1485 }
1486 cur_ops->readunlock(idx);
1487 }
1488 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) {
1489 idx = cur_ops->readlock();
1490 cur_ops->get_gp_state_full(&cookie_full);
1491 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
1492 "%s: Cookie check 5 failed %s(%d) online %*pbl\n",
1493 __func__,
1494 rcu_torture_writer_state_getname(),
1495 rcu_torture_writer_state,
1496 cpumask_pr_args(cpu_online_mask));
1497 if (cur_ops->get_comp_state_full) {
1498 cur_ops->get_comp_state_full(&cookie_full);
1499 WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full));
1500 }
1501 cur_ops->readunlock(idx);
1502 }
1503 switch (synctype[torture_random(&rand) % nsynctypes]) {
1504 case RTWS_DEF_FREE:
1505 rcu_torture_writer_state = RTWS_DEF_FREE;
1506 cur_ops->deferred_free(old_rp);
1507 break;
1508 case RTWS_EXP_SYNC:
1509 rcu_torture_writer_state = RTWS_EXP_SYNC;
1510 do_rtws_sync(&rand, cur_ops->exp_sync);
1511 rcu_torture_pipe_update(old_rp);
1512 break;
1513 case RTWS_COND_GET:
1514 rcu_torture_writer_state = RTWS_COND_GET;
1515 gp_snap = cur_ops->get_gp_state();
1516 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1517 rcu_torture_writer_state = RTWS_COND_SYNC;
1518 cur_ops->cond_sync(gp_snap);
1519 rcu_torture_pipe_update(old_rp);
1520 break;
1521 case RTWS_COND_GET_EXP:
1522 rcu_torture_writer_state = RTWS_COND_GET_EXP;
1523 gp_snap = cur_ops->get_gp_state_exp();
1524 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1525 rcu_torture_writer_state = RTWS_COND_SYNC_EXP;
1526 cur_ops->cond_sync_exp(gp_snap);
1527 rcu_torture_pipe_update(old_rp);
1528 break;
1529 case RTWS_COND_GET_FULL:
1530 rcu_torture_writer_state = RTWS_COND_GET_FULL;
1531 cur_ops->get_gp_state_full(&gp_snap_full);
1532 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1533 rcu_torture_writer_state = RTWS_COND_SYNC_FULL;
1534 cur_ops->cond_sync_full(&gp_snap_full);
1535 rcu_torture_pipe_update(old_rp);
1536 break;
1537 case RTWS_COND_GET_EXP_FULL:
1538 rcu_torture_writer_state = RTWS_COND_GET_EXP_FULL;
1539 cur_ops->get_gp_state_full(&gp_snap_full);
1540 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1541 rcu_torture_writer_state = RTWS_COND_SYNC_EXP_FULL;
1542 cur_ops->cond_sync_exp_full(&gp_snap_full);
1543 rcu_torture_pipe_update(old_rp);
1544 break;
1545 case RTWS_POLL_GET:
1546 rcu_torture_writer_state = RTWS_POLL_GET;
1547 for (i = 0; i < ulo_size; i++)
1548 ulo[i] = cur_ops->get_comp_state();
1549 gp_snap = cur_ops->start_gp_poll();
1550 rcu_torture_writer_state = RTWS_POLL_WAIT;
1551 while (!cur_ops->poll_gp_state(gp_snap)) {
1552 gp_snap1 = cur_ops->get_gp_state();
1553 for (i = 0; i < ulo_size; i++)
1554 if (cur_ops->poll_gp_state(ulo[i]) ||
1555 cur_ops->same_gp_state(ulo[i], gp_snap1)) {
1556 ulo[i] = gp_snap1;
1557 break;
1558 }
1559 WARN_ON_ONCE(ulo_size > 0 && i >= ulo_size);
1560 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1561 &rand);
1562 }
1563 rcu_torture_pipe_update(old_rp);
1564 break;
1565 case RTWS_POLL_GET_FULL:
1566 rcu_torture_writer_state = RTWS_POLL_GET_FULL;
1567 for (i = 0; i < rgo_size; i++)
1568 cur_ops->get_comp_state_full(&rgo[i]);
1569 cur_ops->start_gp_poll_full(&gp_snap_full);
1570 rcu_torture_writer_state = RTWS_POLL_WAIT_FULL;
1571 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1572 cur_ops->get_gp_state_full(&gp_snap1_full);
1573 for (i = 0; i < rgo_size; i++)
1574 if (cur_ops->poll_gp_state_full(&rgo[i]) ||
1575 cur_ops->same_gp_state_full(&rgo[i],
1576 &gp_snap1_full)) {
1577 rgo[i] = gp_snap1_full;
1578 break;
1579 }
1580 WARN_ON_ONCE(rgo_size > 0 && i >= rgo_size);
1581 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1582 &rand);
1583 }
1584 rcu_torture_pipe_update(old_rp);
1585 break;
1586 case RTWS_POLL_GET_EXP:
1587 rcu_torture_writer_state = RTWS_POLL_GET_EXP;
1588 gp_snap = cur_ops->start_gp_poll_exp();
1589 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP;
1590 while (!cur_ops->poll_gp_state_exp(gp_snap))
1591 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1592 &rand);
1593 rcu_torture_pipe_update(old_rp);
1594 break;
1595 case RTWS_POLL_GET_EXP_FULL:
1596 rcu_torture_writer_state = RTWS_POLL_GET_EXP_FULL;
1597 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1598 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP_FULL;
1599 while (!cur_ops->poll_gp_state_full(&gp_snap_full))
1600 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1601 &rand);
1602 rcu_torture_pipe_update(old_rp);
1603 break;
1604 case RTWS_SYNC:
1605 rcu_torture_writer_state = RTWS_SYNC;
1606 do_rtws_sync(&rand, cur_ops->sync);
1607 rcu_torture_pipe_update(old_rp);
1608 break;
1609 default:
1610 WARN_ON_ONCE(1);
1611 break;
1612 }
1613 }
1614 WRITE_ONCE(rcu_torture_current_version,
1615 rcu_torture_current_version + 1);
1616 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1617 if (can_expedite &&
1618 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1619 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1620 if (expediting >= 0)
1621 rcu_expedite_gp();
1622 else
1623 rcu_unexpedite_gp();
1624 if (++expediting > 3)
1625 expediting = -expediting;
1626 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1627 can_expedite = !rcu_gp_is_expedited() &&
1628 !rcu_gp_is_normal();
1629 }
1630 rcu_torture_writer_state = RTWS_STUTTER;
1631 boot_ended = rcu_inkernel_boot_has_ended();
1632 stutter_waited = stutter_wait("rcu_torture_writer");
1633 if (stutter_waited &&
1634 !atomic_read(&rcu_fwd_cb_nodelay) &&
1635 !cur_ops->slow_gps &&
1636 !torture_must_stop() &&
1637 boot_ended &&
1638 time_after(jiffies, stallsdone))
1639 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1640 if (list_empty(&rcu_tortures[i].rtort_free) &&
1641 rcu_access_pointer(rcu_torture_current) != &rcu_tortures[i]) {
1642 tracing_off();
1643 if (cur_ops->gp_kthread_dbg)
1644 cur_ops->gp_kthread_dbg();
1645 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1646 rcu_ftrace_dump(DUMP_ALL);
1647 }
1648 if (stutter_waited)
1649 sched_set_normal(current, oldnice);
1650 } while (!torture_must_stop());
1651 rcu_torture_current = NULL; // Let stats task know that we are done.
1652 /* Reset expediting back to unexpedited. */
1653 if (expediting > 0)
1654 expediting = -expediting;
1655 while (can_expedite && expediting++ < 0)
1656 rcu_unexpedite_gp();
1657 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1658 if (!can_expedite)
1659 pr_alert("%s" TORTURE_FLAG
1660 " Dynamic grace-period expediting was disabled.\n",
1661 torture_type);
1662 kfree(ulo);
1663 kfree(rgo);
1664 rcu_torture_writer_state = RTWS_STOPPING;
1665 torture_kthread_stopping("rcu_torture_writer");
1666 return 0;
1667 }
1668
1669 /*
1670 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1671 * delay between calls.
1672 */
1673 static int
1674 rcu_torture_fakewriter(void *arg)
1675 {
1676 unsigned long gp_snap;
1677 struct rcu_gp_oldstate gp_snap_full;
1678 DEFINE_TORTURE_RANDOM(rand);
1679
1680 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1681 set_user_nice(current, MAX_NICE);
1682
1683 if (WARN_ONCE(nsynctypes == 0,
1684 "%s: No update-side primitives.\n", __func__)) {
1685 /*
1686 * No updates primitives, so don't try updating.
1687 * The resulting test won't be testing much, hence the
1688 * above WARN_ONCE().
1689 */
1690 torture_kthread_stopping("rcu_torture_fakewriter");
1691 return 0;
1692 }
1693
1694 do {
1695 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand);
1696 if (cur_ops->cb_barrier != NULL &&
1697 torture_random(&rand) % (nfakewriters * 8) == 0) {
1698 cur_ops->cb_barrier();
1699 } else {
1700 switch (synctype[torture_random(&rand) % nsynctypes]) {
1701 case RTWS_DEF_FREE:
1702 break;
1703 case RTWS_EXP_SYNC:
1704 cur_ops->exp_sync();
1705 break;
1706 case RTWS_COND_GET:
1707 gp_snap = cur_ops->get_gp_state();
1708 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1709 cur_ops->cond_sync(gp_snap);
1710 break;
1711 case RTWS_COND_GET_EXP:
1712 gp_snap = cur_ops->get_gp_state_exp();
1713 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1714 cur_ops->cond_sync_exp(gp_snap);
1715 break;
1716 case RTWS_COND_GET_FULL:
1717 cur_ops->get_gp_state_full(&gp_snap_full);
1718 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1719 cur_ops->cond_sync_full(&gp_snap_full);
1720 break;
1721 case RTWS_COND_GET_EXP_FULL:
1722 cur_ops->get_gp_state_full(&gp_snap_full);
1723 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1724 cur_ops->cond_sync_exp_full(&gp_snap_full);
1725 break;
1726 case RTWS_POLL_GET:
1727 if (cur_ops->start_poll_irqsoff)
1728 local_irq_disable();
1729 gp_snap = cur_ops->start_gp_poll();
1730 if (cur_ops->start_poll_irqsoff)
1731 local_irq_enable();
1732 while (!cur_ops->poll_gp_state(gp_snap)) {
1733 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1734 &rand);
1735 }
1736 break;
1737 case RTWS_POLL_GET_FULL:
1738 if (cur_ops->start_poll_irqsoff)
1739 local_irq_disable();
1740 cur_ops->start_gp_poll_full(&gp_snap_full);
1741 if (cur_ops->start_poll_irqsoff)
1742 local_irq_enable();
1743 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1744 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1745 &rand);
1746 }
1747 break;
1748 case RTWS_POLL_GET_EXP:
1749 gp_snap = cur_ops->start_gp_poll_exp();
1750 while (!cur_ops->poll_gp_state_exp(gp_snap)) {
1751 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1752 &rand);
1753 }
1754 break;
1755 case RTWS_POLL_GET_EXP_FULL:
1756 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1757 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1758 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1759 &rand);
1760 }
1761 break;
1762 case RTWS_SYNC:
1763 cur_ops->sync();
1764 break;
1765 default:
1766 WARN_ON_ONCE(1);
1767 break;
1768 }
1769 }
1770 stutter_wait("rcu_torture_fakewriter");
1771 } while (!torture_must_stop());
1772
1773 torture_kthread_stopping("rcu_torture_fakewriter");
1774 return 0;
1775 }
1776
1777 static void rcu_torture_timer_cb(struct rcu_head *rhp)
1778 {
1779 kfree(rhp);
1780 }
1781
1782 // Set up and carry out testing of RCU's global memory ordering
1783 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp,
1784 struct torture_random_state *trsp)
1785 {
1786 unsigned long loops;
1787 int noc = torture_num_online_cpus();
1788 int rdrchked;
1789 int rdrchker;
1790 struct rcu_torture_reader_check *rtrcp; // Me.
1791 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking.
1792 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked.
1793 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me.
1794
1795 if (myid < 0)
1796 return; // Don't try this from timer handlers.
1797
1798 // Increment my counter.
1799 rtrcp = &rcu_torture_reader_mbchk[myid];
1800 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1);
1801
1802 // Attempt to assign someone else some checking work.
1803 rdrchked = torture_random(trsp) % nrealreaders;
1804 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1805 rdrchker = torture_random(trsp) % nrealreaders;
1806 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker];
1807 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker &&
1808 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below.
1809 !READ_ONCE(rtp->rtort_chkp) &&
1810 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below.
1811 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops);
1812 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0);
1813 rtrcp->rtc_chkrdr = rdrchked;
1814 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends.
1815 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) ||
1816 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp))
1817 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out.
1818 }
1819
1820 // If assigned some completed work, do it!
1821 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner);
1822 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready))
1823 return; // No work or work not yet ready.
1824 rdrchked = rtrcp_assigner->rtc_chkrdr;
1825 if (WARN_ON_ONCE(rdrchked < 0))
1826 return;
1827 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1828 loops = READ_ONCE(rtrcp_chked->rtc_myloops);
1829 atomic_inc(&n_rcu_torture_mbchk_tries);
1830 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops))
1831 atomic_inc(&n_rcu_torture_mbchk_fail);
1832 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2;
1833 rtrcp_assigner->rtc_ready = 0;
1834 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work.
1835 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign.
1836 }
1837
1838 /*
1839 * Do one extension of an RCU read-side critical section using the
1840 * current reader state in readstate (set to zero for initial entry
1841 * to extended critical section), set the new state as specified by
1842 * newstate (set to zero for final exit from extended critical section),
1843 * and random-number-generator state in trsp. If this is neither the
1844 * beginning or end of the critical section and if there was actually a
1845 * change, do a ->read_delay().
1846 */
1847 static void rcutorture_one_extend(int *readstate, int newstate,
1848 struct torture_random_state *trsp,
1849 struct rt_read_seg *rtrsp)
1850 {
1851 unsigned long flags;
1852 int idxnew1 = -1;
1853 int idxnew2 = -1;
1854 int idxold1 = *readstate;
1855 int idxold2 = idxold1;
1856 int statesnew = ~*readstate & newstate;
1857 int statesold = *readstate & ~newstate;
1858
1859 WARN_ON_ONCE(idxold2 < 0);
1860 WARN_ON_ONCE(idxold2 & ~RCUTORTURE_RDR_ALLBITS);
1861 rtrsp->rt_readstate = newstate;
1862
1863 /* First, put new protection in place to avoid critical-section gap. */
1864 if (statesnew & RCUTORTURE_RDR_BH)
1865 local_bh_disable();
1866 if (statesnew & RCUTORTURE_RDR_RBH)
1867 rcu_read_lock_bh();
1868 if (statesnew & RCUTORTURE_RDR_IRQ)
1869 local_irq_disable();
1870 if (statesnew & RCUTORTURE_RDR_PREEMPT)
1871 preempt_disable();
1872 if (statesnew & RCUTORTURE_RDR_SCHED)
1873 rcu_read_lock_sched();
1874 if (statesnew & RCUTORTURE_RDR_RCU_1)
1875 idxnew1 = (cur_ops->readlock() << RCUTORTURE_RDR_SHIFT_1) & RCUTORTURE_RDR_MASK_1;
1876 if (statesnew & RCUTORTURE_RDR_RCU_2)
1877 idxnew2 = (cur_ops->readlock() << RCUTORTURE_RDR_SHIFT_2) & RCUTORTURE_RDR_MASK_2;
1878
1879 /*
1880 * Next, remove old protection, in decreasing order of strength
1881 * to avoid unlock paths that aren't safe in the stronger
1882 * context. Namely: BH can not be enabled with disabled interrupts.
1883 * Additionally PREEMPT_RT requires that BH is enabled in preemptible
1884 * context.
1885 */
1886 if (statesold & RCUTORTURE_RDR_IRQ)
1887 local_irq_enable();
1888 if (statesold & RCUTORTURE_RDR_PREEMPT)
1889 preempt_enable();
1890 if (statesold & RCUTORTURE_RDR_SCHED)
1891 rcu_read_unlock_sched();
1892 if (statesold & RCUTORTURE_RDR_BH)
1893 local_bh_enable();
1894 if (statesold & RCUTORTURE_RDR_RBH)
1895 rcu_read_unlock_bh();
1896 if (statesold & RCUTORTURE_RDR_RCU_2) {
1897 cur_ops->readunlock((idxold2 & RCUTORTURE_RDR_MASK_2) >> RCUTORTURE_RDR_SHIFT_2);
1898 WARN_ON_ONCE(idxnew2 != -1);
1899 idxold2 = 0;
1900 }
1901 if (statesold & RCUTORTURE_RDR_RCU_1) {
1902 bool lockit;
1903
1904 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff);
1905 if (lockit)
1906 raw_spin_lock_irqsave(&current->pi_lock, flags);
1907 cur_ops->readunlock((idxold1 & RCUTORTURE_RDR_MASK_1) >> RCUTORTURE_RDR_SHIFT_1);
1908 WARN_ON_ONCE(idxnew1 != -1);
1909 idxold1 = 0;
1910 if (lockit)
1911 raw_spin_unlock_irqrestore(&current->pi_lock, flags);
1912 }
1913
1914 /* Delay if neither beginning nor end and there was a change. */
1915 if ((statesnew || statesold) && *readstate && newstate)
1916 cur_ops->read_delay(trsp, rtrsp);
1917
1918 /* Update the reader state. */
1919 if (idxnew1 == -1)
1920 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1;
1921 WARN_ON_ONCE(idxnew1 < 0);
1922 if (idxnew2 == -1)
1923 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2;
1924 WARN_ON_ONCE(idxnew2 < 0);
1925 *readstate = idxnew1 | idxnew2 | newstate;
1926 WARN_ON_ONCE(*readstate < 0);
1927 if (WARN_ON_ONCE(*readstate & ~RCUTORTURE_RDR_ALLBITS))
1928 pr_info("Unexpected readstate value of %#x\n", *readstate);
1929 }
1930
1931 /* Return the biggest extendables mask given current RCU and boot parameters. */
1932 static int rcutorture_extend_mask_max(void)
1933 {
1934 int mask;
1935
1936 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1937 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1938 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2;
1939 return mask;
1940 }
1941
1942 /* Return a random protection state mask, but with at least one bit set. */
1943 static int
1944 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1945 {
1946 int mask = rcutorture_extend_mask_max();
1947 unsigned long randmask1 = torture_random(trsp);
1948 unsigned long randmask2 = randmask1 >> 3;
1949 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
1950 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
1951 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1952
1953 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1); // Can't have reader idx bits.
1954 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
1955 if (!(randmask1 & 0x7))
1956 mask = mask & randmask2;
1957 else
1958 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1959
1960 // Can't have nested RCU reader without outer RCU reader.
1961 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) {
1962 if (oldmask & RCUTORTURE_RDR_RCU_1)
1963 mask &= ~RCUTORTURE_RDR_RCU_2;
1964 else
1965 mask |= RCUTORTURE_RDR_RCU_1;
1966 }
1967
1968 /*
1969 * Can't enable bh w/irq disabled.
1970 */
1971 if (mask & RCUTORTURE_RDR_IRQ)
1972 mask |= oldmask & bhs;
1973
1974 /*
1975 * Ideally these sequences would be detected in debug builds
1976 * (regardless of RT), but until then don't stop testing
1977 * them on non-RT.
1978 */
1979 if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
1980 /* Can't modify BH in atomic context */
1981 if (oldmask & preempts_irq)
1982 mask &= ~bhs;
1983 if ((oldmask | mask) & preempts_irq)
1984 mask |= oldmask & bhs;
1985 }
1986
1987 return mask ?: RCUTORTURE_RDR_RCU_1;
1988 }
1989
1990 /*
1991 * Do a randomly selected number of extensions of an existing RCU read-side
1992 * critical section.
1993 */
1994 static struct rt_read_seg *
1995 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1996 struct rt_read_seg *rtrsp)
1997 {
1998 int i;
1999 int j;
2000 int mask = rcutorture_extend_mask_max();
2001
2002 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
2003 if (!((mask - 1) & mask))
2004 return rtrsp; /* Current RCU reader not extendable. */
2005 /* Bias towards larger numbers of loops. */
2006 i = torture_random(trsp);
2007 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
2008 for (j = 0; j < i; j++) {
2009 mask = rcutorture_extend_mask(*readstate, trsp);
2010 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
2011 }
2012 return &rtrsp[j];
2013 }
2014
2015 /*
2016 * Do one read-side critical section, returning false if there was
2017 * no data to read. Can be invoked both from process context and
2018 * from a timer handler.
2019 */
2020 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
2021 {
2022 bool checkpolling = !(torture_random(trsp) & 0xfff);
2023 unsigned long cookie;
2024 struct rcu_gp_oldstate cookie_full;
2025 int i;
2026 unsigned long started;
2027 unsigned long completed;
2028 int newstate;
2029 struct rcu_torture *p;
2030 int pipe_count;
2031 int readstate = 0;
2032 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
2033 struct rt_read_seg *rtrsp = &rtseg[0];
2034 struct rt_read_seg *rtrsp1;
2035 unsigned long long ts;
2036
2037 WARN_ON_ONCE(!rcu_is_watching());
2038 newstate = rcutorture_extend_mask(readstate, trsp);
2039 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
2040 if (checkpolling) {
2041 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
2042 cookie = cur_ops->get_gp_state();
2043 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
2044 cur_ops->get_gp_state_full(&cookie_full);
2045 }
2046 started = cur_ops->get_gp_seq();
2047 ts = rcu_trace_clock_local();
2048 p = rcu_dereference_check(rcu_torture_current,
2049 !cur_ops->readlock_held || cur_ops->readlock_held());
2050 if (p == NULL) {
2051 /* Wait for rcu_torture_writer to get underway */
2052 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
2053 return false;
2054 }
2055 if (p->rtort_mbtest == 0)
2056 atomic_inc(&n_rcu_torture_mberror);
2057 rcu_torture_reader_do_mbchk(myid, p, trsp);
2058 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
2059 preempt_disable();
2060 pipe_count = READ_ONCE(p->rtort_pipe_count);
2061 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
2062 // Should not happen in a correct RCU implementation,
2063 // happens quite often for torture_type=busted.
2064 pipe_count = RCU_TORTURE_PIPE_LEN;
2065 }
2066 completed = cur_ops->get_gp_seq();
2067 if (pipe_count > 1) {
2068 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
2069 ts, started, completed);
2070 rcu_ftrace_dump(DUMP_ALL);
2071 }
2072 __this_cpu_inc(rcu_torture_count[pipe_count]);
2073 completed = rcutorture_seq_diff(completed, started);
2074 if (completed > RCU_TORTURE_PIPE_LEN) {
2075 /* Should not happen, but... */
2076 completed = RCU_TORTURE_PIPE_LEN;
2077 }
2078 __this_cpu_inc(rcu_torture_batch[completed]);
2079 preempt_enable();
2080 if (checkpolling) {
2081 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
2082 WARN_ONCE(cur_ops->poll_gp_state(cookie),
2083 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
2084 __func__,
2085 rcu_torture_writer_state_getname(),
2086 rcu_torture_writer_state,
2087 cookie, cur_ops->get_gp_state());
2088 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
2089 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
2090 "%s: Cookie check 6 failed %s(%d) online %*pbl\n",
2091 __func__,
2092 rcu_torture_writer_state_getname(),
2093 rcu_torture_writer_state,
2094 cpumask_pr_args(cpu_online_mask));
2095 }
2096 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
2097 WARN_ON_ONCE(readstate);
2098 // This next splat is expected behavior if leakpointer, especially
2099 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
2100 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1);
2101
2102 /* If error or close call, record the sequence of reader protections. */
2103 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
2104 i = 0;
2105 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
2106 err_segs[i++] = *rtrsp1;
2107 rt_read_nsegs = i;
2108 }
2109
2110 return true;
2111 }
2112
2113 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
2114
2115 /*
2116 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
2117 * incrementing the corresponding element of the pipeline array. The
2118 * counter in the element should never be greater than 1, otherwise, the
2119 * RCU implementation is broken.
2120 */
2121 static void rcu_torture_timer(struct timer_list *unused)
2122 {
2123 atomic_long_inc(&n_rcu_torture_timers);
2124 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1);
2125
2126 /* Test call_rcu() invocation from interrupt handler. */
2127 if (cur_ops->call) {
2128 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
2129
2130 if (rhp)
2131 cur_ops->call(rhp, rcu_torture_timer_cb);
2132 }
2133 }
2134
2135 /*
2136 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
2137 * incrementing the corresponding element of the pipeline array. The
2138 * counter in the element should never be greater than 1, otherwise, the
2139 * RCU implementation is broken.
2140 */
2141 static int
2142 rcu_torture_reader(void *arg)
2143 {
2144 unsigned long lastsleep = jiffies;
2145 long myid = (long)arg;
2146 int mynumonline = myid;
2147 DEFINE_TORTURE_RANDOM(rand);
2148 struct timer_list t;
2149
2150 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
2151 set_user_nice(current, MAX_NICE);
2152 if (irqreader && cur_ops->irq_capable)
2153 timer_setup_on_stack(&t, rcu_torture_timer, 0);
2154 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2155 do {
2156 if (irqreader && cur_ops->irq_capable) {
2157 if (!timer_pending(&t))
2158 mod_timer(&t, jiffies + 1);
2159 }
2160 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop())
2161 schedule_timeout_interruptible(HZ);
2162 if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
2163 torture_hrtimeout_us(500, 1000, &rand);
2164 lastsleep = jiffies + 10;
2165 }
2166 while (torture_num_online_cpus() < mynumonline && !torture_must_stop())
2167 schedule_timeout_interruptible(HZ / 5);
2168 stutter_wait("rcu_torture_reader");
2169 } while (!torture_must_stop());
2170 if (irqreader && cur_ops->irq_capable) {
2171 del_timer_sync(&t);
2172 destroy_timer_on_stack(&t);
2173 }
2174 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2175 torture_kthread_stopping("rcu_torture_reader");
2176 return 0;
2177 }
2178
2179 /*
2180 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to
2181 * increase race probabilities and fuzzes the interval between toggling.
2182 */
2183 static int rcu_nocb_toggle(void *arg)
2184 {
2185 int cpu;
2186 int maxcpu = -1;
2187 int oldnice = task_nice(current);
2188 long r;
2189 DEFINE_TORTURE_RANDOM(rand);
2190 ktime_t toggle_delay;
2191 unsigned long toggle_fuzz;
2192 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle);
2193
2194 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started");
2195 while (!rcu_inkernel_boot_has_ended())
2196 schedule_timeout_interruptible(HZ / 10);
2197 for_each_possible_cpu(cpu)
2198 maxcpu = cpu;
2199 WARN_ON(maxcpu < 0);
2200 if (toggle_interval > ULONG_MAX)
2201 toggle_fuzz = ULONG_MAX >> 3;
2202 else
2203 toggle_fuzz = toggle_interval >> 3;
2204 if (toggle_fuzz <= 0)
2205 toggle_fuzz = NSEC_PER_USEC;
2206 do {
2207 r = torture_random(&rand);
2208 cpu = (r >> 1) % (maxcpu + 1);
2209 if (r & 0x1) {
2210 rcu_nocb_cpu_offload(cpu);
2211 atomic_long_inc(&n_nocb_offload);
2212 } else {
2213 rcu_nocb_cpu_deoffload(cpu);
2214 atomic_long_inc(&n_nocb_deoffload);
2215 }
2216 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval;
2217 set_current_state(TASK_INTERRUPTIBLE);
2218 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL);
2219 if (stutter_wait("rcu_nocb_toggle"))
2220 sched_set_normal(current, oldnice);
2221 } while (!torture_must_stop());
2222 torture_kthread_stopping("rcu_nocb_toggle");
2223 return 0;
2224 }
2225
2226 /*
2227 * Print torture statistics. Caller must ensure that there is only
2228 * one call to this function at a given time!!! This is normally
2229 * accomplished by relying on the module system to only have one copy
2230 * of the module loaded, and then by giving the rcu_torture_stats
2231 * kthread full control (or the init/cleanup functions when rcu_torture_stats
2232 * thread is not running).
2233 */
2234 static void
2235 rcu_torture_stats_print(void)
2236 {
2237 int cpu;
2238 int i;
2239 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2240 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2241 struct rcu_torture *rtcp;
2242 static unsigned long rtcv_snap = ULONG_MAX;
2243 static bool splatted;
2244 struct task_struct *wtp;
2245
2246 for_each_possible_cpu(cpu) {
2247 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2248 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
2249 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
2250 }
2251 }
2252 for (i = RCU_TORTURE_PIPE_LEN; i >= 0; i--) {
2253 if (pipesummary[i] != 0)
2254 break;
2255 }
2256
2257 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2258 rtcp = rcu_access_pointer(rcu_torture_current);
2259 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
2260 rtcp,
2261 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
2262 rcu_torture_current_version,
2263 list_empty(&rcu_torture_freelist),
2264 atomic_read(&n_rcu_torture_alloc),
2265 atomic_read(&n_rcu_torture_alloc_fail),
2266 atomic_read(&n_rcu_torture_free));
2267 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld ",
2268 atomic_read(&n_rcu_torture_mberror),
2269 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries),
2270 n_rcu_torture_barrier_error,
2271 n_rcu_torture_boost_ktrerror);
2272 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
2273 n_rcu_torture_boost_failure,
2274 n_rcu_torture_boosts,
2275 atomic_long_read(&n_rcu_torture_timers));
2276 torture_onoff_stats();
2277 pr_cont("barrier: %ld/%ld:%ld ",
2278 data_race(n_barrier_successes),
2279 data_race(n_barrier_attempts),
2280 data_race(n_rcu_torture_barrier_error));
2281 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic.
2282 pr_cont("nocb-toggles: %ld:%ld\n",
2283 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload));
2284
2285 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2286 if (atomic_read(&n_rcu_torture_mberror) ||
2287 atomic_read(&n_rcu_torture_mbchk_fail) ||
2288 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
2289 n_rcu_torture_boost_failure || i > 1) {
2290 pr_cont("%s", "!!! ");
2291 atomic_inc(&n_rcu_torture_error);
2292 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
2293 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail));
2294 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
2295 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
2296 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
2297 WARN_ON_ONCE(i > 1); // Too-short grace period
2298 }
2299 pr_cont("Reader Pipe: ");
2300 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2301 pr_cont(" %ld", pipesummary[i]);
2302 pr_cont("\n");
2303
2304 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2305 pr_cont("Reader Batch: ");
2306 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2307 pr_cont(" %ld", batchsummary[i]);
2308 pr_cont("\n");
2309
2310 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2311 pr_cont("Free-Block Circulation: ");
2312 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2313 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
2314 }
2315 pr_cont("\n");
2316
2317 if (cur_ops->stats)
2318 cur_ops->stats();
2319 if (rtcv_snap == rcu_torture_current_version &&
2320 rcu_access_pointer(rcu_torture_current) &&
2321 !rcu_stall_is_suppressed()) {
2322 int __maybe_unused flags = 0;
2323 unsigned long __maybe_unused gp_seq = 0;
2324
2325 if (cur_ops->get_gp_data)
2326 cur_ops->get_gp_data(&flags, &gp_seq);
2327 wtp = READ_ONCE(writer_task);
2328 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n",
2329 rcu_torture_writer_state_getname(),
2330 rcu_torture_writer_state, gp_seq, flags,
2331 wtp == NULL ? ~0U : wtp->__state,
2332 wtp == NULL ? -1 : (int)task_cpu(wtp));
2333 if (!splatted && wtp) {
2334 sched_show_task(wtp);
2335 splatted = true;
2336 }
2337 if (cur_ops->gp_kthread_dbg)
2338 cur_ops->gp_kthread_dbg();
2339 rcu_ftrace_dump(DUMP_ALL);
2340 }
2341 rtcv_snap = rcu_torture_current_version;
2342 }
2343
2344 /*
2345 * Periodically prints torture statistics, if periodic statistics printing
2346 * was specified via the stat_interval module parameter.
2347 */
2348 static int
2349 rcu_torture_stats(void *arg)
2350 {
2351 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
2352 do {
2353 schedule_timeout_interruptible(stat_interval * HZ);
2354 rcu_torture_stats_print();
2355 torture_shutdown_absorb("rcu_torture_stats");
2356 } while (!torture_must_stop());
2357 torture_kthread_stopping("rcu_torture_stats");
2358 return 0;
2359 }
2360
2361 /* Test mem_dump_obj() and friends. */
2362 static void rcu_torture_mem_dump_obj(void)
2363 {
2364 struct rcu_head *rhp;
2365 struct kmem_cache *kcp;
2366 static int z;
2367
2368 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
2369 if (WARN_ON_ONCE(!kcp))
2370 return;
2371 rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
2372 if (WARN_ON_ONCE(!rhp)) {
2373 kmem_cache_destroy(kcp);
2374 return;
2375 }
2376 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
2377 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
2378 mem_dump_obj(ZERO_SIZE_PTR);
2379 pr_alert("mem_dump_obj(NULL):");
2380 mem_dump_obj(NULL);
2381 pr_alert("mem_dump_obj(%px):", &rhp);
2382 mem_dump_obj(&rhp);
2383 pr_alert("mem_dump_obj(%px):", rhp);
2384 mem_dump_obj(rhp);
2385 pr_alert("mem_dump_obj(%px):", &rhp->func);
2386 mem_dump_obj(&rhp->func);
2387 pr_alert("mem_dump_obj(%px):", &z);
2388 mem_dump_obj(&z);
2389 kmem_cache_free(kcp, rhp);
2390 kmem_cache_destroy(kcp);
2391 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
2392 if (WARN_ON_ONCE(!rhp))
2393 return;
2394 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2395 pr_alert("mem_dump_obj(kmalloc %px):", rhp);
2396 mem_dump_obj(rhp);
2397 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
2398 mem_dump_obj(&rhp->func);
2399 kfree(rhp);
2400 rhp = vmalloc(4096);
2401 if (WARN_ON_ONCE(!rhp))
2402 return;
2403 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2404 pr_alert("mem_dump_obj(vmalloc %px):", rhp);
2405 mem_dump_obj(rhp);
2406 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
2407 mem_dump_obj(&rhp->func);
2408 vfree(rhp);
2409 }
2410
2411 static void
2412 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
2413 {
2414 pr_alert("%s" TORTURE_FLAG
2415 "--- %s: nreaders=%d nfakewriters=%d "
2416 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
2417 "shuffle_interval=%d stutter=%d irqreader=%d "
2418 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
2419 "test_boost=%d/%d test_boost_interval=%d "
2420 "test_boost_duration=%d shutdown_secs=%d "
2421 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
2422 "stall_cpu_block=%d stall_cpu_repeat=%d "
2423 "n_barrier_cbs=%d "
2424 "onoff_interval=%d onoff_holdoff=%d "
2425 "read_exit_delay=%d read_exit_burst=%d "
2426 "reader_flavor=%x "
2427 "nocbs_nthreads=%d nocbs_toggle=%d "
2428 "test_nmis=%d\n",
2429 torture_type, tag, nrealreaders, nfakewriters,
2430 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
2431 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
2432 test_boost, cur_ops->can_boost,
2433 test_boost_interval, test_boost_duration, shutdown_secs,
2434 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
2435 stall_cpu_block, stall_cpu_repeat,
2436 n_barrier_cbs,
2437 onoff_interval, onoff_holdoff,
2438 read_exit_delay, read_exit_burst,
2439 reader_flavor,
2440 nocbs_nthreads, nocbs_toggle,
2441 test_nmis);
2442 }
2443
2444 static int rcutorture_booster_cleanup(unsigned int cpu)
2445 {
2446 struct task_struct *t;
2447
2448 if (boost_tasks[cpu] == NULL)
2449 return 0;
2450 mutex_lock(&boost_mutex);
2451 t = boost_tasks[cpu];
2452 boost_tasks[cpu] = NULL;
2453 rcu_torture_enable_rt_throttle();
2454 mutex_unlock(&boost_mutex);
2455
2456 /* This must be outside of the mutex, otherwise deadlock! */
2457 torture_stop_kthread(rcu_torture_boost, t);
2458 return 0;
2459 }
2460
2461 static int rcutorture_booster_init(unsigned int cpu)
2462 {
2463 int retval;
2464
2465 if (boost_tasks[cpu] != NULL)
2466 return 0; /* Already created, nothing more to do. */
2467
2468 // Testing RCU priority boosting requires rcutorture do
2469 // some serious abuse. Counter this by running ksoftirqd
2470 // at higher priority.
2471 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) {
2472 struct sched_param sp;
2473 struct task_struct *t;
2474
2475 t = per_cpu(ksoftirqd, cpu);
2476 WARN_ON_ONCE(!t);
2477 sp.sched_priority = 2;
2478 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
2479 #ifdef CONFIG_IRQ_FORCED_THREADING
2480 if (force_irqthreads()) {
2481 t = per_cpu(ktimerd, cpu);
2482 WARN_ON_ONCE(!t);
2483 sp.sched_priority = 2;
2484 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
2485 }
2486 #endif
2487 }
2488
2489 /* Don't allow time recalculation while creating a new task. */
2490 mutex_lock(&boost_mutex);
2491 rcu_torture_disable_rt_throttle();
2492 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
2493 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL,
2494 cpu, "rcu_torture_boost_%u");
2495 if (IS_ERR(boost_tasks[cpu])) {
2496 retval = PTR_ERR(boost_tasks[cpu]);
2497 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
2498 n_rcu_torture_boost_ktrerror++;
2499 boost_tasks[cpu] = NULL;
2500 mutex_unlock(&boost_mutex);
2501 return retval;
2502 }
2503 mutex_unlock(&boost_mutex);
2504 return 0;
2505 }
2506
2507 static int rcu_torture_stall_nf(struct notifier_block *nb, unsigned long v, void *ptr)
2508 {
2509 pr_info("%s: v=%lu, duration=%lu.\n", __func__, v, (unsigned long)ptr);
2510 return NOTIFY_OK;
2511 }
2512
2513 static struct notifier_block rcu_torture_stall_block = {
2514 .notifier_call = rcu_torture_stall_nf,
2515 };
2516
2517 /*
2518 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
2519 * induces a CPU stall for the time specified by stall_cpu. If a new
2520 * stall test is added, stallsdone in rcu_torture_writer() must be adjusted.
2521 */
2522 static void rcu_torture_stall_one(int rep, int irqsoff)
2523 {
2524 int idx;
2525 unsigned long stop_at;
2526
2527 if (stall_cpu_holdoff > 0) {
2528 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
2529 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
2530 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
2531 }
2532 if (!kthread_should_stop() && stall_gp_kthread > 0) {
2533 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
2534 rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
2535 for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
2536 if (kthread_should_stop())
2537 break;
2538 schedule_timeout_uninterruptible(HZ);
2539 }
2540 }
2541 if (!kthread_should_stop() && stall_cpu > 0) {
2542 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
2543 stop_at = ktime_get_seconds() + stall_cpu;
2544 /* RCU CPU stall is expected behavior in following code. */
2545 idx = cur_ops->readlock();
2546 if (irqsoff)
2547 local_irq_disable();
2548 else if (!stall_cpu_block)
2549 preempt_disable();
2550 pr_alert("%s start stall episode %d on CPU %d.\n",
2551 __func__, rep + 1, raw_smp_processor_id());
2552 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), stop_at) &&
2553 !kthread_should_stop())
2554 if (stall_cpu_block) {
2555 #ifdef CONFIG_PREEMPTION
2556 preempt_schedule();
2557 #else
2558 schedule_timeout_uninterruptible(HZ);
2559 #endif
2560 } else if (stall_no_softlockup) {
2561 touch_softlockup_watchdog();
2562 }
2563 if (irqsoff)
2564 local_irq_enable();
2565 else if (!stall_cpu_block)
2566 preempt_enable();
2567 cur_ops->readunlock(idx);
2568 }
2569 }
2570
2571 /*
2572 * CPU-stall kthread. Invokes rcu_torture_stall_one() once, and then as many
2573 * additional times as specified by the stall_cpu_repeat module parameter.
2574 * Note that stall_cpu_irqsoff is ignored on the second and subsequent
2575 * stall.
2576 */
2577 static int rcu_torture_stall(void *args)
2578 {
2579 int i;
2580 int repeat = stall_cpu_repeat;
2581 int ret;
2582
2583 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
2584 if (repeat < 0) {
2585 repeat = 0;
2586 WARN_ON_ONCE(IS_BUILTIN(CONFIG_RCU_TORTURE_TEST));
2587 }
2588 if (rcu_cpu_stall_notifiers) {
2589 ret = rcu_stall_chain_notifier_register(&rcu_torture_stall_block);
2590 if (ret)
2591 pr_info("%s: rcu_stall_chain_notifier_register() returned %d, %sexpected.\n",
2592 __func__, ret, !IS_ENABLED(CONFIG_RCU_STALL_COMMON) ? "un" : "");
2593 }
2594 for (i = 0; i <= repeat; i++) {
2595 if (kthread_should_stop())
2596 break;
2597 rcu_torture_stall_one(i, i == 0 ? stall_cpu_irqsoff : 0);
2598 }
2599 pr_alert("%s end.\n", __func__);
2600 if (rcu_cpu_stall_notifiers && !ret) {
2601 ret = rcu_stall_chain_notifier_unregister(&rcu_torture_stall_block);
2602 if (ret)
2603 pr_info("%s: rcu_stall_chain_notifier_unregister() returned %d.\n", __func__, ret);
2604 }
2605 torture_shutdown_absorb("rcu_torture_stall");
2606 while (!kthread_should_stop())
2607 schedule_timeout_interruptible(10 * HZ);
2608 return 0;
2609 }
2610
2611 /* Spawn CPU-stall kthread, if stall_cpu specified. */
2612 static int __init rcu_torture_stall_init(void)
2613 {
2614 if (stall_cpu <= 0 && stall_gp_kthread <= 0)
2615 return 0;
2616 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
2617 }
2618
2619 /* State structure for forward-progress self-propagating RCU callback. */
2620 struct fwd_cb_state {
2621 struct rcu_head rh;
2622 int stop;
2623 };
2624
2625 /*
2626 * Forward-progress self-propagating RCU callback function. Because
2627 * callbacks run from softirq, this function is an implicit RCU read-side
2628 * critical section.
2629 */
2630 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
2631 {
2632 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
2633
2634 if (READ_ONCE(fcsp->stop)) {
2635 WRITE_ONCE(fcsp->stop, 2);
2636 return;
2637 }
2638 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
2639 }
2640
2641 /* State for continuous-flood RCU callbacks. */
2642 struct rcu_fwd_cb {
2643 struct rcu_head rh;
2644 struct rcu_fwd_cb *rfc_next;
2645 struct rcu_fwd *rfc_rfp;
2646 int rfc_gps;
2647 };
2648
2649 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
2650 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
2651 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
2652 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
2653 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
2654
2655 struct rcu_launder_hist {
2656 long n_launders;
2657 unsigned long launder_gp_seq;
2658 };
2659
2660 struct rcu_fwd {
2661 spinlock_t rcu_fwd_lock;
2662 struct rcu_fwd_cb *rcu_fwd_cb_head;
2663 struct rcu_fwd_cb **rcu_fwd_cb_tail;
2664 long n_launders_cb;
2665 unsigned long rcu_fwd_startat;
2666 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
2667 unsigned long rcu_launder_gp_seq_start;
2668 int rcu_fwd_id;
2669 };
2670
2671 static DEFINE_MUTEX(rcu_fwd_mutex);
2672 static struct rcu_fwd *rcu_fwds;
2673 static unsigned long rcu_fwd_seq;
2674 static atomic_long_t rcu_fwd_max_cbs;
2675 static bool rcu_fwd_emergency_stop;
2676
2677 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
2678 {
2679 unsigned long gps;
2680 unsigned long gps_old;
2681 int i;
2682 int j;
2683
2684 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
2685 if (rfp->n_launders_hist[i].n_launders > 0)
2686 break;
2687 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):",
2688 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat);
2689 gps_old = rfp->rcu_launder_gp_seq_start;
2690 for (j = 0; j <= i; j++) {
2691 gps = rfp->n_launders_hist[j].launder_gp_seq;
2692 pr_cont(" %ds/%d: %ld:%ld",
2693 j + 1, FWD_CBS_HIST_DIV,
2694 rfp->n_launders_hist[j].n_launders,
2695 rcutorture_seq_diff(gps, gps_old));
2696 gps_old = gps;
2697 }
2698 pr_cont("\n");
2699 }
2700
2701 /* Callback function for continuous-flood RCU callbacks. */
2702 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
2703 {
2704 unsigned long flags;
2705 int i;
2706 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
2707 struct rcu_fwd_cb **rfcpp;
2708 struct rcu_fwd *rfp = rfcp->rfc_rfp;
2709
2710 rfcp->rfc_next = NULL;
2711 rfcp->rfc_gps++;
2712 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2713 rfcpp = rfp->rcu_fwd_cb_tail;
2714 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
2715 smp_store_release(rfcpp, rfcp);
2716 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
2717 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
2718 if (i >= ARRAY_SIZE(rfp->n_launders_hist))
2719 i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
2720 rfp->n_launders_hist[i].n_launders++;
2721 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
2722 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2723 }
2724
2725 // Give the scheduler a chance, even on nohz_full CPUs.
2726 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
2727 {
2728 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
2729 // Real call_rcu() floods hit userspace, so emulate that.
2730 if (need_resched() || (iter & 0xfff))
2731 schedule();
2732 return;
2733 }
2734 // No userspace emulation: CB invocation throttles call_rcu()
2735 cond_resched();
2736 }
2737
2738 /*
2739 * Free all callbacks on the rcu_fwd_cb_head list, either because the
2740 * test is over or because we hit an OOM event.
2741 */
2742 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
2743 {
2744 unsigned long flags;
2745 unsigned long freed = 0;
2746 struct rcu_fwd_cb *rfcp;
2747
2748 for (;;) {
2749 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2750 rfcp = rfp->rcu_fwd_cb_head;
2751 if (!rfcp) {
2752 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2753 break;
2754 }
2755 rfp->rcu_fwd_cb_head = rfcp->rfc_next;
2756 if (!rfp->rcu_fwd_cb_head)
2757 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2758 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2759 kfree(rfcp);
2760 freed++;
2761 rcu_torture_fwd_prog_cond_resched(freed);
2762 if (tick_nohz_full_enabled()) {
2763 local_irq_save(flags);
2764 rcu_momentary_eqs();
2765 local_irq_restore(flags);
2766 }
2767 }
2768 return freed;
2769 }
2770
2771 /* Carry out need_resched()/cond_resched() forward-progress testing. */
2772 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
2773 int *tested, int *tested_tries)
2774 {
2775 unsigned long cver;
2776 unsigned long dur;
2777 struct fwd_cb_state fcs;
2778 unsigned long gps;
2779 int idx;
2780 int sd;
2781 int sd4;
2782 bool selfpropcb = false;
2783 unsigned long stopat;
2784 static DEFINE_TORTURE_RANDOM(trs);
2785
2786 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2787 if (!cur_ops->sync)
2788 return; // Cannot do need_resched() forward progress testing without ->sync.
2789 if (cur_ops->call && cur_ops->cb_barrier) {
2790 init_rcu_head_on_stack(&fcs.rh);
2791 selfpropcb = true;
2792 }
2793
2794 /* Tight loop containing cond_resched(). */
2795 atomic_inc(&rcu_fwd_cb_nodelay);
2796 cur_ops->sync(); /* Later readers see above write. */
2797 if (selfpropcb) {
2798 WRITE_ONCE(fcs.stop, 0);
2799 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
2800 }
2801 cver = READ_ONCE(rcu_torture_current_version);
2802 gps = cur_ops->get_gp_seq();
2803 sd = cur_ops->stall_dur() + 1;
2804 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
2805 dur = sd4 + torture_random(&trs) % (sd - sd4);
2806 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2807 stopat = rfp->rcu_fwd_startat + dur;
2808 while (time_before(jiffies, stopat) &&
2809 !shutdown_time_arrived() &&
2810 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2811 idx = cur_ops->readlock();
2812 udelay(10);
2813 cur_ops->readunlock(idx);
2814 if (!fwd_progress_need_resched || need_resched())
2815 cond_resched();
2816 }
2817 (*tested_tries)++;
2818 if (!time_before(jiffies, stopat) &&
2819 !shutdown_time_arrived() &&
2820 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2821 (*tested)++;
2822 cver = READ_ONCE(rcu_torture_current_version) - cver;
2823 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2824 WARN_ON(!cver && gps < 2);
2825 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__,
2826 rfp->rcu_fwd_id, dur, cver, gps);
2827 }
2828 if (selfpropcb) {
2829 WRITE_ONCE(fcs.stop, 1);
2830 cur_ops->sync(); /* Wait for running CB to complete. */
2831 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2832 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
2833 }
2834
2835 if (selfpropcb) {
2836 WARN_ON(READ_ONCE(fcs.stop) != 2);
2837 destroy_rcu_head_on_stack(&fcs.rh);
2838 }
2839 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
2840 atomic_dec(&rcu_fwd_cb_nodelay);
2841 }
2842
2843 /* Carry out call_rcu() forward-progress testing. */
2844 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
2845 {
2846 unsigned long cver;
2847 unsigned long flags;
2848 unsigned long gps;
2849 int i;
2850 long n_launders;
2851 long n_launders_cb_snap;
2852 long n_launders_sa;
2853 long n_max_cbs;
2854 long n_max_gps;
2855 struct rcu_fwd_cb *rfcp;
2856 struct rcu_fwd_cb *rfcpn;
2857 unsigned long stopat;
2858 unsigned long stoppedat;
2859
2860 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2861 if (READ_ONCE(rcu_fwd_emergency_stop))
2862 return; /* Get out of the way quickly, no GP wait! */
2863 if (!cur_ops->call)
2864 return; /* Can't do call_rcu() fwd prog without ->call. */
2865
2866 /* Loop continuously posting RCU callbacks. */
2867 atomic_inc(&rcu_fwd_cb_nodelay);
2868 cur_ops->sync(); /* Later readers see above write. */
2869 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2870 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
2871 n_launders = 0;
2872 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
2873 n_launders_sa = 0;
2874 n_max_cbs = 0;
2875 n_max_gps = 0;
2876 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
2877 rfp->n_launders_hist[i].n_launders = 0;
2878 cver = READ_ONCE(rcu_torture_current_version);
2879 gps = cur_ops->get_gp_seq();
2880 rfp->rcu_launder_gp_seq_start = gps;
2881 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2882 while (time_before(jiffies, stopat) &&
2883 !shutdown_time_arrived() &&
2884 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2885 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
2886 rfcpn = NULL;
2887 if (rfcp)
2888 rfcpn = READ_ONCE(rfcp->rfc_next);
2889 if (rfcpn) {
2890 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
2891 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
2892 break;
2893 rfp->rcu_fwd_cb_head = rfcpn;
2894 n_launders++;
2895 n_launders_sa++;
2896 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) {
2897 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
2898 if (WARN_ON_ONCE(!rfcp)) {
2899 schedule_timeout_interruptible(1);
2900 continue;
2901 }
2902 n_max_cbs++;
2903 n_launders_sa = 0;
2904 rfcp->rfc_gps = 0;
2905 rfcp->rfc_rfp = rfp;
2906 } else {
2907 rfcp = NULL;
2908 }
2909 if (rfcp)
2910 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
2911 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
2912 if (tick_nohz_full_enabled()) {
2913 local_irq_save(flags);
2914 rcu_momentary_eqs();
2915 local_irq_restore(flags);
2916 }
2917 }
2918 stoppedat = jiffies;
2919 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
2920 cver = READ_ONCE(rcu_torture_current_version) - cver;
2921 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2922 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2923 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
2924 (void)rcu_torture_fwd_prog_cbfree(rfp);
2925
2926 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
2927 !shutdown_time_arrived()) {
2928 if (WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED) && cur_ops->gp_kthread_dbg)
2929 cur_ops->gp_kthread_dbg();
2930 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",
2931 __func__,
2932 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
2933 n_launders + n_max_cbs - n_launders_cb_snap,
2934 n_launders, n_launders_sa,
2935 n_max_gps, n_max_cbs, cver, gps, num_online_cpus());
2936 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs);
2937 mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
2938 rcu_torture_fwd_cb_hist(rfp);
2939 mutex_unlock(&rcu_fwd_mutex);
2940 }
2941 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
2942 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2943 atomic_dec(&rcu_fwd_cb_nodelay);
2944 }
2945
2946
2947 /*
2948 * OOM notifier, but this only prints diagnostic information for the
2949 * current forward-progress test.
2950 */
2951 static int rcutorture_oom_notify(struct notifier_block *self,
2952 unsigned long notused, void *nfreed)
2953 {
2954 int i;
2955 long ncbs;
2956 struct rcu_fwd *rfp;
2957
2958 mutex_lock(&rcu_fwd_mutex);
2959 rfp = rcu_fwds;
2960 if (!rfp) {
2961 mutex_unlock(&rcu_fwd_mutex);
2962 return NOTIFY_OK;
2963 }
2964 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
2965 __func__);
2966 for (i = 0; i < fwd_progress; i++) {
2967 rcu_torture_fwd_cb_hist(&rfp[i]);
2968 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2);
2969 }
2970 WRITE_ONCE(rcu_fwd_emergency_stop, true);
2971 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
2972 ncbs = 0;
2973 for (i = 0; i < fwd_progress; i++)
2974 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2975 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2976 cur_ops->cb_barrier();
2977 ncbs = 0;
2978 for (i = 0; i < fwd_progress; i++)
2979 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2980 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2981 cur_ops->cb_barrier();
2982 ncbs = 0;
2983 for (i = 0; i < fwd_progress; i++)
2984 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2985 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2986 smp_mb(); /* Frees before return to avoid redoing OOM. */
2987 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
2988 pr_info("%s returning after OOM processing.\n", __func__);
2989 mutex_unlock(&rcu_fwd_mutex);
2990 return NOTIFY_OK;
2991 }
2992
2993 static struct notifier_block rcutorture_oom_nb = {
2994 .notifier_call = rcutorture_oom_notify
2995 };
2996
2997 /* Carry out grace-period forward-progress testing. */
2998 static int rcu_torture_fwd_prog(void *args)
2999 {
3000 bool firsttime = true;
3001 long max_cbs;
3002 int oldnice = task_nice(current);
3003 unsigned long oldseq = READ_ONCE(rcu_fwd_seq);
3004 struct rcu_fwd *rfp = args;
3005 int tested = 0;
3006 int tested_tries = 0;
3007
3008 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
3009 rcu_bind_current_to_nocb();
3010 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
3011 set_user_nice(current, MAX_NICE);
3012 do {
3013 if (!rfp->rcu_fwd_id) {
3014 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
3015 WRITE_ONCE(rcu_fwd_emergency_stop, false);
3016 if (!firsttime) {
3017 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0);
3018 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs);
3019 }
3020 firsttime = false;
3021 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1);
3022 } else {
3023 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop())
3024 schedule_timeout_interruptible(HZ / 20);
3025 oldseq = READ_ONCE(rcu_fwd_seq);
3026 }
3027 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
3028 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id)
3029 rcu_torture_fwd_prog_cr(rfp);
3030 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) &&
3031 (!IS_ENABLED(CONFIG_TINY_RCU) ||
3032 (rcu_inkernel_boot_has_ended() &&
3033 torture_num_online_cpus() > rfp->rcu_fwd_id)))
3034 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
3035
3036 /* Avoid slow periods, better to test when busy. */
3037 if (stutter_wait("rcu_torture_fwd_prog"))
3038 sched_set_normal(current, oldnice);
3039 } while (!torture_must_stop());
3040 /* Short runs might not contain a valid forward-progress attempt. */
3041 if (!rfp->rcu_fwd_id) {
3042 WARN_ON(!tested && tested_tries >= 5);
3043 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
3044 }
3045 torture_kthread_stopping("rcu_torture_fwd_prog");
3046 return 0;
3047 }
3048
3049 /* If forward-progress checking is requested and feasible, spawn the thread. */
3050 static int __init rcu_torture_fwd_prog_init(void)
3051 {
3052 int i;
3053 int ret = 0;
3054 struct rcu_fwd *rfp;
3055
3056 if (!fwd_progress)
3057 return 0; /* Not requested, so don't do it. */
3058 if (fwd_progress >= nr_cpu_ids) {
3059 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n");
3060 fwd_progress = nr_cpu_ids;
3061 } else if (fwd_progress < 0) {
3062 fwd_progress = nr_cpu_ids;
3063 }
3064 if ((!cur_ops->sync && !cur_ops->call) ||
3065 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) ||
3066 cur_ops == &rcu_busted_ops) {
3067 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
3068 fwd_progress = 0;
3069 return 0;
3070 }
3071 if (stall_cpu > 0) {
3072 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
3073 fwd_progress = 0;
3074 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST))
3075 return -EINVAL; /* In module, can fail back to user. */
3076 WARN_ON(1); /* Make sure rcutorture notices conflict. */
3077 return 0;
3078 }
3079 if (fwd_progress_holdoff <= 0)
3080 fwd_progress_holdoff = 1;
3081 if (fwd_progress_div <= 0)
3082 fwd_progress_div = 4;
3083 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL);
3084 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL);
3085 if (!rfp || !fwd_prog_tasks) {
3086 kfree(rfp);
3087 kfree(fwd_prog_tasks);
3088 fwd_prog_tasks = NULL;
3089 fwd_progress = 0;
3090 return -ENOMEM;
3091 }
3092 for (i = 0; i < fwd_progress; i++) {
3093 spin_lock_init(&rfp[i].rcu_fwd_lock);
3094 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head;
3095 rfp[i].rcu_fwd_id = i;
3096 }
3097 mutex_lock(&rcu_fwd_mutex);
3098 rcu_fwds = rfp;
3099 mutex_unlock(&rcu_fwd_mutex);
3100 register_oom_notifier(&rcutorture_oom_nb);
3101 for (i = 0; i < fwd_progress; i++) {
3102 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]);
3103 if (ret) {
3104 fwd_progress = i;
3105 return ret;
3106 }
3107 }
3108 return 0;
3109 }
3110
3111 static void rcu_torture_fwd_prog_cleanup(void)
3112 {
3113 int i;
3114 struct rcu_fwd *rfp;
3115
3116 if (!rcu_fwds || !fwd_prog_tasks)
3117 return;
3118 for (i = 0; i < fwd_progress; i++)
3119 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]);
3120 unregister_oom_notifier(&rcutorture_oom_nb);
3121 mutex_lock(&rcu_fwd_mutex);
3122 rfp = rcu_fwds;
3123 rcu_fwds = NULL;
3124 mutex_unlock(&rcu_fwd_mutex);
3125 kfree(rfp);
3126 kfree(fwd_prog_tasks);
3127 fwd_prog_tasks = NULL;
3128 }
3129
3130 /* Callback function for RCU barrier testing. */
3131 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
3132 {
3133 atomic_inc(&barrier_cbs_invoked);
3134 }
3135
3136 /* IPI handler to get callback posted on desired CPU, if online. */
3137 static int rcu_torture_barrier1cb(void *rcu_void)
3138 {
3139 struct rcu_head *rhp = rcu_void;
3140
3141 cur_ops->call(rhp, rcu_torture_barrier_cbf);
3142 return 0;
3143 }
3144
3145 /* kthread function to register callbacks used to test RCU barriers. */
3146 static int rcu_torture_barrier_cbs(void *arg)
3147 {
3148 long myid = (long)arg;
3149 bool lastphase = false;
3150 bool newphase;
3151 struct rcu_head rcu;
3152
3153 init_rcu_head_on_stack(&rcu);
3154 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
3155 set_user_nice(current, MAX_NICE);
3156 do {
3157 wait_event(barrier_cbs_wq[myid],
3158 (newphase =
3159 smp_load_acquire(&barrier_phase)) != lastphase ||
3160 torture_must_stop());
3161 lastphase = newphase;
3162 if (torture_must_stop())
3163 break;
3164 /*
3165 * The above smp_load_acquire() ensures barrier_phase load
3166 * is ordered before the following ->call().
3167 */
3168 if (smp_call_on_cpu(myid, rcu_torture_barrier1cb, &rcu, 1))
3169 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
3170
3171 if (atomic_dec_and_test(&barrier_cbs_count))
3172 wake_up(&barrier_wq);
3173 } while (!torture_must_stop());
3174 if (cur_ops->cb_barrier != NULL)
3175 cur_ops->cb_barrier();
3176 destroy_rcu_head_on_stack(&rcu);
3177 torture_kthread_stopping("rcu_torture_barrier_cbs");
3178 return 0;
3179 }
3180
3181 /* kthread function to drive and coordinate RCU barrier testing. */
3182 static int rcu_torture_barrier(void *arg)
3183 {
3184 int i;
3185
3186 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
3187 do {
3188 atomic_set(&barrier_cbs_invoked, 0);
3189 atomic_set(&barrier_cbs_count, n_barrier_cbs);
3190 /* Ensure barrier_phase ordered after prior assignments. */
3191 smp_store_release(&barrier_phase, !barrier_phase);
3192 for (i = 0; i < n_barrier_cbs; i++)
3193 wake_up(&barrier_cbs_wq[i]);
3194 wait_event(barrier_wq,
3195 atomic_read(&barrier_cbs_count) == 0 ||
3196 torture_must_stop());
3197 if (torture_must_stop())
3198 break;
3199 n_barrier_attempts++;
3200 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
3201 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
3202 n_rcu_torture_barrier_error++;
3203 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
3204 atomic_read(&barrier_cbs_invoked),
3205 n_barrier_cbs);
3206 WARN_ON(1);
3207 // Wait manually for the remaining callbacks
3208 i = 0;
3209 do {
3210 if (WARN_ON(i++ > HZ))
3211 i = INT_MIN;
3212 schedule_timeout_interruptible(1);
3213 cur_ops->cb_barrier();
3214 } while (atomic_read(&barrier_cbs_invoked) !=
3215 n_barrier_cbs &&
3216 !torture_must_stop());
3217 smp_mb(); // Can't trust ordering if broken.
3218 if (!torture_must_stop())
3219 pr_err("Recovered: barrier_cbs_invoked = %d\n",
3220 atomic_read(&barrier_cbs_invoked));
3221 } else {
3222 n_barrier_successes++;
3223 }
3224 schedule_timeout_interruptible(HZ / 10);
3225 } while (!torture_must_stop());
3226 torture_kthread_stopping("rcu_torture_barrier");
3227 return 0;
3228 }
3229
3230 /* Initialize RCU barrier testing. */
3231 static int rcu_torture_barrier_init(void)
3232 {
3233 int i;
3234 int ret;
3235
3236 if (n_barrier_cbs <= 0)
3237 return 0;
3238 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
3239 pr_alert("%s" TORTURE_FLAG
3240 " Call or barrier ops missing for %s,\n",
3241 torture_type, cur_ops->name);
3242 pr_alert("%s" TORTURE_FLAG
3243 " RCU barrier testing omitted from run.\n",
3244 torture_type);
3245 return 0;
3246 }
3247 atomic_set(&barrier_cbs_count, 0);
3248 atomic_set(&barrier_cbs_invoked, 0);
3249 barrier_cbs_tasks =
3250 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
3251 GFP_KERNEL);
3252 barrier_cbs_wq =
3253 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
3254 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
3255 return -ENOMEM;
3256 for (i = 0; i < n_barrier_cbs; i++) {
3257 init_waitqueue_head(&barrier_cbs_wq[i]);
3258 ret = torture_create_kthread(rcu_torture_barrier_cbs,
3259 (void *)(long)i,
3260 barrier_cbs_tasks[i]);
3261 if (ret)
3262 return ret;
3263 }
3264 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
3265 }
3266
3267 /* Clean up after RCU barrier testing. */
3268 static void rcu_torture_barrier_cleanup(void)
3269 {
3270 int i;
3271
3272 torture_stop_kthread(rcu_torture_barrier, barrier_task);
3273 if (barrier_cbs_tasks != NULL) {
3274 for (i = 0; i < n_barrier_cbs; i++)
3275 torture_stop_kthread(rcu_torture_barrier_cbs,
3276 barrier_cbs_tasks[i]);
3277 kfree(barrier_cbs_tasks);
3278 barrier_cbs_tasks = NULL;
3279 }
3280 if (barrier_cbs_wq != NULL) {
3281 kfree(barrier_cbs_wq);
3282 barrier_cbs_wq = NULL;
3283 }
3284 }
3285
3286 static bool rcu_torture_can_boost(void)
3287 {
3288 static int boost_warn_once;
3289 int prio;
3290
3291 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
3292 return false;
3293 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)
3294 return false;
3295
3296 prio = rcu_get_gp_kthreads_prio();
3297 if (!prio)
3298 return false;
3299
3300 if (prio < 2) {
3301 if (boost_warn_once == 1)
3302 return false;
3303
3304 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);
3305 boost_warn_once = 1;
3306 return false;
3307 }
3308
3309 return true;
3310 }
3311
3312 static bool read_exit_child_stop;
3313 static bool read_exit_child_stopped;
3314 static wait_queue_head_t read_exit_wq;
3315
3316 // Child kthread which just does an rcutorture reader and exits.
3317 static int rcu_torture_read_exit_child(void *trsp_in)
3318 {
3319 struct torture_random_state *trsp = trsp_in;
3320
3321 set_user_nice(current, MAX_NICE);
3322 // Minimize time between reading and exiting.
3323 while (!kthread_should_stop())
3324 schedule_timeout_uninterruptible(HZ / 20);
3325 (void)rcu_torture_one_read(trsp, -1);
3326 return 0;
3327 }
3328
3329 // Parent kthread which creates and destroys read-exit child kthreads.
3330 static int rcu_torture_read_exit(void *unused)
3331 {
3332 bool errexit = false;
3333 int i;
3334 struct task_struct *tsp;
3335 DEFINE_TORTURE_RANDOM(trs);
3336
3337 // Allocate and initialize.
3338 set_user_nice(current, MAX_NICE);
3339 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
3340
3341 // Each pass through this loop does one read-exit episode.
3342 do {
3343 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
3344 for (i = 0; i < read_exit_burst; i++) {
3345 if (READ_ONCE(read_exit_child_stop))
3346 break;
3347 stutter_wait("rcu_torture_read_exit");
3348 // Spawn child.
3349 tsp = kthread_run(rcu_torture_read_exit_child,
3350 &trs, "%s", "rcu_torture_read_exit_child");
3351 if (IS_ERR(tsp)) {
3352 TOROUT_ERRSTRING("out of memory");
3353 errexit = true;
3354 break;
3355 }
3356 cond_resched();
3357 kthread_stop(tsp);
3358 n_read_exits++;
3359 }
3360 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
3361 rcu_barrier(); // Wait for task_struct free, avoid OOM.
3362 i = 0;
3363 for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++)
3364 schedule_timeout_uninterruptible(HZ);
3365 } while (!errexit && !READ_ONCE(read_exit_child_stop));
3366
3367 // Clean up and exit.
3368 smp_store_release(&read_exit_child_stopped, true); // After reaping.
3369 smp_mb(); // Store before wakeup.
3370 wake_up(&read_exit_wq);
3371 while (!torture_must_stop())
3372 schedule_timeout_uninterruptible(HZ / 20);
3373 torture_kthread_stopping("rcu_torture_read_exit");
3374 return 0;
3375 }
3376
3377 static int rcu_torture_read_exit_init(void)
3378 {
3379 if (read_exit_burst <= 0)
3380 return 0;
3381 init_waitqueue_head(&read_exit_wq);
3382 read_exit_child_stop = false;
3383 read_exit_child_stopped = false;
3384 return torture_create_kthread(rcu_torture_read_exit, NULL,
3385 read_exit_task);
3386 }
3387
3388 static void rcu_torture_read_exit_cleanup(void)
3389 {
3390 if (!read_exit_task)
3391 return;
3392 WRITE_ONCE(read_exit_child_stop, true);
3393 smp_mb(); // Above write before wait.
3394 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
3395 torture_stop_kthread(rcutorture_read_exit, read_exit_task);
3396 }
3397
3398 static void rcutorture_test_nmis(int n)
3399 {
3400 #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3401 int cpu;
3402 int dumpcpu;
3403 int i;
3404
3405 for (i = 0; i < n; i++) {
3406 preempt_disable();
3407 cpu = smp_processor_id();
3408 dumpcpu = cpu + 1;
3409 if (dumpcpu >= nr_cpu_ids)
3410 dumpcpu = 0;
3411 pr_alert("%s: CPU %d invoking dump_cpu_task(%d)\n", __func__, cpu, dumpcpu);
3412 dump_cpu_task(dumpcpu);
3413 preempt_enable();
3414 schedule_timeout_uninterruptible(15 * HZ);
3415 }
3416 #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3417 WARN_ONCE(n, "Non-zero rcutorture.test_nmis=%d permitted only when rcutorture is built in.\n", test_nmis);
3418 #endif // #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3419 }
3420
3421 static enum cpuhp_state rcutor_hp;
3422
3423 static void
3424 rcu_torture_cleanup(void)
3425 {
3426 int firsttime;
3427 int flags = 0;
3428 unsigned long gp_seq = 0;
3429 int i;
3430
3431 if (torture_cleanup_begin()) {
3432 if (cur_ops->cb_barrier != NULL) {
3433 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3434 cur_ops->cb_barrier();
3435 }
3436 if (cur_ops->gp_slow_unregister)
3437 cur_ops->gp_slow_unregister(NULL);
3438 return;
3439 }
3440 if (!cur_ops) {
3441 torture_cleanup_end();
3442 return;
3443 }
3444
3445 rcutorture_test_nmis(test_nmis);
3446
3447 if (cur_ops->gp_kthread_dbg)
3448 cur_ops->gp_kthread_dbg();
3449 rcu_torture_read_exit_cleanup();
3450 rcu_torture_barrier_cleanup();
3451 rcu_torture_fwd_prog_cleanup();
3452 torture_stop_kthread(rcu_torture_stall, stall_task);
3453 torture_stop_kthread(rcu_torture_writer, writer_task);
3454
3455 if (nocb_tasks) {
3456 for (i = 0; i < nrealnocbers; i++)
3457 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]);
3458 kfree(nocb_tasks);
3459 nocb_tasks = NULL;
3460 }
3461
3462 if (reader_tasks) {
3463 for (i = 0; i < nrealreaders; i++)
3464 torture_stop_kthread(rcu_torture_reader,
3465 reader_tasks[i]);
3466 kfree(reader_tasks);
3467 reader_tasks = NULL;
3468 }
3469 kfree(rcu_torture_reader_mbchk);
3470 rcu_torture_reader_mbchk = NULL;
3471
3472 if (fakewriter_tasks) {
3473 for (i = 0; i < nfakewriters; i++)
3474 torture_stop_kthread(rcu_torture_fakewriter,
3475 fakewriter_tasks[i]);
3476 kfree(fakewriter_tasks);
3477 fakewriter_tasks = NULL;
3478 }
3479
3480 if (cur_ops->get_gp_data)
3481 cur_ops->get_gp_data(&flags, &gp_seq);
3482 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n",
3483 cur_ops->name, (long)gp_seq, flags,
3484 rcutorture_seq_diff(gp_seq, start_gp_seq));
3485 torture_stop_kthread(rcu_torture_stats, stats_task);
3486 torture_stop_kthread(rcu_torture_fqs, fqs_task);
3487 if (rcu_torture_can_boost() && rcutor_hp >= 0)
3488 cpuhp_remove_state(rcutor_hp);
3489
3490 /*
3491 * Wait for all RCU callbacks to fire, then do torture-type-specific
3492 * cleanup operations.
3493 */
3494 if (cur_ops->cb_barrier != NULL) {
3495 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3496 cur_ops->cb_barrier();
3497 }
3498 if (cur_ops->cleanup != NULL)
3499 cur_ops->cleanup();
3500
3501 rcu_torture_mem_dump_obj();
3502
3503 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
3504
3505 if (err_segs_recorded) {
3506 pr_alert("Failure/close-call rcutorture reader segments:\n");
3507 if (rt_read_nsegs == 0)
3508 pr_alert("\t: No segments recorded!!!\n");
3509 firsttime = 1;
3510 for (i = 0; i < rt_read_nsegs; i++) {
3511 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
3512 if (err_segs[i].rt_delay_jiffies != 0) {
3513 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
3514 err_segs[i].rt_delay_jiffies);
3515 firsttime = 0;
3516 }
3517 if (err_segs[i].rt_delay_ms != 0) {
3518 pr_cont("%s%ldms", firsttime ? "" : "+",
3519 err_segs[i].rt_delay_ms);
3520 firsttime = 0;
3521 }
3522 if (err_segs[i].rt_delay_us != 0) {
3523 pr_cont("%s%ldus", firsttime ? "" : "+",
3524 err_segs[i].rt_delay_us);
3525 firsttime = 0;
3526 }
3527 pr_cont("%s\n",
3528 err_segs[i].rt_preempted ? "preempted" : "");
3529
3530 }
3531 }
3532 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
3533 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
3534 else if (torture_onoff_failures())
3535 rcu_torture_print_module_parms(cur_ops,
3536 "End of test: RCU_HOTPLUG");
3537 else
3538 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
3539 torture_cleanup_end();
3540 if (cur_ops->gp_slow_unregister)
3541 cur_ops->gp_slow_unregister(NULL);
3542 }
3543
3544 static void rcu_torture_leak_cb(struct rcu_head *rhp)
3545 {
3546 }
3547
3548 static void rcu_torture_err_cb(struct rcu_head *rhp)
3549 {
3550 /*
3551 * This -might- happen due to race conditions, but is unlikely.
3552 * The scenario that leads to this happening is that the
3553 * first of the pair of duplicate callbacks is queued,
3554 * someone else starts a grace period that includes that
3555 * callback, then the second of the pair must wait for the
3556 * next grace period. Unlikely, but can happen. If it
3557 * does happen, the debug-objects subsystem won't have splatted.
3558 */
3559 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
3560 }
3561
3562 /*
3563 * Verify that double-free causes debug-objects to complain, but only
3564 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
3565 * cannot be carried out.
3566 */
3567 static void rcu_test_debug_objects(void)
3568 {
3569 struct rcu_head rh1;
3570 struct rcu_head rh2;
3571 int idx;
3572
3573 if (!IS_ENABLED(CONFIG_DEBUG_OBJECTS_RCU_HEAD)) {
3574 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_%s()\n",
3575 KBUILD_MODNAME, cur_ops->name);
3576 return;
3577 }
3578
3579 if (WARN_ON_ONCE(cur_ops->debug_objects &&
3580 (!cur_ops->call || !cur_ops->cb_barrier)))
3581 return;
3582
3583 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
3584
3585 init_rcu_head_on_stack(&rh1);
3586 init_rcu_head_on_stack(&rh2);
3587 pr_alert("%s: WARN: Duplicate call_%s() test starting.\n", KBUILD_MODNAME, cur_ops->name);
3588
3589 /* Try to queue the rh2 pair of callbacks for the same grace period. */
3590 idx = cur_ops->readlock(); /* Make it impossible to finish a grace period. */
3591 cur_ops->call(&rh1, rcu_torture_leak_cb); /* Start grace period. */
3592 cur_ops->call(&rh2, rcu_torture_leak_cb);
3593 cur_ops->call(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
3594 if (rhp) {
3595 cur_ops->call(rhp, rcu_torture_leak_cb);
3596 cur_ops->call(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
3597 }
3598 cur_ops->readunlock(idx);
3599
3600 /* Wait for them all to get done so we can safely return. */
3601 cur_ops->cb_barrier();
3602 pr_alert("%s: WARN: Duplicate call_%s() test complete.\n", KBUILD_MODNAME, cur_ops->name);
3603 destroy_rcu_head_on_stack(&rh1);
3604 destroy_rcu_head_on_stack(&rh2);
3605 kfree(rhp);
3606 }
3607
3608 static void rcutorture_sync(void)
3609 {
3610 static unsigned long n;
3611
3612 if (cur_ops->sync && !(++n & 0xfff))
3613 cur_ops->sync();
3614 }
3615
3616 static DEFINE_MUTEX(mut0);
3617 static DEFINE_MUTEX(mut1);
3618 static DEFINE_MUTEX(mut2);
3619 static DEFINE_MUTEX(mut3);
3620 static DEFINE_MUTEX(mut4);
3621 static DEFINE_MUTEX(mut5);
3622 static DEFINE_MUTEX(mut6);
3623 static DEFINE_MUTEX(mut7);
3624 static DEFINE_MUTEX(mut8);
3625 static DEFINE_MUTEX(mut9);
3626
3627 static DECLARE_RWSEM(rwsem0);
3628 static DECLARE_RWSEM(rwsem1);
3629 static DECLARE_RWSEM(rwsem2);
3630 static DECLARE_RWSEM(rwsem3);
3631 static DECLARE_RWSEM(rwsem4);
3632 static DECLARE_RWSEM(rwsem5);
3633 static DECLARE_RWSEM(rwsem6);
3634 static DECLARE_RWSEM(rwsem7);
3635 static DECLARE_RWSEM(rwsem8);
3636 static DECLARE_RWSEM(rwsem9);
3637
3638 DEFINE_STATIC_SRCU(srcu0);
3639 DEFINE_STATIC_SRCU(srcu1);
3640 DEFINE_STATIC_SRCU(srcu2);
3641 DEFINE_STATIC_SRCU(srcu3);
3642 DEFINE_STATIC_SRCU(srcu4);
3643 DEFINE_STATIC_SRCU(srcu5);
3644 DEFINE_STATIC_SRCU(srcu6);
3645 DEFINE_STATIC_SRCU(srcu7);
3646 DEFINE_STATIC_SRCU(srcu8);
3647 DEFINE_STATIC_SRCU(srcu9);
3648
3649 static int srcu_lockdep_next(const char *f, const char *fl, const char *fs, const char *fu, int i,
3650 int cyclelen, int deadlock)
3651 {
3652 int j = i + 1;
3653
3654 if (j >= cyclelen)
3655 j = deadlock ? 0 : -1;
3656 if (j >= 0)
3657 pr_info("%s: %s(%d), %s(%d), %s(%d)\n", f, fl, i, fs, j, fu, i);
3658 else
3659 pr_info("%s: %s(%d), %s(%d)\n", f, fl, i, fu, i);
3660 return j;
3661 }
3662
3663 // Test lockdep on SRCU-based deadlock scenarios.
3664 static void rcu_torture_init_srcu_lockdep(void)
3665 {
3666 int cyclelen;
3667 int deadlock;
3668 bool err = false;
3669 int i;
3670 int j;
3671 int idx;
3672 struct mutex *muts[] = { &mut0, &mut1, &mut2, &mut3, &mut4,
3673 &mut5, &mut6, &mut7, &mut8, &mut9 };
3674 struct rw_semaphore *rwsems[] = { &rwsem0, &rwsem1, &rwsem2, &rwsem3, &rwsem4,
3675 &rwsem5, &rwsem6, &rwsem7, &rwsem8, &rwsem9 };
3676 struct srcu_struct *srcus[] = { &srcu0, &srcu1, &srcu2, &srcu3, &srcu4,
3677 &srcu5, &srcu6, &srcu7, &srcu8, &srcu9 };
3678 int testtype;
3679
3680 if (!test_srcu_lockdep)
3681 return;
3682
3683 deadlock = test_srcu_lockdep / 1000;
3684 testtype = (test_srcu_lockdep / 10) % 100;
3685 cyclelen = test_srcu_lockdep % 10;
3686 WARN_ON_ONCE(ARRAY_SIZE(muts) != ARRAY_SIZE(srcus));
3687 if (WARN_ONCE(deadlock != !!deadlock,
3688 "%s: test_srcu_lockdep=%d and deadlock digit %d must be zero or one.\n",
3689 __func__, test_srcu_lockdep, deadlock))
3690 err = true;
3691 if (WARN_ONCE(cyclelen <= 0,
3692 "%s: test_srcu_lockdep=%d and cycle-length digit %d must be greater than zero.\n",
3693 __func__, test_srcu_lockdep, cyclelen))
3694 err = true;
3695 if (err)
3696 goto err_out;
3697
3698 if (testtype == 0) {
3699 pr_info("%s: test_srcu_lockdep = %05d: SRCU %d-way %sdeadlock.\n",
3700 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3701 if (deadlock && cyclelen == 1)
3702 pr_info("%s: Expect hang.\n", __func__);
3703 for (i = 0; i < cyclelen; i++) {
3704 j = srcu_lockdep_next(__func__, "srcu_read_lock", "synchronize_srcu",
3705 "srcu_read_unlock", i, cyclelen, deadlock);
3706 idx = srcu_read_lock(srcus[i]);
3707 if (j >= 0)
3708 synchronize_srcu(srcus[j]);
3709 srcu_read_unlock(srcus[i], idx);
3710 }
3711 return;
3712 }
3713
3714 if (testtype == 1) {
3715 pr_info("%s: test_srcu_lockdep = %05d: SRCU/mutex %d-way %sdeadlock.\n",
3716 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3717 for (i = 0; i < cyclelen; i++) {
3718 pr_info("%s: srcu_read_lock(%d), mutex_lock(%d), mutex_unlock(%d), srcu_read_unlock(%d)\n",
3719 __func__, i, i, i, i);
3720 idx = srcu_read_lock(srcus[i]);
3721 mutex_lock(muts[i]);
3722 mutex_unlock(muts[i]);
3723 srcu_read_unlock(srcus[i], idx);
3724
3725 j = srcu_lockdep_next(__func__, "mutex_lock", "synchronize_srcu",
3726 "mutex_unlock", i, cyclelen, deadlock);
3727 mutex_lock(muts[i]);
3728 if (j >= 0)
3729 synchronize_srcu(srcus[j]);
3730 mutex_unlock(muts[i]);
3731 }
3732 return;
3733 }
3734
3735 if (testtype == 2) {
3736 pr_info("%s: test_srcu_lockdep = %05d: SRCU/rwsem %d-way %sdeadlock.\n",
3737 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3738 for (i = 0; i < cyclelen; i++) {
3739 pr_info("%s: srcu_read_lock(%d), down_read(%d), up_read(%d), srcu_read_unlock(%d)\n",
3740 __func__, i, i, i, i);
3741 idx = srcu_read_lock(srcus[i]);
3742 down_read(rwsems[i]);
3743 up_read(rwsems[i]);
3744 srcu_read_unlock(srcus[i], idx);
3745
3746 j = srcu_lockdep_next(__func__, "down_write", "synchronize_srcu",
3747 "up_write", i, cyclelen, deadlock);
3748 down_write(rwsems[i]);
3749 if (j >= 0)
3750 synchronize_srcu(srcus[j]);
3751 up_write(rwsems[i]);
3752 }
3753 return;
3754 }
3755
3756 #ifdef CONFIG_TASKS_TRACE_RCU
3757 if (testtype == 3) {
3758 pr_info("%s: test_srcu_lockdep = %05d: SRCU and Tasks Trace RCU %d-way %sdeadlock.\n",
3759 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
3760 if (deadlock && cyclelen == 1)
3761 pr_info("%s: Expect hang.\n", __func__);
3762 for (i = 0; i < cyclelen; i++) {
3763 char *fl = i == 0 ? "rcu_read_lock_trace" : "srcu_read_lock";
3764 char *fs = i == cyclelen - 1 ? "synchronize_rcu_tasks_trace"
3765 : "synchronize_srcu";
3766 char *fu = i == 0 ? "rcu_read_unlock_trace" : "srcu_read_unlock";
3767
3768 j = srcu_lockdep_next(__func__, fl, fs, fu, i, cyclelen, deadlock);
3769 if (i == 0)
3770 rcu_read_lock_trace();
3771 else
3772 idx = srcu_read_lock(srcus[i]);
3773 if (j >= 0) {
3774 if (i == cyclelen - 1)
3775 synchronize_rcu_tasks_trace();
3776 else
3777 synchronize_srcu(srcus[j]);
3778 }
3779 if (i == 0)
3780 rcu_read_unlock_trace();
3781 else
3782 srcu_read_unlock(srcus[i], idx);
3783 }
3784 return;
3785 }
3786 #endif // #ifdef CONFIG_TASKS_TRACE_RCU
3787
3788 err_out:
3789 pr_info("%s: test_srcu_lockdep = %05d does nothing.\n", __func__, test_srcu_lockdep);
3790 pr_info("%s: test_srcu_lockdep = DNNL.\n", __func__);
3791 pr_info("%s: D: Deadlock if nonzero.\n", __func__);
3792 pr_info("%s: NN: Test number, 0=SRCU, 1=SRCU/mutex, 2=SRCU/rwsem, 3=SRCU/Tasks Trace RCU.\n", __func__);
3793 pr_info("%s: L: Cycle length.\n", __func__);
3794 if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU))
3795 pr_info("%s: NN=3 disallowed because kernel is built with CONFIG_TASKS_TRACE_RCU=n\n", __func__);
3796 }
3797
3798 static int __init
3799 rcu_torture_init(void)
3800 {
3801 long i;
3802 int cpu;
3803 int firsterr = 0;
3804 int flags = 0;
3805 unsigned long gp_seq = 0;
3806 static struct rcu_torture_ops *torture_ops[] = {
3807 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops,
3808 TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
3809 &trivial_ops,
3810 };
3811
3812 if (!torture_init_begin(torture_type, verbose))
3813 return -EBUSY;
3814
3815 /* Process args and tell the world that the torturer is on the job. */
3816 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
3817 cur_ops = torture_ops[i];
3818 if (strcmp(torture_type, cur_ops->name) == 0)
3819 break;
3820 }
3821 if (i == ARRAY_SIZE(torture_ops)) {
3822 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
3823 torture_type);
3824 pr_alert("rcu-torture types:");
3825 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
3826 pr_cont(" %s", torture_ops[i]->name);
3827 pr_cont("\n");
3828 firsterr = -EINVAL;
3829 cur_ops = NULL;
3830 goto unwind;
3831 }
3832 if (cur_ops->fqs == NULL && fqs_duration != 0) {
3833 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
3834 fqs_duration = 0;
3835 }
3836 if (nocbs_nthreads != 0 && (cur_ops != &rcu_ops ||
3837 !IS_ENABLED(CONFIG_RCU_NOCB_CPU))) {
3838 pr_alert("rcu-torture types: %s and CONFIG_RCU_NOCB_CPU=%d, nocb toggle disabled.\n",
3839 cur_ops->name, IS_ENABLED(CONFIG_RCU_NOCB_CPU));
3840 nocbs_nthreads = 0;
3841 }
3842 if (cur_ops->init)
3843 cur_ops->init();
3844
3845 rcu_torture_init_srcu_lockdep();
3846
3847 if (nreaders >= 0) {
3848 nrealreaders = nreaders;
3849 } else {
3850 nrealreaders = num_online_cpus() - 2 - nreaders;
3851 if (nrealreaders <= 0)
3852 nrealreaders = 1;
3853 }
3854 rcu_torture_print_module_parms(cur_ops, "Start of test");
3855 if (cur_ops->get_gp_data)
3856 cur_ops->get_gp_data(&flags, &gp_seq);
3857 start_gp_seq = gp_seq;
3858 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n",
3859 cur_ops->name, (long)gp_seq, flags);
3860
3861 /* Set up the freelist. */
3862
3863 INIT_LIST_HEAD(&rcu_torture_freelist);
3864 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
3865 rcu_tortures[i].rtort_mbtest = 0;
3866 list_add_tail(&rcu_tortures[i].rtort_free,
3867 &rcu_torture_freelist);
3868 }
3869
3870 /* Initialize the statistics so that each run gets its own numbers. */
3871
3872 rcu_torture_current = NULL;
3873 rcu_torture_current_version = 0;
3874 atomic_set(&n_rcu_torture_alloc, 0);
3875 atomic_set(&n_rcu_torture_alloc_fail, 0);
3876 atomic_set(&n_rcu_torture_free, 0);
3877 atomic_set(&n_rcu_torture_mberror, 0);
3878 atomic_set(&n_rcu_torture_mbchk_fail, 0);
3879 atomic_set(&n_rcu_torture_mbchk_tries, 0);
3880 atomic_set(&n_rcu_torture_error, 0);
3881 n_rcu_torture_barrier_error = 0;
3882 n_rcu_torture_boost_ktrerror = 0;
3883 n_rcu_torture_boost_failure = 0;
3884 n_rcu_torture_boosts = 0;
3885 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
3886 atomic_set(&rcu_torture_wcount[i], 0);
3887 for_each_possible_cpu(cpu) {
3888 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
3889 per_cpu(rcu_torture_count, cpu)[i] = 0;
3890 per_cpu(rcu_torture_batch, cpu)[i] = 0;
3891 }
3892 }
3893 err_segs_recorded = 0;
3894 rt_read_nsegs = 0;
3895
3896 /* Start up the kthreads. */
3897
3898 rcu_torture_write_types();
3899 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
3900 writer_task);
3901 if (torture_init_error(firsterr))
3902 goto unwind;
3903 if (nfakewriters > 0) {
3904 fakewriter_tasks = kcalloc(nfakewriters,
3905 sizeof(fakewriter_tasks[0]),
3906 GFP_KERNEL);
3907 if (fakewriter_tasks == NULL) {
3908 TOROUT_ERRSTRING("out of memory");
3909 firsterr = -ENOMEM;
3910 goto unwind;
3911 }
3912 }
3913 for (i = 0; i < nfakewriters; i++) {
3914 firsterr = torture_create_kthread(rcu_torture_fakewriter,
3915 NULL, fakewriter_tasks[i]);
3916 if (torture_init_error(firsterr))
3917 goto unwind;
3918 }
3919 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
3920 GFP_KERNEL);
3921 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk),
3922 GFP_KERNEL);
3923 if (!reader_tasks || !rcu_torture_reader_mbchk) {
3924 TOROUT_ERRSTRING("out of memory");
3925 firsterr = -ENOMEM;
3926 goto unwind;
3927 }
3928 for (i = 0; i < nrealreaders; i++) {
3929 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1;
3930 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
3931 reader_tasks[i]);
3932 if (torture_init_error(firsterr))
3933 goto unwind;
3934 }
3935 nrealnocbers = nocbs_nthreads;
3936 if (WARN_ON(nrealnocbers < 0))
3937 nrealnocbers = 1;
3938 if (WARN_ON(nocbs_toggle < 0))
3939 nocbs_toggle = HZ;
3940 if (nrealnocbers > 0) {
3941 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL);
3942 if (nocb_tasks == NULL) {
3943 TOROUT_ERRSTRING("out of memory");
3944 firsterr = -ENOMEM;
3945 goto unwind;
3946 }
3947 } else {
3948 nocb_tasks = NULL;
3949 }
3950 for (i = 0; i < nrealnocbers; i++) {
3951 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]);
3952 if (torture_init_error(firsterr))
3953 goto unwind;
3954 }
3955 if (stat_interval > 0) {
3956 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
3957 stats_task);
3958 if (torture_init_error(firsterr))
3959 goto unwind;
3960 }
3961 if (test_no_idle_hz && shuffle_interval > 0) {
3962 firsterr = torture_shuffle_init(shuffle_interval * HZ);
3963 if (torture_init_error(firsterr))
3964 goto unwind;
3965 }
3966 if (stutter < 0)
3967 stutter = 0;
3968 if (stutter) {
3969 int t;
3970
3971 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
3972 firsterr = torture_stutter_init(stutter * HZ, t);
3973 if (torture_init_error(firsterr))
3974 goto unwind;
3975 }
3976 if (fqs_duration < 0)
3977 fqs_duration = 0;
3978 if (fqs_holdoff < 0)
3979 fqs_holdoff = 0;
3980 if (fqs_duration && fqs_holdoff) {
3981 /* Create the fqs thread */
3982 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
3983 fqs_task);
3984 if (torture_init_error(firsterr))
3985 goto unwind;
3986 }
3987 if (test_boost_interval < 1)
3988 test_boost_interval = 1;
3989 if (test_boost_duration < 2)
3990 test_boost_duration = 2;
3991 if (rcu_torture_can_boost()) {
3992
3993 boost_starttime = jiffies + test_boost_interval * HZ;
3994
3995 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
3996 rcutorture_booster_init,
3997 rcutorture_booster_cleanup);
3998 rcutor_hp = firsterr;
3999 if (torture_init_error(firsterr))
4000 goto unwind;
4001 }
4002 shutdown_jiffies = jiffies + shutdown_secs * HZ;
4003 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
4004 if (torture_init_error(firsterr))
4005 goto unwind;
4006 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
4007 rcutorture_sync);
4008 if (torture_init_error(firsterr))
4009 goto unwind;
4010 firsterr = rcu_torture_stall_init();
4011 if (torture_init_error(firsterr))
4012 goto unwind;
4013 firsterr = rcu_torture_fwd_prog_init();
4014 if (torture_init_error(firsterr))
4015 goto unwind;
4016 firsterr = rcu_torture_barrier_init();
4017 if (torture_init_error(firsterr))
4018 goto unwind;
4019 firsterr = rcu_torture_read_exit_init();
4020 if (torture_init_error(firsterr))
4021 goto unwind;
4022 if (object_debug)
4023 rcu_test_debug_objects();
4024 torture_init_end();
4025 if (cur_ops->gp_slow_register && !WARN_ON_ONCE(!cur_ops->gp_slow_unregister))
4026 cur_ops->gp_slow_register(&rcu_fwd_cb_nodelay);
4027 return 0;
4028
4029 unwind:
4030 torture_init_end();
4031 rcu_torture_cleanup();
4032 if (shutdown_secs) {
4033 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
4034 kernel_power_off();
4035 }
4036 return firsterr;
4037 }
4038
4039 module_init(rcu_torture_init);
4040 module_exit(rcu_torture_cleanup);
Kernel DRM miscellaneous fixes and cross-tree changes