kernel/scftorture.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // Torture test for smp_call_function() and friends.
   4 //
   5 // Copyright (C) Facebook, 2020.
   6 //
   7 // Author: Paul E. McKenney <paulmck@kernel.org>
   8
   9 #define pr_fmt(fmt) fmt
  10
  11 #include <linux/atomic.h>
  12 #include <linux/bitops.h>
  13 #include <linux/completion.h>
  14 #include <linux/cpu.h>
  15 #include <linux/delay.h>
  16 #include <linux/err.h>
  17 #include <linux/init.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/kthread.h>
  20 #include <linux/kernel.h>
  21 #include <linux/mm.h>
  22 #include <linux/module.h>
  23 #include <linux/moduleparam.h>
  24 #include <linux/notifier.h>
  25 #include <linux/percpu.h>
  26 #include <linux/rcupdate.h>
  27 #include <linux/rcupdate_trace.h>
  28 #include <linux/reboot.h>
  29 #include <linux/sched.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/smp.h>
  32 #include <linux/stat.h>
  33 #include <linux/srcu.h>
  34 #include <linux/slab.h>
  35 #include <linux/torture.h>
  36 #include <linux/types.h>
  37
  38 #define SCFTORT_STRING "scftorture"
  39 #define SCFTORT_FLAG SCFTORT_STRING ": "
  40
  41 #define VERBOSE_SCFTORTOUT(s, x...) \
  42         do { if (verbose) pr_alert(SCFTORT_FLAG s "\n", ## x); } while (0)
  43
  44 #define SCFTORTOUT_ERRSTRING(s, x...) pr_alert(SCFTORT_FLAG "!!! " s "\n", ## x)
  45
  46 MODULE_DESCRIPTION("Torture tests on the smp_call_function() family of primitives");
  47 MODULE_LICENSE("GPL");
  48 MODULE_AUTHOR("Paul E. McKenney <paulmck@kernel.org>");
  49
  50 // Wait until there are multiple CPUs before starting test.
  51 torture_param(int, holdoff, IS_BUILTIN(CONFIG_SCF_TORTURE_TEST) ? 10 : 0,
  52               "Holdoff time before test start (s)");
  53 torture_param(int, longwait, 0, "Include ridiculously long waits? (seconds)");
  54 torture_param(int, nthreads, -1, "# threads, defaults to -1 for all CPUs.");
  55 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  56 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable");
  57 torture_param(int, shutdown_secs, 0, "Shutdown time (ms), <= zero to disable.");
  58 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s.");
  59 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
  60 torture_param(bool, use_cpus_read_lock, 0, "Use cpus_read_lock() to exclude CPU hotplug.");
  61 torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
  62 torture_param(int, weight_resched, -1, "Testing weight for resched_cpu() operations.");
  63 torture_param(int, weight_single, -1, "Testing weight for single-CPU no-wait operations.");
  64 torture_param(int, weight_single_rpc, -1, "Testing weight for single-CPU RPC operations.");
  65 torture_param(int, weight_single_wait, -1, "Testing weight for single-CPU operations.");
  66 torture_param(int, weight_many, -1, "Testing weight for multi-CPU no-wait operations.");
  67 torture_param(int, weight_many_wait, -1, "Testing weight for multi-CPU operations.");
  68 torture_param(int, weight_all, -1, "Testing weight for all-CPU no-wait operations.");
  69 torture_param(int, weight_all_wait, -1, "Testing weight for all-CPU operations.");
  70
  71 static char *torture_type = "";
  72
  73 #ifdef MODULE
  74 # define SCFTORT_SHUTDOWN 0
  75 #else
  76 # define SCFTORT_SHUTDOWN 1
  77 #endif
  78
  79 torture_param(bool, shutdown, SCFTORT_SHUTDOWN, "Shutdown at end of torture test.");
  80
  81 struct scf_statistics {
  82         struct task_struct *task;
  83         int cpu;
  84         long long n_resched;
  85         long long n_single;
  86         long long n_single_ofl;
  87         long long n_single_rpc;
  88         long long n_single_rpc_ofl;
  89         long long n_single_wait;
  90         long long n_single_wait_ofl;
  91         long long n_many;
  92         long long n_many_wait;
  93         long long n_all;
  94         long long n_all_wait;
  95 };
  96
  97 static struct scf_statistics *scf_stats_p;
  98 static struct task_struct *scf_torture_stats_task;
  99 static DEFINE_PER_CPU(long long, scf_invoked_count);
 100 static DEFINE_PER_CPU(struct llist_head, scf_free_pool);
 101
 102 // Data for random primitive selection
 103 #define SCF_PRIM_RESCHED        0
 104 #define SCF_PRIM_SINGLE         1
 105 #define SCF_PRIM_SINGLE_RPC     2
 106 #define SCF_PRIM_MANY           3
 107 #define SCF_PRIM_ALL            4
 108 #define SCF_NPRIMS              8 // Need wait and no-wait versions of each,
 109                                   //  except for SCF_PRIM_RESCHED and
 110                                   //  SCF_PRIM_SINGLE_RPC.
 111
 112 static char *scf_prim_name[] = {
 113         "resched_cpu",
 114         "smp_call_function_single",
 115         "smp_call_function_single_rpc",
 116         "smp_call_function_many",
 117         "smp_call_function",
 118 };
 119
 120 struct scf_selector {
 121         unsigned long scfs_weight;
 122         int scfs_prim;
 123         bool scfs_wait;
 124 };
 125 static struct scf_selector scf_sel_array[SCF_NPRIMS];
 126 static int scf_sel_array_len;
 127 static unsigned long scf_sel_totweight;
 128
 129 // Communicate between caller and handler.
 130 struct scf_check {
 131         bool scfc_in;
 132         bool scfc_out;
 133         int scfc_cpu; // -1 for not _single().
 134         bool scfc_wait;
 135         bool scfc_rpc;
 136         struct completion scfc_completion;
 137         struct llist_node scf_node;
 138 };
 139
 140 // Use to wait for all threads to start.
 141 static atomic_t n_started;
 142 static atomic_t n_errs;
 143 static atomic_t n_mb_in_errs;
 144 static atomic_t n_mb_out_errs;
 145 static atomic_t n_alloc_errs;
 146 static bool scfdone;
 147 static char *bangstr = "";
 148
 149 static DEFINE_TORTURE_RANDOM_PERCPU(scf_torture_rand);
 150
 151 extern void resched_cpu(int cpu); // An alternative IPI vector.
 152
 153 static void scf_add_to_free_list(struct scf_check *scfcp)
 154 {
 155         struct llist_head *pool;
 156         unsigned int cpu;
 157
 158         if (!scfcp)
 159                 return;
 160         cpu = raw_smp_processor_id() % nthreads;
 161         pool = &per_cpu(scf_free_pool, cpu);
 162         llist_add(&scfcp->scf_node, pool);
 163 }
 164
 165 static void scf_cleanup_free_list(unsigned int cpu)
 166 {
 167         struct llist_head *pool;
 168         struct llist_node *node;
 169         struct scf_check *scfcp;
 170
 171         pool = &per_cpu(scf_free_pool, cpu);
 172         node = llist_del_all(pool);
 173         while (node) {
 174                 scfcp = llist_entry(node, struct scf_check, scf_node);
 175                 node = node->next;
 176                 kfree(scfcp);
 177         }
 178 }
 179
 180 // Print torture statistics.  Caller must ensure serialization.
 181 static void scf_torture_stats_print(void)
 182 {
 183         int cpu;
 184         int i;
 185         long long invoked_count = 0;
 186         bool isdone = READ_ONCE(scfdone);
 187         struct scf_statistics scfs = {};
 188
 189         for_each_possible_cpu(cpu)
 190                 invoked_count += data_race(per_cpu(scf_invoked_count, cpu));
 191         for (i = 0; i < nthreads; i++) {
 192                 scfs.n_resched += scf_stats_p[i].n_resched;
 193                 scfs.n_single += scf_stats_p[i].n_single;
 194                 scfs.n_single_ofl += scf_stats_p[i].n_single_ofl;
 195                 scfs.n_single_rpc += scf_stats_p[i].n_single_rpc;
 196                 scfs.n_single_wait += scf_stats_p[i].n_single_wait;
 197                 scfs.n_single_wait_ofl += scf_stats_p[i].n_single_wait_ofl;
 198                 scfs.n_many += scf_stats_p[i].n_many;
 199                 scfs.n_many_wait += scf_stats_p[i].n_many_wait;
 200                 scfs.n_all += scf_stats_p[i].n_all;
 201                 scfs.n_all_wait += scf_stats_p[i].n_all_wait;
 202         }
 203         if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) ||
 204             atomic_read(&n_mb_out_errs) ||
 205             (!IS_ENABLED(CONFIG_KASAN) && atomic_read(&n_alloc_errs)))
 206                 bangstr = "!!! ";
 207         pr_alert("%s %sscf_invoked_count %s: %lld resched: %lld single: %lld/%lld single_ofl: %lld/%lld single_rpc: %lld single_rpc_ofl: %lld many: %lld/%lld all: %lld/%lld ",
 208                  SCFTORT_FLAG, bangstr, isdone ? "VER" : "ver", invoked_count, scfs.n_resched,
 209                  scfs.n_single, scfs.n_single_wait, scfs.n_single_ofl, scfs.n_single_wait_ofl,
 210                  scfs.n_single_rpc, scfs.n_single_rpc_ofl,
 211                  scfs.n_many, scfs.n_many_wait, scfs.n_all, scfs.n_all_wait);
 212         torture_onoff_stats();
 213         pr_cont("ste: %d stnmie: %d stnmoe: %d staf: %d\n", atomic_read(&n_errs),
 214                 atomic_read(&n_mb_in_errs), atomic_read(&n_mb_out_errs),
 215                 atomic_read(&n_alloc_errs));
 216 }
 217
 218 // Periodically prints torture statistics, if periodic statistics printing
 219 // was specified via the stat_interval module parameter.
 220 static int
 221 scf_torture_stats(void *arg)
 222 {
 223         VERBOSE_TOROUT_STRING("scf_torture_stats task started");
 224         do {
 225                 schedule_timeout_interruptible(stat_interval * HZ);
 226                 scf_torture_stats_print();
 227                 torture_shutdown_absorb("scf_torture_stats");
 228         } while (!torture_must_stop());
 229         torture_kthread_stopping("scf_torture_stats");
 230         return 0;
 231 }
 232
 233 // Add a primitive to the scf_sel_array[].
 234 static void scf_sel_add(unsigned long weight, int prim, bool wait)
 235 {
 236         struct scf_selector *scfsp = &scf_sel_array[scf_sel_array_len];
 237
 238         // If no weight, if array would overflow, if computing three-place
 239         // percentages would overflow, or if the scf_prim_name[] array would
 240         // overflow, don't bother.  In the last three two cases, complain.
 241         if (!weight ||
 242             WARN_ON_ONCE(scf_sel_array_len >= ARRAY_SIZE(scf_sel_array)) ||
 243             WARN_ON_ONCE(0 - 100000 * weight <= 100000 * scf_sel_totweight) ||
 244             WARN_ON_ONCE(prim >= ARRAY_SIZE(scf_prim_name)))
 245                 return;
 246         scf_sel_totweight += weight;
 247         scfsp->scfs_weight = scf_sel_totweight;
 248         scfsp->scfs_prim = prim;
 249         scfsp->scfs_wait = wait;
 250         scf_sel_array_len++;
 251 }
 252
 253 // Dump out weighting percentages for scf_prim_name[] array.
 254 static void scf_sel_dump(void)
 255 {
 256         int i;
 257         unsigned long oldw = 0;
 258         struct scf_selector *scfsp;
 259         unsigned long w;
 260
 261         for (i = 0; i < scf_sel_array_len; i++) {
 262                 scfsp = &scf_sel_array[i];
 263                 w = (scfsp->scfs_weight - oldw) * 100000 / scf_sel_totweight;
 264                 pr_info("%s: %3lu.%03lu %s(%s)\n", __func__, w / 1000, w % 1000,
 265                         scf_prim_name[scfsp->scfs_prim],
 266                         scfsp->scfs_wait ? "wait" : "nowait");
 267                 oldw = scfsp->scfs_weight;
 268         }
 269 }
 270
 271 // Randomly pick a primitive and wait/nowait, based on weightings.
 272 static struct scf_selector *scf_sel_rand(struct torture_random_state *trsp)
 273 {
 274         int i;
 275         unsigned long w = torture_random(trsp) % (scf_sel_totweight + 1);
 276
 277         for (i = 0; i < scf_sel_array_len; i++)
 278                 if (scf_sel_array[i].scfs_weight >= w)
 279                         return &scf_sel_array[i];
 280         WARN_ON_ONCE(1);
 281         return &scf_sel_array[0];
 282 }
 283
 284 // Update statistics and occasionally burn up mass quantities of CPU time,
 285 // if told to do so via scftorture.longwait.  Otherwise, occasionally burn
 286 // a little bit.
 287 static void scf_handler(void *scfc_in)
 288 {
 289         int i;
 290         int j;
 291         unsigned long r = torture_random(this_cpu_ptr(&scf_torture_rand));
 292         struct scf_check *scfcp = scfc_in;
 293
 294         if (likely(scfcp)) {
 295                 WRITE_ONCE(scfcp->scfc_out, false); // For multiple receivers.
 296                 if (WARN_ON_ONCE(unlikely(!READ_ONCE(scfcp->scfc_in))))
 297                         atomic_inc(&n_mb_in_errs);
 298         }
 299         this_cpu_inc(scf_invoked_count);
 300         if (longwait <= 0) {
 301                 if (!(r & 0xffc0)) {
 302                         udelay(r & 0x3f);
 303                         goto out;
 304                 }
 305         }
 306         if (r & 0xfff)
 307                 goto out;
 308         r = (r >> 12);
 309         if (longwait <= 0) {
 310                 udelay((r & 0xff) + 1);
 311                 goto out;
 312         }
 313         r = r % longwait + 1;
 314         for (i = 0; i < r; i++) {
 315                 for (j = 0; j < 1000; j++) {
 316                         udelay(1000);
 317                         cpu_relax();
 318                 }
 319         }
 320 out:
 321         if (unlikely(!scfcp))
 322                 return;
 323         if (scfcp->scfc_wait) {
 324                 WRITE_ONCE(scfcp->scfc_out, true);
 325                 if (scfcp->scfc_rpc)
 326                         complete(&scfcp->scfc_completion);
 327         } else {
 328                 scf_add_to_free_list(scfcp);
 329         }
 330 }
 331
 332 // As above, but check for correct CPU.
 333 static void scf_handler_1(void *scfc_in)
 334 {
 335         struct scf_check *scfcp = scfc_in;
 336
 337         if (likely(scfcp) && WARN_ONCE(smp_processor_id() != scfcp->scfc_cpu, "%s: Wanted CPU %d got CPU %d\n", __func__, scfcp->scfc_cpu, smp_processor_id())) {
 338                 atomic_inc(&n_errs);
 339         }
 340         scf_handler(scfcp);
 341 }
 342
 343 // Randomly do an smp_call_function*() invocation.
 344 static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_random_state *trsp)
 345 {
 346         bool allocfail = false;
 347         uintptr_t cpu;
 348         int ret = 0;
 349         struct scf_check *scfcp = NULL;
 350         struct scf_selector *scfsp = scf_sel_rand(trsp);
 351
 352         if (scfsp->scfs_prim == SCF_PRIM_SINGLE || scfsp->scfs_wait) {
 353                 scfcp = kmalloc(sizeof(*scfcp), GFP_ATOMIC);
 354                 if (!scfcp) {
 355                         WARN_ON_ONCE(!IS_ENABLED(CONFIG_KASAN));
 356                         atomic_inc(&n_alloc_errs);
 357                         allocfail = true;
 358                 } else {
 359                         scfcp->scfc_cpu = -1;
 360                         scfcp->scfc_wait = scfsp->scfs_wait;
 361                         scfcp->scfc_out = false;
 362                         scfcp->scfc_rpc = false;
 363                 }
 364         }
 365         if (use_cpus_read_lock)
 366                 cpus_read_lock();
 367         else
 368                 preempt_disable();
 369         switch (scfsp->scfs_prim) {
 370         case SCF_PRIM_RESCHED:
 371                 if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST)) {
 372                         cpu = torture_random(trsp) % nr_cpu_ids;
 373                         scfp->n_resched++;
 374                         resched_cpu(cpu);
 375                         this_cpu_inc(scf_invoked_count);
 376                 }
 377                 break;
 378         case SCF_PRIM_SINGLE:
 379                 cpu = torture_random(trsp) % nr_cpu_ids;
 380                 if (scfsp->scfs_wait)
 381                         scfp->n_single_wait++;
 382                 else
 383                         scfp->n_single++;
 384                 if (scfcp) {
 385                         scfcp->scfc_cpu = cpu;
 386                         barrier(); // Prevent race-reduction compiler optimizations.
 387                         scfcp->scfc_in = true;
 388                 }
 389                 ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, scfsp->scfs_wait);
 390                 if (ret) {
 391                         if (scfsp->scfs_wait)
 392                                 scfp->n_single_wait_ofl++;
 393                         else
 394                                 scfp->n_single_ofl++;
 395                         scf_add_to_free_list(scfcp);
 396                         scfcp = NULL;
 397                 }
 398                 break;
 399         case SCF_PRIM_SINGLE_RPC:
 400                 if (!scfcp)
 401                         break;
 402                 cpu = torture_random(trsp) % nr_cpu_ids;
 403                 scfp->n_single_rpc++;
 404                 scfcp->scfc_cpu = cpu;
 405                 scfcp->scfc_wait = true;
 406                 init_completion(&scfcp->scfc_completion);
 407                 scfcp->scfc_rpc = true;
 408                 barrier(); // Prevent race-reduction compiler optimizations.
 409                 scfcp->scfc_in = true;
 410                 ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, 0);
 411                 if (!ret) {
 412                         if (use_cpus_read_lock)
 413                                 cpus_read_unlock();
 414                         else
 415                                 preempt_enable();
 416                         wait_for_completion(&scfcp->scfc_completion);
 417                         if (use_cpus_read_lock)
 418                                 cpus_read_lock();
 419                         else
 420                                 preempt_disable();
 421                 } else {
 422                         scfp->n_single_rpc_ofl++;
 423                         scf_add_to_free_list(scfcp);
 424                         scfcp = NULL;
 425                 }
 426                 break;
 427         case SCF_PRIM_MANY:
 428                 if (scfsp->scfs_wait)
 429                         scfp->n_many_wait++;
 430                 else
 431                         scfp->n_many++;
 432                 if (scfcp) {
 433                         barrier(); // Prevent race-reduction compiler optimizations.
 434                         scfcp->scfc_in = true;
 435                 }
 436                 smp_call_function_many(cpu_online_mask, scf_handler, scfcp, scfsp->scfs_wait);
 437                 break;
 438         case SCF_PRIM_ALL:
 439                 if (scfsp->scfs_wait)
 440                         scfp->n_all_wait++;
 441                 else
 442                         scfp->n_all++;
 443                 if (scfcp) {
 444                         barrier(); // Prevent race-reduction compiler optimizations.
 445                         scfcp->scfc_in = true;
 446                 }
 447                 smp_call_function(scf_handler, scfcp, scfsp->scfs_wait);
 448                 break;
 449         default:
 450                 WARN_ON_ONCE(1);
 451                 if (scfcp)
 452                         scfcp->scfc_out = true;
 453         }
 454         if (scfcp && scfsp->scfs_wait) {
 455                 if (WARN_ON_ONCE((num_online_cpus() > 1 || scfsp->scfs_prim == SCF_PRIM_SINGLE) &&
 456                                  !scfcp->scfc_out)) {
 457                         pr_warn("%s: Memory-ordering failure, scfs_prim: %d.\n", __func__, scfsp->scfs_prim);
 458                         atomic_inc(&n_mb_out_errs); // Leak rather than trash!
 459                 } else {
 460                         scf_add_to_free_list(scfcp);
 461                 }
 462                 barrier(); // Prevent race-reduction compiler optimizations.
 463         }
 464         if (use_cpus_read_lock)
 465                 cpus_read_unlock();
 466         else
 467                 preempt_enable();
 468         if (allocfail)
 469                 schedule_timeout_idle((1 + longwait) * HZ);  // Let no-wait handlers complete.
 470         else if (!(torture_random(trsp) & 0xfff))
 471                 schedule_timeout_uninterruptible(1);
 472 }
 473
 474 // SCF test kthread.  Repeatedly does calls to members of the
 475 // smp_call_function() family of functions.
 476 static int scftorture_invoker(void *arg)
 477 {
 478         int cpu;
 479         int curcpu;
 480         DEFINE_TORTURE_RANDOM(rand);
 481         struct scf_statistics *scfp = (struct scf_statistics *)arg;
 482         bool was_offline = false;
 483
 484         VERBOSE_SCFTORTOUT("scftorture_invoker %d: task started", scfp->cpu);
 485         cpu = scfp->cpu % nr_cpu_ids;
 486         WARN_ON_ONCE(set_cpus_allowed_ptr(current, cpumask_of(cpu)));
 487         set_user_nice(current, MAX_NICE);
 488         if (holdoff)
 489                 schedule_timeout_interruptible(holdoff * HZ);
 490
 491         VERBOSE_SCFTORTOUT("scftorture_invoker %d: Waiting for all SCF torturers from cpu %d", scfp->cpu, raw_smp_processor_id());
 492
 493         // Make sure that the CPU is affinitized appropriately during testing.
 494         curcpu = raw_smp_processor_id();
 495         WARN_ONCE(curcpu != cpu,
 496                   "%s: Wanted CPU %d, running on %d, nr_cpu_ids = %d\n",
 497                   __func__, scfp->cpu, curcpu, nr_cpu_ids);
 498
 499         if (!atomic_dec_return(&n_started))
 500                 while (atomic_read_acquire(&n_started)) {
 501                         if (torture_must_stop()) {
 502                                 VERBOSE_SCFTORTOUT("scftorture_invoker %d ended before starting", scfp->cpu);
 503                                 goto end;
 504                         }
 505                         schedule_timeout_uninterruptible(1);
 506                 }
 507
 508         VERBOSE_SCFTORTOUT("scftorture_invoker %d started", scfp->cpu);
 509
 510         do {
 511                 scf_cleanup_free_list(cpu);
 512
 513                 scftorture_invoke_one(scfp, &rand);
 514                 while (cpu_is_offline(cpu) && !torture_must_stop()) {
 515                         schedule_timeout_interruptible(HZ / 5);
 516                         was_offline = true;
 517                 }
 518                 if (was_offline) {
 519                         set_cpus_allowed_ptr(current, cpumask_of(cpu));
 520                         was_offline = false;
 521                 }
 522                 cond_resched();
 523                 stutter_wait("scftorture_invoker");
 524         } while (!torture_must_stop());
 525
 526         VERBOSE_SCFTORTOUT("scftorture_invoker %d ended", scfp->cpu);
 527 end:
 528         torture_kthread_stopping("scftorture_invoker");
 529         return 0;
 530 }
 531
 532 static void
 533 scftorture_print_module_parms(const char *tag)
 534 {
 535         pr_alert(SCFTORT_FLAG
 536                  "--- %s:  verbose=%d holdoff=%d longwait=%d nthreads=%d onoff_holdoff=%d onoff_interval=%d shutdown_secs=%d stat_interval=%d stutter=%d use_cpus_read_lock=%d, weight_resched=%d, weight_single=%d, weight_single_rpc=%d, weight_single_wait=%d, weight_many=%d, weight_many_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag,
 537                  verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter, use_cpus_read_lock, weight_resched, weight_single, weight_single_rpc, weight_single_wait, weight_many, weight_many_wait, weight_all, weight_all_wait);
 538 }
 539
 540 static void scf_cleanup_handler(void *unused)
 541 {
 542 }
 543
 544 static void scf_torture_cleanup(void)
 545 {
 546         int i;
 547
 548         if (torture_cleanup_begin())
 549                 return;
 550
 551         WRITE_ONCE(scfdone, true);
 552         if (nthreads && scf_stats_p)
 553                 for (i = 0; i < nthreads; i++)
 554                         torture_stop_kthread("scftorture_invoker", scf_stats_p[i].task);
 555         else
 556                 goto end;
 557         smp_call_function(scf_cleanup_handler, NULL, 1);
 558         torture_stop_kthread(scf_torture_stats, scf_torture_stats_task);
 559         scf_torture_stats_print();  // -After- the stats thread is stopped!
 560         kfree(scf_stats_p);  // -After- the last stats print has completed!
 561         scf_stats_p = NULL;
 562
 563         for (i = 0; i < nr_cpu_ids; i++)
 564                 scf_cleanup_free_list(i);
 565
 566         if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) || atomic_read(&n_mb_out_errs))
 567                 scftorture_print_module_parms("End of test: FAILURE");
 568         else if (torture_onoff_failures())
 569                 scftorture_print_module_parms("End of test: LOCK_HOTPLUG");
 570         else
 571                 scftorture_print_module_parms("End of test: SUCCESS");
 572
 573 end:
 574         torture_cleanup_end();
 575 }
 576
 577 static int __init scf_torture_init(void)
 578 {
 579         long i;
 580         int firsterr = 0;
 581         unsigned long weight_resched1 = weight_resched;
 582         unsigned long weight_single1 = weight_single;
 583         unsigned long weight_single_rpc1 = weight_single_rpc;
 584         unsigned long weight_single_wait1 = weight_single_wait;
 585         unsigned long weight_many1 = weight_many;
 586         unsigned long weight_many_wait1 = weight_many_wait;
 587         unsigned long weight_all1 = weight_all;
 588         unsigned long weight_all_wait1 = weight_all_wait;
 589
 590         if (!torture_init_begin(SCFTORT_STRING, verbose))
 591                 return -EBUSY;
 592
 593         scftorture_print_module_parms("Start of test");
 594
 595         if (weight_resched <= 0 &&
 596             weight_single <= 0 && weight_single_rpc <= 0 && weight_single_wait <= 0 &&
 597             weight_many <= 0 && weight_many_wait <= 0 &&
 598             weight_all <= 0 && weight_all_wait <= 0) {
 599                 weight_resched1 = weight_resched == 0 ? 0 : 2 * nr_cpu_ids;
 600                 weight_single1 = weight_single == 0 ? 0 : 2 * nr_cpu_ids;
 601                 weight_single_rpc1 = weight_single_rpc == 0 ? 0 : 2 * nr_cpu_ids;
 602                 weight_single_wait1 = weight_single_wait == 0 ? 0 : 2 * nr_cpu_ids;
 603                 weight_many1 = weight_many == 0 ? 0 : 2;
 604                 weight_many_wait1 = weight_many_wait == 0 ? 0 : 2;
 605                 weight_all1 = weight_all == 0 ? 0 : 1;
 606                 weight_all_wait1 = weight_all_wait == 0 ? 0 : 1;
 607         } else {
 608                 if (weight_resched == -1)
 609                         weight_resched1 = 0;
 610                 if (weight_single == -1)
 611                         weight_single1 = 0;
 612                 if (weight_single_rpc == -1)
 613                         weight_single_rpc1 = 0;
 614                 if (weight_single_wait == -1)
 615                         weight_single_wait1 = 0;
 616                 if (weight_many == -1)
 617                         weight_many1 = 0;
 618                 if (weight_many_wait == -1)
 619                         weight_many_wait1 = 0;
 620                 if (weight_all == -1)
 621                         weight_all1 = 0;
 622                 if (weight_all_wait == -1)
 623                         weight_all_wait1 = 0;
 624         }
 625         if (weight_resched1 == 0 && weight_single1 == 0 && weight_single_rpc1 == 0 &&
 626             weight_single_wait1 == 0 && weight_many1 == 0 && weight_many_wait1 == 0 &&
 627             weight_all1 == 0 && weight_all_wait1 == 0) {
 628                 SCFTORTOUT_ERRSTRING("all zero weights makes no sense");
 629                 firsterr = -EINVAL;
 630                 goto unwind;
 631         }
 632         if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST))
 633                 scf_sel_add(weight_resched1, SCF_PRIM_RESCHED, false);
 634         else if (weight_resched1)
 635                 SCFTORTOUT_ERRSTRING("built as module, weight_resched ignored");
 636         scf_sel_add(weight_single1, SCF_PRIM_SINGLE, false);
 637         scf_sel_add(weight_single_rpc1, SCF_PRIM_SINGLE_RPC, true);
 638         scf_sel_add(weight_single_wait1, SCF_PRIM_SINGLE, true);
 639         scf_sel_add(weight_many1, SCF_PRIM_MANY, false);
 640         scf_sel_add(weight_many_wait1, SCF_PRIM_MANY, true);
 641         scf_sel_add(weight_all1, SCF_PRIM_ALL, false);
 642         scf_sel_add(weight_all_wait1, SCF_PRIM_ALL, true);
 643         scf_sel_dump();
 644
 645         if (onoff_interval > 0) {
 646                 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, NULL);
 647                 if (torture_init_error(firsterr))
 648                         goto unwind;
 649         }
 650         if (shutdown_secs > 0) {
 651                 firsterr = torture_shutdown_init(shutdown_secs, scf_torture_cleanup);
 652                 if (torture_init_error(firsterr))
 653                         goto unwind;
 654         }
 655         if (stutter > 0) {
 656                 firsterr = torture_stutter_init(stutter, stutter);
 657                 if (torture_init_error(firsterr))
 658                         goto unwind;
 659         }
 660
 661         // Worker tasks invoking smp_call_function().
 662         if (nthreads < 0)
 663                 nthreads = num_online_cpus();
 664         scf_stats_p = kcalloc(nthreads, sizeof(scf_stats_p[0]), GFP_KERNEL);
 665         if (!scf_stats_p) {
 666                 SCFTORTOUT_ERRSTRING("out of memory");
 667                 firsterr = -ENOMEM;
 668                 goto unwind;
 669         }
 670
 671         VERBOSE_SCFTORTOUT("Starting %d smp_call_function() threads", nthreads);
 672
 673         atomic_set(&n_started, nthreads);
 674         for (i = 0; i < nthreads; i++) {
 675                 scf_stats_p[i].cpu = i;
 676                 firsterr = torture_create_kthread(scftorture_invoker, (void *)&scf_stats_p[i],
 677                                                   scf_stats_p[i].task);
 678                 if (torture_init_error(firsterr))
 679                         goto unwind;
 680         }
 681         if (stat_interval > 0) {
 682                 firsterr = torture_create_kthread(scf_torture_stats, NULL, scf_torture_stats_task);
 683                 if (torture_init_error(firsterr))
 684                         goto unwind;
 685         }
 686
 687         torture_init_end();
 688         return 0;
 689
 690 unwind:
 691         torture_init_end();
 692         scf_torture_cleanup();
 693         if (shutdown_secs) {
 694                 WARN_ON(!IS_MODULE(CONFIG_SCF_TORTURE_TEST));
 695                 kernel_power_off();
 696         }
 697         return firsterr;
 698 }
 699
 700 module_init(scf_torture_init);
 701 module_exit(scf_torture_cleanup);