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