the-tree/kernel/scftorture.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 //
0003 // Torture test for smp_call_function() and friends.
0004 //
0005 // Copyright (C) Facebook, 2020.
0006 //
0007 // Author: Paul E. McKenney <paulmck@kernel.org>
0008
0009 #define pr_fmt(fmt) fmt
0010
0011 #include <linux/atomic.h>
0012 #include <linux/bitops.h>
0013 #include <linux/completion.h>
0014 #include <linux/cpu.h>
0015 #include <linux/delay.h>
0016 #include <linux/err.h>
0017 #include <linux/init.h>
0018 #include <linux/interrupt.h>
0019 #include <linux/kthread.h>
0020 #include <linux/kernel.h>
0021 #include <linux/mm.h>
0022 #include <linux/module.h>
0023 #include <linux/moduleparam.h>
0024 #include <linux/notifier.h>
0025 #include <linux/percpu.h>
0026 #include <linux/rcupdate.h>
0027 #include <linux/rcupdate_trace.h>
0028 #include <linux/reboot.h>
0029 #include <linux/sched.h>
0030 #include <linux/spinlock.h>
0031 #include <linux/smp.h>
0032 #include <linux/stat.h>
0033 #include <linux/srcu.h>
0034 #include <linux/slab.h>
0035 #include <linux/torture.h>
0036 #include <linux/types.h>
0037
0038 #define SCFTORT_STRING "scftorture"
0039 #define SCFTORT_FLAG SCFTORT_STRING ": "
0040
0041 #define VERBOSE_SCFTORTOUT(s, x...) \
0042     do { if (verbose) pr_alert(SCFTORT_FLAG s "\n", ## x); } while (0)
0043
0044 #define SCFTORTOUT_ERRSTRING(s, x...) pr_alert(SCFTORT_FLAG "!!! " s "\n", ## x)
0045
0046 MODULE_LICENSE("GPL");
0047 MODULE_AUTHOR("Paul E. McKenney <paulmck@kernel.org>");
0048
0049 // Wait until there are multiple CPUs before starting test.
0050 torture_param(int, holdoff, IS_BUILTIN(CONFIG_SCF_TORTURE_TEST) ? 10 : 0,
0051           "Holdoff time before test start (s)");
0052 torture_param(int, longwait, 0, "Include ridiculously long waits? (seconds)");
0053 torture_param(int, nthreads, -1, "# threads, defaults to -1 for all CPUs.");
0054 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
0055 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable");
0056 torture_param(int, shutdown_secs, 0, "Shutdown time (ms), <= zero to disable.");
0057 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s.");
0058 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
0059 torture_param(bool, use_cpus_read_lock, 0, "Use cpus_read_lock() to exclude CPU hotplug.");
0060 torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
0061 torture_param(int, weight_resched, -1, "Testing weight for resched_cpu() operations.");
0062 torture_param(int, weight_single, -1, "Testing weight for single-CPU no-wait operations.");
0063 torture_param(int, weight_single_rpc, -1, "Testing weight for single-CPU RPC operations.");
0064 torture_param(int, weight_single_wait, -1, "Testing weight for single-CPU operations.");
0065 torture_param(int, weight_many, -1, "Testing weight for multi-CPU no-wait operations.");
0066 torture_param(int, weight_many_wait, -1, "Testing weight for multi-CPU operations.");
0067 torture_param(int, weight_all, -1, "Testing weight for all-CPU no-wait operations.");
0068 torture_param(int, weight_all_wait, -1, "Testing weight for all-CPU operations.");
0069
0070 char *torture_type = "";
0071
0072 #ifdef MODULE
0073 # define SCFTORT_SHUTDOWN 0
0074 #else
0075 # define SCFTORT_SHUTDOWN 1
0076 #endif
0077
0078 torture_param(bool, shutdown, SCFTORT_SHUTDOWN, "Shutdown at end of torture test.");
0079
0080 struct scf_statistics {
0081     struct task_struct *task;
0082     int cpu;
0083     long long n_resched;
0084     long long n_single;
0085     long long n_single_ofl;
0086     long long n_single_rpc;
0087     long long n_single_rpc_ofl;
0088     long long n_single_wait;
0089     long long n_single_wait_ofl;
0090     long long n_many;
0091     long long n_many_wait;
0092     long long n_all;
0093     long long n_all_wait;
0094 };
0095
0096 static struct scf_statistics *scf_stats_p;
0097 static struct task_struct *scf_torture_stats_task;
0098 static DEFINE_PER_CPU(long long, scf_invoked_count);
0099
0100 // Data for random primitive selection
0101 #define SCF_PRIM_RESCHED    0
0102 #define SCF_PRIM_SINGLE     1
0103 #define SCF_PRIM_SINGLE_RPC 2
0104 #define SCF_PRIM_MANY       3
0105 #define SCF_PRIM_ALL        4
0106 #define SCF_NPRIMS      8 // Need wait and no-wait versions of each,
0107                   //  except for SCF_PRIM_RESCHED and
0108                   //  SCF_PRIM_SINGLE_RPC.
0109
0110 static char *scf_prim_name[] = {
0111     "resched_cpu",
0112     "smp_call_function_single",
0113     "smp_call_function_single_rpc",
0114     "smp_call_function_many",
0115     "smp_call_function",
0116 };
0117
0118 struct scf_selector {
0119     unsigned long scfs_weight;
0120     int scfs_prim;
0121     bool scfs_wait;
0122 };
0123 static struct scf_selector scf_sel_array[SCF_NPRIMS];
0124 static int scf_sel_array_len;
0125 static unsigned long scf_sel_totweight;
0126
0127 // Communicate between caller and handler.
0128 struct scf_check {
0129     bool scfc_in;
0130     bool scfc_out;
0131     int scfc_cpu; // -1 for not _single().
0132     bool scfc_wait;
0133     bool scfc_rpc;
0134     struct completion scfc_completion;
0135 };
0136
0137 // Use to wait for all threads to start.
0138 static atomic_t n_started;
0139 static atomic_t n_errs;
0140 static atomic_t n_mb_in_errs;
0141 static atomic_t n_mb_out_errs;
0142 static atomic_t n_alloc_errs;
0143 static bool scfdone;
0144 static char *bangstr = "";
0145
0146 static DEFINE_TORTURE_RANDOM_PERCPU(scf_torture_rand);
0147
0148 extern void resched_cpu(int cpu); // An alternative IPI vector.
0149
0150 // Print torture statistics.  Caller must ensure serialization.
0151 static void scf_torture_stats_print(void)
0152 {
0153     int cpu;
0154     int i;
0155     long long invoked_count = 0;
0156     bool isdone = READ_ONCE(scfdone);
0157     struct scf_statistics scfs = {};
0158
0159     for_each_possible_cpu(cpu)
0160         invoked_count += data_race(per_cpu(scf_invoked_count, cpu));
0161     for (i = 0; i < nthreads; i++) {
0162         scfs.n_resched += scf_stats_p[i].n_resched;
0163         scfs.n_single += scf_stats_p[i].n_single;
0164         scfs.n_single_ofl += scf_stats_p[i].n_single_ofl;
0165         scfs.n_single_rpc += scf_stats_p[i].n_single_rpc;
0166         scfs.n_single_wait += scf_stats_p[i].n_single_wait;
0167         scfs.n_single_wait_ofl += scf_stats_p[i].n_single_wait_ofl;
0168         scfs.n_many += scf_stats_p[i].n_many;
0169         scfs.n_many_wait += scf_stats_p[i].n_many_wait;
0170         scfs.n_all += scf_stats_p[i].n_all;
0171         scfs.n_all_wait += scf_stats_p[i].n_all_wait;
0172     }
0173     if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) ||
0174         atomic_read(&n_mb_out_errs) || atomic_read(&n_alloc_errs))
0175         bangstr = "!!! ";
0176     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 ",
0177          SCFTORT_FLAG, bangstr, isdone ? "VER" : "ver", invoked_count, scfs.n_resched,
0178          scfs.n_single, scfs.n_single_wait, scfs.n_single_ofl, scfs.n_single_wait_ofl,
0179          scfs.n_single_rpc, scfs.n_single_rpc_ofl,
0180          scfs.n_many, scfs.n_many_wait, scfs.n_all, scfs.n_all_wait);
0181     torture_onoff_stats();
0182     pr_cont("ste: %d stnmie: %d stnmoe: %d staf: %d\n", atomic_read(&n_errs),
0183         atomic_read(&n_mb_in_errs), atomic_read(&n_mb_out_errs),
0184         atomic_read(&n_alloc_errs));
0185 }
0186
0187 // Periodically prints torture statistics, if periodic statistics printing
0188 // was specified via the stat_interval module parameter.
0189 static int
0190 scf_torture_stats(void *arg)
0191 {
0192     VERBOSE_TOROUT_STRING("scf_torture_stats task started");
0193     do {
0194         schedule_timeout_interruptible(stat_interval * HZ);
0195         scf_torture_stats_print();
0196         torture_shutdown_absorb("scf_torture_stats");
0197     } while (!torture_must_stop());
0198     torture_kthread_stopping("scf_torture_stats");
0199     return 0;
0200 }
0201
0202 // Add a primitive to the scf_sel_array[].
0203 static void scf_sel_add(unsigned long weight, int prim, bool wait)
0204 {
0205     struct scf_selector *scfsp = &scf_sel_array[scf_sel_array_len];
0206
0207     // If no weight, if array would overflow, if computing three-place
0208     // percentages would overflow, or if the scf_prim_name[] array would
0209     // overflow, don't bother.  In the last three two cases, complain.
0210     if (!weight ||
0211         WARN_ON_ONCE(scf_sel_array_len >= ARRAY_SIZE(scf_sel_array)) ||
0212         WARN_ON_ONCE(0 - 100000 * weight <= 100000 * scf_sel_totweight) ||
0213         WARN_ON_ONCE(prim >= ARRAY_SIZE(scf_prim_name)))
0214         return;
0215     scf_sel_totweight += weight;
0216     scfsp->scfs_weight = scf_sel_totweight;
0217     scfsp->scfs_prim = prim;
0218     scfsp->scfs_wait = wait;
0219     scf_sel_array_len++;
0220 }
0221
0222 // Dump out weighting percentages for scf_prim_name[] array.
0223 static void scf_sel_dump(void)
0224 {
0225     int i;
0226     unsigned long oldw = 0;
0227     struct scf_selector *scfsp;
0228     unsigned long w;
0229
0230     for (i = 0; i < scf_sel_array_len; i++) {
0231         scfsp = &scf_sel_array[i];
0232         w = (scfsp->scfs_weight - oldw) * 100000 / scf_sel_totweight;
0233         pr_info("%s: %3lu.%03lu %s(%s)\n", __func__, w / 1000, w % 1000,
0234             scf_prim_name[scfsp->scfs_prim],
0235             scfsp->scfs_wait ? "wait" : "nowait");
0236         oldw = scfsp->scfs_weight;
0237     }
0238 }
0239
0240 // Randomly pick a primitive and wait/nowait, based on weightings.
0241 static struct scf_selector *scf_sel_rand(struct torture_random_state *trsp)
0242 {
0243     int i;
0244     unsigned long w = torture_random(trsp) % (scf_sel_totweight + 1);
0245
0246     for (i = 0; i < scf_sel_array_len; i++)
0247         if (scf_sel_array[i].scfs_weight >= w)
0248             return &scf_sel_array[i];
0249     WARN_ON_ONCE(1);
0250     return &scf_sel_array[0];
0251 }
0252
0253 // Update statistics and occasionally burn up mass quantities of CPU time,
0254 // if told to do so via scftorture.longwait.  Otherwise, occasionally burn
0255 // a little bit.
0256 static void scf_handler(void *scfc_in)
0257 {
0258     int i;
0259     int j;
0260     unsigned long r = torture_random(this_cpu_ptr(&scf_torture_rand));
0261     struct scf_check *scfcp = scfc_in;
0262
0263     if (likely(scfcp)) {
0264         WRITE_ONCE(scfcp->scfc_out, false); // For multiple receivers.
0265         if (WARN_ON_ONCE(unlikely(!READ_ONCE(scfcp->scfc_in))))
0266             atomic_inc(&n_mb_in_errs);
0267     }
0268     this_cpu_inc(scf_invoked_count);
0269     if (longwait <= 0) {
0270         if (!(r & 0xffc0)) {
0271             udelay(r & 0x3f);
0272             goto out;
0273         }
0274     }
0275     if (r & 0xfff)
0276         goto out;
0277     r = (r >> 12);
0278     if (longwait <= 0) {
0279         udelay((r & 0xff) + 1);
0280         goto out;
0281     }
0282     r = r % longwait + 1;
0283     for (i = 0; i < r; i++) {
0284         for (j = 0; j < 1000; j++) {
0285             udelay(1000);
0286             cpu_relax();
0287         }
0288     }
0289 out:
0290     if (unlikely(!scfcp))
0291         return;
0292     if (scfcp->scfc_wait) {
0293         WRITE_ONCE(scfcp->scfc_out, true);
0294         if (scfcp->scfc_rpc)
0295             complete(&scfcp->scfc_completion);
0296     } else {
0297         kfree(scfcp);
0298     }
0299 }
0300
0301 // As above, but check for correct CPU.
0302 static void scf_handler_1(void *scfc_in)
0303 {
0304     struct scf_check *scfcp = scfc_in;
0305
0306     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())) {
0307         atomic_inc(&n_errs);
0308     }
0309     scf_handler(scfcp);
0310 }
0311
0312 // Randomly do an smp_call_function*() invocation.
0313 static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_random_state *trsp)
0314 {
0315     uintptr_t cpu;
0316     int ret = 0;
0317     struct scf_check *scfcp = NULL;
0318     struct scf_selector *scfsp = scf_sel_rand(trsp);
0319
0320     if (use_cpus_read_lock)
0321         cpus_read_lock();
0322     else
0323         preempt_disable();
0324     if (scfsp->scfs_prim == SCF_PRIM_SINGLE || scfsp->scfs_wait) {
0325         scfcp = kmalloc(sizeof(*scfcp), GFP_ATOMIC);
0326         if (WARN_ON_ONCE(!scfcp)) {
0327             atomic_inc(&n_alloc_errs);
0328         } else {
0329             scfcp->scfc_cpu = -1;
0330             scfcp->scfc_wait = scfsp->scfs_wait;
0331             scfcp->scfc_out = false;
0332             scfcp->scfc_rpc = false;
0333         }
0334     }
0335     switch (scfsp->scfs_prim) {
0336     case SCF_PRIM_RESCHED:
0337         if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST)) {
0338             cpu = torture_random(trsp) % nr_cpu_ids;
0339             scfp->n_resched++;
0340             resched_cpu(cpu);
0341             this_cpu_inc(scf_invoked_count);
0342         }
0343         break;
0344     case SCF_PRIM_SINGLE:
0345         cpu = torture_random(trsp) % nr_cpu_ids;
0346         if (scfsp->scfs_wait)
0347             scfp->n_single_wait++;
0348         else
0349             scfp->n_single++;
0350         if (scfcp) {
0351             scfcp->scfc_cpu = cpu;
0352             barrier(); // Prevent race-reduction compiler optimizations.
0353             scfcp->scfc_in = true;
0354         }
0355         ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, scfsp->scfs_wait);
0356         if (ret) {
0357             if (scfsp->scfs_wait)
0358                 scfp->n_single_wait_ofl++;
0359             else
0360                 scfp->n_single_ofl++;
0361             kfree(scfcp);
0362             scfcp = NULL;
0363         }
0364         break;
0365     case SCF_PRIM_SINGLE_RPC:
0366         if (!scfcp)
0367             break;
0368         cpu = torture_random(trsp) % nr_cpu_ids;
0369         scfp->n_single_rpc++;
0370         scfcp->scfc_cpu = cpu;
0371         scfcp->scfc_wait = true;
0372         init_completion(&scfcp->scfc_completion);
0373         scfcp->scfc_rpc = true;
0374         barrier(); // Prevent race-reduction compiler optimizations.
0375         scfcp->scfc_in = true;
0376         ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, 0);
0377         if (!ret) {
0378             if (use_cpus_read_lock)
0379                 cpus_read_unlock();
0380             else
0381                 preempt_enable();
0382             wait_for_completion(&scfcp->scfc_completion);
0383             if (use_cpus_read_lock)
0384                 cpus_read_lock();
0385             else
0386                 preempt_disable();
0387         } else {
0388             scfp->n_single_rpc_ofl++;
0389             kfree(scfcp);
0390             scfcp = NULL;
0391         }
0392         break;
0393     case SCF_PRIM_MANY:
0394         if (scfsp->scfs_wait)
0395             scfp->n_many_wait++;
0396         else
0397             scfp->n_many++;
0398         if (scfcp) {
0399             barrier(); // Prevent race-reduction compiler optimizations.
0400             scfcp->scfc_in = true;
0401         }
0402         smp_call_function_many(cpu_online_mask, scf_handler, scfcp, scfsp->scfs_wait);
0403         break;
0404     case SCF_PRIM_ALL:
0405         if (scfsp->scfs_wait)
0406             scfp->n_all_wait++;
0407         else
0408             scfp->n_all++;
0409         if (scfcp) {
0410             barrier(); // Prevent race-reduction compiler optimizations.
0411             scfcp->scfc_in = true;
0412         }
0413         smp_call_function(scf_handler, scfcp, scfsp->scfs_wait);
0414         break;
0415     default:
0416         WARN_ON_ONCE(1);
0417         if (scfcp)
0418             scfcp->scfc_out = true;
0419     }
0420     if (scfcp && scfsp->scfs_wait) {
0421         if (WARN_ON_ONCE((num_online_cpus() > 1 || scfsp->scfs_prim == SCF_PRIM_SINGLE) &&
0422                  !scfcp->scfc_out)) {
0423             pr_warn("%s: Memory-ordering failure, scfs_prim: %d.\n", __func__, scfsp->scfs_prim);
0424             atomic_inc(&n_mb_out_errs); // Leak rather than trash!
0425         } else {
0426             kfree(scfcp);
0427         }
0428         barrier(); // Prevent race-reduction compiler optimizations.
0429     }
0430     if (use_cpus_read_lock)
0431         cpus_read_unlock();
0432     else
0433         preempt_enable();
0434     if (!(torture_random(trsp) & 0xfff))
0435         schedule_timeout_uninterruptible(1);
0436 }
0437
0438 // SCF test kthread.  Repeatedly does calls to members of the
0439 // smp_call_function() family of functions.
0440 static int scftorture_invoker(void *arg)
0441 {
0442     int cpu;
0443     int curcpu;
0444     DEFINE_TORTURE_RANDOM(rand);
0445     struct scf_statistics *scfp = (struct scf_statistics *)arg;
0446     bool was_offline = false;
0447
0448     VERBOSE_SCFTORTOUT("scftorture_invoker %d: task started", scfp->cpu);
0449     cpu = scfp->cpu % nr_cpu_ids;
0450     WARN_ON_ONCE(set_cpus_allowed_ptr(current, cpumask_of(cpu)));
0451     set_user_nice(current, MAX_NICE);
0452     if (holdoff)
0453         schedule_timeout_interruptible(holdoff * HZ);
0454
0455     VERBOSE_SCFTORTOUT("scftorture_invoker %d: Waiting for all SCF torturers from cpu %d", scfp->cpu, raw_smp_processor_id());
0456
0457     // Make sure that the CPU is affinitized appropriately during testing.
0458     curcpu = raw_smp_processor_id();
0459     WARN_ONCE(curcpu != scfp->cpu % nr_cpu_ids,
0460           "%s: Wanted CPU %d, running on %d, nr_cpu_ids = %d\n",
0461           __func__, scfp->cpu, curcpu, nr_cpu_ids);
0462
0463     if (!atomic_dec_return(&n_started))
0464         while (atomic_read_acquire(&n_started)) {
0465             if (torture_must_stop()) {
0466                 VERBOSE_SCFTORTOUT("scftorture_invoker %d ended before starting", scfp->cpu);
0467                 goto end;
0468             }
0469             schedule_timeout_uninterruptible(1);
0470         }
0471
0472     VERBOSE_SCFTORTOUT("scftorture_invoker %d started", scfp->cpu);
0473
0474     do {
0475         scftorture_invoke_one(scfp, &rand);
0476         while (cpu_is_offline(cpu) && !torture_must_stop()) {
0477             schedule_timeout_interruptible(HZ / 5);
0478             was_offline = true;
0479         }
0480         if (was_offline) {
0481             set_cpus_allowed_ptr(current, cpumask_of(cpu));
0482             was_offline = false;
0483         }
0484         cond_resched();
0485         stutter_wait("scftorture_invoker");
0486     } while (!torture_must_stop());
0487
0488     VERBOSE_SCFTORTOUT("scftorture_invoker %d ended", scfp->cpu);
0489 end:
0490     torture_kthread_stopping("scftorture_invoker");
0491     return 0;
0492 }
0493
0494 static void
0495 scftorture_print_module_parms(const char *tag)
0496 {
0497     pr_alert(SCFTORT_FLAG
0498          "--- %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,
0499          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);
0500 }
0501
0502 static void scf_cleanup_handler(void *unused)
0503 {
0504 }
0505
0506 static void scf_torture_cleanup(void)
0507 {
0508     int i;
0509
0510     if (torture_cleanup_begin())
0511         return;
0512
0513     WRITE_ONCE(scfdone, true);
0514     if (nthreads && scf_stats_p)
0515         for (i = 0; i < nthreads; i++)
0516             torture_stop_kthread("scftorture_invoker", scf_stats_p[i].task);
0517     else
0518         goto end;
0519     smp_call_function(scf_cleanup_handler, NULL, 0);
0520     torture_stop_kthread(scf_torture_stats, scf_torture_stats_task);
0521     scf_torture_stats_print();  // -After- the stats thread is stopped!
0522     kfree(scf_stats_p);  // -After- the last stats print has completed!
0523     scf_stats_p = NULL;
0524
0525     if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) || atomic_read(&n_mb_out_errs))
0526         scftorture_print_module_parms("End of test: FAILURE");
0527     else if (torture_onoff_failures())
0528         scftorture_print_module_parms("End of test: LOCK_HOTPLUG");
0529     else
0530         scftorture_print_module_parms("End of test: SUCCESS");
0531
0532 end:
0533     torture_cleanup_end();
0534 }
0535
0536 static int __init scf_torture_init(void)
0537 {
0538     long i;
0539     int firsterr = 0;
0540     unsigned long weight_resched1 = weight_resched;
0541     unsigned long weight_single1 = weight_single;
0542     unsigned long weight_single_rpc1 = weight_single_rpc;
0543     unsigned long weight_single_wait1 = weight_single_wait;
0544     unsigned long weight_many1 = weight_many;
0545     unsigned long weight_many_wait1 = weight_many_wait;
0546     unsigned long weight_all1 = weight_all;
0547     unsigned long weight_all_wait1 = weight_all_wait;
0548
0549     if (!torture_init_begin(SCFTORT_STRING, verbose))
0550         return -EBUSY;
0551
0552     scftorture_print_module_parms("Start of test");
0553
0554     if (weight_resched <= 0 &&
0555         weight_single <= 0 && weight_single_rpc <= 0 && weight_single_wait <= 0 &&
0556         weight_many <= 0 && weight_many_wait <= 0 &&
0557         weight_all <= 0 && weight_all_wait <= 0) {
0558         weight_resched1 = weight_resched == 0 ? 0 : 2 * nr_cpu_ids;
0559         weight_single1 = weight_single == 0 ? 0 : 2 * nr_cpu_ids;
0560         weight_single_rpc1 = weight_single_rpc == 0 ? 0 : 2 * nr_cpu_ids;
0561         weight_single_wait1 = weight_single_wait == 0 ? 0 : 2 * nr_cpu_ids;
0562         weight_many1 = weight_many == 0 ? 0 : 2;
0563         weight_many_wait1 = weight_many_wait == 0 ? 0 : 2;
0564         weight_all1 = weight_all == 0 ? 0 : 1;
0565         weight_all_wait1 = weight_all_wait == 0 ? 0 : 1;
0566     } else {
0567         if (weight_resched == -1)
0568             weight_resched1 = 0;
0569         if (weight_single == -1)
0570             weight_single1 = 0;
0571         if (weight_single_rpc == -1)
0572             weight_single_rpc1 = 0;
0573         if (weight_single_wait == -1)
0574             weight_single_wait1 = 0;
0575         if (weight_many == -1)
0576             weight_many1 = 0;
0577         if (weight_many_wait == -1)
0578             weight_many_wait1 = 0;
0579         if (weight_all == -1)
0580             weight_all1 = 0;
0581         if (weight_all_wait == -1)
0582             weight_all_wait1 = 0;
0583     }
0584     if (weight_resched1 == 0 && weight_single1 == 0 && weight_single_rpc1 == 0 &&
0585         weight_single_wait1 == 0 && weight_many1 == 0 && weight_many_wait1 == 0 &&
0586         weight_all1 == 0 && weight_all_wait1 == 0) {
0587         SCFTORTOUT_ERRSTRING("all zero weights makes no sense");
0588         firsterr = -EINVAL;
0589         goto unwind;
0590     }
0591     if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST))
0592         scf_sel_add(weight_resched1, SCF_PRIM_RESCHED, false);
0593     else if (weight_resched1)
0594         SCFTORTOUT_ERRSTRING("built as module, weight_resched ignored");
0595     scf_sel_add(weight_single1, SCF_PRIM_SINGLE, false);
0596     scf_sel_add(weight_single_rpc1, SCF_PRIM_SINGLE_RPC, true);
0597     scf_sel_add(weight_single_wait1, SCF_PRIM_SINGLE, true);
0598     scf_sel_add(weight_many1, SCF_PRIM_MANY, false);
0599     scf_sel_add(weight_many_wait1, SCF_PRIM_MANY, true);
0600     scf_sel_add(weight_all1, SCF_PRIM_ALL, false);
0601     scf_sel_add(weight_all_wait1, SCF_PRIM_ALL, true);
0602     scf_sel_dump();
0603
0604     if (onoff_interval > 0) {
0605         firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, NULL);
0606         if (torture_init_error(firsterr))
0607             goto unwind;
0608     }
0609     if (shutdown_secs > 0) {
0610         firsterr = torture_shutdown_init(shutdown_secs, scf_torture_cleanup);
0611         if (torture_init_error(firsterr))
0612             goto unwind;
0613     }
0614     if (stutter > 0) {
0615         firsterr = torture_stutter_init(stutter, stutter);
0616         if (torture_init_error(firsterr))
0617             goto unwind;
0618     }
0619
0620     // Worker tasks invoking smp_call_function().
0621     if (nthreads < 0)
0622         nthreads = num_online_cpus();
0623     scf_stats_p = kcalloc(nthreads, sizeof(scf_stats_p[0]), GFP_KERNEL);
0624     if (!scf_stats_p) {
0625         SCFTORTOUT_ERRSTRING("out of memory");
0626         firsterr = -ENOMEM;
0627         goto unwind;
0628     }
0629
0630     VERBOSE_SCFTORTOUT("Starting %d smp_call_function() threads", nthreads);
0631
0632     atomic_set(&n_started, nthreads);
0633     for (i = 0; i < nthreads; i++) {
0634         scf_stats_p[i].cpu = i;
0635         firsterr = torture_create_kthread(scftorture_invoker, (void *)&scf_stats_p[i],
0636                           scf_stats_p[i].task);
0637         if (torture_init_error(firsterr))
0638             goto unwind;
0639     }
0640     if (stat_interval > 0) {
0641         firsterr = torture_create_kthread(scf_torture_stats, NULL, scf_torture_stats_task);
0642         if (torture_init_error(firsterr))
0643             goto unwind;
0644     }
0645
0646     torture_init_end();
0647     return 0;
0648
0649 unwind:
0650     torture_init_end();
0651     scf_torture_cleanup();
0652     if (shutdown_secs) {
0653         WARN_ON(!IS_MODULE(CONFIG_SCF_TORTURE_TEST));
0654         kernel_power_off();
0655     }
0656     return firsterr;
0657 }
0658
0659 module_init(scf_torture_init);
0660 module_exit(scf_torture_cleanup);