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-rw-r--r--kernel/scftorture.c578
1 files changed, 578 insertions, 0 deletions
diff --git a/kernel/scftorture.c b/kernel/scftorture.c
new file mode 100644
index 000000000..be86207a2
--- /dev/null
+++ b/kernel/scftorture.c
@@ -0,0 +1,578 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Torture test for smp_call_function() and friends.
+//
+// Copyright (C) Facebook, 2020.
+//
+// Author: Paul E. McKenney <paulmck@kernel.org>
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kthread.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/notifier.h>
+#include <linux/percpu.h>
+#include <linux/rcupdate.h>
+#include <linux/rcupdate_trace.h>
+#include <linux/reboot.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/stat.h>
+#include <linux/srcu.h>
+#include <linux/slab.h>
+#include <linux/torture.h>
+#include <linux/types.h>
+
+#define SCFTORT_STRING "scftorture"
+#define SCFTORT_FLAG SCFTORT_STRING ": "
+
+#define SCFTORTOUT(s, x...) \
+ pr_alert(SCFTORT_FLAG s, ## x)
+
+#define VERBOSE_SCFTORTOUT(s, x...) \
+ do { if (verbose) pr_alert(SCFTORT_FLAG s, ## x); } while (0)
+
+#define VERBOSE_SCFTORTOUT_ERRSTRING(s, x...) \
+ do { if (verbose) pr_alert(SCFTORT_FLAG "!!! " s, ## x); } while (0)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@kernel.org>");
+
+// Wait until there are multiple CPUs before starting test.
+torture_param(int, holdoff, IS_BUILTIN(CONFIG_SCF_TORTURE_TEST) ? 10 : 0,
+ "Holdoff time before test start (s)");
+torture_param(int, longwait, 0, "Include ridiculously long waits? (seconds)");
+torture_param(int, nthreads, -1, "# threads, defaults to -1 for all CPUs.");
+torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
+torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable");
+torture_param(int, shutdown_secs, 0, "Shutdown time (ms), <= zero to disable.");
+torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s.");
+torture_param(int, stutter_cpus, 5, "Number of jiffies to change CPUs under test, 0=disable");
+torture_param(bool, use_cpus_read_lock, 0, "Use cpus_read_lock() to exclude CPU hotplug.");
+torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
+torture_param(int, weight_single, -1, "Testing weight for single-CPU no-wait operations.");
+torture_param(int, weight_single_wait, -1, "Testing weight for single-CPU operations.");
+torture_param(int, weight_many, -1, "Testing weight for multi-CPU no-wait operations.");
+torture_param(int, weight_many_wait, -1, "Testing weight for multi-CPU operations.");
+torture_param(int, weight_all, -1, "Testing weight for all-CPU no-wait operations.");
+torture_param(int, weight_all_wait, -1, "Testing weight for all-CPU operations.");
+
+char *torture_type = "";
+
+#ifdef MODULE
+# define SCFTORT_SHUTDOWN 0
+#else
+# define SCFTORT_SHUTDOWN 1
+#endif
+
+torture_param(bool, shutdown, SCFTORT_SHUTDOWN, "Shutdown at end of torture test.");
+
+struct scf_statistics {
+ struct task_struct *task;
+ int cpu;
+ long long n_single;
+ long long n_single_ofl;
+ long long n_single_wait;
+ long long n_single_wait_ofl;
+ long long n_many;
+ long long n_many_wait;
+ long long n_all;
+ long long n_all_wait;
+};
+
+static struct scf_statistics *scf_stats_p;
+static struct task_struct *scf_torture_stats_task;
+static DEFINE_PER_CPU(long long, scf_invoked_count);
+
+// Data for random primitive selection
+#define SCF_PRIM_SINGLE 0
+#define SCF_PRIM_MANY 1
+#define SCF_PRIM_ALL 2
+#define SCF_NPRIMS (2 * 3) // Need wait and no-wait versions of each.
+
+static char *scf_prim_name[] = {
+ "smp_call_function_single",
+ "smp_call_function_many",
+ "smp_call_function",
+};
+
+struct scf_selector {
+ unsigned long scfs_weight;
+ int scfs_prim;
+ bool scfs_wait;
+};
+static struct scf_selector scf_sel_array[SCF_NPRIMS];
+static int scf_sel_array_len;
+static unsigned long scf_sel_totweight;
+
+// Communicate between caller and handler.
+struct scf_check {
+ bool scfc_in;
+ bool scfc_out;
+ int scfc_cpu; // -1 for not _single().
+ bool scfc_wait;
+};
+
+// Use to wait for all threads to start.
+static atomic_t n_started;
+static atomic_t n_errs;
+static atomic_t n_mb_in_errs;
+static atomic_t n_mb_out_errs;
+static atomic_t n_alloc_errs;
+static bool scfdone;
+static char *bangstr = "";
+
+static DEFINE_TORTURE_RANDOM_PERCPU(scf_torture_rand);
+
+// Print torture statistics. Caller must ensure serialization.
+static void scf_torture_stats_print(void)
+{
+ int cpu;
+ int i;
+ long long invoked_count = 0;
+ bool isdone = READ_ONCE(scfdone);
+ struct scf_statistics scfs = {};
+
+ for_each_possible_cpu(cpu)
+ invoked_count += data_race(per_cpu(scf_invoked_count, cpu));
+ for (i = 0; i < nthreads; i++) {
+ scfs.n_single += scf_stats_p[i].n_single;
+ scfs.n_single_ofl += scf_stats_p[i].n_single_ofl;
+ scfs.n_single_wait += scf_stats_p[i].n_single_wait;
+ scfs.n_single_wait_ofl += scf_stats_p[i].n_single_wait_ofl;
+ scfs.n_many += scf_stats_p[i].n_many;
+ scfs.n_many_wait += scf_stats_p[i].n_many_wait;
+ scfs.n_all += scf_stats_p[i].n_all;
+ scfs.n_all_wait += scf_stats_p[i].n_all_wait;
+ }
+ if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) ||
+ atomic_read(&n_mb_out_errs) ||
+ (!IS_ENABLED(CONFIG_KASAN) && atomic_read(&n_alloc_errs)))
+ bangstr = "!!! ";
+ pr_alert("%s %sscf_invoked_count %s: %lld single: %lld/%lld single_ofl: %lld/%lld many: %lld/%lld all: %lld/%lld ",
+ SCFTORT_FLAG, bangstr, isdone ? "VER" : "ver", invoked_count,
+ scfs.n_single, scfs.n_single_wait, scfs.n_single_ofl, scfs.n_single_wait_ofl,
+ scfs.n_many, scfs.n_many_wait, scfs.n_all, scfs.n_all_wait);
+ torture_onoff_stats();
+ pr_cont("ste: %d stnmie: %d stnmoe: %d staf: %d\n", atomic_read(&n_errs),
+ atomic_read(&n_mb_in_errs), atomic_read(&n_mb_out_errs),
+ atomic_read(&n_alloc_errs));
+}
+
+// Periodically prints torture statistics, if periodic statistics printing
+// was specified via the stat_interval module parameter.
+static int
+scf_torture_stats(void *arg)
+{
+ VERBOSE_TOROUT_STRING("scf_torture_stats task started");
+ do {
+ schedule_timeout_interruptible(stat_interval * HZ);
+ scf_torture_stats_print();
+ torture_shutdown_absorb("scf_torture_stats");
+ } while (!torture_must_stop());
+ torture_kthread_stopping("scf_torture_stats");
+ return 0;
+}
+
+// Add a primitive to the scf_sel_array[].
+static void scf_sel_add(unsigned long weight, int prim, bool wait)
+{
+ struct scf_selector *scfsp = &scf_sel_array[scf_sel_array_len];
+
+ // If no weight, if array would overflow, if computing three-place
+ // percentages would overflow, or if the scf_prim_name[] array would
+ // overflow, don't bother. In the last three two cases, complain.
+ if (!weight ||
+ WARN_ON_ONCE(scf_sel_array_len >= ARRAY_SIZE(scf_sel_array)) ||
+ WARN_ON_ONCE(0 - 100000 * weight <= 100000 * scf_sel_totweight) ||
+ WARN_ON_ONCE(prim >= ARRAY_SIZE(scf_prim_name)))
+ return;
+ scf_sel_totweight += weight;
+ scfsp->scfs_weight = scf_sel_totweight;
+ scfsp->scfs_prim = prim;
+ scfsp->scfs_wait = wait;
+ scf_sel_array_len++;
+}
+
+// Dump out weighting percentages for scf_prim_name[] array.
+static void scf_sel_dump(void)
+{
+ int i;
+ unsigned long oldw = 0;
+ struct scf_selector *scfsp;
+ unsigned long w;
+
+ for (i = 0; i < scf_sel_array_len; i++) {
+ scfsp = &scf_sel_array[i];
+ w = (scfsp->scfs_weight - oldw) * 100000 / scf_sel_totweight;
+ pr_info("%s: %3lu.%03lu %s(%s)\n", __func__, w / 1000, w % 1000,
+ scf_prim_name[scfsp->scfs_prim],
+ scfsp->scfs_wait ? "wait" : "nowait");
+ oldw = scfsp->scfs_weight;
+ }
+}
+
+// Randomly pick a primitive and wait/nowait, based on weightings.
+static struct scf_selector *scf_sel_rand(struct torture_random_state *trsp)
+{
+ int i;
+ unsigned long w = torture_random(trsp) % (scf_sel_totweight + 1);
+
+ for (i = 0; i < scf_sel_array_len; i++)
+ if (scf_sel_array[i].scfs_weight >= w)
+ return &scf_sel_array[i];
+ WARN_ON_ONCE(1);
+ return &scf_sel_array[0];
+}
+
+// Update statistics and occasionally burn up mass quantities of CPU time,
+// if told to do so via scftorture.longwait. Otherwise, occasionally burn
+// a little bit.
+static void scf_handler(void *scfc_in)
+{
+ int i;
+ int j;
+ unsigned long r = torture_random(this_cpu_ptr(&scf_torture_rand));
+ struct scf_check *scfcp = scfc_in;
+
+ if (likely(scfcp)) {
+ WRITE_ONCE(scfcp->scfc_out, false); // For multiple receivers.
+ if (WARN_ON_ONCE(unlikely(!READ_ONCE(scfcp->scfc_in))))
+ atomic_inc(&n_mb_in_errs);
+ }
+ this_cpu_inc(scf_invoked_count);
+ if (longwait <= 0) {
+ if (!(r & 0xffc0)) {
+ udelay(r & 0x3f);
+ goto out;
+ }
+ }
+ if (r & 0xfff)
+ goto out;
+ r = (r >> 12);
+ if (longwait <= 0) {
+ udelay((r & 0xff) + 1);
+ goto out;
+ }
+ r = r % longwait + 1;
+ for (i = 0; i < r; i++) {
+ for (j = 0; j < 1000; j++) {
+ udelay(1000);
+ cpu_relax();
+ }
+ }
+out:
+ if (unlikely(!scfcp))
+ return;
+ if (scfcp->scfc_wait)
+ WRITE_ONCE(scfcp->scfc_out, true);
+ else
+ kfree(scfcp);
+}
+
+// As above, but check for correct CPU.
+static void scf_handler_1(void *scfc_in)
+{
+ struct scf_check *scfcp = scfc_in;
+
+ 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())) {
+ atomic_inc(&n_errs);
+ }
+ scf_handler(scfcp);
+}
+
+// Randomly do an smp_call_function*() invocation.
+static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_random_state *trsp)
+{
+ uintptr_t cpu;
+ int ret = 0;
+ struct scf_check *scfcp = NULL;
+ struct scf_selector *scfsp = scf_sel_rand(trsp);
+
+ if (use_cpus_read_lock)
+ cpus_read_lock();
+ else
+ preempt_disable();
+ if (scfsp->scfs_prim == SCF_PRIM_SINGLE || scfsp->scfs_wait) {
+ scfcp = kmalloc(sizeof(*scfcp), GFP_ATOMIC);
+ if (!scfcp) {
+ WARN_ON_ONCE(!IS_ENABLED(CONFIG_KASAN));
+ atomic_inc(&n_alloc_errs);
+ } else {
+ scfcp->scfc_cpu = -1;
+ scfcp->scfc_wait = scfsp->scfs_wait;
+ scfcp->scfc_out = false;
+ }
+ }
+ switch (scfsp->scfs_prim) {
+ case SCF_PRIM_SINGLE:
+ cpu = torture_random(trsp) % nr_cpu_ids;
+ if (scfsp->scfs_wait)
+ scfp->n_single_wait++;
+ else
+ scfp->n_single++;
+ if (scfcp) {
+ scfcp->scfc_cpu = cpu;
+ barrier(); // Prevent race-reduction compiler optimizations.
+ scfcp->scfc_in = true;
+ }
+ ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, scfsp->scfs_wait);
+ if (ret) {
+ if (scfsp->scfs_wait)
+ scfp->n_single_wait_ofl++;
+ else
+ scfp->n_single_ofl++;
+ kfree(scfcp);
+ scfcp = NULL;
+ }
+ break;
+ case SCF_PRIM_MANY:
+ if (scfsp->scfs_wait)
+ scfp->n_many_wait++;
+ else
+ scfp->n_many++;
+ if (scfcp) {
+ barrier(); // Prevent race-reduction compiler optimizations.
+ scfcp->scfc_in = true;
+ }
+ smp_call_function_many(cpu_online_mask, scf_handler, scfcp, scfsp->scfs_wait);
+ break;
+ case SCF_PRIM_ALL:
+ if (scfsp->scfs_wait)
+ scfp->n_all_wait++;
+ else
+ scfp->n_all++;
+ if (scfcp) {
+ barrier(); // Prevent race-reduction compiler optimizations.
+ scfcp->scfc_in = true;
+ }
+ smp_call_function(scf_handler, scfcp, scfsp->scfs_wait);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ if (scfcp)
+ scfcp->scfc_out = true;
+ }
+ if (scfcp && scfsp->scfs_wait) {
+ if (WARN_ON_ONCE((num_online_cpus() > 1 || scfsp->scfs_prim == SCF_PRIM_SINGLE) &&
+ !scfcp->scfc_out))
+ atomic_inc(&n_mb_out_errs); // Leak rather than trash!
+ else
+ kfree(scfcp);
+ barrier(); // Prevent race-reduction compiler optimizations.
+ }
+ if (use_cpus_read_lock)
+ cpus_read_unlock();
+ else
+ preempt_enable();
+ if (!(torture_random(trsp) & 0xfff))
+ schedule_timeout_uninterruptible(1);
+}
+
+// SCF test kthread. Repeatedly does calls to members of the
+// smp_call_function() family of functions.
+static int scftorture_invoker(void *arg)
+{
+ int cpu;
+ DEFINE_TORTURE_RANDOM(rand);
+ struct scf_statistics *scfp = (struct scf_statistics *)arg;
+ bool was_offline = false;
+
+ VERBOSE_SCFTORTOUT("scftorture_invoker %d: task started", scfp->cpu);
+ cpu = scfp->cpu % nr_cpu_ids;
+ set_cpus_allowed_ptr(current, cpumask_of(cpu));
+ set_user_nice(current, MAX_NICE);
+ if (holdoff)
+ schedule_timeout_interruptible(holdoff * HZ);
+
+ VERBOSE_SCFTORTOUT("scftorture_invoker %d: Waiting for all SCF torturers from cpu %d", scfp->cpu, smp_processor_id());
+
+ // Make sure that the CPU is affinitized appropriately during testing.
+ WARN_ON_ONCE(smp_processor_id() != scfp->cpu);
+
+ if (!atomic_dec_return(&n_started))
+ while (atomic_read_acquire(&n_started)) {
+ if (torture_must_stop()) {
+ VERBOSE_SCFTORTOUT("scftorture_invoker %d ended before starting", scfp->cpu);
+ goto end;
+ }
+ schedule_timeout_uninterruptible(1);
+ }
+
+ VERBOSE_SCFTORTOUT("scftorture_invoker %d started", scfp->cpu);
+
+ do {
+ scftorture_invoke_one(scfp, &rand);
+ while (cpu_is_offline(cpu) && !torture_must_stop()) {
+ schedule_timeout_interruptible(HZ / 5);
+ was_offline = true;
+ }
+ if (was_offline) {
+ set_cpus_allowed_ptr(current, cpumask_of(cpu));
+ was_offline = false;
+ }
+ cond_resched();
+ } while (!torture_must_stop());
+
+ VERBOSE_SCFTORTOUT("scftorture_invoker %d ended", scfp->cpu);
+end:
+ torture_kthread_stopping("scftorture_invoker");
+ return 0;
+}
+
+static void
+scftorture_print_module_parms(const char *tag)
+{
+ pr_alert(SCFTORT_FLAG
+ "--- %s: verbose=%d holdoff=%d longwait=%d nthreads=%d onoff_holdoff=%d onoff_interval=%d shutdown_secs=%d stat_interval=%d stutter_cpus=%d use_cpus_read_lock=%d, weight_single=%d, weight_single_wait=%d, weight_many=%d, weight_many_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag,
+ verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter_cpus, use_cpus_read_lock, weight_single, weight_single_wait, weight_many, weight_many_wait, weight_all, weight_all_wait);
+}
+
+static void scf_cleanup_handler(void *unused)
+{
+}
+
+static void scf_torture_cleanup(void)
+{
+ int i;
+
+ if (torture_cleanup_begin())
+ return;
+
+ WRITE_ONCE(scfdone, true);
+ if (nthreads)
+ for (i = 0; i < nthreads; i++)
+ torture_stop_kthread("scftorture_invoker", scf_stats_p[i].task);
+ else
+ goto end;
+ smp_call_function(scf_cleanup_handler, NULL, 0);
+ torture_stop_kthread(scf_torture_stats, scf_torture_stats_task);
+ scf_torture_stats_print(); // -After- the stats thread is stopped!
+ kfree(scf_stats_p); // -After- the last stats print has completed!
+ scf_stats_p = NULL;
+
+ if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) || atomic_read(&n_mb_out_errs))
+ scftorture_print_module_parms("End of test: FAILURE");
+ else if (torture_onoff_failures())
+ scftorture_print_module_parms("End of test: LOCK_HOTPLUG");
+ else
+ scftorture_print_module_parms("End of test: SUCCESS");
+
+end:
+ torture_cleanup_end();
+}
+
+static int __init scf_torture_init(void)
+{
+ long i;
+ int firsterr = 0;
+ unsigned long weight_single1 = weight_single;
+ unsigned long weight_single_wait1 = weight_single_wait;
+ unsigned long weight_many1 = weight_many;
+ unsigned long weight_many_wait1 = weight_many_wait;
+ unsigned long weight_all1 = weight_all;
+ unsigned long weight_all_wait1 = weight_all_wait;
+
+ if (!torture_init_begin(SCFTORT_STRING, verbose))
+ return -EBUSY;
+
+ scftorture_print_module_parms("Start of test");
+
+ if (weight_single == -1 && weight_single_wait == -1 &&
+ weight_many == -1 && weight_many_wait == -1 &&
+ weight_all == -1 && weight_all_wait == -1) {
+ weight_single1 = 2 * nr_cpu_ids;
+ weight_single_wait1 = 2 * nr_cpu_ids;
+ weight_many1 = 2;
+ weight_many_wait1 = 2;
+ weight_all1 = 1;
+ weight_all_wait1 = 1;
+ } else {
+ if (weight_single == -1)
+ weight_single1 = 0;
+ if (weight_single_wait == -1)
+ weight_single_wait1 = 0;
+ if (weight_many == -1)
+ weight_many1 = 0;
+ if (weight_many_wait == -1)
+ weight_many_wait1 = 0;
+ if (weight_all == -1)
+ weight_all1 = 0;
+ if (weight_all_wait == -1)
+ weight_all_wait1 = 0;
+ }
+ if (weight_single1 == 0 && weight_single_wait1 == 0 &&
+ weight_many1 == 0 && weight_many_wait1 == 0 &&
+ weight_all1 == 0 && weight_all_wait1 == 0) {
+ VERBOSE_SCFTORTOUT_ERRSTRING("all zero weights makes no sense");
+ firsterr = -EINVAL;
+ goto unwind;
+ }
+ scf_sel_add(weight_single1, SCF_PRIM_SINGLE, false);
+ scf_sel_add(weight_single_wait1, SCF_PRIM_SINGLE, true);
+ scf_sel_add(weight_many1, SCF_PRIM_MANY, false);
+ scf_sel_add(weight_many_wait1, SCF_PRIM_MANY, true);
+ scf_sel_add(weight_all1, SCF_PRIM_ALL, false);
+ scf_sel_add(weight_all_wait1, SCF_PRIM_ALL, true);
+ scf_sel_dump();
+
+ if (onoff_interval > 0) {
+ firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, NULL);
+ if (firsterr)
+ goto unwind;
+ }
+ if (shutdown_secs > 0) {
+ firsterr = torture_shutdown_init(shutdown_secs, scf_torture_cleanup);
+ if (firsterr)
+ goto unwind;
+ }
+
+ // Worker tasks invoking smp_call_function().
+ if (nthreads < 0)
+ nthreads = num_online_cpus();
+ scf_stats_p = kcalloc(nthreads, sizeof(scf_stats_p[0]), GFP_KERNEL);
+ if (!scf_stats_p) {
+ VERBOSE_SCFTORTOUT_ERRSTRING("out of memory");
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
+
+ VERBOSE_SCFTORTOUT("Starting %d smp_call_function() threads\n", nthreads);
+
+ atomic_set(&n_started, nthreads);
+ for (i = 0; i < nthreads; i++) {
+ scf_stats_p[i].cpu = i;
+ firsterr = torture_create_kthread(scftorture_invoker, (void *)&scf_stats_p[i],
+ scf_stats_p[i].task);
+ if (firsterr)
+ goto unwind;
+ }
+ if (stat_interval > 0) {
+ firsterr = torture_create_kthread(scf_torture_stats, NULL, scf_torture_stats_task);
+ if (firsterr)
+ goto unwind;
+ }
+
+ torture_init_end();
+ return 0;
+
+unwind:
+ torture_init_end();
+ scf_torture_cleanup();
+ return firsterr;
+}
+
+module_init(scf_torture_init);
+module_exit(scf_torture_cleanup);
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