/* * Read-Copy Update module-based torture test facility * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * Copyright (C) IBM Corporation, 2005, 2006 * * Authors: Paul E. McKenney <paulmck@us.ibm.com> * Josh Triplett <josh@freedesktop.org> * * See also: Documentation/RCU/torture.txt */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/module.h> #include <linux/kthread.h> #include <linux/err.h> #include <linux/spinlock.h> #include <linux/smp.h> #include <linux/rcupdate.h> #include <linux/interrupt.h> #include <linux/sched.h> #include <asm/atomic.h> #include <linux/bitops.h> #include <linux/completion.h> #include <linux/moduleparam.h> #include <linux/percpu.h> #include <linux/notifier.h> #include <linux/reboot.h> #include <linux/freezer.h> #include <linux/cpu.h> #include <linux/delay.h> #include <linux/stat.h> #include <linux/srcu.h> #include <linux/slab.h> #include <asm/byteorder.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and " "Josh Triplett <josh@freedesktop.org>"); static int nreaders = -1; /* # reader threads, defaults to 2*ncpus */ static int nfakewriters = 4; /* # fake writer threads */ static int stat_interval; /* Interval between stats, in seconds. */ /* Defaults to "only at end of test". */ static int verbose; /* Print more debug info. */ static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */ static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/ static int stutter = 5; /* Start/stop testing interval (in sec) */ static int irqreader = 1; /* RCU readers from irq (timers). */ static int fqs_duration = 0; /* Duration of bursts (us), 0 to disable. */ static int fqs_holdoff = 0; /* Hold time within burst (us). */ static int fqs_stutter = 3; /* Wait time between bursts (s). */ static char *torture_type = "rcu"; /* What RCU implementation to torture. */ module_param(nreaders, int, 0444); MODULE_PARM_DESC(nreaders, "Number of RCU reader threads"); module_param(nfakewriters, int, 0444); MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads"); module_param(stat_interval, int, 0444); MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s"); module_param(verbose, bool, 0444); MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s"); module_param(test_no_idle_hz, bool, 0444); MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs"); module_param(shuffle_interval, int, 0444); MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles"); module_param(stutter, int, 0444); MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test"); module_param(irqreader, int, 0444); MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers"); module_param(fqs_duration, int, 0444); MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us)"); module_param(fqs_holdoff, int, 0444); MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)"); module_param(fqs_stutter, int, 0444); MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)"); module_param(torture_type, charp, 0444); MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)"); #define TORTURE_FLAG "-torture:" #define PRINTK_STRING(s) \ do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0) #define VERBOSE_PRINTK_STRING(s) \ do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0) #define VERBOSE_PRINTK_ERRSTRING(s) \ do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0) static char printk_buf[4096]; static int nrealreaders; static struct task_struct *writer_task; static struct task_struct **fakewriter_tasks; static struct task_struct **reader_tasks; static struct task_struct *stats_task; static struct task_struct *shuffler_task; static struct task_struct *stutter_task; static struct task_struct *fqs_task; #define RCU_TORTURE_PIPE_LEN 10 struct rcu_torture { struct rcu_head rtort_rcu; int rtort_pipe_count; struct list_head rtort_free; int rtort_mbtest; }; static LIST_HEAD(rcu_torture_freelist); static struct rcu_torture *rcu_torture_current; static long rcu_torture_current_version; static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; static DEFINE_SPINLOCK(rcu_torture_lock); static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) = { 0 }; static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) = { 0 }; static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; static atomic_t n_rcu_torture_alloc; static atomic_t n_rcu_torture_alloc_fail; static atomic_t n_rcu_torture_free; static atomic_t n_rcu_torture_mberror; static atomic_t n_rcu_torture_error; static long n_rcu_torture_timers; static struct list_head rcu_torture_removed; static cpumask_var_t shuffle_tmp_mask; static int stutter_pause_test; #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE) #define RCUTORTURE_RUNNABLE_INIT 1 #else #define RCUTORTURE_RUNNABLE_INIT 0 #endif int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT; /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */ #define FULLSTOP_DONTSTOP 0 /* Normal operation. */ #define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */ #define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */ static int fullstop = FULLSTOP_RMMOD; DEFINE_MUTEX(fullstop_mutex); /* Protect fullstop transitions and spawning */ /* of kthreads. */ /* * Detect and respond to a system shutdown. */ static int rcutorture_shutdown_notify(struct notifier_block *unused1, unsigned long unused2, void *unused3) { mutex_lock(&fullstop_mutex); if (fullstop == FULLSTOP_DONTSTOP) fullstop = FULLSTOP_SHUTDOWN; else printk(KERN_WARNING /* but going down anyway, so... */ "Concurrent 'rmmod rcutorture' and shutdown illegal!\n"); mutex_unlock(&fullstop_mutex); return NOTIFY_DONE; } /* * Absorb kthreads into a kernel function that won't return, so that * they won't ever access module text or data again. */ static void rcutorture_shutdown_absorb(char *title) { if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { printk(KERN_NOTICE "rcutorture thread %s parking due to system shutdown\n", title); schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT); } } /* * Allocate an element from the rcu_tortures pool. */ static struct rcu_torture * rcu_torture_alloc(void) { struct list_head *p; spin_lock_bh(&rcu_torture_lock); if (list_empty(&rcu_torture_freelist)) { atomic_inc(&n_rcu_torture_alloc_fail); spin_unlock_bh(&rcu_torture_lock); return NULL; } atomic_inc(&n_rcu_torture_alloc); p = rcu_torture_freelist.next; list_del_init(p); spin_unlock_bh(&rcu_torture_lock); return container_of(p, struct rcu_torture, rtort_free); } /* * Free an element to the rcu_tortures pool. */ static void rcu_torture_free(struct rcu_torture *p) { atomic_inc(&n_rcu_torture_free); spin_lock_bh(&rcu_torture_lock); list_add_tail(&p->rtort_free, &rcu_torture_freelist); spin_unlock_bh(&rcu_torture_lock); } struct rcu_random_state { unsigned long rrs_state; long rrs_count; }; #define RCU_RANDOM_MULT 39916801 /* prime */ #define RCU_RANDOM_ADD 479001701 /* prime */ #define RCU_RANDOM_REFRESH 10000 #define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 } /* * Crude but fast random-number generator. Uses a linear congruential * generator, with occasional help from cpu_clock(). */ static unsigned long rcu_random(struct rcu_random_state *rrsp) { if (--rrsp->rrs_count < 0) { rrsp->rrs_state += (unsigned long)cpu_clock(raw_smp_processor_id()); rrsp->rrs_count = RCU_RANDOM_REFRESH; } rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD; return swahw32(rrsp->rrs_state); } static void rcu_stutter_wait(char *title) { while (stutter_pause_test || !rcutorture_runnable) { if (rcutorture_runnable) schedule_timeout_interruptible(1); else schedule_timeout_interruptible(round_jiffies_relative(HZ)); rcutorture_shutdown_absorb(title); } } /* * Operations vector for selecting different types of tests. */ struct rcu_torture_ops { void (*init)(void); void (*cleanup)(void); int (*readlock)(void); void (*read_delay)(struct rcu_random_state *rrsp); void (*readunlock)(int idx); int (*completed)(void); void (*deferred_free)(struct rcu_torture *p); void (*sync)(void); void (*cb_barrier)(void); void (*fqs)(void); int (*stats)(char *page); int irq_capable; char *name; }; static struct rcu_torture_ops *cur_ops; /* * Definitions for rcu torture testing. */ static int rcu_torture_read_lock(void) __acquires(RCU) { rcu_read_lock(); return 0; } static void rcu_read_delay(struct rcu_random_state *rrsp) { const unsigned long shortdelay_us = 200; const unsigned long longdelay_ms = 50; /* We want a short delay sometimes to make a reader delay the grace * period, and we want a long delay occasionally to trigger * force_quiescent_state. */ if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) mdelay(longdelay_ms); if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) udelay(shortdelay_us); } static void rcu_torture_read_unlock(int idx) __releases(RCU) { rcu_read_unlock(); } static int rcu_torture_completed(void) { return rcu_batches_completed(); } static void rcu_torture_cb(struct rcu_head *p) { int i; struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); if (fullstop != FULLSTOP_DONTSTOP) { /* Test is ending, just drop callbacks on the floor. */ /* The next initialization will pick up the pieces. */ return; } i = rp->rtort_pipe_count; if (i > RCU_TORTURE_PIPE_LEN) i = RCU_TORTURE_PIPE_LEN; atomic_inc(&rcu_torture_wcount[i]); if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { rp->rtort_mbtest = 0; rcu_torture_free(rp); } else cur_ops->deferred_free(rp); } static int rcu_no_completed(void) { return 0; } static void rcu_torture_deferred_free(struct rcu_torture *p) { call_rcu(&p->rtort_rcu, rcu_torture_cb); } static struct rcu_torture_ops rcu_ops = { .init = NULL, .cleanup = NULL, .readlock = rcu_torture_read_lock, .read_delay = rcu_read_delay, .readunlock = rcu_torture_read_unlock, .completed = rcu_torture_completed, .deferred_free = rcu_torture_deferred_free, .sync = synchronize_rcu, .cb_barrier = rcu_barrier, .fqs = rcu_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "rcu" }; static void rcu_sync_torture_deferred_free(struct rcu_torture *p) { int i; struct rcu_torture *rp; struct rcu_torture *rp1; cur_ops->sync(); list_add(&p->rtort_free, &rcu_torture_removed); list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { i = rp->rtort_pipe_count; if (i > RCU_TORTURE_PIPE_LEN) i = RCU_TORTURE_PIPE_LEN; atomic_inc(&rcu_torture_wcount[i]); if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { rp->rtort_mbtest = 0; list_del(&rp->rtort_free); rcu_torture_free(rp); } } } static void rcu_sync_torture_init(void) { INIT_LIST_HEAD(&rcu_torture_removed); } static struct rcu_torture_ops rcu_sync_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = rcu_torture_read_lock, .read_delay = rcu_read_delay, .readunlock = rcu_torture_read_unlock, .completed = rcu_torture_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_rcu, .cb_barrier = NULL, .fqs = rcu_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "rcu_sync" }; static struct rcu_torture_ops rcu_expedited_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = rcu_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = rcu_torture_read_unlock, .completed = rcu_no_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_rcu_expedited, .cb_barrier = NULL, .fqs = rcu_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "rcu_expedited" }; /* * Definitions for rcu_bh torture testing. */ static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH) { rcu_read_lock_bh(); return 0; } static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH) { rcu_read_unlock_bh(); } static int rcu_bh_torture_completed(void) { return rcu_batches_completed_bh(); } static void rcu_bh_torture_deferred_free(struct rcu_torture *p) { call_rcu_bh(&p->rtort_rcu, rcu_torture_cb); } struct rcu_bh_torture_synchronize { struct rcu_head head; struct completion completion; }; static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head) { struct rcu_bh_torture_synchronize *rcu; rcu = container_of(head, struct rcu_bh_torture_synchronize, head); complete(&rcu->completion); } static void rcu_bh_torture_synchronize(void) { struct rcu_bh_torture_synchronize rcu; init_rcu_head_on_stack(&rcu.head); init_completion(&rcu.completion); call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb); wait_for_completion(&rcu.completion); destroy_rcu_head_on_stack(&rcu.head); } static struct rcu_torture_ops rcu_bh_ops = { .init = NULL, .cleanup = NULL, .readlock = rcu_bh_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = rcu_bh_torture_read_unlock, .completed = rcu_bh_torture_completed, .deferred_free = rcu_bh_torture_deferred_free, .sync = rcu_bh_torture_synchronize, .cb_barrier = rcu_barrier_bh, .fqs = rcu_bh_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "rcu_bh" }; static struct rcu_torture_ops rcu_bh_sync_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = rcu_bh_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = rcu_bh_torture_read_unlock, .completed = rcu_bh_torture_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = rcu_bh_torture_synchronize, .cb_barrier = NULL, .fqs = rcu_bh_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "rcu_bh_sync" }; /* * Definitions for srcu torture testing. */ static struct srcu_struct srcu_ctl; static void srcu_torture_init(void) { init_srcu_struct(&srcu_ctl); rcu_sync_torture_init(); } static void srcu_torture_cleanup(void) { synchronize_srcu(&srcu_ctl); cleanup_srcu_struct(&srcu_ctl); } static int srcu_torture_read_lock(void) __acquires(&srcu_ctl) { return srcu_read_lock(&srcu_ctl); } static void srcu_read_delay(struct rcu_random_state *rrsp) { long delay; const long uspertick = 1000000 / HZ; const long longdelay = 10; /* We want there to be long-running readers, but not all the time. */ delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick); if (!delay) schedule_timeout_interruptible(longdelay); } static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl) { srcu_read_unlock(&srcu_ctl, idx); } static int srcu_torture_completed(void) { return srcu_batches_completed(&srcu_ctl); } static void srcu_torture_synchronize(void) { synchronize_srcu(&srcu_ctl); } static int srcu_torture_stats(char *page) { int cnt = 0; int cpu; int idx = srcu_ctl.completed & 0x1; cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):", torture_type, TORTURE_FLAG, idx); for_each_possible_cpu(cpu) { cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu, per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx], per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]); } cnt += sprintf(&page[cnt], "\n"); return cnt; } static struct rcu_torture_ops srcu_ops = { .init = srcu_torture_init, .cleanup = srcu_torture_cleanup, .readlock = srcu_torture_read_lock, .read_delay = srcu_read_delay, .readunlock = srcu_torture_read_unlock, .completed = srcu_torture_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = srcu_torture_synchronize, .cb_barrier = NULL, .stats = srcu_torture_stats, .name = "srcu" }; static void srcu_torture_synchronize_expedited(void) { synchronize_srcu_expedited(&srcu_ctl); } static struct rcu_torture_ops srcu_expedited_ops = { .init = srcu_torture_init, .cleanup = srcu_torture_cleanup, .readlock = srcu_torture_read_lock, .read_delay = srcu_read_delay, .readunlock = srcu_torture_read_unlock, .completed = srcu_torture_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = srcu_torture_synchronize_expedited, .cb_barrier = NULL, .stats = srcu_torture_stats, .name = "srcu_expedited" }; /* * Definitions for sched torture testing. */ static int sched_torture_read_lock(void) { preempt_disable(); return 0; } static void sched_torture_read_unlock(int idx) { preempt_enable(); } static void rcu_sched_torture_deferred_free(struct rcu_torture *p) { call_rcu_sched(&p->rtort_rcu, rcu_torture_cb); } static void sched_torture_synchronize(void) { synchronize_sched(); } static struct rcu_torture_ops sched_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = sched_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, .completed = rcu_no_completed, .deferred_free = rcu_sched_torture_deferred_free, .sync = sched_torture_synchronize, .cb_barrier = rcu_barrier_sched, .fqs = rcu_sched_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "sched" }; static struct rcu_torture_ops sched_sync_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = sched_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, .completed = rcu_no_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = sched_torture_synchronize, .cb_barrier = NULL, .fqs = rcu_sched_force_quiescent_state, .stats = NULL, .name = "sched_sync" }; static struct rcu_torture_ops sched_expedited_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = sched_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, .completed = rcu_no_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_sched_expedited, .cb_barrier = NULL, .fqs = rcu_sched_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "sched_expedited" }; /* * RCU torture force-quiescent-state kthread. Repeatedly induces * bursts of calls to force_quiescent_state(), increasing the probability * of occurrence of some important types of race conditions. */ static int rcu_torture_fqs(void *arg) { unsigned long fqs_resume_time; int fqs_burst_remaining; VERBOSE_PRINTK_STRING("rcu_torture_fqs task started"); do { fqs_resume_time = jiffies + fqs_stutter * HZ; while (jiffies - fqs_resume_time > LONG_MAX) { schedule_timeout_interruptible(1); } fqs_burst_remaining = fqs_duration; while (fqs_burst_remaining > 0) { cur_ops->fqs(); udelay(fqs_holdoff); fqs_burst_remaining -= fqs_holdoff; } rcu_stutter_wait("rcu_torture_fqs"); } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping"); rcutorture_shutdown_absorb("rcu_torture_fqs"); while (!kthread_should_stop()) schedule_timeout_uninterruptible(1); return 0; } /* * RCU torture writer kthread. Repeatedly substitutes a new structure * for that pointed to by rcu_torture_current, freeing the old structure * after a series of grace periods (the "pipeline"). */ static int rcu_torture_writer(void *arg) { int i; long oldbatch = rcu_batches_completed(); struct rcu_torture *rp; struct rcu_torture *old_rp; static DEFINE_RCU_RANDOM(rand); VERBOSE_PRINTK_STRING("rcu_torture_writer task started"); set_user_nice(current, 19); do { schedule_timeout_uninterruptible(1); rp = rcu_torture_alloc(); if (rp == NULL) continue; rp->rtort_pipe_count = 0; udelay(rcu_random(&rand) & 0x3ff); old_rp = rcu_torture_current; rp->rtort_mbtest = 1; rcu_assign_pointer(rcu_torture_current, rp); smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ if (old_rp) { i = old_rp->rtort_pipe_count; if (i > RCU_TORTURE_PIPE_LEN) i = RCU_TORTURE_PIPE_LEN; atomic_inc(&rcu_torture_wcount[i]); old_rp->rtort_pipe_count++; cur_ops->deferred_free(old_rp); } rcu_torture_current_version++; oldbatch = cur_ops->completed(); rcu_stutter_wait("rcu_torture_writer"); } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping"); rcutorture_shutdown_absorb("rcu_torture_writer"); while (!kthread_should_stop()) schedule_timeout_uninterruptible(1); return 0; } /* * RCU torture fake writer kthread. Repeatedly calls sync, with a random * delay between calls. */ static int rcu_torture_fakewriter(void *arg) { DEFINE_RCU_RANDOM(rand); VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started"); set_user_nice(current, 19); do { schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10); udelay(rcu_random(&rand) & 0x3ff); cur_ops->sync(); rcu_stutter_wait("rcu_torture_fakewriter"); } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping"); rcutorture_shutdown_absorb("rcu_torture_fakewriter"); while (!kthread_should_stop()) schedule_timeout_uninterruptible(1); return 0; } /* * RCU torture reader from timer handler. Dereferences rcu_torture_current, * incrementing the corresponding element of the pipeline array. The * counter in the element should never be greater than 1, otherwise, the * RCU implementation is broken. */ static void rcu_torture_timer(unsigned long unused) { int idx; int completed; static DEFINE_RCU_RANDOM(rand); static DEFINE_SPINLOCK(rand_lock); struct rcu_torture *p; int pipe_count; idx = cur_ops->readlock(); completed = cur_ops->completed(); p = rcu_dereference_check(rcu_torture_current, rcu_read_lock_held() || rcu_read_lock_bh_held() || rcu_read_lock_sched_held() || srcu_read_lock_held(&srcu_ctl)); if (p == NULL) { /* Leave because rcu_torture_writer is not yet underway */ cur_ops->readunlock(idx); return; } if (p->rtort_mbtest == 0) atomic_inc(&n_rcu_torture_mberror); spin_lock(&rand_lock); cur_ops->read_delay(&rand); n_rcu_torture_timers++; spin_unlock(&rand_lock); preempt_disable(); pipe_count = p->rtort_pipe_count; if (pipe_count > RCU_TORTURE_PIPE_LEN) { /* Should not happen, but... */ pipe_count = RCU_TORTURE_PIPE_LEN; } __this_cpu_inc(rcu_torture_count[pipe_count]); completed = cur_ops->completed() - completed; if (completed > RCU_TORTURE_PIPE_LEN) { /* Should not happen, but... */ completed = RCU_TORTURE_PIPE_LEN; } __this_cpu_inc(rcu_torture_batch[completed]); preempt_enable(); cur_ops->readunlock(idx); } /* * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, * incrementing the corresponding element of the pipeline array. The * counter in the element should never be greater than 1, otherwise, the * RCU implementation is broken. */ static int rcu_torture_reader(void *arg) { int completed; int idx; DEFINE_RCU_RANDOM(rand); struct rcu_torture *p; int pipe_count; struct timer_list t; VERBOSE_PRINTK_STRING("rcu_torture_reader task started"); set_user_nice(current, 19); if (irqreader && cur_ops->irq_capable) setup_timer_on_stack(&t, rcu_torture_timer, 0); do { if (irqreader && cur_ops->irq_capable) { if (!timer_pending(&t)) mod_timer(&t, jiffies + 1); } idx = cur_ops->readlock(); completed = cur_ops->completed(); p = rcu_dereference_check(rcu_torture_current, rcu_read_lock_held() || rcu_read_lock_bh_held() || rcu_read_lock_sched_held() || srcu_read_lock_held(&srcu_ctl)); if (p == NULL) { /* Wait for rcu_torture_writer to get underway */ cur_ops->readunlock(idx); schedule_timeout_interruptible(HZ); continue; } if (p->rtort_mbtest == 0) atomic_inc(&n_rcu_torture_mberror); cur_ops->read_delay(&rand); preempt_disable(); pipe_count = p->rtort_pipe_count; if (pipe_count > RCU_TORTURE_PIPE_LEN) { /* Should not happen, but... */ pipe_count = RCU_TORTURE_PIPE_LEN; } __this_cpu_inc(rcu_torture_count[pipe_count]); completed = cur_ops->completed() - completed; if (completed > RCU_TORTURE_PIPE_LEN) { /* Should not happen, but... */ completed = RCU_TORTURE_PIPE_LEN; } __this_cpu_inc(rcu_torture_batch[completed]); preempt_enable(); cur_ops->readunlock(idx); schedule(); rcu_stutter_wait("rcu_torture_reader"); } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping"); rcutorture_shutdown_absorb("rcu_torture_reader"); if (irqreader && cur_ops->irq_capable) del_timer_sync(&t); while (!kthread_should_stop()) schedule_timeout_uninterruptible(1); return 0; } /* * Create an RCU-torture statistics message in the specified buffer. */ static int rcu_torture_printk(char *page) { int cnt = 0; int cpu; int i; long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; for_each_possible_cpu(cpu) { for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i]; batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i]; } } for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { if (pipesummary[i] != 0) break; } cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG); cnt += sprintf(&page[cnt], "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d " "rtmbe: %d nt: %ld", rcu_torture_current, rcu_torture_current_version, list_empty(&rcu_torture_freelist), atomic_read(&n_rcu_torture_alloc), atomic_read(&n_rcu_torture_alloc_fail), atomic_read(&n_rcu_torture_free), atomic_read(&n_rcu_torture_mberror), n_rcu_torture_timers); if (atomic_read(&n_rcu_torture_mberror) != 0) cnt += sprintf(&page[cnt], " !!!"); cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); if (i > 1) { cnt += sprintf(&page[cnt], "!!! "); atomic_inc(&n_rcu_torture_error); WARN_ON_ONCE(1); } cnt += sprintf(&page[cnt], "Reader Pipe: "); for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) cnt += sprintf(&page[cnt], " %ld", pipesummary[i]); cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); cnt += sprintf(&page[cnt], "Reader Batch: "); for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) cnt += sprintf(&page[cnt], " %ld", batchsummary[i]); cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); cnt += sprintf(&page[cnt], "Free-Block Circulation: "); for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { cnt += sprintf(&page[cnt], " %d", atomic_read(&rcu_torture_wcount[i])); } cnt += sprintf(&page[cnt], "\n"); if (cur_ops->stats) cnt += cur_ops->stats(&page[cnt]); return cnt; } /* * Print torture statistics. Caller must ensure that there is only * one call to this function at a given time!!! This is normally * accomplished by relying on the module system to only have one copy * of the module loaded, and then by giving the rcu_torture_stats * kthread full control (or the init/cleanup functions when rcu_torture_stats * thread is not running). */ static void rcu_torture_stats_print(void) { int cnt; cnt = rcu_torture_printk(printk_buf); printk(KERN_ALERT "%s", printk_buf); } /* * Periodically prints torture statistics, if periodic statistics printing * was specified via the stat_interval module parameter. * * No need to worry about fullstop here, since this one doesn't reference * volatile state or register callbacks. */ static int rcu_torture_stats(void *arg) { VERBOSE_PRINTK_STRING("rcu_torture_stats task started"); do { schedule_timeout_interruptible(stat_interval * HZ); rcu_torture_stats_print(); rcutorture_shutdown_absorb("rcu_torture_stats"); } while (!kthread_should_stop()); VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping"); return 0; } static int rcu_idle_cpu; /* Force all torture tasks off this CPU */ /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs. */ static void rcu_torture_shuffle_tasks(void) { int i; cpumask_setall(shuffle_tmp_mask); get_online_cpus(); /* No point in shuffling if there is only one online CPU (ex: UP) */ if (num_online_cpus() == 1) { put_online_cpus(); return; } if (rcu_idle_cpu != -1) cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask); set_cpus_allowed_ptr(current, shuffle_tmp_mask); if (reader_tasks) { for (i = 0; i < nrealreaders; i++) if (reader_tasks[i]) set_cpus_allowed_ptr(reader_tasks[i], shuffle_tmp_mask); } if (fakewriter_tasks) { for (i = 0; i < nfakewriters; i++) if (fakewriter_tasks[i]) set_cpus_allowed_ptr(fakewriter_tasks[i], shuffle_tmp_mask); } if (writer_task) set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask); if (stats_task) set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask); if (rcu_idle_cpu == -1) rcu_idle_cpu = num_online_cpus() - 1; else rcu_idle_cpu--; put_online_cpus(); } /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the * system to become idle at a time and cut off its timer ticks. This is meant * to test the support for such tickless idle CPU in RCU. */ static int rcu_torture_shuffle(void *arg) { VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started"); do { schedule_timeout_interruptible(shuffle_interval * HZ); rcu_torture_shuffle_tasks(); rcutorture_shutdown_absorb("rcu_torture_shuffle"); } while (!kthread_should_stop()); VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping"); return 0; } /* Cause the rcutorture test to "stutter", starting and stopping all * threads periodically. */ static int rcu_torture_stutter(void *arg) { VERBOSE_PRINTK_STRING("rcu_torture_stutter task started"); do { schedule_timeout_interruptible(stutter * HZ); stutter_pause_test = 1; if (!kthread_should_stop()) schedule_timeout_interruptible(stutter * HZ); stutter_pause_test = 0; rcutorture_shutdown_absorb("rcu_torture_stutter"); } while (!kthread_should_stop()); VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping"); return 0; } static inline void rcu_torture_print_module_parms(char *tag) { printk(KERN_ALERT "%s" TORTURE_FLAG "--- %s: nreaders=%d nfakewriters=%d " "stat_interval=%d verbose=%d test_no_idle_hz=%d " "shuffle_interval=%d stutter=%d irqreader=%d " "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d\n", torture_type, tag, nrealreaders, nfakewriters, stat_interval, verbose, test_no_idle_hz, shuffle_interval, stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter); } static struct notifier_block rcutorture_nb = { .notifier_call = rcutorture_shutdown_notify, }; static void rcu_torture_cleanup(void) { int i; mutex_lock(&fullstop_mutex); if (fullstop == FULLSTOP_SHUTDOWN) { printk(KERN_WARNING /* but going down anyway, so... */ "Concurrent 'rmmod rcutorture' and shutdown illegal!\n"); mutex_unlock(&fullstop_mutex); schedule_timeout_uninterruptible(10); if (cur_ops->cb_barrier != NULL) cur_ops->cb_barrier(); return; } fullstop = FULLSTOP_RMMOD; mutex_unlock(&fullstop_mutex); unregister_reboot_notifier(&rcutorture_nb); if (stutter_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task"); kthread_stop(stutter_task); } stutter_task = NULL; if (shuffler_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task"); kthread_stop(shuffler_task); free_cpumask_var(shuffle_tmp_mask); } shuffler_task = NULL; if (writer_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task"); kthread_stop(writer_task); } writer_task = NULL; if (reader_tasks) { for (i = 0; i < nrealreaders; i++) { if (reader_tasks[i]) { VERBOSE_PRINTK_STRING( "Stopping rcu_torture_reader task"); kthread_stop(reader_tasks[i]); } reader_tasks[i] = NULL; } kfree(reader_tasks); reader_tasks = NULL; } rcu_torture_current = NULL; if (fakewriter_tasks) { for (i = 0; i < nfakewriters; i++) { if (fakewriter_tasks[i]) { VERBOSE_PRINTK_STRING( "Stopping rcu_torture_fakewriter task"); kthread_stop(fakewriter_tasks[i]); } fakewriter_tasks[i] = NULL; } kfree(fakewriter_tasks); fakewriter_tasks = NULL; } if (stats_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task"); kthread_stop(stats_task); } stats_task = NULL; if (fqs_task) { VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task"); kthread_stop(fqs_task); } fqs_task = NULL; /* Wait for all RCU callbacks to fire. */ if (cur_ops->cb_barrier != NULL) cur_ops->cb_barrier(); rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ if (cur_ops->cleanup) cur_ops->cleanup(); if (atomic_read(&n_rcu_torture_error)) rcu_torture_print_module_parms("End of test: FAILURE"); else rcu_torture_print_module_parms("End of test: SUCCESS"); } static int __init rcu_torture_init(void) { int i; int cpu; int firsterr = 0; static struct rcu_torture_ops *torture_ops[] = { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops, &rcu_bh_ops, &rcu_bh_sync_ops, &srcu_ops, &srcu_expedited_ops, &sched_ops, &sched_sync_ops, &sched_expedited_ops, }; mutex_lock(&fullstop_mutex); /* Process args and tell the world that the torturer is on the job. */ for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { cur_ops = torture_ops[i]; if (strcmp(torture_type, cur_ops->name) == 0) break; } if (i == ARRAY_SIZE(torture_ops)) { printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n", torture_type); printk(KERN_ALERT "rcu-torture types:"); for (i = 0; i < ARRAY_SIZE(torture_ops); i++) printk(KERN_ALERT " %s", torture_ops[i]->name); printk(KERN_ALERT "\n"); mutex_unlock(&fullstop_mutex); return -EINVAL; } if (cur_ops->fqs == NULL && fqs_duration != 0) { printk(KERN_ALERT "rcu-torture: ->fqs NULL and non-zero " "fqs_duration, fqs disabled.\n"); fqs_duration = 0; } if (cur_ops->init) cur_ops->init(); /* no "goto unwind" prior to this point!!! */ if (nreaders >= 0) nrealreaders = nreaders; else nrealreaders = 2 * num_online_cpus(); rcu_torture_print_module_parms("Start of test"); fullstop = FULLSTOP_DONTSTOP; /* Set up the freelist. */ INIT_LIST_HEAD(&rcu_torture_freelist); for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { rcu_tortures[i].rtort_mbtest = 0; list_add_tail(&rcu_tortures[i].rtort_free, &rcu_torture_freelist); } /* Initialize the statistics so that each run gets its own numbers. */ rcu_torture_current = NULL; rcu_torture_current_version = 0; atomic_set(&n_rcu_torture_alloc, 0); atomic_set(&n_rcu_torture_alloc_fail, 0); atomic_set(&n_rcu_torture_free, 0); atomic_set(&n_rcu_torture_mberror, 0); atomic_set(&n_rcu_torture_error, 0); for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) atomic_set(&rcu_torture_wcount[i], 0); for_each_possible_cpu(cpu) { for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { per_cpu(rcu_torture_count, cpu)[i] = 0; per_cpu(rcu_torture_batch, cpu)[i] = 0; } } /* Start up the kthreads. */ VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task"); writer_task = kthread_run(rcu_torture_writer, NULL, "rcu_torture_writer"); if (IS_ERR(writer_task)) { firsterr = PTR_ERR(writer_task); VERBOSE_PRINTK_ERRSTRING("Failed to create writer"); writer_task = NULL; goto unwind; } fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]), GFP_KERNEL); if (fakewriter_tasks == NULL) { VERBOSE_PRINTK_ERRSTRING("out of memory"); firsterr = -ENOMEM; goto unwind; } for (i = 0; i < nfakewriters; i++) { VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task"); fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL, "rcu_torture_fakewriter"); if (IS_ERR(fakewriter_tasks[i])) { firsterr = PTR_ERR(fakewriter_tasks[i]); VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter"); fakewriter_tasks[i] = NULL; goto unwind; } } reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]), GFP_KERNEL); if (reader_tasks == NULL) { VERBOSE_PRINTK_ERRSTRING("out of memory"); firsterr = -ENOMEM; goto unwind; } for (i = 0; i < nrealreaders; i++) { VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task"); reader_tasks[i] = kthread_run(rcu_torture_reader, NULL, "rcu_torture_reader"); if (IS_ERR(reader_tasks[i])) { firsterr = PTR_ERR(reader_tasks[i]); VERBOSE_PRINTK_ERRSTRING("Failed to create reader"); reader_tasks[i] = NULL; goto unwind; } } if (stat_interval > 0) { VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task"); stats_task = kthread_run(rcu_torture_stats, NULL, "rcu_torture_stats"); if (IS_ERR(stats_task)) { firsterr = PTR_ERR(stats_task); VERBOSE_PRINTK_ERRSTRING("Failed to create stats"); stats_task = NULL; goto unwind; } } if (test_no_idle_hz) { rcu_idle_cpu = num_online_cpus() - 1; if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) { firsterr = -ENOMEM; VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask"); goto unwind; } /* Create the shuffler thread */ shuffler_task = kthread_run(rcu_torture_shuffle, NULL, "rcu_torture_shuffle"); if (IS_ERR(shuffler_task)) { free_cpumask_var(shuffle_tmp_mask); firsterr = PTR_ERR(shuffler_task); VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler"); shuffler_task = NULL; goto unwind; } } if (stutter < 0) stutter = 0; if (stutter) { /* Create the stutter thread */ stutter_task = kthread_run(rcu_torture_stutter, NULL, "rcu_torture_stutter"); if (IS_ERR(stutter_task)) { firsterr = PTR_ERR(stutter_task); VERBOSE_PRINTK_ERRSTRING("Failed to create stutter"); stutter_task = NULL; goto unwind; } } if (fqs_duration < 0) fqs_duration = 0; if (fqs_duration) { /* Create the stutter thread */ fqs_task = kthread_run(rcu_torture_fqs, NULL, "rcu_torture_fqs"); if (IS_ERR(fqs_task)) { firsterr = PTR_ERR(fqs_task); VERBOSE_PRINTK_ERRSTRING("Failed to create fqs"); fqs_task = NULL; goto unwind; } } register_reboot_notifier(&rcutorture_nb); mutex_unlock(&fullstop_mutex); return 0; unwind: mutex_unlock(&fullstop_mutex); rcu_torture_cleanup(); return firsterr; } module_init(rcu_torture_init); module_exit(rcu_torture_cleanup);