diff options
Diffstat (limited to 'kernel/rcu/rcutorture.c')
| -rw-r--r-- | kernel/rcu/rcutorture.c | 2846 |
1 files changed, 2846 insertions, 0 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c new file mode 100644 index 000000000..6c1aea48a --- /dev/null +++ b/kernel/rcu/rcutorture.c @@ -0,0 +1,2846 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Read-Copy Update module-based torture test facility + * + * Copyright (C) IBM Corporation, 2005, 2006 + * + * Authors: Paul E. McKenney <paulmck@linux.ibm.com> + * Josh Triplett <josh@joshtriplett.org> + * + * See also: Documentation/RCU/torture.rst + */ + +#define pr_fmt(fmt) fmt + +#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_wait.h> +#include <linux/interrupt.h> +#include <linux/sched/signal.h> +#include <uapi/linux/sched/types.h> +#include <linux/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 <linux/trace_clock.h> +#include <asm/byteorder.h> +#include <linux/torture.h> +#include <linux/vmalloc.h> +#include <linux/sched/debug.h> +#include <linux/sched/sysctl.h> +#include <linux/oom.h> +#include <linux/tick.h> +#include <linux/rcupdate_trace.h> + +#include "rcu.h" + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>"); + +/* Bits for ->extendables field, extendables param, and related definitions. */ +#define RCUTORTURE_RDR_SHIFT 8 /* Put SRCU index in upper bits. */ +#define RCUTORTURE_RDR_MASK ((1 << RCUTORTURE_RDR_SHIFT) - 1) +#define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */ +#define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */ +#define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */ +#define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */ +#define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */ +#define RCUTORTURE_RDR_RCU 0x20 /* ... entering another RCU reader. */ +#define RCUTORTURE_RDR_NBITS 6 /* Number of bits defined above. */ +#define RCUTORTURE_MAX_EXTEND \ + (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \ + RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED) +#define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */ + /* Must be power of two minus one. */ +#define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3) + +torture_param(int, extendables, RCUTORTURE_MAX_EXTEND, + "Extend readers by disabling bh (1), irqs (2), or preempt (4)"); +torture_param(int, fqs_duration, 0, + "Duration of fqs bursts (us), 0 to disable"); +torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)"); +torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)"); +torture_param(bool, fwd_progress, 1, "Test grace-period forward progress"); +torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait"); +torture_param(int, fwd_progress_holdoff, 60, + "Time between forward-progress tests (s)"); +torture_param(bool, fwd_progress_need_resched, 1, + "Hide cond_resched() behind need_resched()"); +torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives"); +torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); +torture_param(bool, gp_normal, false, + "Use normal (non-expedited) GP wait primitives"); +torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives"); +torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); +torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers"); +torture_param(int, n_barrier_cbs, 0, + "# of callbacks/kthreads for barrier testing"); +torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads"); +torture_param(int, nreaders, -1, "Number of RCU reader threads"); +torture_param(int, object_debug, 0, + "Enable debug-object double call_rcu() testing"); +torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); +torture_param(int, onoff_interval, 0, + "Time between CPU hotplugs (jiffies), 0=disable"); +torture_param(int, read_exit_delay, 13, + "Delay between read-then-exit episodes (s)"); +torture_param(int, read_exit_burst, 16, + "# of read-then-exit bursts per episode, zero to disable"); +torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles"); +torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable."); +torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable."); +torture_param(int, stall_cpu_holdoff, 10, + "Time to wait before starting stall (s)."); +torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling."); +torture_param(int, stall_cpu_block, 0, "Sleep while stalling."); +torture_param(int, stall_gp_kthread, 0, + "Grace-period kthread stall duration (s)."); +torture_param(int, stat_interval, 60, + "Number of seconds between stats printk()s"); +torture_param(int, stutter, 5, "Number of seconds to run/halt test"); +torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); +torture_param(int, test_boost_duration, 4, + "Duration of each boost test, seconds."); +torture_param(int, test_boost_interval, 7, + "Interval between boost tests, seconds."); +torture_param(bool, test_no_idle_hz, true, + "Test support for tickless idle CPUs"); +torture_param(int, verbose, 1, + "Enable verbose debugging printk()s"); + +static char *torture_type = "rcu"; +module_param(torture_type, charp, 0444); +MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)"); + +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 *fqs_task; +static struct task_struct *boost_tasks[NR_CPUS]; +static struct task_struct *stall_task; +static struct task_struct *fwd_prog_task; +static struct task_struct **barrier_cbs_tasks; +static struct task_struct *barrier_task; +static struct task_struct *read_exit_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 *rcu_torture_current; +static unsigned 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); +static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch); +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_barrier_error; +static long n_rcu_torture_boost_ktrerror; +static long n_rcu_torture_boost_rterror; +static long n_rcu_torture_boost_failure; +static long n_rcu_torture_boosts; +static atomic_long_t n_rcu_torture_timers; +static long n_barrier_attempts; +static long n_barrier_successes; /* did rcu_barrier test succeed? */ +static unsigned long n_read_exits; +static struct list_head rcu_torture_removed; +static unsigned long shutdown_jiffies; +static unsigned long start_gp_seq; + +static int rcu_torture_writer_state; +#define RTWS_FIXED_DELAY 0 +#define RTWS_DELAY 1 +#define RTWS_REPLACE 2 +#define RTWS_DEF_FREE 3 +#define RTWS_EXP_SYNC 4 +#define RTWS_COND_GET 5 +#define RTWS_COND_SYNC 6 +#define RTWS_SYNC 7 +#define RTWS_STUTTER 8 +#define RTWS_STOPPING 9 +static const char * const rcu_torture_writer_state_names[] = { + "RTWS_FIXED_DELAY", + "RTWS_DELAY", + "RTWS_REPLACE", + "RTWS_DEF_FREE", + "RTWS_EXP_SYNC", + "RTWS_COND_GET", + "RTWS_COND_SYNC", + "RTWS_SYNC", + "RTWS_STUTTER", + "RTWS_STOPPING", +}; + +/* Record reader segment types and duration for first failing read. */ +struct rt_read_seg { + int rt_readstate; + unsigned long rt_delay_jiffies; + unsigned long rt_delay_ms; + unsigned long rt_delay_us; + bool rt_preempted; +}; +static int err_segs_recorded; +static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS]; +static int rt_read_nsegs; + +static const char *rcu_torture_writer_state_getname(void) +{ + unsigned int i = READ_ONCE(rcu_torture_writer_state); + + if (i >= ARRAY_SIZE(rcu_torture_writer_state_names)) + return "???"; + return rcu_torture_writer_state_names[i]; +} + +#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) +#define rcu_can_boost() 1 +#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ +#define rcu_can_boost() 0 +#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ + +#ifdef CONFIG_RCU_TRACE +static u64 notrace rcu_trace_clock_local(void) +{ + u64 ts = trace_clock_local(); + + (void)do_div(ts, NSEC_PER_USEC); + return ts; +} +#else /* #ifdef CONFIG_RCU_TRACE */ +static u64 notrace rcu_trace_clock_local(void) +{ + return 0ULL; +} +#endif /* #else #ifdef CONFIG_RCU_TRACE */ + +/* + * Stop aggressive CPU-hog tests a bit before the end of the test in order + * to avoid interfering with test shutdown. + */ +static bool shutdown_time_arrived(void) +{ + return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ); +} + +static unsigned long boost_starttime; /* jiffies of next boost test start. */ +static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ + /* and boost task create/destroy. */ +static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ +static bool barrier_phase; /* Test phase. */ +static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ +static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ +static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); + +static bool rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */ + +/* + * 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); +} + +/* + * Operations vector for selecting different types of tests. + */ + +struct rcu_torture_ops { + int ttype; + void (*init)(void); + void (*cleanup)(void); + int (*readlock)(void); + void (*read_delay)(struct torture_random_state *rrsp, + struct rt_read_seg *rtrsp); + void (*readunlock)(int idx); + unsigned long (*get_gp_seq)(void); + unsigned long (*gp_diff)(unsigned long new, unsigned long old); + void (*deferred_free)(struct rcu_torture *p); + void (*sync)(void); + void (*exp_sync)(void); + unsigned long (*get_state)(void); + void (*cond_sync)(unsigned long oldstate); + call_rcu_func_t call; + void (*cb_barrier)(void); + void (*fqs)(void); + void (*stats)(void); + int (*stall_dur)(void); + int irq_capable; + int can_boost; + int extendables; + int slow_gps; + const 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 torture_random_state *rrsp, struct rt_read_seg *rtrsp) +{ + unsigned long started; + unsigned long completed; + const unsigned long shortdelay_us = 200; + unsigned long longdelay_ms = 300; + unsigned long long ts; + + /* 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 (!READ_ONCE(rcu_fwd_cb_nodelay) && + !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) { + started = cur_ops->get_gp_seq(); + ts = rcu_trace_clock_local(); + if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK)) + longdelay_ms = 5; /* Avoid triggering BH limits. */ + mdelay(longdelay_ms); + rtrsp->rt_delay_ms = longdelay_ms; + completed = cur_ops->get_gp_seq(); + do_trace_rcu_torture_read(cur_ops->name, NULL, ts, + started, completed); + } + if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) { + udelay(shortdelay_us); + rtrsp->rt_delay_us = shortdelay_us; + } + if (!preempt_count() && + !(torture_random(rrsp) % (nrealreaders * 500))) { + torture_preempt_schedule(); /* QS only if preemptible. */ + rtrsp->rt_preempted = true; + } +} + +static void rcu_torture_read_unlock(int idx) __releases(RCU) +{ + rcu_read_unlock(); +} + +/* + * Update callback in the pipe. This should be invoked after a grace period. + */ +static bool +rcu_torture_pipe_update_one(struct rcu_torture *rp) +{ + int i; + + i = READ_ONCE(rp->rtort_pipe_count); + if (i > RCU_TORTURE_PIPE_LEN) + i = RCU_TORTURE_PIPE_LEN; + atomic_inc(&rcu_torture_wcount[i]); + WRITE_ONCE(rp->rtort_pipe_count, i + 1); + if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { + rp->rtort_mbtest = 0; + return true; + } + return false; +} + +/* + * Update all callbacks in the pipe. Suitable for synchronous grace-period + * primitives. + */ +static void +rcu_torture_pipe_update(struct rcu_torture *old_rp) +{ + struct rcu_torture *rp; + struct rcu_torture *rp1; + + if (old_rp) + list_add(&old_rp->rtort_free, &rcu_torture_removed); + list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { + if (rcu_torture_pipe_update_one(rp)) { + list_del(&rp->rtort_free); + rcu_torture_free(rp); + } + } +} + +static void +rcu_torture_cb(struct rcu_head *p) +{ + struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); + + if (torture_must_stop_irq()) { + /* Test is ending, just drop callbacks on the floor. */ + /* The next initialization will pick up the pieces. */ + return; + } + if (rcu_torture_pipe_update_one(rp)) + rcu_torture_free(rp); + else + cur_ops->deferred_free(rp); +} + +static unsigned long 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 void rcu_sync_torture_init(void) +{ + INIT_LIST_HEAD(&rcu_torture_removed); +} + +static struct rcu_torture_ops rcu_ops = { + .ttype = RCU_FLAVOR, + .init = rcu_sync_torture_init, + .readlock = rcu_torture_read_lock, + .read_delay = rcu_read_delay, + .readunlock = rcu_torture_read_unlock, + .get_gp_seq = rcu_get_gp_seq, + .gp_diff = rcu_seq_diff, + .deferred_free = rcu_torture_deferred_free, + .sync = synchronize_rcu, + .exp_sync = synchronize_rcu_expedited, + .get_state = get_state_synchronize_rcu, + .cond_sync = cond_synchronize_rcu, + .call = call_rcu, + .cb_barrier = rcu_barrier, + .fqs = rcu_force_quiescent_state, + .stats = NULL, + .stall_dur = rcu_jiffies_till_stall_check, + .irq_capable = 1, + .can_boost = rcu_can_boost(), + .extendables = RCUTORTURE_MAX_EXTEND, + .name = "rcu" +}; + +/* + * Don't even think about trying any of these in real life!!! + * The names includes "busted", and they really means it! + * The only purpose of these functions is to provide a buggy RCU + * implementation to make sure that rcutorture correctly emits + * buggy-RCU error messages. + */ +static void rcu_busted_torture_deferred_free(struct rcu_torture *p) +{ + /* This is a deliberate bug for testing purposes only! */ + rcu_torture_cb(&p->rtort_rcu); +} + +static void synchronize_rcu_busted(void) +{ + /* This is a deliberate bug for testing purposes only! */ +} + +static void +call_rcu_busted(struct rcu_head *head, rcu_callback_t func) +{ + /* This is a deliberate bug for testing purposes only! */ + func(head); +} + +static struct rcu_torture_ops rcu_busted_ops = { + .ttype = INVALID_RCU_FLAVOR, + .init = rcu_sync_torture_init, + .readlock = rcu_torture_read_lock, + .read_delay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = rcu_torture_read_unlock, + .get_gp_seq = rcu_no_completed, + .deferred_free = rcu_busted_torture_deferred_free, + .sync = synchronize_rcu_busted, + .exp_sync = synchronize_rcu_busted, + .call = call_rcu_busted, + .cb_barrier = NULL, + .fqs = NULL, + .stats = NULL, + .irq_capable = 1, + .name = "busted" +}; + +/* + * Definitions for srcu torture testing. + */ + +DEFINE_STATIC_SRCU(srcu_ctl); +static struct srcu_struct srcu_ctld; +static struct srcu_struct *srcu_ctlp = &srcu_ctl; + +static int srcu_torture_read_lock(void) __acquires(srcu_ctlp) +{ + return srcu_read_lock(srcu_ctlp); +} + +static void +srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) +{ + 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 = torture_random(rrsp) % + (nrealreaders * 2 * longdelay * uspertick); + if (!delay && in_task()) { + schedule_timeout_interruptible(longdelay); + rtrsp->rt_delay_jiffies = longdelay; + } else { + rcu_read_delay(rrsp, rtrsp); + } +} + +static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp) +{ + srcu_read_unlock(srcu_ctlp, idx); +} + +static unsigned long srcu_torture_completed(void) +{ + return srcu_batches_completed(srcu_ctlp); +} + +static void srcu_torture_deferred_free(struct rcu_torture *rp) +{ + call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb); +} + +static void srcu_torture_synchronize(void) +{ + synchronize_srcu(srcu_ctlp); +} + +static void srcu_torture_call(struct rcu_head *head, + rcu_callback_t func) +{ + call_srcu(srcu_ctlp, head, func); +} + +static void srcu_torture_barrier(void) +{ + srcu_barrier(srcu_ctlp); +} + +static void srcu_torture_stats(void) +{ + srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG); +} + +static void srcu_torture_synchronize_expedited(void) +{ + synchronize_srcu_expedited(srcu_ctlp); +} + +static struct rcu_torture_ops srcu_ops = { + .ttype = SRCU_FLAVOR, + .init = rcu_sync_torture_init, + .readlock = srcu_torture_read_lock, + .read_delay = srcu_read_delay, + .readunlock = srcu_torture_read_unlock, + .get_gp_seq = srcu_torture_completed, + .deferred_free = srcu_torture_deferred_free, + .sync = srcu_torture_synchronize, + .exp_sync = srcu_torture_synchronize_expedited, + .call = srcu_torture_call, + .cb_barrier = srcu_torture_barrier, + .stats = srcu_torture_stats, + .irq_capable = 1, + .name = "srcu" +}; + +static void srcu_torture_init(void) +{ + rcu_sync_torture_init(); + WARN_ON(init_srcu_struct(&srcu_ctld)); + srcu_ctlp = &srcu_ctld; +} + +static void srcu_torture_cleanup(void) +{ + cleanup_srcu_struct(&srcu_ctld); + srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */ +} + +/* As above, but dynamically allocated. */ +static struct rcu_torture_ops srcud_ops = { + .ttype = SRCU_FLAVOR, + .init = srcu_torture_init, + .cleanup = srcu_torture_cleanup, + .readlock = srcu_torture_read_lock, + .read_delay = srcu_read_delay, + .readunlock = srcu_torture_read_unlock, + .get_gp_seq = srcu_torture_completed, + .deferred_free = srcu_torture_deferred_free, + .sync = srcu_torture_synchronize, + .exp_sync = srcu_torture_synchronize_expedited, + .call = srcu_torture_call, + .cb_barrier = srcu_torture_barrier, + .stats = srcu_torture_stats, + .irq_capable = 1, + .name = "srcud" +}; + +/* As above, but broken due to inappropriate reader extension. */ +static struct rcu_torture_ops busted_srcud_ops = { + .ttype = SRCU_FLAVOR, + .init = srcu_torture_init, + .cleanup = srcu_torture_cleanup, + .readlock = srcu_torture_read_lock, + .read_delay = rcu_read_delay, + .readunlock = srcu_torture_read_unlock, + .get_gp_seq = srcu_torture_completed, + .deferred_free = srcu_torture_deferred_free, + .sync = srcu_torture_synchronize, + .exp_sync = srcu_torture_synchronize_expedited, + .call = srcu_torture_call, + .cb_barrier = srcu_torture_barrier, + .stats = srcu_torture_stats, + .irq_capable = 1, + .extendables = RCUTORTURE_MAX_EXTEND, + .name = "busted_srcud" +}; + +/* + * Definitions for RCU-tasks torture testing. + */ + +static int tasks_torture_read_lock(void) +{ + return 0; +} + +static void tasks_torture_read_unlock(int idx) +{ +} + +static void rcu_tasks_torture_deferred_free(struct rcu_torture *p) +{ + call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb); +} + +static void synchronize_rcu_mult_test(void) +{ + synchronize_rcu_mult(call_rcu_tasks, call_rcu); +} + +static struct rcu_torture_ops tasks_ops = { + .ttype = RCU_TASKS_FLAVOR, + .init = rcu_sync_torture_init, + .readlock = tasks_torture_read_lock, + .read_delay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = tasks_torture_read_unlock, + .get_gp_seq = rcu_no_completed, + .deferred_free = rcu_tasks_torture_deferred_free, + .sync = synchronize_rcu_tasks, + .exp_sync = synchronize_rcu_mult_test, + .call = call_rcu_tasks, + .cb_barrier = rcu_barrier_tasks, + .fqs = NULL, + .stats = NULL, + .irq_capable = 1, + .slow_gps = 1, + .name = "tasks" +}; + +/* + * Definitions for trivial CONFIG_PREEMPT=n-only torture testing. + * This implementation does not necessarily work well with CPU hotplug. + */ + +static void synchronize_rcu_trivial(void) +{ + int cpu; + + for_each_online_cpu(cpu) { + rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu)); + WARN_ON_ONCE(raw_smp_processor_id() != cpu); + } +} + +static int rcu_torture_read_lock_trivial(void) __acquires(RCU) +{ + preempt_disable(); + return 0; +} + +static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU) +{ + preempt_enable(); +} + +static struct rcu_torture_ops trivial_ops = { + .ttype = RCU_TRIVIAL_FLAVOR, + .init = rcu_sync_torture_init, + .readlock = rcu_torture_read_lock_trivial, + .read_delay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = rcu_torture_read_unlock_trivial, + .get_gp_seq = rcu_no_completed, + .sync = synchronize_rcu_trivial, + .exp_sync = synchronize_rcu_trivial, + .fqs = NULL, + .stats = NULL, + .irq_capable = 1, + .name = "trivial" +}; + +/* + * Definitions for rude RCU-tasks torture testing. + */ + +static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p) +{ + call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb); +} + +static struct rcu_torture_ops tasks_rude_ops = { + .ttype = RCU_TASKS_RUDE_FLAVOR, + .init = rcu_sync_torture_init, + .readlock = rcu_torture_read_lock_trivial, + .read_delay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = rcu_torture_read_unlock_trivial, + .get_gp_seq = rcu_no_completed, + .deferred_free = rcu_tasks_rude_torture_deferred_free, + .sync = synchronize_rcu_tasks_rude, + .exp_sync = synchronize_rcu_tasks_rude, + .call = call_rcu_tasks_rude, + .cb_barrier = rcu_barrier_tasks_rude, + .fqs = NULL, + .stats = NULL, + .irq_capable = 1, + .name = "tasks-rude" +}; + +/* + * Definitions for tracing RCU-tasks torture testing. + */ + +static int tasks_tracing_torture_read_lock(void) +{ + rcu_read_lock_trace(); + return 0; +} + +static void tasks_tracing_torture_read_unlock(int idx) +{ + rcu_read_unlock_trace(); +} + +static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p) +{ + call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb); +} + +static struct rcu_torture_ops tasks_tracing_ops = { + .ttype = RCU_TASKS_TRACING_FLAVOR, + .init = rcu_sync_torture_init, + .readlock = tasks_tracing_torture_read_lock, + .read_delay = srcu_read_delay, /* just reuse srcu's version. */ + .readunlock = tasks_tracing_torture_read_unlock, + .get_gp_seq = rcu_no_completed, + .deferred_free = rcu_tasks_tracing_torture_deferred_free, + .sync = synchronize_rcu_tasks_trace, + .exp_sync = synchronize_rcu_tasks_trace, + .call = call_rcu_tasks_trace, + .cb_barrier = rcu_barrier_tasks_trace, + .fqs = NULL, + .stats = NULL, + .irq_capable = 1, + .slow_gps = 1, + .name = "tasks-tracing" +}; + +static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old) +{ + if (!cur_ops->gp_diff) + return new - old; + return cur_ops->gp_diff(new, old); +} + +static bool __maybe_unused torturing_tasks(void) +{ + return cur_ops == &tasks_ops || cur_ops == &tasks_rude_ops; +} + +/* + * RCU torture priority-boost testing. Runs one real-time thread per + * CPU for moderate bursts, repeatedly registering RCU callbacks and + * spinning waiting for them to be invoked. If a given callback takes + * too long to be invoked, we assume that priority inversion has occurred. + */ + +struct rcu_boost_inflight { + struct rcu_head rcu; + int inflight; +}; + +static void rcu_torture_boost_cb(struct rcu_head *head) +{ + struct rcu_boost_inflight *rbip = + container_of(head, struct rcu_boost_inflight, rcu); + + /* Ensure RCU-core accesses precede clearing ->inflight */ + smp_store_release(&rbip->inflight, 0); +} + +static int old_rt_runtime = -1; + +static void rcu_torture_disable_rt_throttle(void) +{ + /* + * Disable RT throttling so that rcutorture's boost threads don't get + * throttled. Only possible if rcutorture is built-in otherwise the + * user should manually do this by setting the sched_rt_period_us and + * sched_rt_runtime sysctls. + */ + if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1) + return; + + old_rt_runtime = sysctl_sched_rt_runtime; + sysctl_sched_rt_runtime = -1; +} + +static void rcu_torture_enable_rt_throttle(void) +{ + if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1) + return; + + sysctl_sched_rt_runtime = old_rt_runtime; + old_rt_runtime = -1; +} + +static bool rcu_torture_boost_failed(unsigned long start, unsigned long end) +{ + if (end - start > test_boost_duration * HZ - HZ / 2) { + VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); + n_rcu_torture_boost_failure++; + + return true; /* failed */ + } + + return false; /* passed */ +} + +static int rcu_torture_boost(void *arg) +{ + unsigned long call_rcu_time; + unsigned long endtime; + unsigned long oldstarttime; + struct rcu_boost_inflight rbi = { .inflight = 0 }; + + VERBOSE_TOROUT_STRING("rcu_torture_boost started"); + + /* Set real-time priority. */ + sched_set_fifo_low(current); + + init_rcu_head_on_stack(&rbi.rcu); + /* Each pass through the following loop does one boost-test cycle. */ + do { + /* Track if the test failed already in this test interval? */ + bool failed = false; + + /* Increment n_rcu_torture_boosts once per boost-test */ + while (!kthread_should_stop()) { + if (mutex_trylock(&boost_mutex)) { + n_rcu_torture_boosts++; + mutex_unlock(&boost_mutex); + break; + } + schedule_timeout_uninterruptible(1); + } + if (kthread_should_stop()) + goto checkwait; + + /* Wait for the next test interval. */ + oldstarttime = boost_starttime; + while (time_before(jiffies, oldstarttime)) { + schedule_timeout_interruptible(oldstarttime - jiffies); + stutter_wait("rcu_torture_boost"); + if (torture_must_stop()) + goto checkwait; + } + + /* Do one boost-test interval. */ + endtime = oldstarttime + test_boost_duration * HZ; + call_rcu_time = jiffies; + while (time_before(jiffies, endtime)) { + /* If we don't have a callback in flight, post one. */ + if (!smp_load_acquire(&rbi.inflight)) { + /* RCU core before ->inflight = 1. */ + smp_store_release(&rbi.inflight, 1); + call_rcu(&rbi.rcu, rcu_torture_boost_cb); + /* Check if the boost test failed */ + failed = failed || + rcu_torture_boost_failed(call_rcu_time, + jiffies); + call_rcu_time = jiffies; + } + stutter_wait("rcu_torture_boost"); + if (torture_must_stop()) + goto checkwait; + } + + /* + * If boost never happened, then inflight will always be 1, in + * this case the boost check would never happen in the above + * loop so do another one here. + */ + if (!failed && smp_load_acquire(&rbi.inflight)) + rcu_torture_boost_failed(call_rcu_time, jiffies); + + /* + * Set the start time of the next test interval. + * Yes, this is vulnerable to long delays, but such + * delays simply cause a false negative for the next + * interval. Besides, we are running at RT priority, + * so delays should be relatively rare. + */ + while (oldstarttime == boost_starttime && + !kthread_should_stop()) { + if (mutex_trylock(&boost_mutex)) { + boost_starttime = jiffies + + test_boost_interval * HZ; + mutex_unlock(&boost_mutex); + break; + } + schedule_timeout_uninterruptible(1); + } + + /* Go do the stutter. */ +checkwait: stutter_wait("rcu_torture_boost"); + } while (!torture_must_stop()); + + /* Clean up and exit. */ + while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) { + torture_shutdown_absorb("rcu_torture_boost"); + schedule_timeout_uninterruptible(1); + } + destroy_rcu_head_on_stack(&rbi.rcu); + torture_kthread_stopping("rcu_torture_boost"); + return 0; +} + +/* + * 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_TOROUT_STRING("rcu_torture_fqs task started"); + do { + fqs_resume_time = jiffies + fqs_stutter * HZ; + while (time_before(jiffies, fqs_resume_time) && + !kthread_should_stop()) { + schedule_timeout_interruptible(1); + } + fqs_burst_remaining = fqs_duration; + while (fqs_burst_remaining > 0 && + !kthread_should_stop()) { + cur_ops->fqs(); + udelay(fqs_holdoff); + fqs_burst_remaining -= fqs_holdoff; + } + stutter_wait("rcu_torture_fqs"); + } while (!torture_must_stop()); + torture_kthread_stopping("rcu_torture_fqs"); + 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) +{ + bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); + int expediting = 0; + unsigned long gp_snap; + bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal; + bool gp_sync1 = gp_sync; + int i; + struct rcu_torture *rp; + struct rcu_torture *old_rp; + static DEFINE_TORTURE_RANDOM(rand); + int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, + RTWS_COND_GET, RTWS_SYNC }; + int nsynctypes = 0; + + VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); + if (!can_expedite) + pr_alert("%s" TORTURE_FLAG + " GP expediting controlled from boot/sysfs for %s.\n", + torture_type, cur_ops->name); + + /* Initialize synctype[] array. If none set, take default. */ + if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1) + gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true; + if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) { + synctype[nsynctypes++] = RTWS_COND_GET; + pr_info("%s: Testing conditional GPs.\n", __func__); + } else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) { + pr_alert("%s: gp_cond without primitives.\n", __func__); + } + if (gp_exp1 && cur_ops->exp_sync) { + synctype[nsynctypes++] = RTWS_EXP_SYNC; + pr_info("%s: Testing expedited GPs.\n", __func__); + } else if (gp_exp && !cur_ops->exp_sync) { + pr_alert("%s: gp_exp without primitives.\n", __func__); + } + if (gp_normal1 && cur_ops->deferred_free) { + synctype[nsynctypes++] = RTWS_DEF_FREE; + pr_info("%s: Testing asynchronous GPs.\n", __func__); + } else if (gp_normal && !cur_ops->deferred_free) { + pr_alert("%s: gp_normal without primitives.\n", __func__); + } + if (gp_sync1 && cur_ops->sync) { + synctype[nsynctypes++] = RTWS_SYNC; + pr_info("%s: Testing normal GPs.\n", __func__); + } else if (gp_sync && !cur_ops->sync) { + pr_alert("%s: gp_sync without primitives.\n", __func__); + } + if (WARN_ONCE(nsynctypes == 0, + "rcu_torture_writer: No update-side primitives.\n")) { + /* + * No updates primitives, so don't try updating. + * The resulting test won't be testing much, hence the + * above WARN_ONCE(). + */ + rcu_torture_writer_state = RTWS_STOPPING; + torture_kthread_stopping("rcu_torture_writer"); + } + + do { + rcu_torture_writer_state = RTWS_FIXED_DELAY; + schedule_timeout_uninterruptible(1); + rp = rcu_torture_alloc(); + if (rp == NULL) + continue; + rp->rtort_pipe_count = 0; + rcu_torture_writer_state = RTWS_DELAY; + udelay(torture_random(&rand) & 0x3ff); + rcu_torture_writer_state = RTWS_REPLACE; + old_rp = rcu_dereference_check(rcu_torture_current, + current == writer_task); + 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]); + WRITE_ONCE(old_rp->rtort_pipe_count, + old_rp->rtort_pipe_count + 1); + switch (synctype[torture_random(&rand) % nsynctypes]) { + case RTWS_DEF_FREE: + rcu_torture_writer_state = RTWS_DEF_FREE; + cur_ops->deferred_free(old_rp); + break; + case RTWS_EXP_SYNC: + rcu_torture_writer_state = RTWS_EXP_SYNC; + cur_ops->exp_sync(); + rcu_torture_pipe_update(old_rp); + break; + case RTWS_COND_GET: + rcu_torture_writer_state = RTWS_COND_GET; + gp_snap = cur_ops->get_state(); + i = torture_random(&rand) % 16; + if (i != 0) + schedule_timeout_interruptible(i); + udelay(torture_random(&rand) % 1000); + rcu_torture_writer_state = RTWS_COND_SYNC; + cur_ops->cond_sync(gp_snap); + rcu_torture_pipe_update(old_rp); + break; + case RTWS_SYNC: + rcu_torture_writer_state = RTWS_SYNC; + cur_ops->sync(); + rcu_torture_pipe_update(old_rp); + break; + default: + WARN_ON_ONCE(1); + break; + } + } + WRITE_ONCE(rcu_torture_current_version, + rcu_torture_current_version + 1); + /* Cycle through nesting levels of rcu_expedite_gp() calls. */ + if (can_expedite && + !(torture_random(&rand) & 0xff & (!!expediting - 1))) { + WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited()); + if (expediting >= 0) + rcu_expedite_gp(); + else + rcu_unexpedite_gp(); + if (++expediting > 3) + expediting = -expediting; + } else if (!can_expedite) { /* Disabled during boot, recheck. */ + can_expedite = !rcu_gp_is_expedited() && + !rcu_gp_is_normal(); + } + rcu_torture_writer_state = RTWS_STUTTER; + if (stutter_wait("rcu_torture_writer") && + !READ_ONCE(rcu_fwd_cb_nodelay) && + !cur_ops->slow_gps && + !torture_must_stop() && + rcu_inkernel_boot_has_ended()) + for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) + if (list_empty(&rcu_tortures[i].rtort_free) && + rcu_access_pointer(rcu_torture_current) != + &rcu_tortures[i]) { + rcu_ftrace_dump(DUMP_ALL); + WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count); + } + } while (!torture_must_stop()); + rcu_torture_current = NULL; // Let stats task know that we are done. + /* Reset expediting back to unexpedited. */ + if (expediting > 0) + expediting = -expediting; + while (can_expedite && expediting++ < 0) + rcu_unexpedite_gp(); + WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited()); + if (!can_expedite) + pr_alert("%s" TORTURE_FLAG + " Dynamic grace-period expediting was disabled.\n", + torture_type); + rcu_torture_writer_state = RTWS_STOPPING; + torture_kthread_stopping("rcu_torture_writer"); + return 0; +} + +/* + * RCU torture fake writer kthread. Repeatedly calls sync, with a random + * delay between calls. + */ +static int +rcu_torture_fakewriter(void *arg) +{ + DEFINE_TORTURE_RANDOM(rand); + + VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); + set_user_nice(current, MAX_NICE); + + do { + schedule_timeout_uninterruptible(1 + torture_random(&rand)%10); + udelay(torture_random(&rand) & 0x3ff); + if (cur_ops->cb_barrier != NULL && + torture_random(&rand) % (nfakewriters * 8) == 0) { + cur_ops->cb_barrier(); + } else if (gp_normal == gp_exp) { + if (cur_ops->sync && torture_random(&rand) & 0x80) + cur_ops->sync(); + else if (cur_ops->exp_sync) + cur_ops->exp_sync(); + } else if (gp_normal && cur_ops->sync) { + cur_ops->sync(); + } else if (cur_ops->exp_sync) { + cur_ops->exp_sync(); + } + stutter_wait("rcu_torture_fakewriter"); + } while (!torture_must_stop()); + + torture_kthread_stopping("rcu_torture_fakewriter"); + return 0; +} + +static void rcu_torture_timer_cb(struct rcu_head *rhp) +{ + kfree(rhp); +} + +/* + * Do one extension of an RCU read-side critical section using the + * current reader state in readstate (set to zero for initial entry + * to extended critical section), set the new state as specified by + * newstate (set to zero for final exit from extended critical section), + * and random-number-generator state in trsp. If this is neither the + * beginning or end of the critical section and if there was actually a + * change, do a ->read_delay(). + */ +static void rcutorture_one_extend(int *readstate, int newstate, + struct torture_random_state *trsp, + struct rt_read_seg *rtrsp) +{ + unsigned long flags; + int idxnew = -1; + int idxold = *readstate; + int statesnew = ~*readstate & newstate; + int statesold = *readstate & ~newstate; + + WARN_ON_ONCE(idxold < 0); + WARN_ON_ONCE((idxold >> RCUTORTURE_RDR_SHIFT) > 1); + rtrsp->rt_readstate = newstate; + + /* First, put new protection in place to avoid critical-section gap. */ + if (statesnew & RCUTORTURE_RDR_BH) + local_bh_disable(); + if (statesnew & RCUTORTURE_RDR_RBH) + rcu_read_lock_bh(); + if (statesnew & RCUTORTURE_RDR_IRQ) + local_irq_disable(); + if (statesnew & RCUTORTURE_RDR_PREEMPT) + preempt_disable(); + if (statesnew & RCUTORTURE_RDR_SCHED) + rcu_read_lock_sched(); + if (statesnew & RCUTORTURE_RDR_RCU) + idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT; + + /* + * Next, remove old protection, in decreasing order of strength + * to avoid unlock paths that aren't safe in the stronger + * context. Namely: BH can not be enabled with disabled interrupts. + * Additionally PREEMPT_RT requires that BH is enabled in preemptible + * context. + */ + if (statesold & RCUTORTURE_RDR_IRQ) + local_irq_enable(); + if (statesold & RCUTORTURE_RDR_PREEMPT) + preempt_enable(); + if (statesold & RCUTORTURE_RDR_SCHED) + rcu_read_unlock_sched(); + if (statesold & RCUTORTURE_RDR_BH) + local_bh_enable(); + if (statesold & RCUTORTURE_RDR_RBH) + rcu_read_unlock_bh(); + if (statesold & RCUTORTURE_RDR_RCU) { + bool lockit = !statesnew && !(torture_random(trsp) & 0xffff); + + if (lockit) + raw_spin_lock_irqsave(¤t->pi_lock, flags); + cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT); + if (lockit) + raw_spin_unlock_irqrestore(¤t->pi_lock, flags); + } + + /* Delay if neither beginning nor end and there was a change. */ + if ((statesnew || statesold) && *readstate && newstate) + cur_ops->read_delay(trsp, rtrsp); + + /* Update the reader state. */ + if (idxnew == -1) + idxnew = idxold & ~RCUTORTURE_RDR_MASK; + WARN_ON_ONCE(idxnew < 0); + WARN_ON_ONCE((idxnew >> RCUTORTURE_RDR_SHIFT) > 1); + *readstate = idxnew | newstate; + WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) < 0); + WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) > 1); +} + +/* Return the biggest extendables mask given current RCU and boot parameters. */ +static int rcutorture_extend_mask_max(void) +{ + int mask; + + WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND); + mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables; + mask = mask | RCUTORTURE_RDR_RCU; + return mask; +} + +/* Return a random protection state mask, but with at least one bit set. */ +static int +rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) +{ + int mask = rcutorture_extend_mask_max(); + unsigned long randmask1 = torture_random(trsp) >> 8; + unsigned long randmask2 = randmask1 >> 3; + unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED; + unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ; + unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH; + + WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT); + /* Mostly only one bit (need preemption!), sometimes lots of bits. */ + if (!(randmask1 & 0x7)) + mask = mask & randmask2; + else + mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS)); + + /* + * Can't enable bh w/irq disabled. + */ + if (mask & RCUTORTURE_RDR_IRQ) + mask |= oldmask & bhs; + + /* + * Ideally these sequences would be detected in debug builds + * (regardless of RT), but until then don't stop testing + * them on non-RT. + */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) { + /* Can't modify BH in atomic context */ + if (oldmask & preempts_irq) + mask &= ~bhs; + if ((oldmask | mask) & preempts_irq) + mask |= oldmask & bhs; + } + + return mask ?: RCUTORTURE_RDR_RCU; +} + +/* + * Do a randomly selected number of extensions of an existing RCU read-side + * critical section. + */ +static struct rt_read_seg * +rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, + struct rt_read_seg *rtrsp) +{ + int i; + int j; + int mask = rcutorture_extend_mask_max(); + + WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */ + if (!((mask - 1) & mask)) + return rtrsp; /* Current RCU reader not extendable. */ + /* Bias towards larger numbers of loops. */ + i = (torture_random(trsp) >> 3); + i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1; + for (j = 0; j < i; j++) { + mask = rcutorture_extend_mask(*readstate, trsp); + rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]); + } + return &rtrsp[j]; +} + +/* + * Do one read-side critical section, returning false if there was + * no data to read. Can be invoked both from process context and + * from a timer handler. + */ +static bool rcu_torture_one_read(struct torture_random_state *trsp) +{ + int i; + unsigned long started; + unsigned long completed; + int newstate; + struct rcu_torture *p; + int pipe_count; + int readstate = 0; + struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } }; + struct rt_read_seg *rtrsp = &rtseg[0]; + struct rt_read_seg *rtrsp1; + unsigned long long ts; + + WARN_ON_ONCE(!rcu_is_watching()); + newstate = rcutorture_extend_mask(readstate, trsp); + rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++); + started = cur_ops->get_gp_seq(); + ts = rcu_trace_clock_local(); + p = rcu_dereference_check(rcu_torture_current, + rcu_read_lock_bh_held() || + rcu_read_lock_sched_held() || + srcu_read_lock_held(srcu_ctlp) || + rcu_read_lock_trace_held() || + torturing_tasks()); + if (p == NULL) { + /* Wait for rcu_torture_writer to get underway */ + rcutorture_one_extend(&readstate, 0, trsp, rtrsp); + return false; + } + if (p->rtort_mbtest == 0) + atomic_inc(&n_rcu_torture_mberror); + rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp); + preempt_disable(); + pipe_count = READ_ONCE(p->rtort_pipe_count); + if (pipe_count > RCU_TORTURE_PIPE_LEN) { + /* Should not happen, but... */ + pipe_count = RCU_TORTURE_PIPE_LEN; + } + completed = cur_ops->get_gp_seq(); + if (pipe_count > 1) { + do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, + ts, started, completed); + rcu_ftrace_dump(DUMP_ALL); + } + __this_cpu_inc(rcu_torture_count[pipe_count]); + completed = rcutorture_seq_diff(completed, started); + if (completed > RCU_TORTURE_PIPE_LEN) { + /* Should not happen, but... */ + completed = RCU_TORTURE_PIPE_LEN; + } + __this_cpu_inc(rcu_torture_batch[completed]); + preempt_enable(); + rcutorture_one_extend(&readstate, 0, trsp, rtrsp); + WARN_ON_ONCE(readstate & RCUTORTURE_RDR_MASK); + // This next splat is expected behavior if leakpointer, especially + // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels. + WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1); + + /* If error or close call, record the sequence of reader protections. */ + if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) { + i = 0; + for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++) + err_segs[i++] = *rtrsp1; + rt_read_nsegs = i; + } + + return true; +} + +static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand); + +/* + * 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(struct timer_list *unused) +{ + atomic_long_inc(&n_rcu_torture_timers); + (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand)); + + /* Test call_rcu() invocation from interrupt handler. */ + if (cur_ops->call) { + struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT); + + if (rhp) + cur_ops->call(rhp, rcu_torture_timer_cb); + } +} + +/* + * 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) +{ + unsigned long lastsleep = jiffies; + long myid = (long)arg; + int mynumonline = myid; + DEFINE_TORTURE_RANDOM(rand); + struct timer_list t; + + VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); + set_user_nice(current, MAX_NICE); + if (irqreader && cur_ops->irq_capable) + timer_setup_on_stack(&t, rcu_torture_timer, 0); + tick_dep_set_task(current, TICK_DEP_BIT_RCU); + do { + if (irqreader && cur_ops->irq_capable) { + if (!timer_pending(&t)) + mod_timer(&t, jiffies + 1); + } + if (!rcu_torture_one_read(&rand) && !torture_must_stop()) + schedule_timeout_interruptible(HZ); + if (time_after(jiffies, lastsleep) && !torture_must_stop()) { + schedule_timeout_interruptible(1); + lastsleep = jiffies + 10; + } + while (num_online_cpus() < mynumonline && !torture_must_stop()) + schedule_timeout_interruptible(HZ / 5); + stutter_wait("rcu_torture_reader"); + } while (!torture_must_stop()); + if (irqreader && cur_ops->irq_capable) { + del_timer_sync(&t); + destroy_timer_on_stack(&t); + } + tick_dep_clear_task(current, TICK_DEP_BIT_RCU); + torture_kthread_stopping("rcu_torture_reader"); + return 0; +} + +/* + * 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 cpu; + int i; + long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; + long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; + struct rcu_torture *rtcp; + static unsigned long rtcv_snap = ULONG_MAX; + static bool splatted; + struct task_struct *wtp; + + for_each_possible_cpu(cpu) { + for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { + pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]); + batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]); + } + } + for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { + if (pipesummary[i] != 0) + break; + } + + pr_alert("%s%s ", torture_type, TORTURE_FLAG); + rtcp = rcu_access_pointer(rcu_torture_current); + pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", + rtcp, + rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER", + 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)); + pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ", + atomic_read(&n_rcu_torture_mberror), + n_rcu_torture_barrier_error, + n_rcu_torture_boost_ktrerror, + n_rcu_torture_boost_rterror); + pr_cont("rtbf: %ld rtb: %ld nt: %ld ", + n_rcu_torture_boost_failure, + n_rcu_torture_boosts, + atomic_long_read(&n_rcu_torture_timers)); + torture_onoff_stats(); + pr_cont("barrier: %ld/%ld:%ld ", + data_race(n_barrier_successes), + data_race(n_barrier_attempts), + data_race(n_rcu_torture_barrier_error)); + pr_cont("read-exits: %ld\n", data_race(n_read_exits)); + + pr_alert("%s%s ", torture_type, TORTURE_FLAG); + if (atomic_read(&n_rcu_torture_mberror) || + n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror || + n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure || + i > 1) { + pr_cont("%s", "!!! "); + atomic_inc(&n_rcu_torture_error); + WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror)); + WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier() + WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread + WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio + WARN_ON_ONCE(n_rcu_torture_boost_failure); // RCU boost failed + WARN_ON_ONCE(i > 1); // Too-short grace period + } + pr_cont("Reader Pipe: "); + for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) + pr_cont(" %ld", pipesummary[i]); + pr_cont("\n"); + + pr_alert("%s%s ", torture_type, TORTURE_FLAG); + pr_cont("Reader Batch: "); + for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) + pr_cont(" %ld", batchsummary[i]); + pr_cont("\n"); + + pr_alert("%s%s ", torture_type, TORTURE_FLAG); + pr_cont("Free-Block Circulation: "); + for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { + pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); + } + pr_cont("\n"); + + if (cur_ops->stats) + cur_ops->stats(); + if (rtcv_snap == rcu_torture_current_version && + rcu_access_pointer(rcu_torture_current) && + !rcu_stall_is_suppressed()) { + int __maybe_unused flags = 0; + unsigned long __maybe_unused gp_seq = 0; + + rcutorture_get_gp_data(cur_ops->ttype, + &flags, &gp_seq); + srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, + &flags, &gp_seq); + wtp = READ_ONCE(writer_task); + pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#lx cpu %d\n", + rcu_torture_writer_state_getname(), + rcu_torture_writer_state, gp_seq, flags, + wtp == NULL ? ~0UL : wtp->state, + wtp == NULL ? -1 : (int)task_cpu(wtp)); + if (!splatted && wtp) { + sched_show_task(wtp); + splatted = true; + } + show_rcu_gp_kthreads(); + rcu_ftrace_dump(DUMP_ALL); + } + rtcv_snap = rcu_torture_current_version; +} + +/* + * Periodically prints torture statistics, if periodic statistics printing + * was specified via the stat_interval module parameter. + */ +static int +rcu_torture_stats(void *arg) +{ + VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); + do { + schedule_timeout_interruptible(stat_interval * HZ); + rcu_torture_stats_print(); + torture_shutdown_absorb("rcu_torture_stats"); + } while (!torture_must_stop()); + torture_kthread_stopping("rcu_torture_stats"); + return 0; +} + +static void +rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) +{ + pr_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 " + "test_boost=%d/%d test_boost_interval=%d " + "test_boost_duration=%d shutdown_secs=%d " + "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d " + "stall_cpu_block=%d " + "n_barrier_cbs=%d " + "onoff_interval=%d onoff_holdoff=%d " + "read_exit_delay=%d read_exit_burst=%d\n", + torture_type, tag, nrealreaders, nfakewriters, + stat_interval, verbose, test_no_idle_hz, shuffle_interval, + stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, + test_boost, cur_ops->can_boost, + test_boost_interval, test_boost_duration, shutdown_secs, + stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff, + stall_cpu_block, + n_barrier_cbs, + onoff_interval, onoff_holdoff, + read_exit_delay, read_exit_burst); +} + +static int rcutorture_booster_cleanup(unsigned int cpu) +{ + struct task_struct *t; + + if (boost_tasks[cpu] == NULL) + return 0; + mutex_lock(&boost_mutex); + t = boost_tasks[cpu]; + boost_tasks[cpu] = NULL; + rcu_torture_enable_rt_throttle(); + mutex_unlock(&boost_mutex); + + /* This must be outside of the mutex, otherwise deadlock! */ + torture_stop_kthread(rcu_torture_boost, t); + return 0; +} + +static int rcutorture_booster_init(unsigned int cpu) +{ + int retval; + + if (boost_tasks[cpu] != NULL) + return 0; /* Already created, nothing more to do. */ + + /* Don't allow time recalculation while creating a new task. */ + mutex_lock(&boost_mutex); + rcu_torture_disable_rt_throttle(); + VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); + boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL, + cpu_to_node(cpu), + "rcu_torture_boost"); + if (IS_ERR(boost_tasks[cpu])) { + retval = PTR_ERR(boost_tasks[cpu]); + VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); + n_rcu_torture_boost_ktrerror++; + boost_tasks[cpu] = NULL; + mutex_unlock(&boost_mutex); + return retval; + } + kthread_bind(boost_tasks[cpu], cpu); + wake_up_process(boost_tasks[cpu]); + mutex_unlock(&boost_mutex); + return 0; +} + +/* + * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then + * induces a CPU stall for the time specified by stall_cpu. + */ +static int rcu_torture_stall(void *args) +{ + int idx; + unsigned long stop_at; + + VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); + if (stall_cpu_holdoff > 0) { + VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); + schedule_timeout_interruptible(stall_cpu_holdoff * HZ); + VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); + } + if (!kthread_should_stop() && stall_gp_kthread > 0) { + VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall"); + rcu_gp_set_torture_wait(stall_gp_kthread * HZ); + for (idx = 0; idx < stall_gp_kthread + 2; idx++) { + if (kthread_should_stop()) + break; + schedule_timeout_uninterruptible(HZ); + } + } + if (!kthread_should_stop() && stall_cpu > 0) { + VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall"); + stop_at = ktime_get_seconds() + stall_cpu; + /* RCU CPU stall is expected behavior in following code. */ + idx = cur_ops->readlock(); + if (stall_cpu_irqsoff) + local_irq_disable(); + else if (!stall_cpu_block) + preempt_disable(); + pr_alert("rcu_torture_stall start on CPU %d.\n", + raw_smp_processor_id()); + while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), + stop_at)) + if (stall_cpu_block) + schedule_timeout_uninterruptible(HZ); + if (stall_cpu_irqsoff) + local_irq_enable(); + else if (!stall_cpu_block) + preempt_enable(); + cur_ops->readunlock(idx); + } + pr_alert("rcu_torture_stall end.\n"); + torture_shutdown_absorb("rcu_torture_stall"); + while (!kthread_should_stop()) + schedule_timeout_interruptible(10 * HZ); + return 0; +} + +/* Spawn CPU-stall kthread, if stall_cpu specified. */ +static int __init rcu_torture_stall_init(void) +{ + if (stall_cpu <= 0 && stall_gp_kthread <= 0) + return 0; + return torture_create_kthread(rcu_torture_stall, NULL, stall_task); +} + +/* State structure for forward-progress self-propagating RCU callback. */ +struct fwd_cb_state { + struct rcu_head rh; + int stop; +}; + +/* + * Forward-progress self-propagating RCU callback function. Because + * callbacks run from softirq, this function is an implicit RCU read-side + * critical section. + */ +static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp) +{ + struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh); + + if (READ_ONCE(fcsp->stop)) { + WRITE_ONCE(fcsp->stop, 2); + return; + } + cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb); +} + +/* State for continuous-flood RCU callbacks. */ +struct rcu_fwd_cb { + struct rcu_head rh; + struct rcu_fwd_cb *rfc_next; + struct rcu_fwd *rfc_rfp; + int rfc_gps; +}; + +#define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */ +#define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */ +#define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */ +#define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */ +#define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)) + +struct rcu_launder_hist { + long n_launders; + unsigned long launder_gp_seq; +}; + +struct rcu_fwd { + spinlock_t rcu_fwd_lock; + struct rcu_fwd_cb *rcu_fwd_cb_head; + struct rcu_fwd_cb **rcu_fwd_cb_tail; + long n_launders_cb; + unsigned long rcu_fwd_startat; + struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST]; + unsigned long rcu_launder_gp_seq_start; +}; + +static DEFINE_MUTEX(rcu_fwd_mutex); +static struct rcu_fwd *rcu_fwds; +static bool rcu_fwd_emergency_stop; + +static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) +{ + unsigned long gps; + unsigned long gps_old; + int i; + int j; + + for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--) + if (rfp->n_launders_hist[i].n_launders > 0) + break; + pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):", + __func__, jiffies - rfp->rcu_fwd_startat); + gps_old = rfp->rcu_launder_gp_seq_start; + for (j = 0; j <= i; j++) { + gps = rfp->n_launders_hist[j].launder_gp_seq; + pr_cont(" %ds/%d: %ld:%ld", + j + 1, FWD_CBS_HIST_DIV, + rfp->n_launders_hist[j].n_launders, + rcutorture_seq_diff(gps, gps_old)); + gps_old = gps; + } + pr_cont("\n"); +} + +/* Callback function for continuous-flood RCU callbacks. */ +static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp) +{ + unsigned long flags; + int i; + struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh); + struct rcu_fwd_cb **rfcpp; + struct rcu_fwd *rfp = rfcp->rfc_rfp; + + rfcp->rfc_next = NULL; + rfcp->rfc_gps++; + spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); + rfcpp = rfp->rcu_fwd_cb_tail; + rfp->rcu_fwd_cb_tail = &rfcp->rfc_next; + WRITE_ONCE(*rfcpp, rfcp); + WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1); + i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV)); + if (i >= ARRAY_SIZE(rfp->n_launders_hist)) + i = ARRAY_SIZE(rfp->n_launders_hist) - 1; + rfp->n_launders_hist[i].n_launders++; + rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq(); + spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); +} + +// Give the scheduler a chance, even on nohz_full CPUs. +static void rcu_torture_fwd_prog_cond_resched(unsigned long iter) +{ + if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) { + // Real call_rcu() floods hit userspace, so emulate that. + if (need_resched() || (iter & 0xfff)) + schedule(); + return; + } + // No userspace emulation: CB invocation throttles call_rcu() + cond_resched(); +} + +/* + * Free all callbacks on the rcu_fwd_cb_head list, either because the + * test is over or because we hit an OOM event. + */ +static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp) +{ + unsigned long flags; + unsigned long freed = 0; + struct rcu_fwd_cb *rfcp; + + for (;;) { + spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); + rfcp = rfp->rcu_fwd_cb_head; + if (!rfcp) { + spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); + break; + } + rfp->rcu_fwd_cb_head = rfcp->rfc_next; + if (!rfp->rcu_fwd_cb_head) + rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; + spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); + kfree(rfcp); + freed++; + rcu_torture_fwd_prog_cond_resched(freed); + if (tick_nohz_full_enabled()) { + local_irq_save(flags); + rcu_momentary_dyntick_idle(); + local_irq_restore(flags); + } + } + return freed; +} + +/* Carry out need_resched()/cond_resched() forward-progress testing. */ +static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp, + int *tested, int *tested_tries) +{ + unsigned long cver; + unsigned long dur; + struct fwd_cb_state fcs; + unsigned long gps; + int idx; + int sd; + int sd4; + bool selfpropcb = false; + unsigned long stopat; + static DEFINE_TORTURE_RANDOM(trs); + + if (cur_ops->call && cur_ops->sync && cur_ops->cb_barrier) { + init_rcu_head_on_stack(&fcs.rh); + selfpropcb = true; + } + + /* Tight loop containing cond_resched(). */ + WRITE_ONCE(rcu_fwd_cb_nodelay, true); + cur_ops->sync(); /* Later readers see above write. */ + if (selfpropcb) { + WRITE_ONCE(fcs.stop, 0); + cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb); + } + cver = READ_ONCE(rcu_torture_current_version); + gps = cur_ops->get_gp_seq(); + sd = cur_ops->stall_dur() + 1; + sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div; + dur = sd4 + torture_random(&trs) % (sd - sd4); + WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); + stopat = rfp->rcu_fwd_startat + dur; + while (time_before(jiffies, stopat) && + !shutdown_time_arrived() && + !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { + idx = cur_ops->readlock(); + udelay(10); + cur_ops->readunlock(idx); + if (!fwd_progress_need_resched || need_resched()) + cond_resched(); + } + (*tested_tries)++; + if (!time_before(jiffies, stopat) && + !shutdown_time_arrived() && + !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { + (*tested)++; + cver = READ_ONCE(rcu_torture_current_version) - cver; + gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); + WARN_ON(!cver && gps < 2); + pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps); + } + if (selfpropcb) { + WRITE_ONCE(fcs.stop, 1); + cur_ops->sync(); /* Wait for running CB to complete. */ + cur_ops->cb_barrier(); /* Wait for queued callbacks. */ + } + + if (selfpropcb) { + WARN_ON(READ_ONCE(fcs.stop) != 2); + destroy_rcu_head_on_stack(&fcs.rh); + } + schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */ + WRITE_ONCE(rcu_fwd_cb_nodelay, false); +} + +/* Carry out call_rcu() forward-progress testing. */ +static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) +{ + unsigned long cver; + unsigned long flags; + unsigned long gps; + int i; + long n_launders; + long n_launders_cb_snap; + long n_launders_sa; + long n_max_cbs; + long n_max_gps; + struct rcu_fwd_cb *rfcp; + struct rcu_fwd_cb *rfcpn; + unsigned long stopat; + unsigned long stoppedat; + + if (READ_ONCE(rcu_fwd_emergency_stop)) + return; /* Get out of the way quickly, no GP wait! */ + if (!cur_ops->call) + return; /* Can't do call_rcu() fwd prog without ->call. */ + + /* Loop continuously posting RCU callbacks. */ + WRITE_ONCE(rcu_fwd_cb_nodelay, true); + cur_ops->sync(); /* Later readers see above write. */ + WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); + stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES; + n_launders = 0; + rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread + n_launders_sa = 0; + n_max_cbs = 0; + n_max_gps = 0; + for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++) + rfp->n_launders_hist[i].n_launders = 0; + cver = READ_ONCE(rcu_torture_current_version); + gps = cur_ops->get_gp_seq(); + rfp->rcu_launder_gp_seq_start = gps; + tick_dep_set_task(current, TICK_DEP_BIT_RCU); + while (time_before(jiffies, stopat) && + !shutdown_time_arrived() && + !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { + rfcp = READ_ONCE(rfp->rcu_fwd_cb_head); + rfcpn = NULL; + if (rfcp) + rfcpn = READ_ONCE(rfcp->rfc_next); + if (rfcpn) { + if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS && + ++n_max_gps >= MIN_FWD_CBS_LAUNDERED) + break; + rfp->rcu_fwd_cb_head = rfcpn; + n_launders++; + n_launders_sa++; + } else { + rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL); + if (WARN_ON_ONCE(!rfcp)) { + schedule_timeout_interruptible(1); + continue; + } + n_max_cbs++; + n_launders_sa = 0; + rfcp->rfc_gps = 0; + rfcp->rfc_rfp = rfp; + } + cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); + rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs); + if (tick_nohz_full_enabled()) { + local_irq_save(flags); + rcu_momentary_dyntick_idle(); + local_irq_restore(flags); + } + } + stoppedat = jiffies; + n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb); + cver = READ_ONCE(rcu_torture_current_version) - cver; + gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); + cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */ + (void)rcu_torture_fwd_prog_cbfree(rfp); + + if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) && + !shutdown_time_arrived()) { + WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED); + pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n", + __func__, + stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat, + n_launders + n_max_cbs - n_launders_cb_snap, + n_launders, n_launders_sa, + n_max_gps, n_max_cbs, cver, gps); + rcu_torture_fwd_cb_hist(rfp); + } + schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ + tick_dep_clear_task(current, TICK_DEP_BIT_RCU); + WRITE_ONCE(rcu_fwd_cb_nodelay, false); +} + + +/* + * OOM notifier, but this only prints diagnostic information for the + * current forward-progress test. + */ +static int rcutorture_oom_notify(struct notifier_block *self, + unsigned long notused, void *nfreed) +{ + struct rcu_fwd *rfp; + + mutex_lock(&rcu_fwd_mutex); + rfp = rcu_fwds; + if (!rfp) { + mutex_unlock(&rcu_fwd_mutex); + return NOTIFY_OK; + } + WARN(1, "%s invoked upon OOM during forward-progress testing.\n", + __func__); + rcu_torture_fwd_cb_hist(rfp); + rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp->rcu_fwd_startat)) / 2); + WRITE_ONCE(rcu_fwd_emergency_stop, true); + smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ + pr_info("%s: Freed %lu RCU callbacks.\n", + __func__, rcu_torture_fwd_prog_cbfree(rfp)); + rcu_barrier(); + pr_info("%s: Freed %lu RCU callbacks.\n", + __func__, rcu_torture_fwd_prog_cbfree(rfp)); + rcu_barrier(); + pr_info("%s: Freed %lu RCU callbacks.\n", + __func__, rcu_torture_fwd_prog_cbfree(rfp)); + smp_mb(); /* Frees before return to avoid redoing OOM. */ + (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */ + pr_info("%s returning after OOM processing.\n", __func__); + mutex_unlock(&rcu_fwd_mutex); + return NOTIFY_OK; +} + +static struct notifier_block rcutorture_oom_nb = { + .notifier_call = rcutorture_oom_notify +}; + +/* Carry out grace-period forward-progress testing. */ +static int rcu_torture_fwd_prog(void *args) +{ + struct rcu_fwd *rfp = args; + int tested = 0; + int tested_tries = 0; + + VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started"); + rcu_bind_current_to_nocb(); + if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST)) + set_user_nice(current, MAX_NICE); + do { + schedule_timeout_interruptible(fwd_progress_holdoff * HZ); + WRITE_ONCE(rcu_fwd_emergency_stop, false); + if (!IS_ENABLED(CONFIG_TINY_RCU) || + rcu_inkernel_boot_has_ended()) + rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries); + if (rcu_inkernel_boot_has_ended()) + rcu_torture_fwd_prog_cr(rfp); + + /* Avoid slow periods, better to test when busy. */ + stutter_wait("rcu_torture_fwd_prog"); + } while (!torture_must_stop()); + /* Short runs might not contain a valid forward-progress attempt. */ + WARN_ON(!tested && tested_tries >= 5); + pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries); + torture_kthread_stopping("rcu_torture_fwd_prog"); + return 0; +} + +/* If forward-progress checking is requested and feasible, spawn the thread. */ +static int __init rcu_torture_fwd_prog_init(void) +{ + struct rcu_fwd *rfp; + + if (!fwd_progress) + return 0; /* Not requested, so don't do it. */ + if (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0 || + cur_ops == &rcu_busted_ops) { + VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test"); + return 0; + } + if (stall_cpu > 0) { + VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); + if (IS_MODULE(CONFIG_RCU_TORTURE_TESTS)) + return -EINVAL; /* In module, can fail back to user. */ + WARN_ON(1); /* Make sure rcutorture notices conflict. */ + return 0; + } + if (fwd_progress_holdoff <= 0) + fwd_progress_holdoff = 1; + if (fwd_progress_div <= 0) + fwd_progress_div = 4; + rfp = kzalloc(sizeof(*rfp), GFP_KERNEL); + if (!rfp) + return -ENOMEM; + spin_lock_init(&rfp->rcu_fwd_lock); + rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; + mutex_lock(&rcu_fwd_mutex); + rcu_fwds = rfp; + mutex_unlock(&rcu_fwd_mutex); + register_oom_notifier(&rcutorture_oom_nb); + return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task); +} + +static void rcu_torture_fwd_prog_cleanup(void) +{ + struct rcu_fwd *rfp; + + torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task); + rfp = rcu_fwds; + mutex_lock(&rcu_fwd_mutex); + rcu_fwds = NULL; + mutex_unlock(&rcu_fwd_mutex); + unregister_oom_notifier(&rcutorture_oom_nb); + kfree(rfp); +} + +/* Callback function for RCU barrier testing. */ +static void rcu_torture_barrier_cbf(struct rcu_head *rcu) +{ + atomic_inc(&barrier_cbs_invoked); +} + +/* IPI handler to get callback posted on desired CPU, if online. */ +static void rcu_torture_barrier1cb(void *rcu_void) +{ + struct rcu_head *rhp = rcu_void; + + cur_ops->call(rhp, rcu_torture_barrier_cbf); +} + +/* kthread function to register callbacks used to test RCU barriers. */ +static int rcu_torture_barrier_cbs(void *arg) +{ + long myid = (long)arg; + bool lastphase = false; + bool newphase; + struct rcu_head rcu; + + init_rcu_head_on_stack(&rcu); + VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); + set_user_nice(current, MAX_NICE); + do { + wait_event(barrier_cbs_wq[myid], + (newphase = + smp_load_acquire(&barrier_phase)) != lastphase || + torture_must_stop()); + lastphase = newphase; + if (torture_must_stop()) + break; + /* + * The above smp_load_acquire() ensures barrier_phase load + * is ordered before the following ->call(). + */ + if (smp_call_function_single(myid, rcu_torture_barrier1cb, + &rcu, 1)) { + // IPI failed, so use direct call from current CPU. + cur_ops->call(&rcu, rcu_torture_barrier_cbf); + } + if (atomic_dec_and_test(&barrier_cbs_count)) + wake_up(&barrier_wq); + } while (!torture_must_stop()); + if (cur_ops->cb_barrier != NULL) + cur_ops->cb_barrier(); + destroy_rcu_head_on_stack(&rcu); + torture_kthread_stopping("rcu_torture_barrier_cbs"); + return 0; +} + +/* kthread function to drive and coordinate RCU barrier testing. */ +static int rcu_torture_barrier(void *arg) +{ + int i; + + VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); + do { + atomic_set(&barrier_cbs_invoked, 0); + atomic_set(&barrier_cbs_count, n_barrier_cbs); + /* Ensure barrier_phase ordered after prior assignments. */ + smp_store_release(&barrier_phase, !barrier_phase); + for (i = 0; i < n_barrier_cbs; i++) + wake_up(&barrier_cbs_wq[i]); + wait_event(barrier_wq, + atomic_read(&barrier_cbs_count) == 0 || + torture_must_stop()); + if (torture_must_stop()) + break; + n_barrier_attempts++; + cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ + if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { + n_rcu_torture_barrier_error++; + pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", + atomic_read(&barrier_cbs_invoked), + n_barrier_cbs); + WARN_ON(1); + // Wait manually for the remaining callbacks + i = 0; + do { + if (WARN_ON(i++ > HZ)) + i = INT_MIN; + schedule_timeout_interruptible(1); + cur_ops->cb_barrier(); + } while (atomic_read(&barrier_cbs_invoked) != + n_barrier_cbs && + !torture_must_stop()); + smp_mb(); // Can't trust ordering if broken. + if (!torture_must_stop()) + pr_err("Recovered: barrier_cbs_invoked = %d\n", + atomic_read(&barrier_cbs_invoked)); + } else { + n_barrier_successes++; + } + schedule_timeout_interruptible(HZ / 10); + } while (!torture_must_stop()); + torture_kthread_stopping("rcu_torture_barrier"); + return 0; +} + +/* Initialize RCU barrier testing. */ +static int rcu_torture_barrier_init(void) +{ + int i; + int ret; + + if (n_barrier_cbs <= 0) + return 0; + if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { + pr_alert("%s" TORTURE_FLAG + " Call or barrier ops missing for %s,\n", + torture_type, cur_ops->name); + pr_alert("%s" TORTURE_FLAG + " RCU barrier testing omitted from run.\n", + torture_type); + return 0; + } + atomic_set(&barrier_cbs_count, 0); + atomic_set(&barrier_cbs_invoked, 0); + barrier_cbs_tasks = + kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]), + GFP_KERNEL); + barrier_cbs_wq = + kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL); + if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) + return -ENOMEM; + for (i = 0; i < n_barrier_cbs; i++) { + init_waitqueue_head(&barrier_cbs_wq[i]); + ret = torture_create_kthread(rcu_torture_barrier_cbs, + (void *)(long)i, + barrier_cbs_tasks[i]); + if (ret) + return ret; + } + return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); +} + +/* Clean up after RCU barrier testing. */ +static void rcu_torture_barrier_cleanup(void) +{ + int i; + + torture_stop_kthread(rcu_torture_barrier, barrier_task); + if (barrier_cbs_tasks != NULL) { + for (i = 0; i < n_barrier_cbs; i++) + torture_stop_kthread(rcu_torture_barrier_cbs, + barrier_cbs_tasks[i]); + kfree(barrier_cbs_tasks); + barrier_cbs_tasks = NULL; + } + if (barrier_cbs_wq != NULL) { + kfree(barrier_cbs_wq); + barrier_cbs_wq = NULL; + } +} + +static bool rcu_torture_can_boost(void) +{ + static int boost_warn_once; + int prio; + + if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2) + return false; + + prio = rcu_get_gp_kthreads_prio(); + if (!prio) + return false; + + if (prio < 2) { + if (boost_warn_once == 1) + return false; + + pr_alert("%s: WARN: RCU kthread priority too low to test boosting. Skipping RCU boost test. Try passing rcutree.kthread_prio > 1 on the kernel command line.\n", KBUILD_MODNAME); + boost_warn_once = 1; + return false; + } + + return true; +} + +static bool read_exit_child_stop; +static bool read_exit_child_stopped; +static wait_queue_head_t read_exit_wq; + +// Child kthread which just does an rcutorture reader and exits. +static int rcu_torture_read_exit_child(void *trsp_in) +{ + struct torture_random_state *trsp = trsp_in; + + set_user_nice(current, MAX_NICE); + // Minimize time between reading and exiting. + while (!kthread_should_stop()) + schedule_timeout_uninterruptible(1); + (void)rcu_torture_one_read(trsp); + return 0; +} + +// Parent kthread which creates and destroys read-exit child kthreads. +static int rcu_torture_read_exit(void *unused) +{ + int count = 0; + bool errexit = false; + int i; + struct task_struct *tsp; + DEFINE_TORTURE_RANDOM(trs); + + // Allocate and initialize. + set_user_nice(current, MAX_NICE); + VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test"); + + // Each pass through this loop does one read-exit episode. + do { + if (++count > read_exit_burst) { + VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode"); + rcu_barrier(); // Wait for task_struct free, avoid OOM. + for (i = 0; i < read_exit_delay; i++) { + schedule_timeout_uninterruptible(HZ); + if (READ_ONCE(read_exit_child_stop)) + break; + } + if (!READ_ONCE(read_exit_child_stop)) + VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode"); + count = 0; + } + if (READ_ONCE(read_exit_child_stop)) + break; + // Spawn child. + tsp = kthread_run(rcu_torture_read_exit_child, + &trs, "%s", + "rcu_torture_read_exit_child"); + if (IS_ERR(tsp)) { + VERBOSE_TOROUT_ERRSTRING("out of memory"); + errexit = true; + tsp = NULL; + break; + } + cond_resched(); + kthread_stop(tsp); + n_read_exits ++; + stutter_wait("rcu_torture_read_exit"); + } while (!errexit && !READ_ONCE(read_exit_child_stop)); + + // Clean up and exit. + smp_store_release(&read_exit_child_stopped, true); // After reaping. + smp_mb(); // Store before wakeup. + wake_up(&read_exit_wq); + while (!torture_must_stop()) + schedule_timeout_uninterruptible(1); + torture_kthread_stopping("rcu_torture_read_exit"); + return 0; +} + +static int rcu_torture_read_exit_init(void) +{ + if (read_exit_burst <= 0) + return -EINVAL; + init_waitqueue_head(&read_exit_wq); + read_exit_child_stop = false; + read_exit_child_stopped = false; + return torture_create_kthread(rcu_torture_read_exit, NULL, + read_exit_task); +} + +static void rcu_torture_read_exit_cleanup(void) +{ + if (!read_exit_task) + return; + WRITE_ONCE(read_exit_child_stop, true); + smp_mb(); // Above write before wait. + wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped)); + torture_stop_kthread(rcutorture_read_exit, read_exit_task); +} + +static enum cpuhp_state rcutor_hp; + +static void +rcu_torture_cleanup(void) +{ + int firsttime; + int flags = 0; + unsigned long gp_seq = 0; + int i; + + if (torture_cleanup_begin()) { + if (cur_ops->cb_barrier != NULL) + cur_ops->cb_barrier(); + return; + } + if (!cur_ops) { + torture_cleanup_end(); + return; + } + + show_rcu_gp_kthreads(); + rcu_torture_read_exit_cleanup(); + rcu_torture_barrier_cleanup(); + rcu_torture_fwd_prog_cleanup(); + torture_stop_kthread(rcu_torture_stall, stall_task); + torture_stop_kthread(rcu_torture_writer, writer_task); + + if (reader_tasks) { + for (i = 0; i < nrealreaders; i++) + torture_stop_kthread(rcu_torture_reader, + reader_tasks[i]); + kfree(reader_tasks); + } + + if (fakewriter_tasks) { + for (i = 0; i < nfakewriters; i++) { + torture_stop_kthread(rcu_torture_fakewriter, + fakewriter_tasks[i]); + } + kfree(fakewriter_tasks); + fakewriter_tasks = NULL; + } + + rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); + srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); + pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n", + cur_ops->name, (long)gp_seq, flags, + rcutorture_seq_diff(gp_seq, start_gp_seq)); + torture_stop_kthread(rcu_torture_stats, stats_task); + torture_stop_kthread(rcu_torture_fqs, fqs_task); + if (rcu_torture_can_boost()) + cpuhp_remove_state(rcutor_hp); + + /* + * Wait for all RCU callbacks to fire, then do torture-type-specific + * cleanup operations. + */ + if (cur_ops->cb_barrier != NULL) + cur_ops->cb_barrier(); + if (cur_ops->cleanup != NULL) + cur_ops->cleanup(); + + rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ + + if (err_segs_recorded) { + pr_alert("Failure/close-call rcutorture reader segments:\n"); + if (rt_read_nsegs == 0) + pr_alert("\t: No segments recorded!!!\n"); + firsttime = 1; + for (i = 0; i < rt_read_nsegs; i++) { + pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate); + if (err_segs[i].rt_delay_jiffies != 0) { + pr_cont("%s%ldjiffies", firsttime ? "" : "+", + err_segs[i].rt_delay_jiffies); + firsttime = 0; + } + if (err_segs[i].rt_delay_ms != 0) { + pr_cont("%s%ldms", firsttime ? "" : "+", + err_segs[i].rt_delay_ms); + firsttime = 0; + } + if (err_segs[i].rt_delay_us != 0) { + pr_cont("%s%ldus", firsttime ? "" : "+", + err_segs[i].rt_delay_us); + firsttime = 0; + } + pr_cont("%s\n", + err_segs[i].rt_preempted ? "preempted" : ""); + + } + } + if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) + rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); + else if (torture_onoff_failures()) + rcu_torture_print_module_parms(cur_ops, + "End of test: RCU_HOTPLUG"); + else + rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); + torture_cleanup_end(); +} + +#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD +static void rcu_torture_leak_cb(struct rcu_head *rhp) +{ +} + +static void rcu_torture_err_cb(struct rcu_head *rhp) +{ + /* + * This -might- happen due to race conditions, but is unlikely. + * The scenario that leads to this happening is that the + * first of the pair of duplicate callbacks is queued, + * someone else starts a grace period that includes that + * callback, then the second of the pair must wait for the + * next grace period. Unlikely, but can happen. If it + * does happen, the debug-objects subsystem won't have splatted. + */ + pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME); +} +#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ + +/* + * Verify that double-free causes debug-objects to complain, but only + * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test + * cannot be carried out. + */ +static void rcu_test_debug_objects(void) +{ +#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD + struct rcu_head rh1; + struct rcu_head rh2; + + init_rcu_head_on_stack(&rh1); + init_rcu_head_on_stack(&rh2); + pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME); + + /* Try to queue the rh2 pair of callbacks for the same grace period. */ + preempt_disable(); /* Prevent preemption from interrupting test. */ + rcu_read_lock(); /* Make it impossible to finish a grace period. */ + call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */ + local_irq_disable(); /* Make it harder to start a new grace period. */ + call_rcu(&rh2, rcu_torture_leak_cb); + call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ + local_irq_enable(); + rcu_read_unlock(); + preempt_enable(); + + /* Wait for them all to get done so we can safely return. */ + rcu_barrier(); + pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME); + destroy_rcu_head_on_stack(&rh1); + destroy_rcu_head_on_stack(&rh2); +#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ + pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME); +#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ +} + +static void rcutorture_sync(void) +{ + static unsigned long n; + + if (cur_ops->sync && !(++n & 0xfff)) + cur_ops->sync(); +} + +static int __init +rcu_torture_init(void) +{ + long i; + int cpu; + int firsterr = 0; + int flags = 0; + unsigned long gp_seq = 0; + static struct rcu_torture_ops *torture_ops[] = { + &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, + &busted_srcud_ops, &tasks_ops, &tasks_rude_ops, + &tasks_tracing_ops, &trivial_ops, + }; + + if (!torture_init_begin(torture_type, verbose)) + return -EBUSY; + + /* 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)) { + pr_alert("rcu-torture: invalid torture type: \"%s\"\n", + torture_type); + pr_alert("rcu-torture types:"); + for (i = 0; i < ARRAY_SIZE(torture_ops); i++) + pr_cont(" %s", torture_ops[i]->name); + pr_cont("\n"); + WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); + firsterr = -EINVAL; + cur_ops = NULL; + goto unwind; + } + if (cur_ops->fqs == NULL && fqs_duration != 0) { + pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); + fqs_duration = 0; + } + if (cur_ops->init) + cur_ops->init(); + + if (nreaders >= 0) { + nrealreaders = nreaders; + } else { + nrealreaders = num_online_cpus() - 2 - nreaders; + if (nrealreaders <= 0) + nrealreaders = 1; + } + rcu_torture_print_module_parms(cur_ops, "Start of test"); + rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); + srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); + start_gp_seq = gp_seq; + pr_alert("%s: Start-test grace-period state: g%ld f%#x\n", + cur_ops->name, (long)gp_seq, flags); + + /* 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); + n_rcu_torture_barrier_error = 0; + n_rcu_torture_boost_ktrerror = 0; + n_rcu_torture_boost_rterror = 0; + n_rcu_torture_boost_failure = 0; + n_rcu_torture_boosts = 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; + } + } + err_segs_recorded = 0; + rt_read_nsegs = 0; + + /* Start up the kthreads. */ + + firsterr = torture_create_kthread(rcu_torture_writer, NULL, + writer_task); + if (firsterr) + goto unwind; + if (nfakewriters > 0) { + fakewriter_tasks = kcalloc(nfakewriters, + sizeof(fakewriter_tasks[0]), + GFP_KERNEL); + if (fakewriter_tasks == NULL) { + VERBOSE_TOROUT_ERRSTRING("out of memory"); + firsterr = -ENOMEM; + goto unwind; + } + } + for (i = 0; i < nfakewriters; i++) { + firsterr = torture_create_kthread(rcu_torture_fakewriter, + NULL, fakewriter_tasks[i]); + if (firsterr) + goto unwind; + } + reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), + GFP_KERNEL); + if (reader_tasks == NULL) { + VERBOSE_TOROUT_ERRSTRING("out of memory"); + firsterr = -ENOMEM; + goto unwind; + } + for (i = 0; i < nrealreaders; i++) { + firsterr = torture_create_kthread(rcu_torture_reader, (void *)i, + reader_tasks[i]); + if (firsterr) + goto unwind; + } + if (stat_interval > 0) { + firsterr = torture_create_kthread(rcu_torture_stats, NULL, + stats_task); + if (firsterr) + goto unwind; + } + if (test_no_idle_hz && shuffle_interval > 0) { + firsterr = torture_shuffle_init(shuffle_interval * HZ); + if (firsterr) + goto unwind; + } + if (stutter < 0) + stutter = 0; + if (stutter) { + int t; + + t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; + firsterr = torture_stutter_init(stutter * HZ, t); + if (firsterr) + goto unwind; + } + if (fqs_duration < 0) + fqs_duration = 0; + if (fqs_duration) { + /* Create the fqs thread */ + firsterr = torture_create_kthread(rcu_torture_fqs, NULL, + fqs_task); + if (firsterr) + goto unwind; + } + if (test_boost_interval < 1) + test_boost_interval = 1; + if (test_boost_duration < 2) + test_boost_duration = 2; + if (rcu_torture_can_boost()) { + + boost_starttime = jiffies + test_boost_interval * HZ; + + firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE", + rcutorture_booster_init, + rcutorture_booster_cleanup); + if (firsterr < 0) + goto unwind; + rcutor_hp = firsterr; + } + shutdown_jiffies = jiffies + shutdown_secs * HZ; + firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); + if (firsterr) + goto unwind; + firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, + rcutorture_sync); + if (firsterr) + goto unwind; + firsterr = rcu_torture_stall_init(); + if (firsterr) + goto unwind; + firsterr = rcu_torture_fwd_prog_init(); + if (firsterr) + goto unwind; + firsterr = rcu_torture_barrier_init(); + if (firsterr) + goto unwind; + firsterr = rcu_torture_read_exit_init(); + if (firsterr) + goto unwind; + if (object_debug) + rcu_test_debug_objects(); + torture_init_end(); + return 0; + +unwind: + torture_init_end(); + rcu_torture_cleanup(); + return firsterr; +} + +module_init(rcu_torture_init); +module_exit(rcu_torture_cleanup); |