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Diffstat (limited to 'kernel/rcu/rcutorture.c')
| -rw-r--r-- | kernel/rcu/rcutorture.c | 3654 |
1 files changed, 3654 insertions, 0 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c new file mode 100644 index 000000000..503c2aa84 --- /dev/null +++ b/kernel/rcu/rcutorture.c @@ -0,0 +1,3654 @@ +// 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 <linux/nmi.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_1 8 /* Put SRCU index in upper bits. */ +#define RCUTORTURE_RDR_MASK_1 (1 << RCUTORTURE_RDR_SHIFT_1) +#define RCUTORTURE_RDR_SHIFT_2 9 /* Put SRCU index in upper bits. */ +#define RCUTORTURE_RDR_MASK_2 (1 << RCUTORTURE_RDR_SHIFT_2) +#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_1 0x20 /* ... entering another RCU reader. */ +#define RCUTORTURE_RDR_RCU_2 0x40 /* ... entering another RCU reader. */ +#define RCUTORTURE_RDR_NBITS 7 /* 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(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)"); +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_cond_exp, false, "Use conditional/async expedited GP wait primitives"); +torture_param(bool, gp_cond_full, false, "Use conditional/async full-state GP wait primitives"); +torture_param(bool, gp_cond_exp_full, false, + "Use conditional/async full-stateexpedited 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_poll, false, "Use polling GP wait primitives"); +torture_param(bool, gp_poll_exp, false, "Use polling expedited GP wait primitives"); +torture_param(bool, gp_poll_full, false, "Use polling full-state GP wait primitives"); +torture_param(bool, gp_poll_exp_full, false, "Use polling full-state 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, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable"); +torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)"); +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(bool, stall_no_softlockup, false, "Avoid softlockup warning during cpu stall."); +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 nrealnocbers; +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 **nocb_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_tasks; +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 + +// Mailbox-like structure to check RCU global memory ordering. +struct rcu_torture_reader_check { + unsigned long rtc_myloops; + int rtc_chkrdr; + unsigned long rtc_chkloops; + int rtc_ready; + struct rcu_torture_reader_check *rtc_assigner; +} ____cacheline_internodealigned_in_smp; + +// Update-side data structure used to check RCU readers. +struct rcu_torture { + struct rcu_head rtort_rcu; + int rtort_pipe_count; + struct list_head rtort_free; + int rtort_mbtest; + struct rcu_torture_reader_check *rtort_chkp; +}; + +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 struct rcu_torture_reader_check *rcu_torture_reader_mbchk; +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_mbchk_fail; +static atomic_t n_rcu_torture_mbchk_tries; +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 atomic_long_t n_nocb_offload; +static atomic_long_t n_nocb_deoffload; + +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_GET_FULL 6 +#define RTWS_COND_GET_EXP 7 +#define RTWS_COND_GET_EXP_FULL 8 +#define RTWS_COND_SYNC 9 +#define RTWS_COND_SYNC_FULL 10 +#define RTWS_COND_SYNC_EXP 11 +#define RTWS_COND_SYNC_EXP_FULL 12 +#define RTWS_POLL_GET 13 +#define RTWS_POLL_GET_FULL 14 +#define RTWS_POLL_GET_EXP 15 +#define RTWS_POLL_GET_EXP_FULL 16 +#define RTWS_POLL_WAIT 17 +#define RTWS_POLL_WAIT_FULL 18 +#define RTWS_POLL_WAIT_EXP 19 +#define RTWS_POLL_WAIT_EXP_FULL 20 +#define RTWS_SYNC 21 +#define RTWS_STUTTER 22 +#define RTWS_STOPPING 23 +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_GET_FULL", + "RTWS_COND_GET_EXP", + "RTWS_COND_GET_EXP_FULL", + "RTWS_COND_SYNC", + "RTWS_COND_SYNC_FULL", + "RTWS_COND_SYNC_EXP", + "RTWS_COND_SYNC_EXP_FULL", + "RTWS_POLL_GET", + "RTWS_POLL_GET_FULL", + "RTWS_POLL_GET_EXP", + "RTWS_POLL_GET_EXP_FULL", + "RTWS_POLL_WAIT", + "RTWS_POLL_WAIT_FULL", + "RTWS_POLL_WAIT_EXP", + "RTWS_POLL_WAIT_EXP_FULL", + "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]; +} + +#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 atomic_t 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); + int (*readlock_held)(void); + 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_gp_state_exp)(void); + unsigned long (*start_gp_poll_exp)(void); + void (*start_gp_poll_exp_full)(struct rcu_gp_oldstate *rgosp); + bool (*poll_gp_state_exp)(unsigned long oldstate); + void (*cond_sync_exp)(unsigned long oldstate); + void (*cond_sync_exp_full)(struct rcu_gp_oldstate *rgosp); + unsigned long (*get_gp_state)(void); + void (*get_gp_state_full)(struct rcu_gp_oldstate *rgosp); + unsigned long (*get_gp_completed)(void); + void (*get_gp_completed_full)(struct rcu_gp_oldstate *rgosp); + unsigned long (*start_gp_poll)(void); + void (*start_gp_poll_full)(struct rcu_gp_oldstate *rgosp); + bool (*poll_gp_state)(unsigned long oldstate); + bool (*poll_gp_state_full)(struct rcu_gp_oldstate *rgosp); + bool (*poll_need_2gp)(bool poll, bool poll_full); + void (*cond_sync)(unsigned long oldstate); + void (*cond_sync_full)(struct rcu_gp_oldstate *rgosp); + call_rcu_func_t call; + void (*cb_barrier)(void); + void (*fqs)(void); + void (*stats)(void); + void (*gp_kthread_dbg)(void); + bool (*check_boost_failed)(unsigned long gp_state, int *cpup); + int (*stall_dur)(void); + long cbflood_max; + int irq_capable; + int can_boost; + int extendables; + int slow_gps; + int no_pi_lock; + const char *name; +}; + +static struct rcu_torture_ops *cur_ops; + +/* + * Definitions for rcu torture testing. + */ + +static int torture_readlock_not_held(void) +{ + return rcu_read_lock_bh_held() || rcu_read_lock_sched_held(); +} + +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 (!atomic_read(&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; + struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp); + + if (rtrcp) { + WRITE_ONCE(rp->rtort_chkp, NULL); + smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire(). + } + 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 bool rcu_poll_need_2gp(bool poll, bool poll_full) +{ + return poll; +} + +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, + .readlock_held = torture_readlock_not_held, + .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_gp_state = get_state_synchronize_rcu, + .get_gp_state_full = get_state_synchronize_rcu_full, + .get_gp_completed = get_completed_synchronize_rcu, + .get_gp_completed_full = get_completed_synchronize_rcu_full, + .start_gp_poll = start_poll_synchronize_rcu, + .start_gp_poll_full = start_poll_synchronize_rcu_full, + .poll_gp_state = poll_state_synchronize_rcu, + .poll_gp_state_full = poll_state_synchronize_rcu_full, + .poll_need_2gp = rcu_poll_need_2gp, + .cond_sync = cond_synchronize_rcu, + .cond_sync_full = cond_synchronize_rcu_full, + .get_gp_state_exp = get_state_synchronize_rcu, + .start_gp_poll_exp = start_poll_synchronize_rcu_expedited, + .start_gp_poll_exp_full = start_poll_synchronize_rcu_expedited_full, + .poll_gp_state_exp = poll_state_synchronize_rcu, + .cond_sync_exp = cond_synchronize_rcu_expedited, + .call = call_rcu, + .cb_barrier = rcu_barrier, + .fqs = rcu_force_quiescent_state, + .stats = NULL, + .gp_kthread_dbg = show_rcu_gp_kthreads, + .check_boost_failed = rcu_check_boost_fail, + .stall_dur = rcu_jiffies_till_stall_check, + .irq_capable = 1, + .can_boost = IS_ENABLED(CONFIG_RCU_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, + .readlock_held = torture_readlock_not_held, + .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 int torture_srcu_read_lock_held(void) +{ + return srcu_read_lock_held(srcu_ctlp); +} + +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 unsigned long srcu_torture_get_gp_state(void) +{ + return get_state_synchronize_srcu(srcu_ctlp); +} + +static unsigned long srcu_torture_start_gp_poll(void) +{ + return start_poll_synchronize_srcu(srcu_ctlp); +} + +static bool srcu_torture_poll_gp_state(unsigned long oldstate) +{ + return poll_state_synchronize_srcu(srcu_ctlp, oldstate); +} + +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, + .readlock_held = torture_srcu_read_lock_held, + .get_gp_seq = srcu_torture_completed, + .deferred_free = srcu_torture_deferred_free, + .sync = srcu_torture_synchronize, + .exp_sync = srcu_torture_synchronize_expedited, + .get_gp_state = srcu_torture_get_gp_state, + .start_gp_poll = srcu_torture_start_gp_poll, + .poll_gp_state = srcu_torture_poll_gp_state, + .call = srcu_torture_call, + .cb_barrier = srcu_torture_barrier, + .stats = srcu_torture_stats, + .cbflood_max = 50000, + .irq_capable = 1, + .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), + .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, + .readlock_held = torture_srcu_read_lock_held, + .get_gp_seq = srcu_torture_completed, + .deferred_free = srcu_torture_deferred_free, + .sync = srcu_torture_synchronize, + .exp_sync = srcu_torture_synchronize_expedited, + .get_gp_state = srcu_torture_get_gp_state, + .start_gp_poll = srcu_torture_start_gp_poll, + .poll_gp_state = srcu_torture_poll_gp_state, + .call = srcu_torture_call, + .cb_barrier = srcu_torture_barrier, + .stats = srcu_torture_stats, + .cbflood_max = 50000, + .irq_capable = 1, + .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), + .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, + .readlock_held = torture_srcu_read_lock_held, + .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, + .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), + .extendables = RCUTORTURE_MAX_EXTEND, + .name = "busted_srcud" +}; + +/* + * 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, + .readlock_held = torture_readlock_not_held, + .get_gp_seq = rcu_no_completed, + .sync = synchronize_rcu_trivial, + .exp_sync = synchronize_rcu_trivial, + .fqs = NULL, + .stats = NULL, + .irq_capable = 1, + .name = "trivial" +}; + +#ifdef CONFIG_TASKS_RCU + +/* + * 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, + .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread, + .fqs = NULL, + .stats = NULL, + .irq_capable = 1, + .slow_gps = 1, + .name = "tasks" +}; + +#define TASKS_OPS &tasks_ops, + +#else // #ifdef CONFIG_TASKS_RCU + +#define TASKS_OPS + +#endif // #else #ifdef CONFIG_TASKS_RCU + + +#ifdef CONFIG_TASKS_RUDE_RCU + +/* + * 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, + .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread, + .cbflood_max = 50000, + .fqs = NULL, + .stats = NULL, + .irq_capable = 1, + .name = "tasks-rude" +}; + +#define TASKS_RUDE_OPS &tasks_rude_ops, + +#else // #ifdef CONFIG_TASKS_RUDE_RCU + +#define TASKS_RUDE_OPS + +#endif // #else #ifdef CONFIG_TASKS_RUDE_RCU + + +#ifdef CONFIG_TASKS_TRACE_RCU + +/* + * 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, + .readlock_held = rcu_read_lock_trace_held, + .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, + .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread, + .cbflood_max = 50000, + .fqs = NULL, + .stats = NULL, + .irq_capable = 1, + .slow_gps = 1, + .name = "tasks-tracing" +}; + +#define TASKS_TRACING_OPS &tasks_tracing_ops, + +#else // #ifdef CONFIG_TASKS_TRACE_RCU + +#define TASKS_TRACING_OPS + +#endif // #else #ifdef CONFIG_TASKS_TRACE_RCU + + +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); +} + +/* + * RCU torture priority-boost testing. Runs one real-time thread per + * CPU for moderate bursts, repeatedly starting grace periods and waiting + * for them to complete. If a given grace period takes too long, we assume + * that priority inversion has occurred. + */ + +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 gp_state, unsigned long *start) +{ + int cpu; + static int dbg_done; + unsigned long end = jiffies; + bool gp_done; + unsigned long j; + static unsigned long last_persist; + unsigned long lp; + unsigned long mininterval = test_boost_duration * HZ - HZ / 2; + + if (end - *start > mininterval) { + // Recheck after checking time to avoid false positives. + smp_mb(); // Time check before grace-period check. + if (cur_ops->poll_gp_state(gp_state)) + return false; // passed, though perhaps just barely + if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) { + // At most one persisted message per boost test. + j = jiffies; + lp = READ_ONCE(last_persist); + if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp) + pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu); + return false; // passed on a technicality + } + VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); + n_rcu_torture_boost_failure++; + if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) { + pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n", + current->rt_priority, gp_state, end - *start); + cur_ops->gp_kthread_dbg(); + // Recheck after print to flag grace period ending during splat. + gp_done = cur_ops->poll_gp_state(gp_state); + pr_info("Boost inversion: GP %lu %s.\n", gp_state, + gp_done ? "ended already" : "still pending"); + + } + + return true; // failed + } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) { + *start = jiffies; + } + + return false; // passed +} + +static int rcu_torture_boost(void *arg) +{ + unsigned long endtime; + unsigned long gp_state; + unsigned long gp_state_time; + unsigned long oldstarttime; + + VERBOSE_TOROUT_STRING("rcu_torture_boost started"); + + /* Set real-time priority. */ + sched_set_fifo_low(current); + + /* Each pass through the following loop does one boost-test cycle. */ + do { + bool failed = false; // Test failed already in this test interval + bool gp_initiated = false; + + if (kthread_should_stop()) + goto checkwait; + + /* Wait for the next test interval. */ + oldstarttime = READ_ONCE(boost_starttime); + while (time_before(jiffies, oldstarttime)) { + schedule_timeout_interruptible(oldstarttime - jiffies); + if (stutter_wait("rcu_torture_boost")) + sched_set_fifo_low(current); + if (torture_must_stop()) + goto checkwait; + } + + // Do one boost-test interval. + endtime = oldstarttime + test_boost_duration * HZ; + while (time_before(jiffies, endtime)) { + // Has current GP gone too long? + if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) + failed = rcu_torture_boost_failed(gp_state, &gp_state_time); + // If we don't have a grace period in flight, start one. + if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) { + gp_state = cur_ops->start_gp_poll(); + gp_initiated = true; + gp_state_time = jiffies; + } + if (stutter_wait("rcu_torture_boost")) { + sched_set_fifo_low(current); + // If the grace period already ended, + // we don't know when that happened, so + // start over. + if (cur_ops->poll_gp_state(gp_state)) + gp_initiated = false; + } + if (torture_must_stop()) + goto checkwait; + } + + // In case the grace period extended beyond the end of the loop. + if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) + rcu_torture_boost_failed(gp_state, &gp_state_time); + + /* + * 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 == READ_ONCE(boost_starttime) && !kthread_should_stop()) { + if (mutex_trylock(&boost_mutex)) { + if (oldstarttime == boost_starttime) { + WRITE_ONCE(boost_starttime, + jiffies + test_boost_interval * HZ); + n_rcu_torture_boosts++; + } + mutex_unlock(&boost_mutex); + break; + } + schedule_timeout_uninterruptible(1); + } + + /* Go do the stutter. */ +checkwait: if (stutter_wait("rcu_torture_boost")) + sched_set_fifo_low(current); + } while (!torture_must_stop()); + + /* Clean up and exit. */ + while (!kthread_should_stop()) { + torture_shutdown_absorb("rcu_torture_boost"); + schedule_timeout_uninterruptible(1); + } + 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; + int oldnice = task_nice(current); + + 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; + } + if (stutter_wait("rcu_torture_fqs")) + sched_set_normal(current, oldnice); + } while (!torture_must_stop()); + torture_kthread_stopping("rcu_torture_fqs"); + return 0; +} + +// Used by writers to randomly choose from the available grace-period primitives. +static int synctype[ARRAY_SIZE(rcu_torture_writer_state_names)] = { }; +static int nsynctypes; + +/* + * Determine which grace-period primitives are available. + */ +static void rcu_torture_write_types(void) +{ + bool gp_cond1 = gp_cond, gp_cond_exp1 = gp_cond_exp, gp_cond_full1 = gp_cond_full; + bool gp_cond_exp_full1 = gp_cond_exp_full, gp_exp1 = gp_exp, gp_poll_exp1 = gp_poll_exp; + bool gp_poll_exp_full1 = gp_poll_exp_full, gp_normal1 = gp_normal, gp_poll1 = gp_poll; + bool gp_poll_full1 = gp_poll_full, gp_sync1 = gp_sync; + + /* Initialize synctype[] array. If none set, take default. */ + if (!gp_cond1 && + !gp_cond_exp1 && + !gp_cond_full1 && + !gp_cond_exp_full1 && + !gp_exp1 && + !gp_poll_exp1 && + !gp_poll_exp_full1 && + !gp_normal1 && + !gp_poll1 && + !gp_poll_full1 && + !gp_sync1) { + gp_cond1 = true; + gp_cond_exp1 = true; + gp_cond_full1 = true; + gp_cond_exp_full1 = true; + gp_exp1 = true; + gp_poll_exp1 = true; + gp_poll_exp_full1 = true; + gp_normal1 = true; + gp_poll1 = true; + gp_poll_full1 = true; + gp_sync1 = true; + } + if (gp_cond1 && cur_ops->get_gp_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_gp_state || !cur_ops->cond_sync)) { + pr_alert("%s: gp_cond without primitives.\n", __func__); + } + if (gp_cond_exp1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp) { + synctype[nsynctypes++] = RTWS_COND_GET_EXP; + pr_info("%s: Testing conditional expedited GPs.\n", __func__); + } else if (gp_cond_exp && (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp)) { + pr_alert("%s: gp_cond_exp without primitives.\n", __func__); + } + if (gp_cond_full1 && cur_ops->get_gp_state && cur_ops->cond_sync_full) { + synctype[nsynctypes++] = RTWS_COND_GET_FULL; + pr_info("%s: Testing conditional full-state GPs.\n", __func__); + } else if (gp_cond_full && (!cur_ops->get_gp_state || !cur_ops->cond_sync_full)) { + pr_alert("%s: gp_cond_full without primitives.\n", __func__); + } + if (gp_cond_exp_full1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp_full) { + synctype[nsynctypes++] = RTWS_COND_GET_EXP_FULL; + pr_info("%s: Testing conditional full-state expedited GPs.\n", __func__); + } else if (gp_cond_exp_full && + (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp_full)) { + pr_alert("%s: gp_cond_exp_full 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_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) { + synctype[nsynctypes++] = RTWS_POLL_GET; + pr_info("%s: Testing polling GPs.\n", __func__); + } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) { + pr_alert("%s: gp_poll without primitives.\n", __func__); + } + if (gp_poll_full1 && cur_ops->start_gp_poll_full && cur_ops->poll_gp_state_full) { + synctype[nsynctypes++] = RTWS_POLL_GET_FULL; + pr_info("%s: Testing polling full-state GPs.\n", __func__); + } else if (gp_poll_full && (!cur_ops->start_gp_poll_full || !cur_ops->poll_gp_state_full)) { + pr_alert("%s: gp_poll_full without primitives.\n", __func__); + } + if (gp_poll_exp1 && cur_ops->start_gp_poll_exp && cur_ops->poll_gp_state_exp) { + synctype[nsynctypes++] = RTWS_POLL_GET_EXP; + pr_info("%s: Testing polling expedited GPs.\n", __func__); + } else if (gp_poll_exp && (!cur_ops->start_gp_poll_exp || !cur_ops->poll_gp_state_exp)) { + pr_alert("%s: gp_poll_exp without primitives.\n", __func__); + } + if (gp_poll_exp_full1 && cur_ops->start_gp_poll_exp_full && cur_ops->poll_gp_state_full) { + synctype[nsynctypes++] = RTWS_POLL_GET_EXP_FULL; + pr_info("%s: Testing polling full-state expedited GPs.\n", __func__); + } else if (gp_poll_exp_full && + (!cur_ops->start_gp_poll_exp_full || !cur_ops->poll_gp_state_full)) { + pr_alert("%s: gp_poll_exp_full 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__); + } +} + +/* + * Do the specified rcu_torture_writer() synchronous grace period, + * while also testing out the polled APIs. Note well that the single-CPU + * grace-period optimizations must be accounted for. + */ +static void do_rtws_sync(struct torture_random_state *trsp, void (*sync)(void)) +{ + unsigned long cookie; + struct rcu_gp_oldstate cookie_full; + bool dopoll; + bool dopoll_full; + unsigned long r = torture_random(trsp); + + dopoll = cur_ops->get_gp_state && cur_ops->poll_gp_state && !(r & 0x300); + dopoll_full = cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full && !(r & 0xc00); + if (dopoll || dopoll_full) + cpus_read_lock(); + if (dopoll) + cookie = cur_ops->get_gp_state(); + if (dopoll_full) + cur_ops->get_gp_state_full(&cookie_full); + if (cur_ops->poll_need_2gp && cur_ops->poll_need_2gp(dopoll, dopoll_full)) + sync(); + sync(); + WARN_ONCE(dopoll && !cur_ops->poll_gp_state(cookie), + "%s: Cookie check 3 failed %pS() online %*pbl.", + __func__, sync, cpumask_pr_args(cpu_online_mask)); + WARN_ONCE(dopoll_full && !cur_ops->poll_gp_state_full(&cookie_full), + "%s: Cookie check 4 failed %pS() online %*pbl", + __func__, sync, cpumask_pr_args(cpu_online_mask)); + if (dopoll || dopoll_full) + cpus_read_unlock(); +} + +/* + * 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 boot_ended; + bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); + unsigned long cookie; + struct rcu_gp_oldstate cookie_full; + int expediting = 0; + unsigned long gp_snap; + struct rcu_gp_oldstate gp_snap_full; + int i; + int idx; + int oldnice = task_nice(current); + struct rcu_torture *rp; + struct rcu_torture *old_rp; + static DEFINE_TORTURE_RANDOM(rand); + bool stutter_waited; + + 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); + if (WARN_ONCE(nsynctypes == 0, + "%s: No update-side primitives.\n", __func__)) { + /* + * 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"); + return 0; + } + + do { + rcu_torture_writer_state = RTWS_FIXED_DELAY; + torture_hrtimeout_us(500, 1000, &rand); + 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); + + // Make sure readers block polled grace periods. + if (cur_ops->get_gp_state && cur_ops->poll_gp_state) { + idx = cur_ops->readlock(); + cookie = cur_ops->get_gp_state(); + WARN_ONCE(cur_ops->poll_gp_state(cookie), + "%s: Cookie check 1 failed %s(%d) %lu->%lu\n", + __func__, + rcu_torture_writer_state_getname(), + rcu_torture_writer_state, + cookie, cur_ops->get_gp_state()); + if (cur_ops->get_gp_completed) { + cookie = cur_ops->get_gp_completed(); + WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie)); + } + cur_ops->readunlock(idx); + } + if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) { + idx = cur_ops->readlock(); + cur_ops->get_gp_state_full(&cookie_full); + WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full), + "%s: Cookie check 5 failed %s(%d) online %*pbl\n", + __func__, + rcu_torture_writer_state_getname(), + rcu_torture_writer_state, + cpumask_pr_args(cpu_online_mask)); + if (cur_ops->get_gp_completed_full) { + cur_ops->get_gp_completed_full(&cookie_full); + WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full)); + } + cur_ops->readunlock(idx); + } + 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; + do_rtws_sync(&rand, 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_gp_state(); + torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); + rcu_torture_writer_state = RTWS_COND_SYNC; + cur_ops->cond_sync(gp_snap); + rcu_torture_pipe_update(old_rp); + break; + case RTWS_COND_GET_EXP: + rcu_torture_writer_state = RTWS_COND_GET_EXP; + gp_snap = cur_ops->get_gp_state_exp(); + torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); + rcu_torture_writer_state = RTWS_COND_SYNC_EXP; + cur_ops->cond_sync_exp(gp_snap); + rcu_torture_pipe_update(old_rp); + break; + case RTWS_COND_GET_FULL: + rcu_torture_writer_state = RTWS_COND_GET_FULL; + cur_ops->get_gp_state_full(&gp_snap_full); + torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); + rcu_torture_writer_state = RTWS_COND_SYNC_FULL; + cur_ops->cond_sync_full(&gp_snap_full); + rcu_torture_pipe_update(old_rp); + break; + case RTWS_COND_GET_EXP_FULL: + rcu_torture_writer_state = RTWS_COND_GET_EXP_FULL; + cur_ops->get_gp_state_full(&gp_snap_full); + torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); + rcu_torture_writer_state = RTWS_COND_SYNC_EXP_FULL; + cur_ops->cond_sync_exp_full(&gp_snap_full); + rcu_torture_pipe_update(old_rp); + break; + case RTWS_POLL_GET: + rcu_torture_writer_state = RTWS_POLL_GET; + gp_snap = cur_ops->start_gp_poll(); + rcu_torture_writer_state = RTWS_POLL_WAIT; + while (!cur_ops->poll_gp_state(gp_snap)) + torture_hrtimeout_jiffies(torture_random(&rand) % 16, + &rand); + rcu_torture_pipe_update(old_rp); + break; + case RTWS_POLL_GET_FULL: + rcu_torture_writer_state = RTWS_POLL_GET_FULL; + cur_ops->start_gp_poll_full(&gp_snap_full); + rcu_torture_writer_state = RTWS_POLL_WAIT_FULL; + while (!cur_ops->poll_gp_state_full(&gp_snap_full)) + torture_hrtimeout_jiffies(torture_random(&rand) % 16, + &rand); + rcu_torture_pipe_update(old_rp); + break; + case RTWS_POLL_GET_EXP: + rcu_torture_writer_state = RTWS_POLL_GET_EXP; + gp_snap = cur_ops->start_gp_poll_exp(); + rcu_torture_writer_state = RTWS_POLL_WAIT_EXP; + while (!cur_ops->poll_gp_state_exp(gp_snap)) + torture_hrtimeout_jiffies(torture_random(&rand) % 16, + &rand); + rcu_torture_pipe_update(old_rp); + break; + case RTWS_POLL_GET_EXP_FULL: + rcu_torture_writer_state = RTWS_POLL_GET_EXP_FULL; + cur_ops->start_gp_poll_exp_full(&gp_snap_full); + rcu_torture_writer_state = RTWS_POLL_WAIT_EXP_FULL; + while (!cur_ops->poll_gp_state_full(&gp_snap_full)) + torture_hrtimeout_jiffies(torture_random(&rand) % 16, + &rand); + rcu_torture_pipe_update(old_rp); + break; + case RTWS_SYNC: + rcu_torture_writer_state = RTWS_SYNC; + do_rtws_sync(&rand, 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; + boot_ended = rcu_inkernel_boot_has_ended(); + stutter_waited = stutter_wait("rcu_torture_writer"); + if (stutter_waited && + !atomic_read(&rcu_fwd_cb_nodelay) && + !cur_ops->slow_gps && + !torture_must_stop() && + boot_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]) { + tracing_off(); + WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count); + rcu_ftrace_dump(DUMP_ALL); + } + if (stutter_waited) + sched_set_normal(current, oldnice); + } 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) +{ + unsigned long gp_snap; + struct rcu_gp_oldstate gp_snap_full; + DEFINE_TORTURE_RANDOM(rand); + + VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); + set_user_nice(current, MAX_NICE); + + if (WARN_ONCE(nsynctypes == 0, + "%s: No update-side primitives.\n", __func__)) { + /* + * No updates primitives, so don't try updating. + * The resulting test won't be testing much, hence the + * above WARN_ONCE(). + */ + torture_kthread_stopping("rcu_torture_fakewriter"); + return 0; + } + + do { + torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand); + if (cur_ops->cb_barrier != NULL && + torture_random(&rand) % (nfakewriters * 8) == 0) { + cur_ops->cb_barrier(); + } else { + switch (synctype[torture_random(&rand) % nsynctypes]) { + case RTWS_DEF_FREE: + break; + case RTWS_EXP_SYNC: + cur_ops->exp_sync(); + break; + case RTWS_COND_GET: + gp_snap = cur_ops->get_gp_state(); + torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); + cur_ops->cond_sync(gp_snap); + break; + case RTWS_COND_GET_EXP: + gp_snap = cur_ops->get_gp_state_exp(); + torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); + cur_ops->cond_sync_exp(gp_snap); + break; + case RTWS_COND_GET_FULL: + cur_ops->get_gp_state_full(&gp_snap_full); + torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); + cur_ops->cond_sync_full(&gp_snap_full); + break; + case RTWS_COND_GET_EXP_FULL: + cur_ops->get_gp_state_full(&gp_snap_full); + torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); + cur_ops->cond_sync_exp_full(&gp_snap_full); + break; + case RTWS_POLL_GET: + gp_snap = cur_ops->start_gp_poll(); + while (!cur_ops->poll_gp_state(gp_snap)) { + torture_hrtimeout_jiffies(torture_random(&rand) % 16, + &rand); + } + break; + case RTWS_POLL_GET_FULL: + cur_ops->start_gp_poll_full(&gp_snap_full); + while (!cur_ops->poll_gp_state_full(&gp_snap_full)) { + torture_hrtimeout_jiffies(torture_random(&rand) % 16, + &rand); + } + break; + case RTWS_POLL_GET_EXP: + gp_snap = cur_ops->start_gp_poll_exp(); + while (!cur_ops->poll_gp_state_exp(gp_snap)) { + torture_hrtimeout_jiffies(torture_random(&rand) % 16, + &rand); + } + break; + case RTWS_POLL_GET_EXP_FULL: + cur_ops->start_gp_poll_exp_full(&gp_snap_full); + while (!cur_ops->poll_gp_state_full(&gp_snap_full)) { + torture_hrtimeout_jiffies(torture_random(&rand) % 16, + &rand); + } + break; + case RTWS_SYNC: + cur_ops->sync(); + break; + default: + WARN_ON_ONCE(1); + break; + } + } + 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); +} + +// Set up and carry out testing of RCU's global memory ordering +static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp, + struct torture_random_state *trsp) +{ + unsigned long loops; + int noc = torture_num_online_cpus(); + int rdrchked; + int rdrchker; + struct rcu_torture_reader_check *rtrcp; // Me. + struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking. + struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked. + struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me. + + if (myid < 0) + return; // Don't try this from timer handlers. + + // Increment my counter. + rtrcp = &rcu_torture_reader_mbchk[myid]; + WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1); + + // Attempt to assign someone else some checking work. + rdrchked = torture_random(trsp) % nrealreaders; + rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; + rdrchker = torture_random(trsp) % nrealreaders; + rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker]; + if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker && + smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below. + !READ_ONCE(rtp->rtort_chkp) && + !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below. + rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops); + WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0); + rtrcp->rtc_chkrdr = rdrchked; + WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends. + if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) || + cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp)) + (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out. + } + + // If assigned some completed work, do it! + rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner); + if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready)) + return; // No work or work not yet ready. + rdrchked = rtrcp_assigner->rtc_chkrdr; + if (WARN_ON_ONCE(rdrchked < 0)) + return; + rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; + loops = READ_ONCE(rtrcp_chked->rtc_myloops); + atomic_inc(&n_rcu_torture_mbchk_tries); + if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops)) + atomic_inc(&n_rcu_torture_mbchk_fail); + rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2; + rtrcp_assigner->rtc_ready = 0; + smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work. + smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign. +} + +/* + * 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 idxnew1 = -1; + int idxnew2 = -1; + int idxold1 = *readstate; + int idxold2 = idxold1; + int statesnew = ~*readstate & newstate; + int statesold = *readstate & ~newstate; + + WARN_ON_ONCE(idxold2 < 0); + WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 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_1) + idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1; + if (statesnew & RCUTORTURE_RDR_RCU_2) + idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2; + + /* + * 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_2) { + cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1); + WARN_ON_ONCE(idxnew2 != -1); + idxold2 = 0; + } + if (statesold & RCUTORTURE_RDR_RCU_1) { + bool lockit; + + lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff); + if (lockit) + raw_spin_lock_irqsave(¤t->pi_lock, flags); + cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1); + WARN_ON_ONCE(idxnew1 != -1); + idxold1 = 0; + 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 (idxnew1 == -1) + idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1; + WARN_ON_ONCE(idxnew1 < 0); + if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1)) + pr_info("Unexpected idxnew1 value of %#x\n", idxnew1); + if (idxnew2 == -1) + idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2; + WARN_ON_ONCE(idxnew2 < 0); + WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1); + *readstate = idxnew1 | idxnew2 | newstate; + WARN_ON_ONCE(*readstate < 0); + if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1)) + pr_info("Unexpected idxnew2 value of %#x\n", idxnew2); +} + +/* 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_1 | RCUTORTURE_RDR_RCU_2; + 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_1); + /* 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 have nested RCU reader without outer RCU reader. + if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) { + if (oldmask & RCUTORTURE_RDR_RCU_1) + mask &= ~RCUTORTURE_RDR_RCU_2; + else + mask |= RCUTORTURE_RDR_RCU_1; + } + + /* + * 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_1; +} + +/* + * 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, long myid) +{ + bool checkpolling = !(torture_random(trsp) & 0xfff); + unsigned long cookie; + struct rcu_gp_oldstate cookie_full; + 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++); + if (checkpolling) { + if (cur_ops->get_gp_state && cur_ops->poll_gp_state) + cookie = cur_ops->get_gp_state(); + if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) + cur_ops->get_gp_state_full(&cookie_full); + } + started = cur_ops->get_gp_seq(); + ts = rcu_trace_clock_local(); + p = rcu_dereference_check(rcu_torture_current, + !cur_ops->readlock_held || cur_ops->readlock_held()); + 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); + rcu_torture_reader_do_mbchk(myid, p, trsp); + 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(); + if (checkpolling) { + if (cur_ops->get_gp_state && cur_ops->poll_gp_state) + WARN_ONCE(cur_ops->poll_gp_state(cookie), + "%s: Cookie check 2 failed %s(%d) %lu->%lu\n", + __func__, + rcu_torture_writer_state_getname(), + rcu_torture_writer_state, + cookie, cur_ops->get_gp_state()); + if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) + WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full), + "%s: Cookie check 6 failed %s(%d) online %*pbl\n", + __func__, + rcu_torture_writer_state_getname(), + rcu_torture_writer_state, + cpumask_pr_args(cpu_online_mask)); + } + rcutorture_one_extend(&readstate, 0, trsp, rtrsp); + WARN_ON_ONCE(readstate); + // 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), -1); + + /* 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, myid) && !torture_must_stop()) + schedule_timeout_interruptible(HZ); + if (time_after(jiffies, lastsleep) && !torture_must_stop()) { + torture_hrtimeout_us(500, 1000, &rand); + lastsleep = jiffies + 10; + } + while (torture_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; +} + +/* + * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to + * increase race probabilities and fuzzes the interval between toggling. + */ +static int rcu_nocb_toggle(void *arg) +{ + int cpu; + int maxcpu = -1; + int oldnice = task_nice(current); + long r; + DEFINE_TORTURE_RANDOM(rand); + ktime_t toggle_delay; + unsigned long toggle_fuzz; + ktime_t toggle_interval = ms_to_ktime(nocbs_toggle); + + VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started"); + while (!rcu_inkernel_boot_has_ended()) + schedule_timeout_interruptible(HZ / 10); + for_each_online_cpu(cpu) + maxcpu = cpu; + WARN_ON(maxcpu < 0); + if (toggle_interval > ULONG_MAX) + toggle_fuzz = ULONG_MAX >> 3; + else + toggle_fuzz = toggle_interval >> 3; + if (toggle_fuzz <= 0) + toggle_fuzz = NSEC_PER_USEC; + do { + r = torture_random(&rand); + cpu = (r >> 4) % (maxcpu + 1); + if (r & 0x1) { + rcu_nocb_cpu_offload(cpu); + atomic_long_inc(&n_nocb_offload); + } else { + rcu_nocb_cpu_deoffload(cpu); + atomic_long_inc(&n_nocb_deoffload); + } + toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval; + set_current_state(TASK_INTERRUPTIBLE); + schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL); + if (stutter_wait("rcu_nocb_toggle")) + sched_set_normal(current, oldnice); + } while (!torture_must_stop()); + torture_kthread_stopping("rcu_nocb_toggle"); + 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; 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 rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ", + atomic_read(&n_rcu_torture_mberror), + atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries), + 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 ", data_race(n_read_exits)); // Statistic. + pr_cont("nocb-toggles: %ld:%ld\n", + atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload)); + + pr_alert("%s%s ", torture_type, TORTURE_FLAG); + if (atomic_read(&n_rcu_torture_mberror) || + atomic_read(&n_rcu_torture_mbchk_fail) || + 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(atomic_read(&n_rcu_torture_mbchk_fail)); + 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); // boost failed (TIMER_SOFTIRQ RT prio?) + 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 %#x cpu %d\n", + rcu_torture_writer_state_getname(), + rcu_torture_writer_state, gp_seq, flags, + wtp == NULL ? ~0U : wtp->__state, + wtp == NULL ? -1 : (int)task_cpu(wtp)); + if (!splatted && wtp) { + sched_show_task(wtp); + splatted = true; + } + if (cur_ops->gp_kthread_dbg) + cur_ops->gp_kthread_dbg(); + 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; +} + +/* Test mem_dump_obj() and friends. */ +static void rcu_torture_mem_dump_obj(void) +{ + struct rcu_head *rhp; + struct kmem_cache *kcp; + static int z; + + kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL); + if (WARN_ON_ONCE(!kcp)) + return; + rhp = kmem_cache_alloc(kcp, GFP_KERNEL); + if (WARN_ON_ONCE(!rhp)) { + kmem_cache_destroy(kcp); + return; + } + pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z); + pr_alert("mem_dump_obj(ZERO_SIZE_PTR):"); + mem_dump_obj(ZERO_SIZE_PTR); + pr_alert("mem_dump_obj(NULL):"); + mem_dump_obj(NULL); + pr_alert("mem_dump_obj(%px):", &rhp); + mem_dump_obj(&rhp); + pr_alert("mem_dump_obj(%px):", rhp); + mem_dump_obj(rhp); + pr_alert("mem_dump_obj(%px):", &rhp->func); + mem_dump_obj(&rhp->func); + pr_alert("mem_dump_obj(%px):", &z); + mem_dump_obj(&z); + kmem_cache_free(kcp, rhp); + kmem_cache_destroy(kcp); + rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); + if (WARN_ON_ONCE(!rhp)) + return; + pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); + pr_alert("mem_dump_obj(kmalloc %px):", rhp); + mem_dump_obj(rhp); + pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func); + mem_dump_obj(&rhp->func); + kfree(rhp); + rhp = vmalloc(4096); + if (WARN_ON_ONCE(!rhp)) + return; + pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); + pr_alert("mem_dump_obj(vmalloc %px):", rhp); + mem_dump_obj(rhp); + pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func); + mem_dump_obj(&rhp->func); + vfree(rhp); +} + +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 " + "nocbs_nthreads=%d nocbs_toggle=%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, + nocbs_nthreads, nocbs_toggle); +} + +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. */ + + // Testing RCU priority boosting requires rcutorture do + // some serious abuse. Counter this by running ksoftirqd + // at higher priority. + if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) { + struct sched_param sp; + struct task_struct *t; + + t = per_cpu(ksoftirqd, cpu); + WARN_ON_ONCE(!t); + sp.sched_priority = 2; + sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); + } + + /* 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_run_on_cpu(rcu_torture_boost, NULL, + cpu, "rcu_torture_boost_%u"); + 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; + } + 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("%s start on CPU %d.\n", + __func__, raw_smp_processor_id()); + while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), + stop_at)) + if (stall_cpu_block) { +#ifdef CONFIG_PREEMPTION + preempt_schedule(); +#else + schedule_timeout_uninterruptible(HZ); +#endif + } else if (stall_no_softlockup) { + touch_softlockup_watchdog(); + } + if (stall_cpu_irqsoff) + local_irq_enable(); + else if (!stall_cpu_block) + preempt_enable(); + cur_ops->readunlock(idx); + } + pr_alert("%s end.\n", __func__); + 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; + int rcu_fwd_id; +}; + +static DEFINE_MUTEX(rcu_fwd_mutex); +static struct rcu_fwd *rcu_fwds; +static unsigned long rcu_fwd_seq; +static atomic_long_t rcu_fwd_max_cbs; +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 %d (duration %lu jiffies):", + __func__, rfp->rcu_fwd_id, 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); + + pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); + if (!cur_ops->sync) + return; // Cannot do need_resched() forward progress testing without ->sync. + if (cur_ops->call && cur_ops->cb_barrier) { + init_rcu_head_on_stack(&fcs.rh); + selfpropcb = true; + } + + /* Tight loop containing cond_resched(). */ + atomic_inc(&rcu_fwd_cb_nodelay); + 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: %d Duration %ld cver %ld gps %ld\n", __func__, + rfp->rcu_fwd_id, dur, cver, gps); + } + if (selfpropcb) { + WRITE_ONCE(fcs.stop, 1); + cur_ops->sync(); /* Wait for running CB to complete. */ + pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); + 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. */ + atomic_dec(&rcu_fwd_cb_nodelay); +} + +/* 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; + + pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); + 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. */ + atomic_inc(&rcu_fwd_cb_nodelay); + 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 if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) { + 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; + } else { + rfcp = NULL; + } + if (rfcp) + 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); + pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); + 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); + atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs); + mutex_lock(&rcu_fwd_mutex); // Serialize histograms. + rcu_torture_fwd_cb_hist(rfp); + mutex_unlock(&rcu_fwd_mutex); + } + schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ + tick_dep_clear_task(current, TICK_DEP_BIT_RCU); + atomic_dec(&rcu_fwd_cb_nodelay); +} + + +/* + * 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) +{ + int i; + long ncbs; + 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__); + for (i = 0; i < fwd_progress; i++) { + rcu_torture_fwd_cb_hist(&rfp[i]); + rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2); + } + WRITE_ONCE(rcu_fwd_emergency_stop, true); + smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ + ncbs = 0; + for (i = 0; i < fwd_progress; i++) + ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); + pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); + cur_ops->cb_barrier(); + ncbs = 0; + for (i = 0; i < fwd_progress; i++) + ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); + pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); + cur_ops->cb_barrier(); + ncbs = 0; + for (i = 0; i < fwd_progress; i++) + ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); + pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); + 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) +{ + bool firsttime = true; + long max_cbs; + int oldnice = task_nice(current); + unsigned long oldseq = READ_ONCE(rcu_fwd_seq); + 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 { + if (!rfp->rcu_fwd_id) { + schedule_timeout_interruptible(fwd_progress_holdoff * HZ); + WRITE_ONCE(rcu_fwd_emergency_stop, false); + if (!firsttime) { + max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0); + pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs); + } + firsttime = false; + WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1); + } else { + while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop()) + schedule_timeout_interruptible(1); + oldseq = READ_ONCE(rcu_fwd_seq); + } + pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); + if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id) + rcu_torture_fwd_prog_cr(rfp); + if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) && + (!IS_ENABLED(CONFIG_TINY_RCU) || + (rcu_inkernel_boot_has_ended() && + torture_num_online_cpus() > rfp->rcu_fwd_id))) + rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries); + + /* Avoid slow periods, better to test when busy. */ + if (stutter_wait("rcu_torture_fwd_prog")) + sched_set_normal(current, oldnice); + } while (!torture_must_stop()); + /* Short runs might not contain a valid forward-progress attempt. */ + if (!rfp->rcu_fwd_id) { + 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) +{ + int i; + int ret = 0; + struct rcu_fwd *rfp; + + if (!fwd_progress) + return 0; /* Not requested, so don't do it. */ + if (fwd_progress >= nr_cpu_ids) { + VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n"); + fwd_progress = nr_cpu_ids; + } else if (fwd_progress < 0) { + fwd_progress = nr_cpu_ids; + } + if ((!cur_ops->sync && !cur_ops->call) || + (!cur_ops->cbflood_max && (!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"); + fwd_progress = 0; + return 0; + } + if (stall_cpu > 0) { + VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); + fwd_progress = 0; + if (IS_MODULE(CONFIG_RCU_TORTURE_TEST)) + 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 = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL); + fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL); + if (!rfp || !fwd_prog_tasks) { + kfree(rfp); + kfree(fwd_prog_tasks); + fwd_prog_tasks = NULL; + fwd_progress = 0; + return -ENOMEM; + } + for (i = 0; i < fwd_progress; i++) { + spin_lock_init(&rfp[i].rcu_fwd_lock); + rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head; + rfp[i].rcu_fwd_id = i; + } + mutex_lock(&rcu_fwd_mutex); + rcu_fwds = rfp; + mutex_unlock(&rcu_fwd_mutex); + register_oom_notifier(&rcutorture_oom_nb); + for (i = 0; i < fwd_progress; i++) { + ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]); + if (ret) { + fwd_progress = i; + return ret; + } + } + return 0; +} + +static void rcu_torture_fwd_prog_cleanup(void) +{ + int i; + struct rcu_fwd *rfp; + + if (!rcu_fwds || !fwd_prog_tasks) + return; + for (i = 0; i < fwd_progress; i++) + torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]); + unregister_oom_notifier(&rcutorture_oom_nb); + mutex_lock(&rcu_fwd_mutex); + rfp = rcu_fwds; + rcu_fwds = NULL; + mutex_unlock(&rcu_fwd_mutex); + kfree(rfp); + kfree(fwd_prog_tasks); + fwd_prog_tasks = NULL; +} + +/* 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; + if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state) + 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, -1); + return 0; +} + +// Parent kthread which creates and destroys read-exit child kthreads. +static int rcu_torture_read_exit(void *unused) +{ + 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 { + VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode"); + for (i = 0; i < read_exit_burst; i++) { + if (READ_ONCE(read_exit_child_stop)) + break; + stutter_wait("rcu_torture_read_exit"); + // Spawn child. + tsp = kthread_run(rcu_torture_read_exit_child, + &trs, "%s", "rcu_torture_read_exit_child"); + if (IS_ERR(tsp)) { + TOROUT_ERRSTRING("out of memory"); + errexit = true; + break; + } + cond_resched(); + kthread_stop(tsp); + n_read_exits++; + } + VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode"); + rcu_barrier(); // Wait for task_struct free, avoid OOM. + i = 0; + for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++) + schedule_timeout_uninterruptible(HZ); + } 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 0; + 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) { + pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); + cur_ops->cb_barrier(); + } + rcu_gp_slow_unregister(NULL); + return; + } + if (!cur_ops) { + torture_cleanup_end(); + rcu_gp_slow_unregister(NULL); + return; + } + + if (cur_ops->gp_kthread_dbg) + cur_ops->gp_kthread_dbg(); + 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 (nocb_tasks) { + for (i = 0; i < nrealnocbers; i++) + torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]); + kfree(nocb_tasks); + nocb_tasks = NULL; + } + + if (reader_tasks) { + for (i = 0; i < nrealreaders; i++) + torture_stop_kthread(rcu_torture_reader, + reader_tasks[i]); + kfree(reader_tasks); + reader_tasks = NULL; + } + kfree(rcu_torture_reader_mbchk); + rcu_torture_reader_mbchk = NULL; + + 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() && rcutor_hp >= 0) + 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) { + pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); + cur_ops->cb_barrier(); + } + if (cur_ops->cleanup != NULL) + cur_ops->cleanup(); + + rcu_torture_mem_dump_obj(); + + 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(); + rcu_gp_slow_unregister(&rcu_fwd_cb_nodelay); +} + +#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; + struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); + + 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. */ + if (rhp) { + call_rcu(rhp, rcu_torture_leak_cb); + call_rcu(rhp, rcu_torture_err_cb); /* Another 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); + kfree(rhp); +#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"); + 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_mbchk_fail, 0); + atomic_set(&n_rcu_torture_mbchk_tries, 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. */ + + rcu_torture_write_types(); + firsterr = torture_create_kthread(rcu_torture_writer, NULL, + writer_task); + if (torture_init_error(firsterr)) + goto unwind; + if (nfakewriters > 0) { + fakewriter_tasks = kcalloc(nfakewriters, + sizeof(fakewriter_tasks[0]), + GFP_KERNEL); + if (fakewriter_tasks == NULL) { + 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 (torture_init_error(firsterr)) + goto unwind; + } + reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), + GFP_KERNEL); + rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk), + GFP_KERNEL); + if (!reader_tasks || !rcu_torture_reader_mbchk) { + TOROUT_ERRSTRING("out of memory"); + firsterr = -ENOMEM; + goto unwind; + } + for (i = 0; i < nrealreaders; i++) { + rcu_torture_reader_mbchk[i].rtc_chkrdr = -1; + firsterr = torture_create_kthread(rcu_torture_reader, (void *)i, + reader_tasks[i]); + if (torture_init_error(firsterr)) + goto unwind; + } + nrealnocbers = nocbs_nthreads; + if (WARN_ON(nrealnocbers < 0)) + nrealnocbers = 1; + if (WARN_ON(nocbs_toggle < 0)) + nocbs_toggle = HZ; + if (nrealnocbers > 0) { + nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL); + if (nocb_tasks == NULL) { + TOROUT_ERRSTRING("out of memory"); + firsterr = -ENOMEM; + goto unwind; + } + } else { + nocb_tasks = NULL; + } + for (i = 0; i < nrealnocbers; i++) { + firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]); + if (torture_init_error(firsterr)) + goto unwind; + } + if (stat_interval > 0) { + firsterr = torture_create_kthread(rcu_torture_stats, NULL, + stats_task); + if (torture_init_error(firsterr)) + goto unwind; + } + if (test_no_idle_hz && shuffle_interval > 0) { + firsterr = torture_shuffle_init(shuffle_interval * HZ); + if (torture_init_error(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 (torture_init_error(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 (torture_init_error(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); + rcutor_hp = firsterr; + if (torture_init_error(firsterr)) + goto unwind; + } + shutdown_jiffies = jiffies + shutdown_secs * HZ; + firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); + if (torture_init_error(firsterr)) + goto unwind; + firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, + rcutorture_sync); + if (torture_init_error(firsterr)) + goto unwind; + firsterr = rcu_torture_stall_init(); + if (torture_init_error(firsterr)) + goto unwind; + firsterr = rcu_torture_fwd_prog_init(); + if (torture_init_error(firsterr)) + goto unwind; + firsterr = rcu_torture_barrier_init(); + if (torture_init_error(firsterr)) + goto unwind; + firsterr = rcu_torture_read_exit_init(); + if (torture_init_error(firsterr)) + goto unwind; + if (object_debug) + rcu_test_debug_objects(); + torture_init_end(); + rcu_gp_slow_register(&rcu_fwd_cb_nodelay); + return 0; + +unwind: + torture_init_end(); + rcu_torture_cleanup(); + if (shutdown_secs) { + WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); + kernel_power_off(); + } + return firsterr; +} + +module_init(rcu_torture_init); +module_exit(rcu_torture_cleanup); |