diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 97c497bdafac..237de62df194 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5524,7 +5524,42 @@ rcutorture.gp_cond= [KNL] Use conditional/asynchronous update-side - primitives, if available. + normal-grace-period primitives, if available. + + rcutorture.gp_cond_exp= [KNL] + Use conditional/asynchronous update-side + expedited-grace-period primitives, if available. + + rcutorture.gp_cond_full= [KNL] + Use conditional/asynchronous update-side + normal-grace-period primitives that also take + concurrent expedited grace periods into account, + if available. + + rcutorture.gp_cond_exp_full= [KNL] + Use conditional/asynchronous update-side + expedited-grace-period primitives that also take + concurrent normal grace periods into account, + if available. + + rcutorture.gp_cond_wi= [KNL] + Nominal wait interval for normal conditional + grace periods (specified by rcutorture's + gp_cond and gp_cond_full module parameters), + in microseconds. The actual wait interval will + be randomly selected to nanosecond granularity up + to this wait interval. Defaults to 16 jiffies, + for example, 16,000 microseconds on a system + with HZ=1000. + + rcutorture.gp_cond_wi_exp= [KNL] + Nominal wait interval for expedited conditional + grace periods (specified by rcutorture's + gp_cond_exp and gp_cond_exp_full module + parameters), in microseconds. The actual wait + interval will be randomly selected to nanosecond + granularity up to this wait interval. Defaults to + 128 microseconds. rcutorture.gp_exp= [KNL] Use expedited update-side primitives, if available. @@ -5533,6 +5568,43 @@ Use normal (non-expedited) asynchronous update-side primitives, if available. + rcutorture.gp_poll= [KNL] + Use polled update-side normal-grace-period + primitives, if available. + + rcutorture.gp_poll_exp= [KNL] + Use polled update-side expedited-grace-period + primitives, if available. + + rcutorture.gp_poll_full= [KNL] + Use polled update-side normal-grace-period + primitives that also take concurrent expedited + grace periods into account, if available. + + rcutorture.gp_poll_exp_full= [KNL] + Use polled update-side expedited-grace-period + primitives that also take concurrent normal + grace periods into account, if available. + + rcutorture.gp_poll_wi= [KNL] + Nominal wait interval for normal conditional + grace periods (specified by rcutorture's + gp_poll and gp_poll_full module parameters), + in microseconds. The actual wait interval will + be randomly selected to nanosecond granularity up + to this wait interval. Defaults to 16 jiffies, + for example, 16,000 microseconds on a system + with HZ=1000. + + rcutorture.gp_poll_wi_exp= [KNL] + Nominal wait interval for expedited conditional + grace periods (specified by rcutorture's + gp_poll_exp and gp_poll_exp_full module + parameters), in microseconds. The actual wait + interval will be randomly selected to nanosecond + granularity up to this wait interval. Defaults to + 128 microseconds. + rcutorture.gp_sync= [KNL] Use normal (non-expedited) synchronous update-side primitives, if available. If all @@ -5586,6 +5658,22 @@ Set time (jiffies) between CPU-hotplug operations, or zero to disable CPU-hotplug testing. + rcutorture.preempt_duration= [KNL] + Set duration (in milliseconds) of preemptions + by a high-priority FIFO real-time task. Set to + zero (the default) to disable. The CPUs to + preempt are selected randomly from the set that + are online at a given point in time. Races with + CPUs going offline are ignored, with that attempt + at preemption skipped. + + rcutorture.preempt_interval= [KNL] + Set interval (in milliseconds, defaulting to one + second) between preemptions by a high-priority + FIFO real-time task. This delay is mediated + by an hrtimer and is further fuzzed to avoid + inadvertent synchronizations. + rcutorture.read_exit_burst= [KNL] The number of times in a given read-then-exit episode that a set of read-then-exit kthreads diff --git a/MAINTAINERS b/MAINTAINERS index a97e2ba9a469..5161f7800b9b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13343,7 +13343,7 @@ L: linux-kernel@vger.kernel.org L: linux-arch@vger.kernel.org L: lkmm@lists.linux.dev S: Supported -T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev +T: git git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git rcu/dev F: Documentation/atomic_bitops.txt F: Documentation/atomic_t.txt F: Documentation/core-api/refcount-vs-atomic.rst @@ -19674,7 +19674,7 @@ R: Mathieu Desnoyers R: Lai Jiangshan L: rcu@vger.kernel.org S: Supported -T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev +T: git git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git rcu/dev F: tools/testing/selftests/rcutorture RDACM20 Camera Sensor @@ -19753,7 +19753,7 @@ R: Zqiang L: rcu@vger.kernel.org S: Supported W: http://www.rdrop.com/users/paulmck/RCU/ -T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev +T: git git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git rcu/dev F: Documentation/RCU/ F: include/linux/rcu* F: kernel/rcu/ @@ -21658,7 +21658,7 @@ R: Mathieu Desnoyers L: rcu@vger.kernel.org S: Supported W: http://www.rdrop.com/users/paulmck/RCU/ -T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev +T: git git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git rcu/dev F: include/linux/srcu*.h F: kernel/rcu/srcu*.c @@ -23789,7 +23789,7 @@ M: "Paul E. McKenney" M: Josh Triplett L: linux-kernel@vger.kernel.org S: Supported -T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev +T: git git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git rcu/dev F: Documentation/RCU/torture.rst F: kernel/locking/locktorture.c F: kernel/rcu/rcuscale.c diff --git a/include/linux/rcupdate_wait.h b/include/linux/rcupdate_wait.h index 303ab9bee155..f9bed3d3f78d 100644 --- a/include/linux/rcupdate_wait.h +++ b/include/linux/rcupdate_wait.h @@ -65,4 +65,15 @@ static inline void cond_resched_rcu(void) #endif } +// Has the current task blocked within its current RCU read-side +// critical section? +static inline bool has_rcu_reader_blocked(void) +{ +#ifdef CONFIG_PREEMPT_RCU + return !list_empty(¤t->rcu_node_entry); +#else + return false; +#endif +} + #endif /* _LINUX_SCHED_RCUPDATE_WAIT_H */ diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 08339eb8a01c..d7ba46e74f58 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -43,6 +43,12 @@ int init_srcu_struct(struct srcu_struct *ssp); #define __SRCU_DEP_MAP_INIT(srcu_name) #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ +/* Values for SRCU Tree srcu_data ->srcu_reader_flavor, but also used by rcutorture. */ +#define SRCU_READ_FLAVOR_NORMAL 0x1 // srcu_read_lock(). +#define SRCU_READ_FLAVOR_NMI 0x2 // srcu_read_lock_nmisafe(). +#define SRCU_READ_FLAVOR_LITE 0x4 // srcu_read_lock_lite(). +#define SRCU_READ_FLAVOR_ALL 0x7 // All of the above. + #ifdef CONFIG_TINY_SRCU #include #elif defined(CONFIG_TREE_SRCU) @@ -232,13 +238,14 @@ static inline int srcu_read_lock_held(const struct srcu_struct *ssp) * a mutex that is held elsewhere while calling synchronize_srcu() or * synchronize_srcu_expedited(). * - * The return value from srcu_read_lock() must be passed unaltered - * to the matching srcu_read_unlock(). Note that srcu_read_lock() and - * the matching srcu_read_unlock() must occur in the same context, for - * example, it is illegal to invoke srcu_read_unlock() in an irq handler - * if the matching srcu_read_lock() was invoked in process context. Or, - * for that matter to invoke srcu_read_unlock() from one task and the - * matching srcu_read_lock() from another. + * The return value from srcu_read_lock() is guaranteed to be + * non-negative. This value must be passed unaltered to the matching + * srcu_read_unlock(). Note that srcu_read_lock() and the matching + * srcu_read_unlock() must occur in the same context, for example, it is + * illegal to invoke srcu_read_unlock() in an irq handler if the matching + * srcu_read_lock() was invoked in process context. Or, for that matter to + * invoke srcu_read_unlock() from one task and the matching srcu_read_lock() + * from another. */ static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp) { diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h index 490aeecc6bb4..b17814c9d1c7 100644 --- a/include/linux/srcutree.h +++ b/include/linux/srcutree.h @@ -26,6 +26,7 @@ struct srcu_data { atomic_long_t srcu_lock_count[2]; /* Locks per CPU. */ atomic_long_t srcu_unlock_count[2]; /* Unlocks per CPU. */ int srcu_reader_flavor; /* Reader flavor for srcu_struct structure? */ + /* Values: SRCU_READ_FLAVOR_.* */ /* Update-side state. */ spinlock_t __private lock ____cacheline_internodealigned_in_smp; @@ -43,11 +44,6 @@ struct srcu_data { struct srcu_struct *ssp; }; -/* Values for ->srcu_reader_flavor. */ -#define SRCU_READ_FLAVOR_NORMAL 0x1 // srcu_read_lock(). -#define SRCU_READ_FLAVOR_NMI 0x2 // srcu_read_lock_nmisafe(). -#define SRCU_READ_FLAVOR_LITE 0x4 // srcu_read_lock_lite(). - /* * Node in SRCU combining tree, similar in function to rcu_data. */ @@ -258,7 +254,7 @@ static inline void srcu_check_read_flavor_lite(struct srcu_struct *ssp) if (likely(READ_ONCE(sdp->srcu_reader_flavor) & SRCU_READ_FLAVOR_LITE)) return; - // Note that the cmpxchg() in srcu_check_read_flavor() is fully ordered. + // Note that the cmpxchg() in __srcu_check_read_flavor() is fully ordered. __srcu_check_read_flavor(ssp, SRCU_READ_FLAVOR_LITE); } diff --git a/include/linux/torture.h b/include/linux/torture.h index c2e979f82f8d..0134e7221cae 100644 --- a/include/linux/torture.h +++ b/include/linux/torture.h @@ -130,7 +130,7 @@ void _torture_stop_kthread(char *m, struct task_struct **tp); #endif #if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST) || IS_ENABLED(CONFIG_LOCK_TORTURE_TEST) || IS_MODULE(CONFIG_LOCK_TORTURE_TEST) -long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask); +long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask, bool dowarn); #endif #endif /* __LINUX_TORTURE_H */ diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index de95ec07e477..cc33470f4de9 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -106,7 +106,7 @@ static const struct kernel_param_ops lt_bind_ops = { module_param_cb(bind_readers, <_bind_ops, &bind_readers, 0644); module_param_cb(bind_writers, <_bind_ops, &bind_writers, 0644); -long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask); +long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask, bool dowarn); static struct task_struct *stats_task; static struct task_struct **writer_tasks; @@ -1358,7 +1358,7 @@ static int __init lock_torture_init(void) if (torture_init_error(firsterr)) goto unwind; if (cpumask_nonempty(bind_writers)) - torture_sched_setaffinity(writer_tasks[i]->pid, bind_writers); + torture_sched_setaffinity(writer_tasks[i]->pid, bind_writers, true); create_reader: if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress)) @@ -1369,7 +1369,7 @@ static int __init lock_torture_init(void) if (torture_init_error(firsterr)) goto unwind; if (cpumask_nonempty(bind_readers)) - torture_sched_setaffinity(reader_tasks[j]->pid, bind_readers); + torture_sched_setaffinity(reader_tasks[j]->pid, bind_readers, true); } if (stat_interval > 0) { firsterr = torture_create_kthread(lock_torture_stats, NULL, diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug index 9b0b52e1836f..6af90510a1ca 100644 --- a/kernel/rcu/Kconfig.debug +++ b/kernel/rcu/Kconfig.debug @@ -53,6 +53,37 @@ config RCU_TORTURE_TEST Say M if you want the RCU torture tests to build as a module. Say N if you are unsure. +config RCU_TORTURE_TEST_CHK_RDR_STATE + tristate "Check rcutorture reader state" + depends on RCU_TORTURE_TEST + default n + help + This option causes rcutorture to check the desired rcutorture + reader state for each segment against the actual context. + Note that PREEMPT_COUNT must be enabled if the preempt-disabled + and bh-disabled checks are to take effect, and that PREEMPT_RCU + must be enabled for the RCU-nesting checks to take effect. + These checks add overhead, and this Kconfig options is therefore + disabled by default. + + Say Y here if you want rcutorture reader contexts checked. + Say N if you are unsure. + +config RCU_TORTURE_TEST_LOG_CPU + tristate "Log CPU for rcutorture failures" + depends on RCU_TORTURE_TEST + default n + help + This option causes rcutorture to decorate each entry of its + log of failure/close-call rcutorture reader segments with the + number of the CPU that the reader was running on at the time. + This information can be useful, but it does incur additional + overhead, overhead that can make both failures and close calls + less probable. + + Say Y here if you want CPU IDs logged. + Say N if you are unsure. + config RCU_REF_SCALE_TEST tristate "Scalability tests for read-side synchronization (RCU and others)" depends on DEBUG_KERNEL diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 612d27690335..d26fb1d33ed9 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -92,12 +92,20 @@ torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait 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(int, gp_cond_wi, 16 * USEC_PER_SEC / HZ, + "Wait interval for normal conditional grace periods, us (default 16 jiffies)"); +torture_param(int, gp_cond_wi_exp, 128, + "Wait interval for expedited conditional grace periods, us (default 128 us)"); 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(int, gp_poll_wi, 16 * USEC_PER_SEC / HZ, + "Wait interval for normal polled grace periods, us (default 16 jiffies)"); +torture_param(int, gp_poll_wi_exp, 128, + "Wait interval for expedited polled grace periods, us (default 128 us)"); 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"); @@ -109,9 +117,11 @@ 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, preempt_duration, 0, "Preemption duration (ms), zero to disable"); +torture_param(int, preempt_interval, MSEC_PER_SEC, "Interval between preemptions (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, reader_flavor, 0x1, "Reader flavors to use, one per bit."); +torture_param(int, reader_flavor, SRCU_READ_FLAVOR_NORMAL, "Reader flavors to use, one per bit."); 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."); @@ -149,6 +159,7 @@ 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; +static struct task_struct *preempt_task; #define RCU_TORTURE_PIPE_LEN 10 @@ -259,10 +270,13 @@ struct rt_read_seg { unsigned long rt_delay_ms; unsigned long rt_delay_us; bool rt_preempted; + int rt_cpu; + int rt_end_cpu; }; static int err_segs_recorded; static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS]; static int rt_read_nsegs; +static int rt_read_preempted; static const char *rcu_torture_writer_state_getname(void) { @@ -353,7 +367,8 @@ struct rcu_torture_ops { void (*read_delay)(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp); void (*readunlock)(int idx); - int (*readlock_held)(void); + int (*readlock_held)(void); // lockdep. + int (*readlock_nesting)(void); // actual nesting, if available, -1 if not. unsigned long (*get_gp_seq)(void); unsigned long (*gp_diff)(unsigned long new, unsigned long old); void (*deferred_free)(struct rcu_torture *p); @@ -390,6 +405,7 @@ struct rcu_torture_ops { void (*get_gp_data)(int *flags, unsigned long *gp_seq); void (*gp_slow_register)(atomic_t *rgssp); void (*gp_slow_unregister)(atomic_t *rgssp); + bool (*reader_blocked)(void); long cbflood_max; int irq_capable; int can_boost; @@ -448,10 +464,8 @@ rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) rtrsp->rt_delay_us = shortdelay_us; } if (!preempt_count() && - !(torture_random(rrsp) % (nrealreaders * 500))) { + !(torture_random(rrsp) % (nrealreaders * 500))) torture_preempt_schedule(); /* QS only if preemptible. */ - rtrsp->rt_preempted = true; - } } static void rcu_torture_read_unlock(int idx) @@ -459,6 +473,15 @@ static void rcu_torture_read_unlock(int idx) rcu_read_unlock(); } +static int rcu_torture_readlock_nesting(void) +{ + if (IS_ENABLED(CONFIG_PREEMPT_RCU)) + return rcu_preempt_depth(); + if (IS_ENABLED(CONFIG_PREEMPT_COUNT)) + return (preempt_count() & PREEMPT_MASK); + return -1; +} + /* * Update callback in the pipe. This should be invoked after a grace period. */ @@ -548,6 +571,7 @@ static struct rcu_torture_ops rcu_ops = { .read_delay = rcu_read_delay, .readunlock = rcu_torture_read_unlock, .readlock_held = torture_readlock_not_held, + .readlock_nesting = rcu_torture_readlock_nesting, .get_gp_seq = rcu_get_gp_seq, .gp_diff = rcu_seq_diff, .deferred_free = rcu_torture_deferred_free, @@ -573,6 +597,7 @@ static struct rcu_torture_ops rcu_ops = { .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, + .cond_sync_exp_full = cond_synchronize_rcu_expedited_full, .call = call_rcu_hurry, .cb_barrier = rcu_barrier, .fqs = rcu_force_quiescent_state, @@ -582,6 +607,9 @@ static struct rcu_torture_ops rcu_ops = { .get_gp_data = rcutorture_get_gp_data, .gp_slow_register = rcu_gp_slow_register, .gp_slow_unregister = rcu_gp_slow_unregister, + .reader_blocked = IS_ENABLED(CONFIG_RCU_TORTURE_TEST_LOG_CPU) + ? has_rcu_reader_blocked + : NULL, .irq_capable = 1, .can_boost = IS_ENABLED(CONFIG_RCU_BOOST), .extendables = RCUTORTURE_MAX_EXTEND, @@ -628,6 +656,7 @@ static struct rcu_torture_ops rcu_busted_ops = { .exp_sync = synchronize_rcu_busted, .call = call_rcu_busted, .irq_capable = 1, + .extendables = RCUTORTURE_MAX_EXTEND, .name = "busted" }; @@ -650,17 +679,17 @@ static int srcu_torture_read_lock(void) int idx; int ret = 0; - if ((reader_flavor & 0x1) || !(reader_flavor & 0x7)) { + if ((reader_flavor & SRCU_READ_FLAVOR_NORMAL) || !(reader_flavor & SRCU_READ_FLAVOR_ALL)) { idx = srcu_read_lock(srcu_ctlp); WARN_ON_ONCE(idx & ~0x1); ret += idx; } - if (reader_flavor & 0x2) { + if (reader_flavor & SRCU_READ_FLAVOR_NMI) { idx = srcu_read_lock_nmisafe(srcu_ctlp); WARN_ON_ONCE(idx & ~0x1); ret += idx << 1; } - if (reader_flavor & 0x4) { + if (reader_flavor & SRCU_READ_FLAVOR_LITE) { idx = srcu_read_lock_lite(srcu_ctlp); WARN_ON_ONCE(idx & ~0x1); ret += idx << 2; @@ -690,11 +719,11 @@ srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) static void srcu_torture_read_unlock(int idx) { WARN_ON_ONCE((reader_flavor && (idx & ~reader_flavor)) || (!reader_flavor && (idx & ~0x1))); - if (reader_flavor & 0x4) + if (reader_flavor & SRCU_READ_FLAVOR_LITE) srcu_read_unlock_lite(srcu_ctlp, (idx & 0x4) >> 2); - if (reader_flavor & 0x2) + if (reader_flavor & SRCU_READ_FLAVOR_NMI) srcu_read_unlock_nmisafe(srcu_ctlp, (idx & 0x2) >> 1); - if ((reader_flavor & 0x1) || !(reader_flavor & 0x7)) + if ((reader_flavor & SRCU_READ_FLAVOR_NORMAL) || !(reader_flavor & SRCU_READ_FLAVOR_ALL)) srcu_read_unlock(srcu_ctlp, idx & 0x1); } @@ -857,7 +886,7 @@ static void synchronize_rcu_trivial(void) int cpu; for_each_online_cpu(cpu) { - torture_sched_setaffinity(current->pid, cpumask_of(cpu)); + torture_sched_setaffinity(current->pid, cpumask_of(cpu), true); WARN_ON_ONCE(raw_smp_processor_id() != cpu); } } @@ -1347,6 +1376,7 @@ static void rcu_torture_write_types(void) pr_alert("%s: gp_sync without primitives.\n", __func__); } pr_alert("%s: Testing %d update types.\n", __func__, nsynctypes); + pr_info("%s: gp_cond_wi %d gp_cond_wi_exp %d gp_poll_wi %d gp_poll_wi_exp %d\n", __func__, gp_cond_wi, gp_cond_wi_exp, gp_poll_wi, gp_poll_wi_exp); } /* @@ -1513,7 +1543,8 @@ rcu_torture_writer(void *arg) 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); + torture_hrtimeout_us(torture_random(&rand) % gp_cond_wi, + 1000, &rand); rcu_torture_writer_state = RTWS_COND_SYNC; cur_ops->cond_sync(gp_snap); rcu_torture_pipe_update(old_rp); @@ -1521,7 +1552,8 @@ rcu_torture_writer(void *arg) 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); + torture_hrtimeout_us(torture_random(&rand) % gp_cond_wi_exp, + 1000, &rand); rcu_torture_writer_state = RTWS_COND_SYNC_EXP; cur_ops->cond_sync_exp(gp_snap); rcu_torture_pipe_update(old_rp); @@ -1529,7 +1561,8 @@ rcu_torture_writer(void *arg) 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); + torture_hrtimeout_us(torture_random(&rand) % gp_cond_wi, + 1000, &rand); rcu_torture_writer_state = RTWS_COND_SYNC_FULL; cur_ops->cond_sync_full(&gp_snap_full); rcu_torture_pipe_update(old_rp); @@ -1537,7 +1570,8 @@ rcu_torture_writer(void *arg) 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); + torture_hrtimeout_us(torture_random(&rand) % gp_cond_wi_exp, + 1000, &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); @@ -1557,8 +1591,8 @@ rcu_torture_writer(void *arg) break; } WARN_ON_ONCE(ulo_size > 0 && i >= ulo_size); - torture_hrtimeout_jiffies(torture_random(&rand) % 16, - &rand); + torture_hrtimeout_us(torture_random(&rand) % gp_poll_wi, + 1000, &rand); } rcu_torture_pipe_update(old_rp); break; @@ -1578,8 +1612,8 @@ rcu_torture_writer(void *arg) break; } WARN_ON_ONCE(rgo_size > 0 && i >= rgo_size); - torture_hrtimeout_jiffies(torture_random(&rand) % 16, - &rand); + torture_hrtimeout_us(torture_random(&rand) % gp_poll_wi, + 1000, &rand); } rcu_torture_pipe_update(old_rp); break; @@ -1588,8 +1622,8 @@ rcu_torture_writer(void *arg) 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); + torture_hrtimeout_us(torture_random(&rand) % gp_poll_wi_exp, + 1000, &rand); rcu_torture_pipe_update(old_rp); break; case RTWS_POLL_GET_EXP_FULL: @@ -1597,8 +1631,8 @@ rcu_torture_writer(void *arg) 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); + torture_hrtimeout_us(torture_random(&rand) % gp_poll_wi_exp, + 1000, &rand); rcu_torture_pipe_update(old_rp); break; case RTWS_SYNC: @@ -1835,6 +1869,44 @@ static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp, smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign. } +// Verify the specified RCUTORTURE_RDR* state. +#define ROEC_ARGS "%s %s: Current %#x To add %#x To remove %#x preempt_count() %#x\n", __func__, s, curstate, new, old, preempt_count() +static void rcutorture_one_extend_check(char *s, int curstate, int new, int old, bool insoftirq) +{ + if (!IS_ENABLED(CONFIG_RCU_TORTURE_TEST_CHK_RDR_STATE)) + return; + + WARN_ONCE(!(curstate & RCUTORTURE_RDR_IRQ) && irqs_disabled(), ROEC_ARGS); + WARN_ONCE((curstate & RCUTORTURE_RDR_IRQ) && !irqs_disabled(), ROEC_ARGS); + + // If CONFIG_PREEMPT_COUNT=n, further checks are unreliable. + if (!IS_ENABLED(CONFIG_PREEMPT_COUNT)) + return; + + WARN_ONCE((curstate & (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH)) && + !(preempt_count() & SOFTIRQ_MASK), ROEC_ARGS); + WARN_ONCE((curstate & (RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED)) && + !(preempt_count() & PREEMPT_MASK), ROEC_ARGS); + WARN_ONCE(cur_ops->readlock_nesting && + (curstate & (RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2)) && + cur_ops->readlock_nesting() == 0, ROEC_ARGS); + + // Timer handlers have all sorts of stuff disabled, so ignore + // unintended disabling. + if (insoftirq) + return; + + WARN_ONCE(cur_ops->extendables && + !(curstate & (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH)) && + (preempt_count() & SOFTIRQ_MASK), ROEC_ARGS); + WARN_ONCE(cur_ops->extendables && + !(curstate & (RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED)) && + (preempt_count() & PREEMPT_MASK), ROEC_ARGS); + WARN_ONCE(cur_ops->readlock_nesting && + !(curstate & (RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2)) && + cur_ops->readlock_nesting() > 0, ROEC_ARGS); +} + /* * Do one extension of an RCU read-side critical section using the * current reader state in readstate (set to zero for initial entry @@ -1844,10 +1916,11 @@ static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp, * 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, +static void rcutorture_one_extend(int *readstate, int newstate, bool insoftirq, struct torture_random_state *trsp, struct rt_read_seg *rtrsp) { + bool first; unsigned long flags; int idxnew1 = -1; int idxnew2 = -1; @@ -1856,8 +1929,10 @@ static void rcutorture_one_extend(int *readstate, int newstate, int statesnew = ~*readstate & newstate; int statesold = *readstate & ~newstate; + first = idxold1 == 0; WARN_ON_ONCE(idxold2 < 0); WARN_ON_ONCE(idxold2 & ~RCUTORTURE_RDR_ALLBITS); + rcutorture_one_extend_check("before change", idxold1, statesnew, statesold, insoftirq); rtrsp->rt_readstate = newstate; /* First, put new protection in place to avoid critical-section gap. */ @@ -1876,6 +1951,21 @@ static void rcutorture_one_extend(int *readstate, int newstate, if (statesnew & RCUTORTURE_RDR_RCU_2) idxnew2 = (cur_ops->readlock() << RCUTORTURE_RDR_SHIFT_2) & RCUTORTURE_RDR_MASK_2; + // Complain unless both the old and the new protection is in place. + rcutorture_one_extend_check("during change", + idxold1 | statesnew, statesnew, statesold, insoftirq); + + // Sample CPU under both sets of protections to reduce confusion. + if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_LOG_CPU)) { + int cpu = raw_smp_processor_id(); + rtrsp->rt_cpu = cpu; + if (!first) { + rtrsp[-1].rt_end_cpu = cpu; + if (cur_ops->reader_blocked) + rtrsp[-1].rt_preempted = cur_ops->reader_blocked(); + } + } + /* * Next, remove old protection, in decreasing order of strength * to avoid unlock paths that aren't safe in the stronger @@ -1926,6 +2016,7 @@ static void rcutorture_one_extend(int *readstate, int newstate, WARN_ON_ONCE(*readstate < 0); if (WARN_ON_ONCE(*readstate & ~RCUTORTURE_RDR_ALLBITS)) pr_info("Unexpected readstate value of %#x\n", *readstate); + rcutorture_one_extend_check("after change", *readstate, statesnew, statesold, insoftirq); } /* Return the biggest extendables mask given current RCU and boot parameters. */ @@ -1992,7 +2083,7 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) * critical section. */ static struct rt_read_seg * -rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, +rcutorture_loop_extend(int *readstate, bool insoftirq, struct torture_random_state *trsp, struct rt_read_seg *rtrsp) { int i; @@ -2007,7 +2098,7 @@ rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, 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]); + rcutorture_one_extend(readstate, mask, insoftirq, trsp, &rtrsp[j]); } return &rtrsp[j]; } @@ -2028,6 +2119,7 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) int newstate; struct rcu_torture *p; int pipe_count; + bool preempted = false; int readstate = 0; struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } }; struct rt_read_seg *rtrsp = &rtseg[0]; @@ -2036,7 +2128,7 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) WARN_ON_ONCE(!rcu_is_watching()); newstate = rcutorture_extend_mask(readstate, trsp); - rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++); + rcutorture_one_extend(&readstate, newstate, myid < 0, trsp, rtrsp++); if (checkpolling) { if (cur_ops->get_gp_state && cur_ops->poll_gp_state) cookie = cur_ops->get_gp_state(); @@ -2049,13 +2141,13 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) !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); + rcutorture_one_extend(&readstate, 0, myid < 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); + rtrsp = rcutorture_loop_extend(&readstate, myid < 0, trsp, rtrsp); preempt_disable(); pipe_count = READ_ONCE(p->rtort_pipe_count); if (pipe_count > RCU_TORTURE_PIPE_LEN) { @@ -2093,7 +2185,9 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) rcu_torture_writer_state, cpumask_pr_args(cpu_online_mask)); } - rcutorture_one_extend(&readstate, 0, trsp, rtrsp); + if (cur_ops->reader_blocked) + preempted = cur_ops->reader_blocked(); + rcutorture_one_extend(&readstate, 0, myid < 0, trsp, rtrsp); WARN_ON_ONCE(readstate); // This next splat is expected behavior if leakpointer, especially // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels. @@ -2105,6 +2199,7 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++) err_segs[i++] = *rtrsp1; rt_read_nsegs = i; + rt_read_preempted = preempted; } return true; @@ -2425,7 +2520,8 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) "read_exit_delay=%d read_exit_burst=%d " "reader_flavor=%x " "nocbs_nthreads=%d nocbs_toggle=%d " - "test_nmis=%d\n", + "test_nmis=%d " + "preempt_duration=%d preempt_interval=%d\n", torture_type, tag, nrealreaders, nfakewriters, stat_interval, verbose, test_no_idle_hz, shuffle_interval, stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, @@ -2438,7 +2534,8 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) read_exit_delay, read_exit_burst, reader_flavor, nocbs_nthreads, nocbs_toggle, - test_nmis); + test_nmis, + preempt_duration, preempt_interval); } static int rcutorture_booster_cleanup(unsigned int cpu) @@ -3068,12 +3165,12 @@ static int __init rcu_torture_fwd_prog_init(void) fwd_progress = 0; return 0; } - if (stall_cpu > 0) { - VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); + if (stall_cpu > 0 || (preempt_duration > 0 && IS_ENABLED(CONFIG_RCU_NOCB_CPU))) { + VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall and/or preemption 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. */ + WARN_ON(1); /* Make sure rcutorture scripting notices conflict. */ return 0; } if (fwd_progress_holdoff <= 0) @@ -3418,6 +3515,35 @@ static void rcutorture_test_nmis(int n) #endif // #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) } +// Randomly preempt online CPUs. +static int rcu_torture_preempt(void *unused) +{ + int cpu = -1; + DEFINE_TORTURE_RANDOM(rand); + + schedule_timeout_idle(stall_cpu_holdoff); + do { + // Wait for preempt_interval ms with up to 100us fuzz. + torture_hrtimeout_ms(preempt_interval, 100, &rand); + // Select online CPU. + cpu = cpumask_next(cpu, cpu_online_mask); + if (cpu >= nr_cpu_ids) + cpu = cpumask_next(-1, cpu_online_mask); + WARN_ON_ONCE(cpu >= nr_cpu_ids); + // Move to that CPU, if can't do so, retry later. + if (torture_sched_setaffinity(current->pid, cpumask_of(cpu), false)) + continue; + // Preempt at high-ish priority, then reset to normal. + sched_set_fifo(current); + torture_sched_setaffinity(current->pid, cpu_present_mask, true); + mdelay(preempt_duration); + sched_set_normal(current, 0); + stutter_wait("rcu_torture_preempt"); + } while (!torture_must_stop()); + torture_kthread_stopping("rcu_torture_preempt"); + return 0; +} + static enum cpuhp_state rcutor_hp; static void @@ -3446,6 +3572,7 @@ rcu_torture_cleanup(void) if (cur_ops->gp_kthread_dbg) cur_ops->gp_kthread_dbg(); + torture_stop_kthread(rcu_torture_preempt, preempt_task); rcu_torture_read_exit_cleanup(); rcu_torture_barrier_cleanup(); rcu_torture_fwd_prog_cleanup(); @@ -3508,26 +3635,49 @@ rcu_torture_cleanup(void) 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); + pr_alert("\t%d: %#4x", 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 (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_LOG_CPU)) { + pr_cont(" CPU %2d", err_segs[i].rt_cpu); + if (err_segs[i].rt_cpu != err_segs[i].rt_end_cpu) + pr_cont("->%-2d", err_segs[i].rt_end_cpu); + else + pr_cont(" ..."); + } if (err_segs[i].rt_delay_ms != 0) { - pr_cont("%s%ldms", firsttime ? "" : "+", + 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 ? "" : "+", + pr_cont(" %s%ldus", firsttime ? "" : "+", err_segs[i].rt_delay_us); firsttime = 0; } - pr_cont("%s\n", - err_segs[i].rt_preempted ? "preempted" : ""); + pr_cont("%s", err_segs[i].rt_preempted ? " preempted" : ""); + if (err_segs[i].rt_readstate & RCUTORTURE_RDR_BH) + pr_cont(" BH"); + if (err_segs[i].rt_readstate & RCUTORTURE_RDR_IRQ) + pr_cont(" IRQ"); + if (err_segs[i].rt_readstate & RCUTORTURE_RDR_PREEMPT) + pr_cont(" PREEMPT"); + if (err_segs[i].rt_readstate & RCUTORTURE_RDR_RBH) + pr_cont(" RBH"); + if (err_segs[i].rt_readstate & RCUTORTURE_RDR_SCHED) + pr_cont(" SCHED"); + if (err_segs[i].rt_readstate & RCUTORTURE_RDR_RCU_1) + pr_cont(" RCU_1"); + if (err_segs[i].rt_readstate & RCUTORTURE_RDR_RCU_2) + pr_cont(" RCU_2"); + pr_cont("\n"); } + if (rt_read_preempted) + pr_alert("\tReader was preempted.\n"); } if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); @@ -4019,6 +4169,11 @@ rcu_torture_init(void) firsterr = rcu_torture_read_exit_init(); if (torture_init_error(firsterr)) goto unwind; + if (preempt_duration > 0) { + firsterr = torture_create_kthread(rcu_torture_preempt, NULL, preempt_task); + if (torture_init_error(firsterr)) + goto unwind; + } if (object_debug) rcu_test_debug_objects(); torture_init_end(); diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c index aacfcc9838b3..1b47376acdc4 100644 --- a/kernel/rcu/refscale.c +++ b/kernel/rcu/refscale.c @@ -36,6 +36,7 @@ #include #include #include +#include #include "rcu.h" @@ -531,6 +532,39 @@ static const struct ref_scale_ops acqrel_ops = { static volatile u64 stopopts; +static void ref_sched_clock_section(const int nloops) +{ + u64 x = 0; + int i; + + preempt_disable(); + for (i = nloops; i >= 0; i--) + x += sched_clock(); + preempt_enable(); + stopopts = x; +} + +static void ref_sched_clock_delay_section(const int nloops, const int udl, const int ndl) +{ + u64 x = 0; + int i; + + preempt_disable(); + for (i = nloops; i >= 0; i--) { + x += sched_clock(); + un_delay(udl, ndl); + } + preempt_enable(); + stopopts = x; +} + +static const struct ref_scale_ops sched_clock_ops = { + .readsection = ref_sched_clock_section, + .delaysection = ref_sched_clock_delay_section, + .name = "sched-clock" +}; + + static void ref_clock_section(const int nloops) { u64 x = 0; @@ -1130,9 +1164,9 @@ ref_scale_init(void) int firsterr = 0; static const struct ref_scale_ops *scale_ops[] = { &rcu_ops, &srcu_ops, &srcu_lite_ops, RCU_TRACE_OPS RCU_TASKS_OPS - &refcnt_ops, &rwlock_ops, &rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops, - &clock_ops, &jiffies_ops, &typesafe_ref_ops, &typesafe_lock_ops, - &typesafe_seqlock_ops, + &refcnt_ops, &rwlock_ops, &rwsem_ops, &lock_ops, &lock_irq_ops, + &acqrel_ops, &sched_clock_ops, &clock_ops, &jiffies_ops, + &typesafe_ref_ops, &typesafe_lock_ops, &typesafe_seqlock_ops, }; if (!torture_init_begin(scale_type, verbose)) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 5e2e53464794..b83c74c4dcc0 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -738,7 +738,8 @@ EXPORT_SYMBOL_GPL(__srcu_check_read_flavor); /* * Counts the new reader in the appropriate per-CPU element of the * srcu_struct. - * Returns an index that must be passed to the matching srcu_read_unlock(). + * Returns a guaranteed non-negative index that must be passed to the + * matching __srcu_read_unlock(). */ int __srcu_read_lock(struct srcu_struct *ssp) { @@ -1076,7 +1077,6 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp, /* If grace period not already in progress, start it. */ if (!WARN_ON_ONCE(rcu_seq_done(&sup->srcu_gp_seq, s)) && rcu_seq_state(sup->srcu_gp_seq) == SRCU_STATE_IDLE) { - WARN_ON_ONCE(ULONG_CMP_GE(sup->srcu_gp_seq, sup->srcu_gp_seq_needed)); srcu_gp_start(ssp); // And how can that list_add() in the "else" clause diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 3885aae5f9cb..16b575dcb296 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3084,8 +3084,11 @@ __call_rcu_common(struct rcu_head *head, rcu_callback_t func, bool lazy_in) head->func = func; head->next = NULL; kasan_record_aux_stack(head); + local_irq_save(flags); rdp = this_cpu_ptr(&rcu_data); + RCU_LOCKDEP_WARN(!rcu_rdp_cpu_online(rdp), "Callback enqueued on offline CPU!"); + lazy = lazy_in && !rcu_async_should_hurry(); /* Add the callback to our list. */ diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index fb664d3a01c9..77efed89c79e 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -227,16 +227,16 @@ static void __maybe_unused rcu_report_exp_rnp(struct rcu_node *rnp, bool wake) /* * Report expedited quiescent state for multiple CPUs, all covered by the - * specified leaf rcu_node structure. + * specified leaf rcu_node structure, which is acquired by the caller. */ -static void rcu_report_exp_cpu_mult(struct rcu_node *rnp, +static void rcu_report_exp_cpu_mult(struct rcu_node *rnp, unsigned long flags, unsigned long mask, bool wake) + __releases(rnp->lock) { int cpu; - unsigned long flags; struct rcu_data *rdp; - raw_spin_lock_irqsave_rcu_node(rnp, flags); + raw_lockdep_assert_held_rcu_node(rnp); if (!(rnp->expmask & mask)) { raw_spin_unlock_irqrestore_rcu_node(rnp, flags); return; @@ -257,8 +257,13 @@ static void rcu_report_exp_cpu_mult(struct rcu_node *rnp, */ static void rcu_report_exp_rdp(struct rcu_data *rdp) { + unsigned long flags; + struct rcu_node *rnp = rdp->mynode; + + raw_spin_lock_irqsave_rcu_node(rnp, flags); WRITE_ONCE(rdp->cpu_no_qs.b.exp, false); - rcu_report_exp_cpu_mult(rdp->mynode, rdp->grpmask, true); + ASSERT_EXCLUSIVE_WRITER(rdp->cpu_no_qs.b.exp); + rcu_report_exp_cpu_mult(rnp, flags, rdp->grpmask, true); } /* Common code for work-done checking. */ @@ -432,8 +437,10 @@ static void __sync_rcu_exp_select_node_cpus(struct rcu_exp_work *rewp) raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } /* Report quiescent states for those that went offline. */ - if (mask_ofl_test) - rcu_report_exp_cpu_mult(rnp, mask_ofl_test, false); + if (mask_ofl_test) { + raw_spin_lock_irqsave_rcu_node(rnp, flags); + rcu_report_exp_cpu_mult(rnp, flags, mask_ofl_test, false); + } } static void rcu_exp_sel_wait_wake(unsigned long s); @@ -712,6 +719,18 @@ static void rcu_exp_sel_wait_wake(unsigned long s) rcu_exp_wait_wake(s); } +/* Request an expedited quiescent state. */ +static void rcu_exp_need_qs(void) +{ + lockdep_assert_irqs_disabled(); + ASSERT_EXCLUSIVE_WRITER_SCOPED(*this_cpu_ptr(&rcu_data.cpu_no_qs.b.exp)); + __this_cpu_write(rcu_data.cpu_no_qs.b.exp, true); + /* Store .exp before .rcu_urgent_qs. */ + smp_store_release(this_cpu_ptr(&rcu_data.rcu_urgent_qs), true); + set_tsk_need_resched(current); + set_preempt_need_resched(); +} + #ifdef CONFIG_PREEMPT_RCU /* @@ -730,24 +749,34 @@ static void rcu_exp_handler(void *unused) struct task_struct *t = current; /* - * First, the common case of not being in an RCU read-side + * First, is there no need for a quiescent state from this CPU, + * or is this CPU already looking for a quiescent state for the + * current grace period? If either is the case, just leave. + * However, this should not happen due to the preemptible + * sync_sched_exp_online_cleanup() implementation being a no-op, + * so warn if this does happen. + */ + ASSERT_EXCLUSIVE_WRITER_SCOPED(rdp->cpu_no_qs.b.exp); + if (WARN_ON_ONCE(!(READ_ONCE(rnp->expmask) & rdp->grpmask) || + READ_ONCE(rdp->cpu_no_qs.b.exp))) + return; + + /* + * Second, the common case of not being in an RCU read-side * critical section. If also enabled or idle, immediately * report the quiescent state, otherwise defer. */ if (!depth) { if (!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)) || - rcu_is_cpu_rrupt_from_idle()) { + rcu_is_cpu_rrupt_from_idle()) rcu_report_exp_rdp(rdp); - } else { - WRITE_ONCE(rdp->cpu_no_qs.b.exp, true); - set_tsk_need_resched(t); - set_preempt_need_resched(); - } + else + rcu_exp_need_qs(); return; } /* - * Second, the less-common case of being in an RCU read-side + * Third, the less-common case of being in an RCU read-side * critical section. In this case we can count on a future * rcu_read_unlock(). However, this rcu_read_unlock() might * execute on some other CPU, but in that case there will be @@ -768,7 +797,7 @@ static void rcu_exp_handler(void *unused) return; } - // Finally, negative nesting depth should not happen. + // Fourth and finally, negative nesting depth should not happen. WARN_ON_ONCE(1); } @@ -835,16 +864,6 @@ static void rcu_exp_print_detail_task_stall_rnp(struct rcu_node *rnp) #else /* #ifdef CONFIG_PREEMPT_RCU */ -/* Request an expedited quiescent state. */ -static void rcu_exp_need_qs(void) -{ - __this_cpu_write(rcu_data.cpu_no_qs.b.exp, true); - /* Store .exp before .rcu_urgent_qs. */ - smp_store_release(this_cpu_ptr(&rcu_data.rcu_urgent_qs), true); - set_tsk_need_resched(current); - set_preempt_need_resched(); -} - /* Invoked on each online non-idle CPU for expedited quiescent state. */ static void rcu_exp_handler(void *unused) { @@ -852,6 +871,7 @@ static void rcu_exp_handler(void *unused) struct rcu_node *rnp = rdp->mynode; bool preempt_bh_enabled = !(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)); + ASSERT_EXCLUSIVE_WRITER_SCOPED(rdp->cpu_no_qs.b.exp); if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) || __this_cpu_read(rcu_data.cpu_no_qs.b.exp)) return; diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 3927ea5f7955..bb7ca6eb9ef0 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -275,6 +275,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp) rcu_report_exp_rdp(rdp); else WARN_ON_ONCE(rdp->cpu_no_qs.b.exp); + ASSERT_EXCLUSIVE_WRITER_SCOPED(rdp->cpu_no_qs.b.exp); } /* diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index f8436969e0c8..c912b594ba98 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -527,12 +527,12 @@ EXPORT_SYMBOL_GPL(do_trace_rcu_torture_read); #if IS_ENABLED(CONFIG_RCU_TORTURE_TEST) || IS_MODULE(CONFIG_RCU_TORTURE_TEST) || IS_ENABLED(CONFIG_LOCK_TORTURE_TEST) || IS_MODULE(CONFIG_LOCK_TORTURE_TEST) /* Get rcutorture access to sched_setaffinity(). */ -long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask) +long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask, bool dowarn) { int ret; ret = sched_setaffinity(pid, in_mask); - WARN_ONCE(ret, "%s: sched_setaffinity(%d) returned %d\n", __func__, pid, ret); + WARN_ONCE(dowarn && ret, "%s: sched_setaffinity(%d) returned %d\n", __func__, pid, ret); return ret; } EXPORT_SYMBOL_GPL(torture_sched_setaffinity); diff --git a/tools/testing/selftests/rcutorture/bin/kvm-remote.sh b/tools/testing/selftests/rcutorture/bin/kvm-remote.sh index 134cdef5a6e0..48a8052d5dae 100755 --- a/tools/testing/selftests/rcutorture/bin/kvm-remote.sh +++ b/tools/testing/selftests/rcutorture/bin/kvm-remote.sh @@ -181,10 +181,11 @@ done # Function to check for presence of a file on the specified system. # Complain if the system cannot be reached, and retry after a wait. -# Currently just waits forever if a machine disappears. +# Currently just waits 15 minutes if a machine disappears. # # Usage: checkremotefile system pathname checkremotefile () { + local nsshfails=0 local ret local sleeptime=60 @@ -195,6 +196,11 @@ checkremotefile () { if test "$ret" -eq 255 then echo " ---" ssh failure to $1 checking for file $2, retry after $sleeptime seconds. `date` | tee -a "$oldrun/remote-log" + nsshfails=$((nsshfails+1)) + if ((nsshfails > 15)) + then + return 255 + fi elif test "$ret" -eq 0 then return 0 @@ -268,12 +274,23 @@ echo All batches started. `date` | tee -a "$oldrun/remote-log" for i in $systems do echo " ---" Waiting for $i `date` | tee -a "$oldrun/remote-log" - while checkremotefile "$i" "$resdir/$ds/remote.run" + while : do + checkremotefile "$i" "$resdir/$ds/remote.run" + ret=$? + if test "$ret" -eq 1 + then + echo " ---" Collecting results from $i `date` | tee -a "$oldrun/remote-log" + ( cd "$oldrun"; ssh -o BatchMode=yes $i "cd $rundir; tar -czf - kvm-remote-*.sh.out */console.log */kvm-test-1-run*.sh.out */qemu[_-]pid */qemu-retval */qemu-affinity; rm -rf $T > /dev/null 2>&1" | tar -xzf - ) + break; + fi + if test "$ret" -eq 255 + then + echo System $i persistent ssh failure, lost results `date` | tee -a "$oldrun/remote-log" + break; + fi sleep 30 done - echo " ---" Collecting results from $i `date` | tee -a "$oldrun/remote-log" - ( cd "$oldrun"; ssh -o BatchMode=yes $i "cd $rundir; tar -czf - kvm-remote-*.sh.out */console.log */kvm-test-1-run*.sh.out */qemu[_-]pid */qemu-retval */qemu-affinity; rm -rf $T > /dev/null 2>&1" | tar -xzf - ) done ( kvm-end-run-stats.sh "$oldrun" "$starttime"; echo $? > $T/exitcode ) | tee -a "$oldrun/remote-log" diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot b/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot index 8e50bfd4b710..90318591dae2 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot @@ -5,3 +5,4 @@ rcutree.gp_cleanup_delay=3 rcutree.kthread_prio=2 threadirqs rcutree.use_softirq=0 +rcutorture.preempt_duration=10