On Thu, Mar 27, 2025 at 11:26:01AM +0800, Z qiang wrote:
> >
> > This commit adds a new rcutorture.n_up_down kernel boot parameter
> > that specifies the number of outstanding SRCU up/down readers, which
> > begin in kthread context and end in an hrtimer handler. There is a new
> > kthread ("rcu_torture_updown") that scans an per-reader array looking
> > for elements whose readers have ended. This kthread sleeps between one
> > and two milliseconds between consecutive scans.
> >
> > [ paulmck: Apply kernel test robot feedback. ]
> >
> > Signed-off-by: Paul E. McKenney <paul...@kernel.org>
> > ---
> > kernel/rcu/rcutorture.c | 227 ++++++++++++++++++++++++++++++++++++----
> > 1 file changed, 208 insertions(+), 19 deletions(-)
> >
> > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> > index b0e96df636226..6afcd33e724ba 100644
> > --- a/kernel/rcu/rcutorture.c
> > +++ b/kernel/rcu/rcutorture.c
> > @@ -55,22 +55,24 @@ MODULE_DESCRIPTION("Read-Copy Update module-based
> > torture test facility");
> > MODULE_LICENSE("GPL");
> > MODULE_AUTHOR("Paul E. McKenney <paul...@linux.ibm.com> and Josh Triplett
> > <j...@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 (0xff << RCUTORTURE_RDR_SHIFT_1)
> > -#define RCUTORTURE_RDR_SHIFT_2 16 /* Put SRCU index in upper bits. */
> > -#define RCUTORTURE_RDR_MASK_2 (0xff << 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 \
> > +// 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 (0xff << RCUTORTURE_RDR_SHIFT_1)
> > +#define RCUTORTURE_RDR_SHIFT_2 16 // Put SRCU index in upper bits.
> > +#define RCUTORTURE_RDR_MASK_2 (0xff << 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_UPDOWN 0x80 // ... up-read from task,
> > down-read from timer.
> > + // Note: Manual start,
> > automatic end.
> > +#define RCUTORTURE_RDR_NBITS 8 // Number of bits defined above.
> > +#define RCUTORTURE_MAX_EXTEND \
> > (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
> > - RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
> > + RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED) // Intentionally omit
> > RCUTORTURE_RDR_UPDOWN.
> > #define RCUTORTURE_RDR_ALLBITS \
> > (RCUTORTURE_MAX_EXTEND | RCUTORTURE_RDR_RCU_1 |
> > RCUTORTURE_RDR_RCU_2 | \
> > RCUTORTURE_RDR_MASK_1 | RCUTORTURE_RDR_MASK_2)
> > @@ -110,6 +112,7 @@ 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, n_up_down, 32, "# of concurrent up/down hrtimer-based
> > RCU readers");
> > 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");
> > @@ -152,6 +155,7 @@ static int nrealfakewriters;
> > static struct task_struct *writer_task;
> > static struct task_struct **fakewriter_tasks;
> > static struct task_struct **reader_tasks;
> > +static struct task_struct *updown_task;
> > static struct task_struct **nocb_tasks;
> > static struct task_struct *stats_task;
> > static struct task_struct *fqs_task;
> > @@ -374,6 +378,8 @@ struct rcu_torture_ops {
> > void (*readunlock)(int idx);
> > int (*readlock_held)(void); // lockdep.
> > int (*readlock_nesting)(void); // actual nesting, if available, -1
> > if not.
> > + int (*down_read)(void);
> > + void (*up_read)(int idx);
> > unsigned long (*get_gp_seq)(void);
> > unsigned long (*gp_diff)(unsigned long new, unsigned long old);
> > void (*deferred_free)(struct rcu_torture *p);
> > @@ -421,6 +427,7 @@ struct rcu_torture_ops {
> > int no_pi_lock;
> > int debug_objects;
> > int start_poll_irqsoff;
> > + int have_up_down;
> > const char *name;
> > };
> >
> > @@ -754,6 +761,50 @@ static int torture_srcu_read_lock_held(void)
> > return srcu_read_lock_held(srcu_ctlp);
> > }
> >
> > +static bool srcu_torture_have_up_down(void)
> > +{
> > + int rf = reader_flavor;
> > +
> > + if (!rf)
> > + rf = SRCU_READ_FLAVOR_NORMAL;
> > + return !!(cur_ops->have_up_down & rf);
> > +}
> > +
> > +static int srcu_torture_down_read(void)
> > +{
> > + int idx;
> > + struct srcu_ctr __percpu *scp;
> > +
> > + WARN_ON_ONCE(reader_flavor & ~SRCU_READ_FLAVOR_ALL);
> > + WARN_ON_ONCE(reader_flavor & (reader_flavor - 1));
> > +
> > + if ((reader_flavor & SRCU_READ_FLAVOR_NORMAL) || !(reader_flavor &
> > SRCU_READ_FLAVOR_ALL)) {
> > + idx = srcu_down_read(srcu_ctlp);
> > + WARN_ON_ONCE(idx & ~0x1);
> > + return idx;
> > + }
> > + if (reader_flavor & SRCU_READ_FLAVOR_FAST) {
> > + scp = srcu_down_read_fast(srcu_ctlp);
> > + idx = __srcu_ptr_to_ctr(srcu_ctlp, scp);
> > + WARN_ON_ONCE(idx & ~0x1);
> > + return idx << 3;
> > + }
> > + WARN_ON_ONCE(1);
> > + return 0;
> > +}
> > +
> > +static void srcu_torture_up_read(int idx)
> > +{
> > + WARN_ON_ONCE((reader_flavor && (idx & ~reader_flavor)) ||
> > (!reader_flavor && (idx & ~0x1)));
> > + if (reader_flavor & SRCU_READ_FLAVOR_FAST)
> > + srcu_up_read_fast(srcu_ctlp, __srcu_ctr_to_ptr(srcu_ctlp,
> > (idx & 0x8) >> 3));
> > + else if ((reader_flavor & SRCU_READ_FLAVOR_NORMAL) ||
> > + !(reader_flavor & SRCU_READ_FLAVOR_ALL))
> > + srcu_up_read(srcu_ctlp, idx & 0x1);
> > + else
> > + WARN_ON_ONCE(1);
> > +}
> > +
> > static unsigned long srcu_torture_completed(void)
> > {
> > return srcu_batches_completed(srcu_ctlp);
> > @@ -811,6 +862,8 @@ static struct rcu_torture_ops srcu_ops = {
> > .readlock = srcu_torture_read_lock,
> > .read_delay = srcu_read_delay,
> > .readunlock = srcu_torture_read_unlock,
> > + .down_read = srcu_torture_down_read,
> > + .up_read = srcu_torture_up_read,
> > .readlock_held = torture_srcu_read_lock_held,
> > .get_gp_seq = srcu_torture_completed,
> > .gp_diff = rcu_seq_diff,
> > @@ -831,6 +884,8 @@ static struct rcu_torture_ops srcu_ops = {
> > .irq_capable = 1,
> > .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
> > .debug_objects = 1,
> > + .have_up_down = IS_ENABLED(CONFIG_TINY_SRCU)
> > + ? 0 : SRCU_READ_FLAVOR_NORMAL |
> > SRCU_READ_FLAVOR_FAST,
> > .name = "srcu"
> > };
> >
> > @@ -856,6 +911,8 @@ static struct rcu_torture_ops srcud_ops = {
> > .read_delay = srcu_read_delay,
> > .readunlock = srcu_torture_read_unlock,
> > .readlock_held = torture_srcu_read_lock_held,
> > + .down_read = srcu_torture_down_read,
> > + .up_read = srcu_torture_up_read,
> > .get_gp_seq = srcu_torture_completed,
> > .gp_diff = rcu_seq_diff,
> > .deferred_free = srcu_torture_deferred_free,
> > @@ -875,6 +932,8 @@ static struct rcu_torture_ops srcud_ops = {
> > .irq_capable = 1,
> > .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
> > .debug_objects = 1,
> > + .have_up_down = IS_ENABLED(CONFIG_TINY_SRCU)
> > + ? 0 : SRCU_READ_FLAVOR_NORMAL |
> > SRCU_READ_FLAVOR_FAST,
> > .name = "srcud"
> > };
> >
> > @@ -1985,7 +2044,7 @@ static void rcutorture_one_extend(int *readstate, int
> > newstate, bool insoftirq,
> >
> > first = idxold1 == 0;
> > WARN_ON_ONCE(idxold2 < 0);
> > - WARN_ON_ONCE(idxold2 & ~RCUTORTURE_RDR_ALLBITS);
> > + WARN_ON_ONCE(idxold2 & ~(RCUTORTURE_RDR_ALLBITS |
> > RCUTORTURE_RDR_UPDOWN));
> > rcutorture_one_extend_check("before change", idxold1, statesnew,
> > statesold, insoftirq);
> > rtrsp->rt_readstate = newstate;
> >
> > @@ -2061,6 +2120,11 @@ static void rcutorture_one_extend(int *readstate,
> > int newstate, bool insoftirq,
> > if (lockit)
> > raw_spin_unlock_irqrestore(¤t->pi_lock,
> > flags);
> > }
> > + if (statesold & RCUTORTURE_RDR_UPDOWN) {
> > + cur_ops->up_read((idxold1 & RCUTORTURE_RDR_MASK_1) >>
> > RCUTORTURE_RDR_SHIFT_1);
> > + WARN_ON_ONCE(idxnew1 != -1);
> > + idxold1 = 0;
> > + }
> >
> > /* Delay if neither beginning nor end and there was a change. */
> > if ((statesnew || statesold) && *readstate && newstate)
> > @@ -2201,7 +2265,8 @@ static bool rcu_torture_one_read_start(struct
> > rcu_torture_one_read_state *rtorsp
> > rtorsp->started = cur_ops->get_gp_seq();
> > rtorsp->ts = rcu_trace_clock_local();
> > rtorsp->p = rcu_dereference_check(rcu_torture_current,
> > - !cur_ops->readlock_held ||
> > cur_ops->readlock_held());
> > + !cur_ops->readlock_held ||
> > cur_ops->readlock_held() ||
> > + (rtorsp->readstate &
> > RCUTORTURE_RDR_UPDOWN));
> > if (rtorsp->p == NULL) {
> > /* Wait for rcu_torture_writer to get underway */
> > rcutorture_one_extend(&rtorsp->readstate, 0, myid < 0,
> > trsp, rtorsp->rtrsp);
> > @@ -2370,6 +2435,123 @@ rcu_torture_reader(void *arg)
> > return 0;
> > }
> >
> > +struct rcu_torture_one_read_state_updown {
> > + struct hrtimer rtorsu_hrt;
> > + bool rtorsu_inuse;
> > + struct torture_random_state rtorsu_trs;
> > + struct rcu_torture_one_read_state rtorsu_rtors;
> > +};
> > +
> > +static struct rcu_torture_one_read_state_updown *updownreaders;
> > +static DEFINE_TORTURE_RANDOM(rcu_torture_updown_rand);
> > +static int rcu_torture_updown(void *arg);
> > +
> > +static enum hrtimer_restart rcu_torture_updown_hrt(struct hrtimer *hrtp)
> > +{
> > + struct rcu_torture_one_read_state_updown *rtorsup;
> > +
> > + rtorsup = container_of(hrtp, struct
> > rcu_torture_one_read_state_updown, rtorsu_hrt);
> > + rcu_torture_one_read_end(&rtorsup->rtorsu_rtors,
> > &rtorsup->rtorsu_trs, -1);
> > + smp_store_release(&rtorsup->rtorsu_inuse, false);
> > + return HRTIMER_NORESTART;
> > +}
> > +
> > +static int rcu_torture_updown_init(void)
> > +{
> > + int i;
> > + struct torture_random_state *rand = &rcu_torture_updown_rand;
> > + int ret;
> > +
> > + if (n_up_down < 0)
> > + return 0;
> > + if (!srcu_torture_have_up_down()) {
> > + VERBOSE_TOROUT_STRING("rcu_torture_updown_init: Disabling
> > up/down reader tests due to lack of primitives");
> > + return 0;
> > + }
> > + updownreaders = kcalloc(n_up_down, sizeof(*updownreaders),
> > GFP_KERNEL);
> > + if (!updownreaders) {
> > + VERBOSE_TOROUT_STRING("rcu_torture_updown_init: Out of
> > memory, disabling up/down reader tests");
> > + return -ENOMEM;
> > + }
> > + for (i = 0; i < n_up_down; i++) {
> > +
> > init_rcu_torture_one_read_state(&updownreaders[i].rtorsu_rtors, rand);
> > + hrtimer_init(&updownreaders[i].rtorsu_hrt, CLOCK_MONOTONIC,
> > + HRTIMER_MODE_REL | HRTIMER_MODE_SOFT);
> > + updownreaders[i].rtorsu_hrt.function =
> > rcu_torture_updown_hrt;
> > + torture_random_init(&updownreaders[i].rtorsu_trs);
> > +
> > init_rcu_torture_one_read_state(&updownreaders[i].rtorsu_rtors,
> > +
> > &updownreaders[i].rtorsu_trs);
> > + }
> > + ret = torture_create_kthread(rcu_torture_updown, rand, updown_task);
> > + if (ret) {
> > + kfree(updownreaders);
> > + updownreaders = NULL;
> > + }
> > + return ret;
> > +}
> > +
> > +static void rcu_torture_updown_cleanup(void)
> > +{
> > + struct rcu_torture_one_read_state_updown *rtorsup;
> > +
> > + for (rtorsup = updownreaders; rtorsup < &updownreaders[n_up_down];
> > rtorsup++) {
> > + if (!smp_load_acquire(&rtorsup->rtorsu_inuse))
> > + continue;
> > + (void)hrtimer_cancel(&rtorsup->rtorsu_hrt);
> > + WARN_ON_ONCE(rtorsup->rtorsu_inuse);
>
> Hello, Paul
>
> When I rmmod rcutorture, the following warning is triggered:
>
> [ 809.227012] WARNING: CPU: 7 PID: 662 at
> kernel/rcu/rcutorture.c:2506 rcu_torture_updown+0x3ff/0x620
> [rcutorture]
> [ 809.227038] Modules linked in: rcutorture(-) torture [last
> unloaded: rcutorture]
> [ 809.227052] CPU: 7 UID: 0 PID: 662 Comm: rcu_torture_upd Not
> tainted 6.14.0-rc1-yoctodev-standard+ #103
> f927b67579e64efac707898e59c492a894becb07
> [ 809.227057] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
> BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
> [ 809.227061] RIP: 0010:rcu_torture_updown+0x3ff/0x620 [rcutorture]
> [ 809.227112] Call Trace:
> [ 809.227114] <TASK>
> [ 809.227118] ? show_regs+0x65/0x70
> [ 809.227127] ? __warn+0xd5/0x310
> [ 809.227137] ? rcu_torture_updown+0x3ff/0x620 [rcutorture
> 1eb1c0a0090f471c5e98b34f024c9030cef829ed]
> [ 809.227155] ? report_bug+0x23e/0x490
> [ 809.227172] ? handle_bug+0x5b/0xa0
> [ 809.227180] ? exc_invalid_op+0x1c/0x50
> [ 809.227188] ? asm_exc_invalid_op+0x1f/0x30
> [ 809.227210] ? hrtimer_try_to_cancel+0x160/0x490
> [ 809.227216] ? _raw_spin_unlock_irqrestore+0x4a/0x80
> [ 809.227225] ? rcu_torture_updown+0x3ff/0x620 [rcutorture
> 1eb1c0a0090f471c5e98b34f024c9030cef829ed]
> [ 809.227255] ? rcu_torture_updown+0x340/0x620 [rcutorture
> 1eb1c0a0090f471c5e98b34f024c9030cef829ed]
> [ 809.227320] ? __pfx_rcu_torture_updown+0x10/0x10 [rcutorture
> 1eb1c0a0090f471c5e98b34f024c9030cef829ed]
> [ 809.227337] kthread+0x3d9/0x810
> [ 809.227349] ? __pfx_kthread+0x10/0x10
> [ 809.227357] ? rt_spin_unlock+0x4c/0x90
> [ 809.227362] ? rt_spin_unlock+0x4c/0x90
> [ 809.227367] ? calculate_sigpending+0x88/0xa0
> [ 809.227372] ? __pfx_kthread+0x10/0x10
> [ 809.227380] ret_from_fork+0x40/0x70
> [ 809.227383] ? __pfx_kthread+0x10/0x10
> [ 809.227390] ret_from_fork_asm+0x1a/0x30
> [ 809.227420] </TASK>
>
> If rtorsu_hrt timer is still in timer_queue, invoke hrtimer_cancel() will
> remove it from timerqueue and directly return, so the rcu_torture_updown_hrt()
> will not be executed and the rtorsup->rtorsu_inuse cannot be set false.
>
> How about modifying it as follows:
>
> diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> index 04d7a2173b95..ecf3d3797f7e 100644
> --- a/kernel/rcu/rcutorture.c
> +++ b/kernel/rcu/rcutorture.c
> @@ -2502,8 +2502,7 @@ static void rcu_torture_updown_cleanup(void)
> for (rtorsup = updownreaders; rtorsup <
> &updownreaders[n_up_down]; rtorsup++) {
> if (!smp_load_acquire(&rtorsup->rtorsu_inuse))
> continue;
> - (void)hrtimer_cancel(&rtorsup->rtorsu_hrt);
> - if (WARN_ON_ONCE(rtorsup->rtorsu_inuse)) {
> + if (hrtimer_cancel(&rtorsup->rtorsu_hrt) ||
> WARN_ON_ONCE(rtorsup->rtorsu_inuse)) {
>
> rcu_torture_one_read_end(&rtorsup->rtorsu_rtors, &rtorsup->rtorsu_trs,
> -1);
> WARN_ONCE(rtorsup->rtorsu_nups >=
> rtorsup->rtorsu_ndowns, "%s: Up without matching down #%zu.\n",
> __func__, rtorsup - updownreaders);
> rtorsup->rtorsu_nups++;
Good eyes, thank you! I have applied this fix with attribution.
Thanx, Paul
> Thanks
> Zqiang
>
> > +
> > + }
> > + kfree(updownreaders);
> > + updownreaders = NULL;
> > +}
> > +
> > +/*
> > + * RCU torture up/down reader kthread, starting RCU readers in kthread
> > + * context and ending them in hrtimer handlers. Otherwise similar to
> > + * rcu_torture_reader().
> > + */
> > +static int
> > +rcu_torture_updown(void *arg)
> > +{
> > + int idx;
> > + int rawidx;
> > + struct rcu_torture_one_read_state_updown *rtorsup;
> > + ktime_t t;
> > +
> > + VERBOSE_TOROUT_STRING("rcu_torture_updown task started");
> > + do {
> > + for (rtorsup = updownreaders; rtorsup <
> > &updownreaders[n_up_down]; rtorsup++) {
> > + if (torture_must_stop())
> > + break;
> > + if (smp_load_acquire(&rtorsup->rtorsu_inuse))
> > + continue;
> > +
> > init_rcu_torture_one_read_state(&rtorsup->rtorsu_rtors,
> > +
> > &rtorsup->rtorsu_trs);
> > + rawidx = cur_ops->down_read();
> > + idx = (rawidx << RCUTORTURE_RDR_SHIFT_1) &
> > RCUTORTURE_RDR_MASK_1;
> > + rtorsup->rtorsu_rtors.readstate = idx |
> > RCUTORTURE_RDR_UPDOWN;
> > + rtorsup->rtorsu_rtors.rtrsp++;
> > + if
> > (!rcu_torture_one_read_start(&rtorsup->rtorsu_rtors,
> > +
> > &rtorsup->rtorsu_trs, -1)) {
> > + cur_ops->up_read(rawidx);
> > + schedule_timeout_idle(HZ);
> > + continue;
> > + }
> > + smp_store_release(&rtorsup->rtorsu_inuse, true);
> > + t = torture_random(&rtorsup->rtorsu_trs) & 0xfffff;
> > // One per million.
> > + if (t < 10 * 1000)
> > + t = 200 * 1000 * 1000;
> > + hrtimer_start(&rtorsup->rtorsu_hrt, t,
> > + HRTIMER_MODE_REL | HRTIMER_MODE_SOFT);
> > + }
> > + torture_hrtimeout_ms(1, 1000, &rcu_torture_updown_rand);
> > + stutter_wait("rcu_torture_updown");
> > + } while (!torture_must_stop());
> > + rcu_torture_updown_cleanup();
> > + torture_kthread_stopping("rcu_torture_updown");
> > + return 0;
> > +}
> > +
> > /*
> > * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to
> > * increase race probabilities and fuzzes the interval between toggling.
> > @@ -2620,7 +2802,7 @@ rcu_torture_print_module_parms(struct rcu_torture_ops
> > *cur_ops, const char *tag)
> > "reader_flavor=%x "
> > "nocbs_nthreads=%d nocbs_toggle=%d "
> > "test_nmis=%d "
> > - "preempt_duration=%d preempt_interval=%d\n",
> > + "preempt_duration=%d preempt_interval=%d n_up_down=%d\n",
> > torture_type, tag, nrealreaders, nrealfakewriters,
> > stat_interval, verbose, test_no_idle_hz, shuffle_interval,
> > stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
> > @@ -2634,7 +2816,7 @@ rcu_torture_print_module_parms(struct rcu_torture_ops
> > *cur_ops, const char *tag)
> > reader_flavor,
> > nocbs_nthreads, nocbs_toggle,
> > test_nmis,
> > - preempt_duration, preempt_interval);
> > + preempt_duration, preempt_interval, n_up_down);
> > }
> >
> > static int rcutorture_booster_cleanup(unsigned int cpu)
> > @@ -3686,6 +3868,10 @@ rcu_torture_cleanup(void)
> > nocb_tasks = NULL;
> > }
> >
> > + if (updown_task) {
> > + torture_stop_kthread(rcu_torture_updown, updown_task);
> > + updown_task = NULL;
> > + }
> > if (reader_tasks) {
> > for (i = 0; i < nrealreaders; i++)
> > torture_stop_kthread(rcu_torture_reader,
> > @@ -4216,6 +4402,9 @@ rcu_torture_init(void)
> > if (torture_init_error(firsterr))
> > goto unwind;
> > }
> > + firsterr = rcu_torture_updown_init();
> > + if (torture_init_error(firsterr))
> > + goto unwind;
> > nrealnocbers = nocbs_nthreads;
> > if (WARN_ON(nrealnocbers < 0))
> > nrealnocbers = 1;
> > --
> > 2.40.1
> >
> >
