Merge branches 'fixes.2021.10.07a', 'scftorture.2021.09.16a', 'tasks.2021.09.15a...

fixes.2021.10.07a: Miscellaneous fixes.
scftorture.2021.09.16a: smp_call_function torture-test updates.
tasks.2021.09.15a: Tasks-trace RCU updates.
torture.2021.09.13b: Other torture-test updates.
torturescript.2021.09.16a: Torture-test scripting updates.

diff --combined kernel/rcu/rcutorture.c
index f640cbd9262c0d2d923d9f5b2e878b99ba2b4623,ab4215266ebee7484227094273ee170c11583a08,ab4215266ebee7484227094273ee170c11583a08,fb079b78c232cbb320bdc5f605c381d9bd33b765,ab4215266ebee7484227094273ee170c11583a08..8b410d982990ce0642d269798e774833f95fb4f5
--- 1/kernel/rcu/rcutorture.c
--- 2/kernel/rcu/rcutorture.c
--- 3/kernel/rcu/rcutorture.c
--- 4/kernel/rcu/rcutorture.c
--- 5/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@@@@@ -1432,28 -1432,28 -1432,28 -1432,34 -1432,28 +1432,34 @@@@@@ static void rcutorture_one_extend(int *
        /* 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_RBH)
--- -           rcu_read_lock_bh();
        if (statesnew & RCUTORTURE_RDR_SCHED)
                rcu_read_lock_sched();
        if (statesnew & RCUTORTURE_RDR_RCU)
                idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT;
     
--- -   /* Next, remove old protection, irq first due to bh conflict. */
+++ +   /*
+++ +    * 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_BH)
--- -           local_bh_enable();
        if (statesold & RCUTORTURE_RDR_PREEMPT)
                preempt_enable();
--- -   if (statesold & RCUTORTURE_RDR_RBH)
--- -           rcu_read_unlock_bh();
        if (statesold & RCUTORTURE_RDR_SCHED)
                rcu_read_unlock_sched();
+++ +   if (statesold & RCUTORTURE_RDR_BH)
+++ +           local_bh_enable();
+++ +   if (statesold & RCUTORTURE_RDR_RBH)
+++ +           rcu_read_unlock_bh();
        if (statesold & RCUTORTURE_RDR_RCU) {
                bool lockit = !statesnew && !(torture_random(trsp) & 0xffff);
     
@@@@@@ -1496,6 -1496,6 -1496,6 -1502,9 -1496,6 +1502,9 @@@@@@ rcutorture_extend_mask(int oldmask, str
        int mask = rcutorture_extend_mask_max();
        unsigned long randmask1 = torture_random(trsp) >> 8;
        unsigned long randmask2 = randmask1 >> 3;
+++ +   unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
+++ +   unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
+++ +   unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
     
        WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
        /* Mostly only one bit (need preemption!), sometimes lots of bits. */
@@@@@@ -1503,11 -1503,11 -1503,11 -1512,26 -1503,11 +1512,26 @@@@@@
                mask = mask & randmask2;
        else
                mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
--- -   /* Can't enable bh w/irq disabled. */
--- -   if ((mask & RCUTORTURE_RDR_IRQ) &&
--- -       ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
--- -        (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
--- -           mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
+++ +
+++ +   /*
+++ +    * 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;
     }
     
@@@@@@ -2449,7 -2449,7 -2449,7 -2473,7 -2449,7 +2473,7 @@@@@@ static int __init rcu_torture_fwd_prog_
        }
        if (stall_cpu > 0) {
                VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
 ----           if (IS_MODULE(CONFIG_RCU_TORTURE_TESTS))
 ++++           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;
@@@@@@ -2741,7 -2741,7 -2741,7 -2765,7 -2741,7 +2765,7 @@@@@@ static int rcu_torture_read_exit(void *
     static int rcu_torture_read_exit_init(void)
     {
        if (read_exit_burst <= 0)
--- -           return -EINVAL;
+++ +           return 0;
        init_waitqueue_head(&read_exit_wq);
        read_exit_child_stop = false;
        read_exit_child_stopped = false;
@@@@@@ -2819,7 -2819,7 -2819,7 -2843,7 -2819,7 +2843,7 @@@@@@ rcu_torture_cleanup(void
                 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())
+++ +   if (rcu_torture_can_boost() && rcutor_hp >= 0)
                cpuhp_remove_state(rcutor_hp);
     
        /*
@@@@@@ -3037,7 -3037,7 -3037,7 -3061,7 -3037,7 +3061,7 @@@@@@ rcu_torture_init(void
        rcu_torture_write_types();
        firsterr = torture_create_kthread(rcu_torture_writer, NULL,
                                          writer_task);
--- -   if (firsterr)
+++ +   if (torture_init_error(firsterr))
                goto unwind;
        if (nfakewriters > 0) {
                fakewriter_tasks = kcalloc(nfakewriters,
@@@@@@ -3052,7 -3052,7 -3052,7 -3076,7 -3052,7 +3076,7 @@@@@@
        for (i = 0; i < nfakewriters; i++) {
                firsterr = torture_create_kthread(rcu_torture_fakewriter,
                                                  NULL, fakewriter_tasks[i]);
--- -           if (firsterr)
+++ +           if (torture_init_error(firsterr))
                        goto unwind;
        }
        reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
@@@@@@ -3068,7 -3068,7 -3068,7 -3092,7 -3068,7 +3092,7 @@@@@@
                rcu_torture_reader_mbchk[i].rtc_chkrdr = -1;
                firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
                                                  reader_tasks[i]);
--- -           if (firsterr)
+++ +           if (torture_init_error(firsterr))
                        goto unwind;
        }
        nrealnocbers = nocbs_nthreads;
@@@@@@ -3088,18 -3088,18 -3088,18 -3112,18 -3088,18 +3112,18 @@@@@@
        }
        for (i = 0; i < nrealnocbers; i++) {
                firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]);
--- -           if (firsterr)
+++ +           if (torture_init_error(firsterr))
                        goto unwind;
        }
        if (stat_interval > 0) {
                firsterr = torture_create_kthread(rcu_torture_stats, NULL,
                                                  stats_task);
--- -           if (firsterr)
+++ +           if (torture_init_error(firsterr))
                        goto unwind;
        }
        if (test_no_idle_hz && shuffle_interval > 0) {
                firsterr = torture_shuffle_init(shuffle_interval * HZ);
--- -           if (firsterr)
+++ +           if (torture_init_error(firsterr))
                        goto unwind;
        }
        if (stutter < 0)
@@@@@@ -3109,7 -3109,7 -3109,7 -3133,7 -3109,7 +3133,7 @@@@@@
     
                t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
                firsterr = torture_stutter_init(stutter * HZ, t);
--- -           if (firsterr)
+++ +           if (torture_init_error(firsterr))
                        goto unwind;
        }
        if (fqs_duration < 0)
@@@@@@ -3118,7 -3118,7 -3118,7 -3142,7 -3118,7 +3142,7 @@@@@@
                /* Create the fqs thread */
                firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
                                                  fqs_task);
--- -           if (firsterr)
+++ +           if (torture_init_error(firsterr))
                        goto unwind;
        }
        if (test_boost_interval < 1)
@@@@@@ -3132,9 -3132,9 -3132,9 -3156,9 -3132,9 +3156,9 @@@@@@
                firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
                                             rcutorture_booster_init,
                                             rcutorture_booster_cleanup);
--- -           if (firsterr < 0)
--- -                   goto unwind;
                rcutor_hp = firsterr;
+++ +           if (torture_init_error(firsterr))
+++ +                   goto unwind;
     
                // Testing RCU priority boosting requires rcutorture do
                // some serious abuse.  Counter this by running ksoftirqd
@@@@@@ -3153,23 -3153,23 -3153,23 -3177,23 -3153,23 +3177,23 @@@@@@
        }
        shutdown_jiffies = jiffies + shutdown_secs * HZ;
        firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
--- -   if (firsterr)
+++ +   if (torture_init_error(firsterr))
                goto unwind;
        firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
                                      rcutorture_sync);
--- -   if (firsterr)
+++ +   if (torture_init_error(firsterr))
                goto unwind;
        firsterr = rcu_torture_stall_init();
--- -   if (firsterr)
+++ +   if (torture_init_error(firsterr))
                goto unwind;
        firsterr = rcu_torture_fwd_prog_init();
--- -   if (firsterr)
+++ +   if (torture_init_error(firsterr))
                goto unwind;
        firsterr = rcu_torture_barrier_init();
--- -   if (firsterr)
+++ +   if (torture_init_error(firsterr))
                goto unwind;
        firsterr = rcu_torture_read_exit_init();
--- -   if (firsterr)
+++ +   if (torture_init_error(firsterr))
                goto unwind;
        if (object_debug)
                rcu_test_debug_objects();