Merge branch 'core-rcu-2021.07.04' of...

Merge branch 'core-rcu-2021.07.04' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull RCU updates from Paul McKenney:

 - Bitmap parsing support for "all" as an alias for all bits

 - Documentation updates

 - Miscellaneous fixes, including some that overlap into mm and lockdep

 - kvfree_rcu() updates

 - mem_dump_obj() updates, with acks from one of the slab-allocator
   maintainers

 - RCU NOCB CPU updates, including limited deoffloading

 - SRCU updates

 - Tasks-RCU updates

 - Torture-test updates

* 'core-rcu-2021.07.04' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (78 commits)
  tasks-rcu: Make show_rcu_tasks_gp_kthreads() be static inline
  rcu-tasks: Make ksoftirqd provide RCU Tasks quiescent states
  rcu: Add missing __releases() annotation
  rcu: Remove obsolete rcu_read_unlock() deadlock commentary
  rcu: Improve comments describing RCU read-side critical sections
  rcu: Create an unrcu_pointer() to remove __rcu from a pointer
  srcu: Early test SRCU polling start
  rcu: Fix various typos in comments
  rcu/nocb: Unify timers
  rcu/nocb: Prepare for fine-grained deferred wakeup
  rcu/nocb: Only cancel nocb timer if not polling
  rcu/nocb: Delete bypass_timer upon nocb_gp wakeup
  rcu/nocb: Cancel nocb_timer upon nocb_gp wakeup
  rcu/nocb: Allow de-offloading rdp leader
  rcu/nocb: Directly call __wake_nocb_gp() from bypass timer
  rcu: Don't penalize priority boosting when there is nothing to boost
  rcu: Point to documentation of ordering guarantees
  rcu: Make rcu_gp_cleanup() be noinline for tracing
  rcu: Restrict RCU_STRICT_GRACE_PERIOD to at most four CPUs
  rcu: Make show_rcu_gp_kthreads() dump rcu_node structures blocking GP
  ...

Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst

@@ -21,7 +21,7 @@ Any code that happens after the end of a given RCU grace period is guaranteed
 to see the effects of all accesses prior to the beginning of that grace
 period that are within RCU read-side critical sections.
 Similarly, any code that happens before the beginning of a given RCU grace
-period is guaranteed to see the effects of all accesses following the end
+period is guaranteed to not see the effects of all accesses following the end
 of that grace period that are within RCU read-side critical sections.
 
 Note well that RCU-sched read-side critical sections include any region
@@ -339,14 +339,14 @@ The diagram below shows the path of ordering if the leftmost
 leftmost ``rcu_node`` structure offlines its last CPU and if the next
 ``rcu_node`` structure has no online CPUs).
 
-.. kernel-figure:: TreeRCU-gp-init-1.svg
+.. kernel-figure:: TreeRCU-gp-init-2.svg
 
 The final ``rcu_gp_init()`` pass through the ``rcu_node`` tree traverses
 breadth-first, setting each ``rcu_node`` structure's ``->gp_seq`` field
 to the newly advanced value from the ``rcu_state`` structure, as shown
 in the following diagram.
 
-.. kernel-figure:: TreeRCU-gp-init-1.svg
+.. kernel-figure:: TreeRCU-gp-init-3.svg
 
 This change will also cause each CPU's next call to
 ``__note_gp_changes()`` to notice that a new grace period has started,

Documentation/admin-guide/kernel-parameters.rst

@@ -76,6 +76,11 @@ to change, such as less cores in the CPU list, then N and any ranges using N
 will also change.  Use the same on a small 4 core system, and "16-N" becomes
 "16-3" and now the same boot input will be flagged as invalid (start > end).
 
+The special case-tolerant group name "all" has a meaning of selecting all CPUs,
+so that "nohz_full=all" is the equivalent of "nohz_full=0-N".
+
+The semantics of "N" and "all" is supported on a level of bitmaps and holds for
+all users of bitmap_parse().
 
 This document may not be entirely up to date and comprehensive. The command
 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable

Documentation/admin-guide/kernel-parameters.txt

@@ -4354,6 +4354,11 @@
 			whole algorithm to behave better in low memory
 			condition.
 
+	rcutree.rcu_delay_page_cache_fill_msec= [KNL]
+			Set the page-cache refill delay (in milliseconds)
+			in response to low-memory conditions.  The range
+			of permitted values is in the range 0:100000.
+
 	rcutree.jiffies_till_first_fqs= [KNL]
 			Set delay from grace-period initialization to
 			first attempt to force quiescent states.

include/linux/rcupdate.h

@@ -315,7 +315,7 @@ static inline int rcu_read_lock_any_held(void)
 #define RCU_LOCKDEP_WARN(c, s)						\
 	do {								\
 		static bool __section(".data.unlikely") __warned;	\
-		if (debug_lockdep_rcu_enabled() && !__warned && (c)) {	\
+		if ((c) && debug_lockdep_rcu_enabled() && !__warned) {	\
 			__warned = true;				\
 			lockdep_rcu_suspicious(__FILE__, __LINE__, s);	\
 		}							\
@@ -373,7 +373,7 @@ static inline void rcu_preempt_sleep_check(void) { }
 #define unrcu_pointer(p)						\
 ({									\
 	typeof(*p) *_________p1 = (typeof(*p) *__force)(p);		\
-	rcu_check_sparse(p, __rcu); 					\
+	rcu_check_sparse(p, __rcu);					\
 	((typeof(*p) __force __kernel *)(_________p1)); 		\
 })
 
@@ -532,7 +532,12 @@ do {									      \
  * @p: The pointer to read, prior to dereferencing
  * @c: The conditions under which the dereference will take place
  *
- * This is the RCU-bh counterpart to rcu_dereference_check().
+ * This is the RCU-bh counterpart to rcu_dereference_check().  However,
+ * please note that starting in v5.0 kernels, vanilla RCU grace periods
+ * wait for local_bh_disable() regions of code in addition to regions of
+ * code demarked by rcu_read_lock() and rcu_read_unlock().  This means
+ * that synchronize_rcu(), call_rcu, and friends all take not only
+ * rcu_read_lock() but also rcu_read_lock_bh() into account.
  */
 #define rcu_dereference_bh_check(p, c) \
 	__rcu_dereference_check((p), (c) || rcu_read_lock_bh_held(), __rcu)
@@ -543,6 +548,11 @@ do {									      \
  * @c: The conditions under which the dereference will take place
  *
  * This is the RCU-sched counterpart to rcu_dereference_check().
+ * However, please note that starting in v5.0 kernels, vanilla RCU grace
+ * periods wait for preempt_disable() regions of code in addition to
+ * regions of code demarked by rcu_read_lock() and rcu_read_unlock().
+ * This means that synchronize_rcu(), call_rcu, and friends all take not
+ * only rcu_read_lock() but also rcu_read_lock_sched() into account.
  */
 #define rcu_dereference_sched_check(p, c) \
 	__rcu_dereference_check((p), (c) || rcu_read_lock_sched_held(), \
@@ -634,6 +644,12 @@ do {									      \
  * sections, invocation of the corresponding RCU callback is deferred
  * until after the all the other CPUs exit their critical sections.
  *
+ * In v5.0 and later kernels, synchronize_rcu() and call_rcu() also
+ * wait for regions of code with preemption disabled, including regions of
+ * code with interrupts or softirqs disabled.  In pre-v5.0 kernels, which
+ * define synchronize_sched(), only code enclosed within rcu_read_lock()
+ * and rcu_read_unlock() are guaranteed to be waited for.
+ *
  * Note, however, that RCU callbacks are permitted to run concurrently
  * with new RCU read-side critical sections.  One way that this can happen
  * is via the following sequence of events: (1) CPU 0 enters an RCU
@@ -686,33 +702,12 @@ static __always_inline void rcu_read_lock(void)
 /**
  * rcu_read_unlock() - marks the end of an RCU read-side critical section.
  *
- * In most situations, rcu_read_unlock() is immune from deadlock.
- * However, in kernels built with CONFIG_RCU_BOOST, rcu_read_unlock()
- * is responsible for deboosting, which it does via rt_mutex_unlock().
- * Unfortunately, this function acquires the scheduler's runqueue and
- * priority-inheritance spinlocks.  This means that deadlock could result
- * if the caller of rcu_read_unlock() already holds one of these locks or
- * any lock that is ever acquired while holding them.
- *
- * That said, RCU readers are never priority boosted unless they were
- * preempted.  Therefore, one way to avoid deadlock is to make sure
- * that preemption never happens within any RCU read-side critical
- * section whose outermost rcu_read_unlock() is called with one of
- * rt_mutex_unlock()'s locks held.  Such preemption can be avoided in
- * a number of ways, for example, by invoking preempt_disable() before
- * critical section's outermost rcu_read_lock().
- *
- * Given that the set of locks acquired by rt_mutex_unlock() might change
- * at any time, a somewhat more future-proofed approach is to make sure
- * that that preemption never happens within any RCU read-side critical
- * section whose outermost rcu_read_unlock() is called with irqs disabled.
- * This approach relies on the fact that rt_mutex_unlock() currently only
- * acquires irq-disabled locks.
- *
- * The second of these two approaches is best in most situations,
- * however, the first approach can also be useful, at least to those
- * developers willing to keep abreast of the set of locks acquired by
- * rt_mutex_unlock().
+ * In almost all situations, rcu_read_unlock() is immune from deadlock.
+ * In recent kernels that have consolidated synchronize_sched() and
+ * synchronize_rcu_bh() into synchronize_rcu(), this deadlock immunity
+ * also extends to the scheduler's runqueue and priority-inheritance
+ * spinlocks, courtesy of the quiescent-state deferral that is carried
+ * out when rcu_read_unlock() is invoked with interrupts disabled.
  *
  * See rcu_read_lock() for more information.
  */
@@ -728,9 +723,11 @@ static inline void rcu_read_unlock(void)
 /**
  * rcu_read_lock_bh() - mark the beginning of an RCU-bh critical section
  *
- * This is equivalent of rcu_read_lock(), but also disables softirqs.
- * Note that anything else that disables softirqs can also serve as
- * an RCU read-side critical section.
+ * This is equivalent to rcu_read_lock(), but also disables softirqs.
+ * Note that anything else that disables softirqs can also serve as an RCU
+ * read-side critical section.  However, please note that this equivalence
+ * applies only to v5.0 and later.  Before v5.0, rcu_read_lock() and
+ * rcu_read_lock_bh() were unrelated.
  *
  * Note that rcu_read_lock_bh() and the matching rcu_read_unlock_bh()
  * must occur in the same context, for example, it is illegal to invoke
@@ -763,9 +760,12 @@ static inline void rcu_read_unlock_bh(void)
 /**
  * rcu_read_lock_sched() - mark the beginning of a RCU-sched critical section
  *
- * This is equivalent of rcu_read_lock(), but disables preemption.
- * Read-side critical sections can also be introduced by anything else
- * that disables preemption, including local_irq_disable() and friends.
+ * This is equivalent to rcu_read_lock(), but also disables preemption.
+ * Read-side critical sections can also be introduced by anything else that
+ * disables preemption, including local_irq_disable() and friends.  However,
+ * please note that the equivalence to rcu_read_lock() applies only to
+ * v5.0 and later.  Before v5.0, rcu_read_lock() and rcu_read_lock_sched()
+ * were unrelated.
  *
  * Note that rcu_read_lock_sched() and the matching rcu_read_unlock_sched()
  * must occur in the same context, for example, it is illegal to invoke

include/linux/rcutiny.h

@@ -86,7 +86,6 @@ static inline void rcu_irq_enter(void) { }
 static inline void rcu_irq_exit_irqson(void) { }
 static inline void rcu_irq_enter_irqson(void) { }
 static inline void rcu_irq_exit(void) { }
-static inline void rcu_irq_exit_preempt(void) { }
 static inline void rcu_irq_exit_check_preempt(void) { }
 #define rcu_is_idle_cpu(cpu) \
 	(is_idle_task(current) && !in_nmi() && !in_irq() && !in_serving_softirq())

include/linux/rcutree.h

@@ -49,7 +49,6 @@ void rcu_idle_enter(void);
 void rcu_idle_exit(void);
 void rcu_irq_enter(void);
 void rcu_irq_exit(void);
-void rcu_irq_exit_preempt(void);
 void rcu_irq_enter_irqson(void);
 void rcu_irq_exit_irqson(void);
 bool rcu_is_idle_cpu(int cpu);

include/linux/srcu.h

@@ -64,6 +64,12 @@ unsigned long get_state_synchronize_srcu(struct srcu_struct *ssp);
 unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp);
 bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie);
 
+#ifdef CONFIG_SRCU
+void srcu_init(void);
+#else /* #ifdef CONFIG_SRCU */
+static inline void srcu_init(void) { }
+#endif /* #else #ifdef CONFIG_SRCU */
+
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 
 /**

include/linux/srcutree.h

@@ -82,9 +82,7 @@ struct srcu_struct {
 						/*  callback for the barrier */
 						/*  operation. */
 	struct delayed_work work;
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map dep_map;
-#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 };
 
 /* Values for state variable (bottom bits of ->srcu_gp_seq). */

include/linux/timer.h

@@ -192,8 +192,6 @@ extern int try_to_del_timer_sync(struct timer_list *timer);
 
 #define del_singleshot_timer_sync(t) del_timer_sync(t)
 
-extern bool timer_curr_running(struct timer_list *timer);
-
 extern void init_timers(void);
 struct hrtimer;
 extern enum hrtimer_restart it_real_fn(struct hrtimer *);

include/trace/events/rcu.h

@@ -278,6 +278,7 @@ TRACE_EVENT_RCU(rcu_exp_funnel_lock,
  * "WakeNot": Don't wake rcuo kthread.
  * "WakeNotPoll": Don't wake rcuo kthread because it is polling.
  * "WakeOvfIsDeferred": Wake rcuo kthread later, CB list is huge.
+ * "WakeBypassIsDeferred": Wake rcuo kthread later, bypass list is contended.
  * "WokeEmpty": rcuo CB kthread woke to find empty list.
  */
 TRACE_EVENT_RCU(rcu_nocb_wake,

init/main.c

@@ -42,6 +42,7 @@
 #include <linux/profile.h>
 #include <linux/kfence.h>
 #include <linux/rcupdate.h>
+#include <linux/srcu.h>
 #include <linux/moduleparam.h>
 #include <linux/kallsyms.h>
 #include <linux/writeback.h>
@@ -1008,6 +1009,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
 	tick_init();
 	rcu_init_nohz();
 	init_timers();
+	srcu_init();
 	hrtimers_init();
 	softirq_init();
 	timekeeping_init();

kernel/locking/lockdep.c

@@ -6506,6 +6506,7 @@ asmlinkage __visible void lockdep_sys_exit(void)
 void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
 {
 	struct task_struct *curr = current;
+	int dl = READ_ONCE(debug_locks);
 
 	/* Note: the following can be executed concurrently, so be careful. */
 	pr_warn("\n");
@@ -6515,11 +6516,12 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
 	pr_warn("-----------------------------\n");
 	pr_warn("%s:%d %s!\n", file, line, s);
 	pr_warn("\nother info that might help us debug this:\n\n");
-	pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
+	pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n%s",
 	       !rcu_lockdep_current_cpu_online()
 			? "RCU used illegally from offline CPU!\n"
 			: "",
-	       rcu_scheduler_active, debug_locks);
+	       rcu_scheduler_active, dl,
+	       dl ? "" : "Possible false positive due to lockdep disabling via debug_locks = 0\n");
 
 	/*
 	 * If a CPU is in the RCU-free window in idle (ie: in the section

kernel/rcu/Kconfig.debug

@@ -116,7 +116,7 @@ config RCU_EQS_DEBUG
 
 config RCU_STRICT_GRACE_PERIOD
 	bool "Provide debug RCU implementation with short grace periods"
-	depends on DEBUG_KERNEL && RCU_EXPERT
+	depends on DEBUG_KERNEL && RCU_EXPERT && NR_CPUS <= 4
 	default n
 	select PREEMPT_COUNT if PREEMPT=n
 	help

kernel/rcu/rcu.h

@@ -308,6 +308,8 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
 	}
 }
 
+extern void rcu_init_geometry(void);
+
 /* Returns a pointer to the first leaf rcu_node structure. */
 #define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])
 
@@ -422,12 +424,6 @@ do {									\
 
 #endif /* #if defined(CONFIG_SRCU) || !defined(CONFIG_TINY_RCU) */
 
-#ifdef CONFIG_SRCU
-void srcu_init(void);
-#else /* #ifdef CONFIG_SRCU */
-static inline void srcu_init(void) { }
-#endif /* #else #ifdef CONFIG_SRCU */
-
 #ifdef CONFIG_TINY_RCU
 /* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
 static inline bool rcu_gp_is_normal(void) { return true; }
@@ -441,7 +437,11 @@ bool rcu_gp_is_expedited(void);  /* Internal RCU use. */
 void rcu_expedite_gp(void);
 void rcu_unexpedite_gp(void);
 void rcupdate_announce_bootup_oddness(void);
+#ifdef CONFIG_TASKS_RCU_GENERIC
 void show_rcu_tasks_gp_kthreads(void);
+#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
+static inline void show_rcu_tasks_gp_kthreads(void) {}
+#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
 void rcu_request_urgent_qs_task(struct task_struct *t);
 #endif /* #else #ifdef CONFIG_TINY_RCU */
 
@@ -519,6 +519,7 @@ static inline unsigned long rcu_exp_batches_completed(void) { return 0; }
 static inline unsigned long
 srcu_batches_completed(struct srcu_struct *sp) { return 0; }
 static inline void rcu_force_quiescent_state(void) { }
+static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; }
 static inline void show_rcu_gp_kthreads(void) { }
 static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
 static inline void rcu_fwd_progress_check(unsigned long j) { }
@@ -527,6 +528,7 @@ bool rcu_dynticks_zero_in_eqs(int cpu, int *vp);
 unsigned long rcu_get_gp_seq(void);
 unsigned long rcu_exp_batches_completed(void);
 unsigned long srcu_batches_completed(struct srcu_struct *sp);
+bool rcu_check_boost_fail(unsigned long gp_state, int *cpup);
 void show_rcu_gp_kthreads(void);
 int rcu_get_gp_kthreads_prio(void);
 void rcu_fwd_progress_check(unsigned long j);

kernel/rcu/refscale.c

@@ -362,6 +362,111 @@ static struct ref_scale_ops rwsem_ops = {
 	.name		= "rwsem"
 };
 
+// Definitions for global spinlock
+static DEFINE_SPINLOCK(test_lock);
+
+static void ref_lock_section(const int nloops)
+{
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		spin_lock(&test_lock);
+		spin_unlock(&test_lock);
+	}
+	preempt_enable();
+}
+
+static void ref_lock_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		spin_lock(&test_lock);
+		un_delay(udl, ndl);
+		spin_unlock(&test_lock);
+	}
+	preempt_enable();
+}
+
+static struct ref_scale_ops lock_ops = {
+	.readsection	= ref_lock_section,
+	.delaysection	= ref_lock_delay_section,
+	.name		= "lock"
+};
+
+// Definitions for global irq-save spinlock
+
+static void ref_lock_irq_section(const int nloops)
+{
+	unsigned long flags;
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		spin_lock_irqsave(&test_lock, flags);
+		spin_unlock_irqrestore(&test_lock, flags);
+	}
+	preempt_enable();
+}
+
+static void ref_lock_irq_delay_section(const int nloops, const int udl, const int ndl)
+{
+	unsigned long flags;
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		spin_lock_irqsave(&test_lock, flags);
+		un_delay(udl, ndl);
+		spin_unlock_irqrestore(&test_lock, flags);
+	}
+	preempt_enable();
+}
+
+static struct ref_scale_ops lock_irq_ops = {
+	.readsection	= ref_lock_irq_section,
+	.delaysection	= ref_lock_irq_delay_section,
+	.name		= "lock-irq"
+};
+
+// Definitions acquire-release.
+static DEFINE_PER_CPU(unsigned long, test_acqrel);
+
+static void ref_acqrel_section(const int nloops)
+{
+	unsigned long x;
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		x = smp_load_acquire(this_cpu_ptr(&test_acqrel));
+		smp_store_release(this_cpu_ptr(&test_acqrel), x + 1);
+	}
+	preempt_enable();
+}
+
+static void ref_acqrel_delay_section(const int nloops, const int udl, const int ndl)
+{
+	unsigned long x;
+	int i;
+
+	preempt_disable();
+	for (i = nloops; i >= 0; i--) {
+		x = smp_load_acquire(this_cpu_ptr(&test_acqrel));
+		un_delay(udl, ndl);
+		smp_store_release(this_cpu_ptr(&test_acqrel), x + 1);
+	}
+	preempt_enable();
+}
+
+static struct ref_scale_ops acqrel_ops = {
+	.readsection	= ref_acqrel_section,
+	.delaysection	= ref_acqrel_delay_section,
+	.name		= "acqrel"
+};
+
 static void rcu_scale_one_reader(void)
 {
 	if (readdelay <= 0)
@@ -653,8 +758,8 @@ ref_scale_init(void)
 	long i;
 	int firsterr = 0;
 	static struct ref_scale_ops *scale_ops[] = {
-		&rcu_ops, &srcu_ops, &rcu_trace_ops, &rcu_tasks_ops,
-		&refcnt_ops, &rwlock_ops, &rwsem_ops,
+		&rcu_ops, &srcu_ops, &rcu_trace_ops, &rcu_tasks_ops, &refcnt_ops, &rwlock_ops,
+		&rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops,
 	};
 
 	if (!torture_init_begin(scale_type, verbose))

kernel/rcu/srcutree.c

@@ -80,7 +80,7 @@ do {									\
  * srcu_read_unlock() running against them.  So if the is_static parameter
  * is set, don't initialize ->srcu_lock_count[] and ->srcu_unlock_count[].
  */
-static void init_srcu_struct_nodes(struct srcu_struct *ssp, bool is_static)
+static void init_srcu_struct_nodes(struct srcu_struct *ssp)
 {
 	int cpu;
 	int i;
@@ -90,6 +90,9 @@ static void init_srcu_struct_nodes(struct srcu_struct *ssp, bool is_static)
 	struct srcu_node *snp;
 	struct srcu_node *snp_first;
 
+	/* Initialize geometry if it has not already been initialized. */
+	rcu_init_geometry();
+
 	/* Work out the overall tree geometry. */
 	ssp->level[0] = &ssp->node[0];
 	for (i = 1; i < rcu_num_lvls; i++)
@@ -148,14 +151,6 @@ static void init_srcu_struct_nodes(struct srcu_struct *ssp, bool is_static)
 		timer_setup(&sdp->delay_work, srcu_delay_timer, 0);
 		sdp->ssp = ssp;
 		sdp->grpmask = 1 << (cpu - sdp->mynode->grplo);
-		if (is_static)
-			continue;
-
-		/* Dynamically allocated, better be no srcu_read_locks()! */
-		for (i = 0; i < ARRAY_SIZE(sdp->srcu_lock_count); i++) {
-			sdp->srcu_lock_count[i] = 0;
-			sdp->srcu_unlock_count[i] = 0;
-		}
 	}
 }
 
@@ -179,7 +174,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
 		ssp->sda = alloc_percpu(struct srcu_data);
 	if (!ssp->sda)
 		return -ENOMEM;
-	init_srcu_struct_nodes(ssp, is_static);
+	init_srcu_struct_nodes(ssp);
 	ssp->srcu_gp_seq_needed_exp = 0;
 	ssp->srcu_last_gp_end = ktime_get_mono_fast_ns();
 	smp_store_release(&ssp->srcu_gp_seq_needed, 0); /* Init done. */
@@ -777,9 +772,9 @@ static bool srcu_might_be_idle(struct srcu_struct *ssp)
 	spin_unlock_irqrestore_rcu_node(sdp, flags);
 
 	/*
-	 * No local callbacks, so probabalistically probe global state.
+	 * No local callbacks, so probabilistically probe global state.
 	 * Exact information would require acquiring locks, which would
-	 * kill scalability, hence the probabalistic nature of the probe.
+	 * kill scalability, hence the probabilistic nature of the probe.
 	 */
 
 	/* First, see if enough time has passed since the last GP. */
@@ -1000,6 +995,9 @@ EXPORT_SYMBOL_GPL(synchronize_srcu_expedited);
  * synchronize_srcu(), srcu_read_lock(), and srcu_read_unlock() are
  * passed the same srcu_struct structure.
  *
+ * Implementation of these memory-ordering guarantees is similar to
+ * that of synchronize_rcu().
+ *
  * If SRCU is likely idle, expedite the first request.  This semantic
  * was provided by Classic SRCU, and is relied upon by its users, so TREE
  * SRCU must also provide it.  Note that detecting idleness is heuristic
@@ -1392,11 +1390,15 @@ void __init srcu_init(void)
 {
 	struct srcu_struct *ssp;
 
+	/*
+	 * Once that is set, call_srcu() can follow the normal path and
+	 * queue delayed work. This must follow RCU workqueues creation
+	 * and timers initialization.
+	 */
 	srcu_init_done = true;
 	while (!list_empty(&srcu_boot_list)) {
 		ssp = list_first_entry(&srcu_boot_list, struct srcu_struct,
 				      work.work.entry);
-		check_init_srcu_struct(ssp);
 		list_del_init(&ssp->work.work.entry);
 		queue_work(rcu_gp_wq, &ssp->work.work);
 	}

kernel/rcu/sync.c

@@ -94,9 +94,9 @@ static void rcu_sync_func(struct rcu_head *rhp)
 		rcu_sync_call(rsp);
 	} else {
 		/*
-		 * We're at least a GP after the last rcu_sync_exit(); eveybody
+		 * We're at least a GP after the last rcu_sync_exit(); everybody
 		 * will now have observed the write side critical section.
-		 * Let 'em rip!.
+		 * Let 'em rip!
 		 */
 		WRITE_ONCE(rsp->gp_state, GP_IDLE);
 	}

kernel/rcu/tasks.h

@@ -23,7 +23,7 @@ typedef void (*postgp_func_t)(struct rcu_tasks *rtp);
  * struct rcu_tasks - Definition for a Tasks-RCU-like mechanism.
  * @cbs_head: Head of callback list.
  * @cbs_tail: Tail pointer for callback list.
- * @cbs_wq: Wait queue allowning new callback to get kthread's attention.
+ * @cbs_wq: Wait queue allowing new callback to get kthread's attention.
  * @cbs_lock: Lock protecting callback list.
  * @kthread_ptr: This flavor's grace-period/callback-invocation kthread.
  * @gp_func: This flavor's grace-period-wait function.
@@ -377,6 +377,46 @@ static void rcu_tasks_wait_gp(struct rcu_tasks *rtp)
 // Finally, this implementation does not support high call_rcu_tasks()
 // rates from multiple CPUs.  If this is required, per-CPU callback lists
 // will be needed.
+//
+// The implementation uses rcu_tasks_wait_gp(), which relies on function
+// pointers in the rcu_tasks structure.  The rcu_spawn_tasks_kthread()
+// function sets these function pointers up so that rcu_tasks_wait_gp()
+// invokes these functions in this order:
+//
+// rcu_tasks_pregp_step():
+//	Invokes synchronize_rcu() in order to wait for all in-flight
+//	t->on_rq and t->nvcsw transitions to complete.	This works because
+//	all such transitions are carried out with interrupts disabled.
+// rcu_tasks_pertask(), invoked on every non-idle task:
+//	For every runnable non-idle task other than the current one, use
+//	get_task_struct() to pin down that task, snapshot that task's
+//	number of voluntary context switches, and add that task to the
+//	holdout list.
+// rcu_tasks_postscan():
+//	Invoke synchronize_srcu() to ensure that all tasks that were
+//	in the process of exiting (and which thus might not know to
+//	synchronize with this RCU Tasks grace period) have completed
+//	exiting.
+// check_all_holdout_tasks(), repeatedly until holdout list is empty:
+//	Scans the holdout list, attempting to identify a quiescent state
+//	for each task on the list.  If there is a quiescent state, the
+//	corresponding task is removed from the holdout list.
+// rcu_tasks_postgp():
+//	Invokes synchronize_rcu() in order to ensure that all prior
+//	t->on_rq and t->nvcsw transitions are seen by all CPUs and tasks
+//	to have happened before the end of this RCU Tasks grace period.
+//	Again, this works because all such transitions are carried out
+//	with interrupts disabled.
+//
+// For each exiting task, the exit_tasks_rcu_start() and
+// exit_tasks_rcu_finish() functions begin and end, respectively, the SRCU
+// read-side critical sections waited for by rcu_tasks_postscan().
+//
+// Pre-grace-period update-side code is ordered before the grace via the
+// ->cbs_lock and the smp_mb__after_spinlock().  Pre-grace-period read-side
+// code is ordered before the grace period via synchronize_rcu() call
+// in rcu_tasks_pregp_step() and by the scheduler's locks and interrupt
+// disabling.
 
 /* Pre-grace-period preparation. */
 static void rcu_tasks_pregp_step(void)
@@ -504,7 +544,7 @@ DEFINE_RCU_TASKS(rcu_tasks, rcu_tasks_wait_gp, call_rcu_tasks, "RCU Tasks");
  * or transition to usermode execution.  As such, there are no read-side
  * primitives analogous to rcu_read_lock() and rcu_read_unlock() because
  * this primitive is intended to determine that all tasks have passed
- * through a safe state, not so much for data-strcuture synchronization.
+ * through a safe state, not so much for data-structure synchronization.
  *
  * See the description of call_rcu() for more detailed information on
  * memory ordering guarantees.
@@ -605,8 +645,13 @@ void exit_tasks_rcu_finish(void) { exit_tasks_rcu_finish_trace(current); }
 // passing an empty function to schedule_on_each_cpu().  This approach
 // provides an asynchronous call_rcu_tasks_rude() API and batching
 // of concurrent calls to the synchronous synchronize_rcu_rude() API.
-// This sends IPIs far and wide and induces otherwise unnecessary context
-// switches on all online CPUs, whether idle or not.
+// This invokes schedule_on_each_cpu() in order to send IPIs far and wide
+// and induces otherwise unnecessary context switches on all online CPUs,
+// whether idle or not.
+//
+// Callback handling is provided by the rcu_tasks_kthread() function.
+//
+// Ordering is provided by the scheduler's context-switch code.
 
 // Empty function to allow workqueues to force a context switch.
 static void rcu_tasks_be_rude(struct work_struct *work)
@@ -637,7 +682,7 @@ DEFINE_RCU_TASKS(rcu_tasks_rude, rcu_tasks_rude_wait_gp, call_rcu_tasks_rude,
  * there are no read-side primitives analogous to rcu_read_lock() and
  * rcu_read_unlock() because this primitive is intended to determine
  * that all tasks have passed through a safe state, not so much for
- * data-strcuture synchronization.
+ * data-structure synchronization.
  *
  * See the description of call_rcu() for more detailed information on
  * memory ordering guarantees.
@@ -1163,7 +1208,7 @@ static void exit_tasks_rcu_finish_trace(struct task_struct *t)
  * there are no read-side primitives analogous to rcu_read_lock() and
  * rcu_read_unlock() because this primitive is intended to determine
  * that all tasks have passed through a safe state, not so much for
- * data-strcuture synchronization.
+ * data-structure synchronization.
  *
  * See the description of call_rcu() for more detailed information on
  * memory ordering guarantees.
@@ -1356,5 +1401,4 @@ void __init rcu_init_tasks_generic(void)
 
 #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
 static inline void rcu_tasks_bootup_oddness(void) {}
-void show_rcu_tasks_gp_kthreads(void) {}
 #endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */

kernel/rcu/tiny.c

@@ -221,5 +221,4 @@ void __init rcu_init(void)
 {
 	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
 	rcu_early_boot_tests();
-	srcu_init();
 }

kernel/rcu/tree.h

@@ -115,6 +115,7 @@ struct rcu_node {
 				/*  boosting for this rcu_node structure. */
 	unsigned int boost_kthread_status;
 				/* State of boost_kthread_task for tracing. */
+	unsigned long n_boosts;	/* Number of boosts for this rcu_node structure. */
 #ifdef CONFIG_RCU_NOCB_CPU
 	struct swait_queue_head nocb_gp_wq[2];
 				/* Place for rcu_nocb_kthread() to wait GP. */
@@ -153,7 +154,7 @@ struct rcu_data {
 	unsigned long	gp_seq;		/* Track rsp->gp_seq counter. */
 	unsigned long	gp_seq_needed;	/* Track furthest future GP request. */
 	union rcu_noqs	cpu_no_qs;	/* No QSes yet for this CPU. */
-	bool		core_needs_qs;	/* Core waits for quiesc state. */
+	bool		core_needs_qs;	/* Core waits for quiescent state. */
 	bool		beenonline;	/* CPU online at least once. */
 	bool		gpwrap;		/* Possible ->gp_seq wrap. */
 	bool		exp_deferred_qs; /* This CPU awaiting a deferred QS? */
@@ -218,7 +219,6 @@ struct rcu_data {
 
 	/* The following fields are used by GP kthread, hence own cacheline. */
 	raw_spinlock_t nocb_gp_lock ____cacheline_internodealigned_in_smp;
-	struct timer_list nocb_bypass_timer; /* Force nocb_bypass flush. */
 	u8 nocb_gp_sleep;		/* Is the nocb GP thread asleep? */
 	u8 nocb_gp_bypass;		/* Found a bypass on last scan? */
 	u8 nocb_gp_gp;			/* GP to wait for on last scan? */
@@ -257,10 +257,10 @@ struct rcu_data {
 };
 
 /* Values for nocb_defer_wakeup field in struct rcu_data. */
-#define RCU_NOCB_WAKE_OFF	-1
 #define RCU_NOCB_WAKE_NOT	0
-#define RCU_NOCB_WAKE		1
-#define RCU_NOCB_WAKE_FORCE	2
+#define RCU_NOCB_WAKE_BYPASS	1
+#define RCU_NOCB_WAKE		2
+#define RCU_NOCB_WAKE_FORCE	3
 
 #define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500))
 					/* For jiffies_till_first_fqs and */
@@ -417,8 +417,8 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
 static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
 static bool rcu_is_callbacks_kthread(void);
 static void rcu_cpu_kthread_setup(unsigned int cpu);
+static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp);
 static void __init rcu_spawn_boost_kthreads(void);
-static void rcu_prepare_kthreads(int cpu);
 static void rcu_cleanup_after_idle(void);
 static void rcu_prepare_for_idle(void);
 static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
@@ -434,7 +434,7 @@ static bool rcu_nocb_try_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
 				bool *was_alldone, unsigned long flags);
 static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_empty,
 				 unsigned long flags);
-static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp);
+static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level);
 static bool do_nocb_deferred_wakeup(struct rcu_data *rdp);
 static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp);
 static void rcu_spawn_cpu_nocb_kthread(int cpu);

kernel/rcu/tree_stall.h

@@ -314,6 +314,7 @@ static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
  * tasks blocked within RCU read-side critical sections.
  */
 static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags)
+	__releases(rnp->lock)
 {
 	raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
 	return 0;
@@ -716,6 +717,63 @@ static void check_cpu_stall(struct rcu_data *rdp)
 // RCU forward-progress mechanisms, including of callback invocation.
 
 
+/*
+ * Check to see if a failure to end RCU priority inversion was due to
+ * a CPU not passing through a quiescent state.  When this happens, there
+ * is nothing that RCU priority boosting can do to help, so we shouldn't
+ * count this as an RCU priority boosting failure.  A return of true says
+ * RCU priority boosting is to blame, and false says otherwise.  If false
+ * is returned, the first of the CPUs to blame is stored through cpup.
+ * If there was no CPU blocking the current grace period, but also nothing
+ * in need of being boosted, *cpup is set to -1.  This can happen in case
+ * of vCPU preemption while the last CPU is reporting its quiscent state,
+ * for example.
+ *
+ * If cpup is NULL, then a lockless quick check is carried out, suitable
+ * for high-rate usage.  On the other hand, if cpup is non-NULL, each
+ * rcu_node structure's ->lock is acquired, ruling out high-rate usage.
+ */
+bool rcu_check_boost_fail(unsigned long gp_state, int *cpup)
+{
+	bool atb = false;
+	int cpu;
+	unsigned long flags;
+	struct rcu_node *rnp;
+
+	rcu_for_each_leaf_node(rnp) {
+		if (!cpup) {
+			if (READ_ONCE(rnp->qsmask)) {
+				return false;
+			} else {
+				if (READ_ONCE(rnp->gp_tasks))
+					atb = true;
+				continue;
+			}
+		}
+		*cpup = -1;
+		raw_spin_lock_irqsave_rcu_node(rnp, flags);
+		if (rnp->gp_tasks)
+			atb = true;
+		if (!rnp->qsmask) {
+			// No CPUs without quiescent states for this rnp.
+			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+			continue;
+		}
+		// Find the first holdout CPU.
+		for_each_leaf_node_possible_cpu(rnp, cpu) {
+			if (rnp->qsmask & (1UL << (cpu - rnp->grplo))) {
+				raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+				*cpup = cpu;
+				return false;
+			}
+		}
+		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+	}
+	// Can't blame CPUs, so must blame RCU priority boosting.
+	return atb;
+}
+EXPORT_SYMBOL_GPL(rcu_check_boost_fail);
+
 /*
  * Show the state of the grace-period kthreads.
  */
@@ -726,6 +784,7 @@ void show_rcu_gp_kthreads(void)
 	unsigned long j;
 	unsigned long ja;
 	unsigned long jr;
+	unsigned long js;
 	unsigned long jw;
 	struct rcu_data *rdp;
 	struct rcu_node *rnp;
@@ -734,21 +793,30 @@ void show_rcu_gp_kthreads(void)
 	j = jiffies;
 	ja = j - data_race(rcu_state.gp_activity);
 	jr = j - data_race(rcu_state.gp_req_activity);
+	js = j - data_race(rcu_state.gp_start);
 	jw = j - data_race(rcu_state.gp_wake_time);
-	pr_info("%s: wait state: %s(%d) ->state: %#x delta ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_flags %#x\n",
+	pr_info("%s: wait state: %s(%d) ->state: %#lx ->rt_priority %u delta ->gp_start %lu ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_max %lu ->gp_flags %#x\n",
 		rcu_state.name, gp_state_getname(rcu_state.gp_state),
-		rcu_state.gp_state, t ? t->__state : 0x1ffff,
-		ja, jr, jw, (long)data_race(rcu_state.gp_wake_seq),
+		rcu_state.gp_state, t ? t->__state : 0x1ffffL, t ? t->rt_priority : 0xffU,
+		js, ja, jr, jw, (long)data_race(rcu_state.gp_wake_seq),
 		(long)data_race(rcu_state.gp_seq),
 		(long)data_race(rcu_get_root()->gp_seq_needed),
+		data_race(rcu_state.gp_max),
 		data_race(rcu_state.gp_flags));
 	rcu_for_each_node_breadth_first(rnp) {
-		if (ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq),
-				 READ_ONCE(rnp->gp_seq_needed)))
+		if (ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq), READ_ONCE(rnp->gp_seq_needed)) &&
+		    !data_race(rnp->qsmask) && !data_race(rnp->boost_tasks) &&
+		    !data_race(rnp->exp_tasks) && !data_race(rnp->gp_tasks))
 			continue;
-		pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld\n",
-			rnp->grplo, rnp->grphi, (long)data_race(rnp->gp_seq),
-			(long)data_race(rnp->gp_seq_needed));
+		pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld ->qsmask %#lx %c%c%c%c ->n_boosts %ld\n",
+			rnp->grplo, rnp->grphi,
+			(long)data_race(rnp->gp_seq), (long)data_race(rnp->gp_seq_needed),
+			data_race(rnp->qsmask),
+			".b"[!!data_race(rnp->boost_kthread_task)],
+			".B"[!!data_race(rnp->boost_tasks)],
+			".E"[!!data_race(rnp->exp_tasks)],
+			".G"[!!data_race(rnp->gp_tasks)],
+			data_race(rnp->n_boosts));
 		if (!rcu_is_leaf_node(rnp))
 			continue;
 		for_each_leaf_node_possible_cpu(rnp, cpu) {

kernel/rcu/update.c

@@ -277,7 +277,7 @@ EXPORT_SYMBOL_GPL(rcu_callback_map);
 
 noinstr int notrace debug_lockdep_rcu_enabled(void)
 {
-	return rcu_scheduler_active != RCU_SCHEDULER_INACTIVE && debug_locks &&
+	return rcu_scheduler_active != RCU_SCHEDULER_INACTIVE && READ_ONCE(debug_locks) &&
 	       current->lockdep_recursion == 0;
 }
 EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
@@ -524,6 +524,7 @@ static void test_callback(struct rcu_head *r)
 }
 
 DEFINE_STATIC_SRCU(early_srcu);
+static unsigned long early_srcu_cookie;
 
 struct early_boot_kfree_rcu {
 	struct rcu_head rh;
@@ -536,8 +537,10 @@ static void early_boot_test_call_rcu(void)
 	struct early_boot_kfree_rcu *rhp;
 
 	call_rcu(&head, test_callback);
-	if (IS_ENABLED(CONFIG_SRCU))
+	if (IS_ENABLED(CONFIG_SRCU)) {
+		early_srcu_cookie = start_poll_synchronize_srcu(&early_srcu);
 		call_srcu(&early_srcu, &shead, test_callback);
+	}
 	rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
 	if (!WARN_ON_ONCE(!rhp))
 		kfree_rcu(rhp, rh);
@@ -563,6 +566,7 @@ static int rcu_verify_early_boot_tests(void)
 		if (IS_ENABLED(CONFIG_SRCU)) {
 			early_boot_test_counter++;
 			srcu_barrier(&early_srcu);
+			WARN_ON_ONCE(!poll_state_synchronize_srcu(&early_srcu, early_srcu_cookie));
 		}
 	}
 	if (rcu_self_test_counter != early_boot_test_counter) {

kernel/time/timer.c

@@ -1237,20 +1237,6 @@ int try_to_del_timer_sync(struct timer_list *timer)
 }
 EXPORT_SYMBOL(try_to_del_timer_sync);
 
-bool timer_curr_running(struct timer_list *timer)
-{
-	int i;
-
-	for (i = 0; i < NR_BASES; i++) {
-		struct timer_base *base = this_cpu_ptr(&timer_bases[i]);
-
-		if (base->running_timer == timer)
-			return true;
-	}
-
-	return false;
-}
-
 #ifdef CONFIG_PREEMPT_RT
 static __init void timer_base_init_expiry_lock(struct timer_base *base)
 {

lib/bitmap.c

@@ -581,6 +581,14 @@ static const char *bitmap_parse_region(const char *str, struct region *r)
 {
 	unsigned int lastbit = r->nbits - 1;
 
+	if (!strncasecmp(str, "all", 3)) {
+		r->start = 0;
+		r->end = lastbit;
+		str += 3;
+
+		goto check_pattern;
+	}
+
 	str = bitmap_getnum(str, &r->start, lastbit);
 	if (IS_ERR(str))
 		return str;
@@ -595,6 +603,7 @@ static const char *bitmap_parse_region(const char *str, struct region *r)
 	if (IS_ERR(str))
 		return str;
 
+check_pattern:
 	if (end_of_region(*str))
 		goto no_pattern;
 

lib/test_bitmap.c

@@ -366,6 +366,13 @@ static const struct test_bitmap_parselist parselist_tests[] __initconst = {
 	{0, "0-31:1/3,1-31:1/3,2-31:1/3",	&exp1[8 * step], 32, 0},
 	{0, "1-10:8/12,8-31:24/29,0-31:0/3",	&exp1[9 * step], 32, 0},
 
+	{0,	  "all",		&exp1[8 * step], 32, 0},
+	{0,	  "0, 1, all,  ",	&exp1[8 * step], 32, 0},
+	{0,	  "all:1/2",		&exp1[4 * step], 32, 0},
+	{0,	  "ALL:1/2",		&exp1[4 * step], 32, 0},
+	{-EINVAL, "al", NULL, 8, 0},
+	{-EINVAL, "alll", NULL, 8, 0},
+
 	{-EINVAL, "-1",	NULL, 8, 0},
 	{-EINVAL, "-0",	NULL, 8, 0},
 	{-EINVAL, "10-1", NULL, 8, 0},

mm/oom_kill.c

@@ -922,7 +922,7 @@ static void __oom_kill_process(struct task_struct *victim, const char *message)
 			continue;
 		}
 		/*
-		 * No kthead_use_mm() user needs to read from the userspace so
+		 * No kthread_use_mm() user needs to read from the userspace so
 		 * we are ok to reap it.
 		 */
 		if (unlikely(p->flags & PF_KTHREAD))

mm/slab.h

@@ -634,6 +634,7 @@ struct kmem_obj_info {
 	struct kmem_cache *kp_slab_cache;
 	void *kp_ret;
 	void *kp_stack[KS_ADDRS_COUNT];
+	void *kp_free_stack[KS_ADDRS_COUNT];
 };
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page);
 #endif

mm/slab_common.c

@@ -575,7 +575,7 @@ EXPORT_SYMBOL_GPL(kmem_valid_obj);
  * depends on the type of object and on how much debugging is enabled.
  * For a slab-cache object, the fact that it is a slab object is printed,
  * and, if available, the slab name, return address, and stack trace from
- * the allocation of that object.
+ * the allocation and last free path of that object.
  *
  * This function will splat if passed a pointer to a non-slab object.
  * If you are not sure what type of object you have, you should instead
@@ -620,6 +620,16 @@ void kmem_dump_obj(void *object)
 			break;
 		pr_info("    %pS\n", kp.kp_stack[i]);
 	}
+
+	if (kp.kp_free_stack[0])
+		pr_cont(" Free path:\n");
+
+	for (i = 0; i < ARRAY_SIZE(kp.kp_free_stack); i++) {
+		if (!kp.kp_free_stack[i])
+			break;
+		pr_info("    %pS\n", kp.kp_free_stack[i]);
+	}
+
 }
 EXPORT_SYMBOL_GPL(kmem_dump_obj);
 #endif

mm/slub.c

@@ -4045,6 +4045,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 	    !(s->flags & SLAB_STORE_USER))
 		return;
 #ifdef CONFIG_SLUB_DEBUG
+	objp = fixup_red_left(s, objp);
 	trackp = get_track(s, objp, TRACK_ALLOC);
 	kpp->kp_ret = (void *)trackp->addr;
 #ifdef CONFIG_STACKTRACE
@@ -4053,6 +4054,13 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 		if (!kpp->kp_stack[i])
 			break;
 	}
+
+	trackp = get_track(s, objp, TRACK_FREE);
+	for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) {
+		kpp->kp_free_stack[i] = (void *)trackp->addrs[i];
+		if (!kpp->kp_free_stack[i])
+			break;
+	}
 #endif
 #endif
 }

mm/util.c

@@ -983,7 +983,7 @@ int __weak memcmp_pages(struct page *page1, struct page *page2)
  * depends on the type of object and on how much debugging is enabled.
  * For example, for a slab-cache object, the slab name is printed, and,
  * if available, the return address and stack trace from the allocation
- * of that object.
+ * and last free path of that object.
  */
 void mem_dump_obj(void *object)
 {

tools/rcu/rcu-cbs.py

+#!/usr/bin/env drgn
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Dump out the number of RCU callbacks outstanding.
+#
+# On older kernels having multiple flavors of RCU, this dumps out the
+# number of callbacks for the most heavily used flavor.
+#
+# Usage: sudo drgn rcu-cbs.py
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+import sys
+import drgn
+from drgn import NULL, Object
+from drgn.helpers.linux import *
+
+def get_rdp0(prog):
+	try:
+		rdp0 = prog.variable('rcu_preempt_data', 'kernel/rcu/tree.c');
+	except LookupError:
+		rdp0 = NULL;
+
+	if rdp0 == NULL:
+		try:
+			rdp0 = prog.variable('rcu_sched_data',
+					     'kernel/rcu/tree.c');
+		except LookupError:
+			rdp0 = NULL;
+
+	if rdp0 == NULL:
+		rdp0 = prog.variable('rcu_data', 'kernel/rcu/tree.c');
+	return rdp0.address_of_();
+
+rdp0 = get_rdp0(prog);
+
+# Sum up RCU callbacks.
+sum = 0;
+for cpu in for_each_possible_cpu(prog):
+	rdp = per_cpu_ptr(rdp0, cpu);
+	len = rdp.cblist.len.value_();
+	# print("CPU " + str(cpu) + " RCU callbacks: " + str(len));
+	sum += len;
+print("Number of RCU callbacks in flight: " + str(sum));

tools/testing/selftests/rcutorture/bin/kvm-again.sh

@@ -29,7 +29,7 @@ then
 	echo "Usage: $scriptname /path/to/old/run [ options ]"
 	exit 1
 fi
-if ! cp "$oldrun/batches" $T/batches.oldrun
+if ! cp "$oldrun/scenarios" $T/scenarios.oldrun
 then
 	# Later on, can reconstitute this from console.log files.
 	echo Prior run batches file does not exist: $oldrun/batches
@@ -143,6 +143,8 @@ then
 	usage
 fi
 rm -f "$rundir"/*/{console.log,console.log.diags,qemu_pid,qemu-retval,Warnings,kvm-test-1-run.sh.out,kvm-test-1-run-qemu.sh.out,vmlinux} "$rundir"/log
+touch "$rundir/log"
+echo $scriptname $args | tee -a "$rundir/log"
 echo $oldrun > "$rundir/re-run"
 if ! test -d "$rundir/../../bin"
 then
@@ -165,22 +167,12 @@ done
 grep '^#' $i | sed -e 's/^# //' > $T/qemu-cmd-settings
 . $T/qemu-cmd-settings
 
-grep -v '^#' $T/batches.oldrun | awk '
-BEGIN {
-	oldbatch = 1;
-}
-
+grep -v '^#' $T/scenarios.oldrun | awk '
 {
-	if (oldbatch != $1) {
-		print "kvm-test-1-run-batch.sh" curbatch;
-		curbatch = "";
-		oldbatch = $1;
-	}
-	curbatch = curbatch " " $2;
-}
-
-END {
-	print "kvm-test-1-run-batch.sh" curbatch
+	curbatch = "";
+	for (i = 2; i <= NF; i++)
+		curbatch = curbatch " " $i;
+	print "kvm-test-1-run-batch.sh" curbatch;
 }' > $T/runbatches.sh
 
 if test -n "$dryrun"
@@ -188,12 +180,5 @@ then
 	echo ---- Dryrun complete, directory: $rundir | tee -a "$rundir/log"
 else
 	( cd "$rundir"; sh $T/runbatches.sh )
-	kcsan-collapse.sh "$rundir" | tee -a "$rundir/log"
-	echo | tee -a "$rundir/log"
-	echo ---- Results directory: $rundir | tee -a "$rundir/log"
-	kvm-recheck.sh "$rundir" > $T/kvm-recheck.sh.out 2>&1
-	ret=$?
-	cat $T/kvm-recheck.sh.out | tee -a "$rundir/log"
-	echo " --- Done at `date` (`get_starttime_duration $starttime`) exitcode $ret" | tee -a "$rundir/log"
-	exit $ret
+	kvm-end-run-stats.sh "$rundir" "$starttime"
 fi

tools/testing/selftests/rcutorture/bin/kvm-build.sh

@@ -40,8 +40,10 @@ if test $retval -gt 1
 then
 	exit 2
 fi
-ncpus=`cpus2use.sh`
-make -j$ncpus $TORTURE_KMAKE_ARG > $resdir/Make.out 2>&1
+
+# Tell "make" to use double the number of real CPUs on the build system.
+ncpus="`getconf _NPROCESSORS_ONLN`"
+make -j$((2 * ncpus)) $TORTURE_KMAKE_ARG > $resdir/Make.out 2>&1
 retval=$?
 if test $retval -ne 0 || grep "rcu[^/]*": < $resdir/Make.out | egrep -q "Stop|Error|error:|warning:" || egrep -q "Stop|Error|error:" < $resdir/Make.out
 then

tools/testing/selftests/rcutorture/bin/kvm-end-run-stats.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Check the status of the specified run.
+#
+# Usage: kvm-end-run-stats.sh /path/to/run starttime
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+# scriptname=$0
+# args="$*"
+rundir="$1"
+if ! test -d "$rundir"
+then
+	echo kvm-end-run-stats.sh: Specified run directory does not exist: $rundir
+	exit 1
+fi
+
+T=${TMPDIR-/tmp}/kvm-end-run-stats.sh.$$
+trap 'rm -rf $T' 0
+mkdir $T
+
+KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
+PATH=${KVM}/bin:$PATH; export PATH
+. functions.sh
+default_starttime="`get_starttime`"
+starttime="${2-default_starttime}"
+
+echo | tee -a "$rundir/log"
+echo | tee -a "$rundir/log"
+echo " --- `date` Test summary:" | tee -a "$rundir/log"
+echo Results directory: $rundir | tee -a "$rundir/log"
+kcsan-collapse.sh "$rundir" | tee -a "$rundir/log"
+kvm-recheck.sh "$rundir" > $T/kvm-recheck.sh.out 2>&1
+ret=$?
+cat $T/kvm-recheck.sh.out | tee -a "$rundir/log"
+echo " --- Done at `date` (`get_starttime_duration $starttime`) exitcode $ret" | tee -a "$rundir/log"
+exit $ret

tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh

@@ -43,7 +43,7 @@ then
 else
 	echo No build errors.
 fi
-if grep -q -e "--buildonly" < ${rundir}/log
+if grep -q -e "--build-\?only" < ${rundir}/log && ! test -f "${rundir}/remote-log"
 then
 	echo Build-only run, no console logs to check.
 	exit $editorret

tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh

@@ -31,7 +31,7 @@ then
 	echo "$configfile ------- " $stopstate
 else
 	title="$configfile ------- $ngps GPs"
-	dur=`sed -e 's/^.* rcutorture.shutdown_secs=//' -e 's/ .*$//' < $i/qemu-cmd 2> /dev/null`
+	dur=`grep -v '^#' $i/qemu-cmd | sed -e 's/^.* rcutorture.shutdown_secs=//' -e 's/ .*$//'`
 	if test -z "$dur"
 	then
 		:

tools/testing/selftests/rcutorture/bin/kvm-remote.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Run a series of tests on remote systems under KVM.
+#
+# Usage: kvm-remote.sh "systems" [ <kvm.sh args> ]
+#	 kvm-remote.sh "systems" /path/to/old/run [ <kvm-again.sh args> ]
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+scriptname=$0
+args="$*"
+
+if ! test -d tools/testing/selftests/rcutorture/bin
+then
+	echo $scriptname must be run from top-level directory of kernel source tree.
+	exit 1
+fi
+
+KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
+PATH=${KVM}/bin:$PATH; export PATH
+. functions.sh
+
+starttime="`get_starttime`"
+
+systems="$1"
+if test -z "$systems"
+then
+	echo $scriptname: Empty list of systems will go nowhere good, giving up.
+	exit 1
+fi
+shift
+
+# Pathnames:
+# T:	  /tmp/kvm-remote.sh.$$
+# resdir: /tmp/kvm-remote.sh.$$/res
+# rundir: /tmp/kvm-remote.sh.$$/res/$ds ("-remote" suffix)
+# oldrun: `pwd`/tools/testing/.../res/$otherds
+#
+# Pathname segments:
+# TD:	  kvm-remote.sh.$$
+# ds:	  yyyy.mm.dd-hh.mm.ss-remote
+
+TD=kvm-remote.sh.$$
+T=${TMPDIR-/tmp}/$TD
+trap 'rm -rf $T' 0
+mkdir $T
+
+resdir="$T/res"
+ds=`date +%Y.%m.%d-%H.%M.%S`-remote
+rundir=$resdir/$ds
+echo Results directory: $rundir
+echo $scriptname $args
+if echo $1 | grep -q '^--'
+then
+	# Fresh build.  Create a datestamp unless the caller supplied one.
+	datestamp="`echo "$@" | awk -v ds="$ds" '{
+		for (i = 1; i < NF; i++) {
+			if ($i == "--datestamp") {
+				ds = "";
+				break;
+			}
+		}
+		if (ds != "")
+			print "--datestamp " ds;
+	}'`"
+	kvm.sh --remote "$@" $datestamp --buildonly > $T/kvm.sh.out 2>&1
+	ret=$?
+	if test "$ret" -ne 0
+	then
+		echo $scriptname: kvm.sh failed exit code $?
+		cat $T/kvm.sh.out
+		exit 2
+	fi
+	oldrun="`grep -m 1 "^Results directory: " $T/kvm.sh.out | awk '{ print $3 }'`"
+	touch "$oldrun/remote-log"
+	echo $scriptname $args >> "$oldrun/remote-log"
+	echo | tee -a "$oldrun/remote-log"
+	echo " ----" kvm.sh output: "(`date`)" | tee -a "$oldrun/remote-log"
+	cat $T/kvm.sh.out | tee -a "$oldrun/remote-log"
+	# We are going to run this, so remove the buildonly files.
+	rm -f "$oldrun"/*/buildonly
+	kvm-again.sh $oldrun --dryrun --remote --rundir "$rundir" > $T/kvm-again.sh.out 2>&1
+	ret=$?
+	if test "$ret" -ne 0
+	then
+		echo $scriptname: kvm-again.sh failed exit code $? | tee -a "$oldrun/remote-log"
+		cat $T/kvm-again.sh.out | tee -a "$oldrun/remote-log"
+		exit 2
+	fi
+else
+	# Re-use old run.
+	oldrun="$1"
+	if ! echo $oldrun | grep -q '^/'
+	then
+		oldrun="`pwd`/$oldrun"
+	fi
+	shift
+	touch "$oldrun/remote-log"
+	echo $scriptname $args >> "$oldrun/remote-log"
+	kvm-again.sh "$oldrun" "$@" --dryrun --remote --rundir "$rundir" > $T/kvm-again.sh.out 2>&1
+	ret=$?
+	if test "$ret" -ne 0
+	then
+		echo $scriptname: kvm-again.sh failed exit code $? | tee -a "$oldrun/remote-log"
+		cat $T/kvm-again.sh.out | tee -a "$oldrun/remote-log"
+		exit 2
+	fi
+	cp -a "$rundir" "$KVM/res/"
+	oldrun="$KVM/res/$ds"
+fi
+echo | tee -a "$oldrun/remote-log"
+echo " ----" kvm-again.sh output: "(`date`)" | tee -a "$oldrun/remote-log"
+cat $T/kvm-again.sh.out
+echo | tee -a "$oldrun/remote-log"
+echo Remote run directory: $rundir | tee -a "$oldrun/remote-log"
+echo Local build-side run directory: $oldrun | tee -a "$oldrun/remote-log"
+
+# Create the kvm-remote-N.sh scripts in the bin directory.
+awk < "$rundir"/scenarios -v dest="$T/bin" -v rundir="$rundir" '
+{
+	n = $1;
+	sub(/\./, "", n);
+	fn = dest "/kvm-remote-" n ".sh"
+	scenarios = "";
+	for (i = 2; i <= NF; i++)
+		scenarios = scenarios " " $i;
+	print "kvm-test-1-run-batch.sh" scenarios > fn;
+	print "rm " rundir "/remote.run" >> fn;
+}'
+chmod +x $T/bin/kvm-remote-*.sh
+( cd "`dirname $T`"; tar -chzf $T/binres.tgz "$TD/bin" "$TD/res" )
+
+# Check first to avoid the need for cleanup for system-name typos
+for i in $systems
+do
+	ncpus="`ssh $i getconf _NPROCESSORS_ONLN 2> /dev/null`"
+	echo $i: $ncpus CPUs " " `date` | tee -a "$oldrun/remote-log"
+	ret=$?
+	if test "$ret" -ne 0
+	then
+		echo System $i unreachable, giving up. | tee -a "$oldrun/remote-log"
+		exit 4 | tee -a "$oldrun/remote-log"
+	fi
+done
+
+# Download and expand the tarball on all systems.
+for i in $systems
+do
+	echo Downloading tarball to $i `date` | tee -a "$oldrun/remote-log"
+	cat $T/binres.tgz | ssh $i "cd /tmp; tar -xzf -"
+	ret=$?
+	if test "$ret" -ne 0
+	then
+		echo Unable to download $T/binres.tgz to system $i, giving up. | tee -a "$oldrun/remote-log"
+		exit 10 | tee -a "$oldrun/remote-log"
+	fi
+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.
+#
+# Usage: checkremotefile system pathname
+checkremotefile () {
+	local ret
+	local sleeptime=60
+
+	while :
+	do
+		ssh $1 "test -f \"$2\""
+		ret=$?
+		if test "$ret" -ne 255
+		then
+			return $ret
+		fi
+		echo " ---" ssh failure to $1 checking for file $2, retry after $sleeptime seconds. `date`
+		sleep $sleeptime
+	done
+}
+
+# Function to start batches on idle remote $systems
+#
+# Usage: startbatches curbatch nbatches
+#
+# Batches are numbered starting at 1.  Returns the next batch to start.
+# Be careful to redirect all debug output to FD 2 (stderr).
+startbatches () {
+	local curbatch="$1"
+	local nbatches="$2"
+	local ret
+
+	# Each pass through the following loop examines one system.
+	for i in $systems
+	do
+		if test "$curbatch" -gt "$nbatches"
+		then
+			echo $((nbatches + 1))
+			return 0
+		fi
+		if checkremotefile "$i" "$resdir/$ds/remote.run" 1>&2
+		then
+			continue # System still running last test, skip.
+		fi
+		ssh "$i" "cd \"$resdir/$ds\"; touch remote.run; PATH=\"$T/bin:$PATH\" nohup kvm-remote-$curbatch.sh > kvm-remote-$curbatch.sh.out 2>&1 &" 1>&2
+		ret=$?
+		if test "$ret" -ne 0
+		then
+			echo ssh $i failed: exitcode $ret 1>&2
+			exit 11
+		fi
+		echo " ----" System $i Batch `head -n $curbatch < "$rundir"/scenarios | tail -1` `date` 1>&2
+		curbatch=$((curbatch + 1))
+	done
+	echo $curbatch
+}
+
+# Launch all the scenarios.
+nbatches="`wc -l "$rundir"/scenarios | awk '{ print $1 }'`"
+curbatch=1
+while test "$curbatch" -le "$nbatches"
+do
+	startbatches $curbatch $nbatches > $T/curbatch 2> $T/startbatches.stderr
+	curbatch="`cat $T/curbatch`"
+	if test -s "$T/startbatches.stderr"
+	then
+		cat "$T/startbatches.stderr" | tee -a "$oldrun/remote-log"
+	fi
+	if test "$curbatch" -le "$nbatches"
+	then
+		sleep 30
+	fi
+done
+echo All batches started. `date`
+
+# Wait for all remaining scenarios to complete and collect results.
+for i in $systems
+do
+	while checkremotefile "$i" "$resdir/$ds/remote.run"
+	do
+		sleep 30
+	done
+	( cd "$oldrun"; ssh $i "cd $rundir; tar -czf - kvm-remote-*.sh.out */console.log */kvm-test-1-run*.sh.out */qemu_pid */qemu-retval; 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"
+exit "`cat $T/exitcode`"

tools/testing/selftests/rcutorture/bin/kvm.sh

@@ -20,6 +20,9 @@ mkdir $T
 
 cd `dirname $scriptname`/../../../../../
 
+# This script knows only English.
+LANG=en_US.UTF-8; export LANG
+
 dur=$((30*60))
 dryrun=""
 KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
@@ -41,6 +44,7 @@ TORTURE_KCONFIG_KASAN_ARG=""
 TORTURE_KCONFIG_KCSAN_ARG=""
 TORTURE_KMAKE_ARG=""
 TORTURE_QEMU_MEM=512
+TORTURE_REMOTE=
 TORTURE_SHUTDOWN_GRACE=180
 TORTURE_SUITE=rcu
 TORTURE_MOD=rcutorture
@@ -64,7 +68,7 @@ usage () {
 	echo "       --cpus N"
 	echo "       --datestamp string"
 	echo "       --defconfig string"
-	echo "       --dryrun batches|sched|script"
+	echo "       --dryrun batches|scenarios|sched|script"
 	echo "       --duration minutes | <seconds>s | <hours>h | <days>d"
 	echo "       --gdb"
 	echo "       --help"
@@ -77,6 +81,7 @@ usage () {
 	echo "       --no-initrd"
 	echo "       --qemu-args qemu-arguments"
 	echo "       --qemu-cmd qemu-system-..."
+	echo "       --remote"
 	echo "       --results absolute-pathname"
 	echo "       --torture lock|rcu|rcuscale|refscale|scf"
 	echo "       --trust-make"
@@ -112,10 +117,13 @@ do
 		checkarg --cpus "(number)" "$#" "$2" '^[0-9]*$' '^--'
 		cpus=$2
 		TORTURE_ALLOTED_CPUS="$2"
-		max_cpus="`identify_qemu_vcpus`"
-		if test "$TORTURE_ALLOTED_CPUS" -gt "$max_cpus"
+		if test -z "$TORTURE_REMOTE"
 		then
-			TORTURE_ALLOTED_CPUS=$max_cpus
+			max_cpus="`identify_qemu_vcpus`"
+			if test "$TORTURE_ALLOTED_CPUS" -gt "$max_cpus"
+			then
+				TORTURE_ALLOTED_CPUS=$max_cpus
+			fi
 		fi
 		shift
 		;;
@@ -130,7 +138,7 @@ do
 		shift
 		;;
 	--dryrun)
-		checkarg --dryrun "batches|sched|script" $# "$2" 'batches\|sched\|script' '^--'
+		checkarg --dryrun "batches|sched|script" $# "$2" 'batches\|scenarios\|sched\|script' '^--'
 		dryrun=$2
 		shift
 		;;
@@ -206,6 +214,9 @@ do
 		TORTURE_QEMU_CMD="$2"
 		shift
 		;;
+	--remote)
+		TORTURE_REMOTE=1
+		;;
 	--results)
 		checkarg --results "(absolute pathname)" "$#" "$2" '^/' '^error'
 		resdir=$2
@@ -550,20 +561,7 @@ END {
 	if (ncpus != 0)
 		dump(first, i, batchnum);
 }' >> $T/script
-
-cat << '___EOF___' >> $T/script
-echo | tee -a $TORTURE_RESDIR/log
-echo | tee -a $TORTURE_RESDIR/log
-echo " --- `date` Test summary:" | tee -a $TORTURE_RESDIR/log
-___EOF___
-cat << ___EOF___ >> $T/script
-echo Results directory: $resdir/$ds | tee -a $resdir/$ds/log
-kcsan-collapse.sh $resdir/$ds | tee -a $resdir/$ds/log
-kvm-recheck.sh $resdir/$ds > $T/kvm-recheck.sh.out 2>&1
-___EOF___
-echo 'ret=$?' >> $T/script
-echo "cat $T/kvm-recheck.sh.out | tee -a $resdir/$ds/log" >> $T/script
-echo 'exit $ret' >> $T/script
+echo kvm-end-run-stats.sh "$resdir/$ds" "$starttime" >> $T/script
 
 # Extract the tests and their batches from the script.
 egrep 'Start batch|Starting build\.' $T/script | grep -v ">>" |
@@ -577,6 +575,25 @@ egrep 'Start batch|Starting build\.' $T/script | grep -v ">>" |
 		print batchno, $1, $2
 	}' > $T/batches
 
+# As above, but one line per batch.
+grep -v '^#' $T/batches | awk '
+BEGIN {
+	oldbatch = 1;
+}
+
+{
+	if (oldbatch != $1) {
+		print ++n ". " curbatch;
+		curbatch = "";
+		oldbatch = $1;
+	}
+	curbatch = curbatch " " $2;
+}
+
+END {
+	print ++n ". " curbatch;
+}' > $T/scenarios
+
 if test "$dryrun" = script
 then
 	cat $T/script
@@ -597,13 +614,17 @@ elif test "$dryrun" = batches
 then
 	cat $T/batches
 	exit 0
+elif test "$dryrun" = scenarios
+then
+	cat $T/scenarios
+	exit 0
 else
 	# Not a dryrun.  Record the batches and the number of CPUs, then run the script.
 	bash $T/script
 	ret=$?
 	cp $T/batches $resdir/$ds/batches
+	cp $T/scenarios $resdir/$ds/scenarios
 	echo '#' cpus=$cpus >> $resdir/$ds/batches
-	echo " --- Done at `date` (`get_starttime_duration $starttime`) exitcode $ret" | tee -a $resdir/$ds/log
 	exit $ret
 fi
 

tools/testing/selftests/rcutorture/bin/torture.sh

@@ -302,7 +302,7 @@ function torture_set {
 			kcsan_kmake_tag="--kmake-args"
 			cur_kcsan_kmake_args="$kcsan_kmake_args"
 		fi
-		torture_one $* --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y" $kcsan_kmake_tag $cur_kcsan_kmake_args --kcsan
+		torture_one "$@" --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y" $kcsan_kmake_tag $cur_kcsan_kmake_args --kcsan
 	fi
 }
 

tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST

+CONFIG_SMP=y
+CONFIG_NR_CPUS=16
+CONFIG_PREEMPT_NONE=n
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=y
+#CHECK#CONFIG_PREEMPT_RCU=y
+CONFIG_HZ_PERIODIC=y
+CONFIG_NO_HZ_IDLE=n
+CONFIG_NO_HZ_FULL=n
+CONFIG_RCU_TRACE=y
+CONFIG_HOTPLUG_CPU=y
+CONFIG_RCU_FANOUT=2
+CONFIG_RCU_FANOUT_LEAF=2
+CONFIG_RCU_NOCB_CPU=n
+CONFIG_DEBUG_LOCK_ALLOC=n
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
+CONFIG_RCU_EXPERT=y

tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST.boot

+rcutorture.test_boost=2
+rcutorture.stutter=0
+rcutree.gp_preinit_delay=12
+rcutree.gp_init_delay=3
+rcutree.gp_cleanup_delay=3
+rcutree.kthread_prio=2
+threadirqs
+tree.use_softirq=0

tools/testing/selftests/rcutorture/configs/rcuscale/TREE

@@ -7,7 +7,7 @@ CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
 CONFIG_RCU_FAST_NO_HZ=n
-CONFIG_HOTPLUG_CPU=n
+CONFIG_HOTPLUG_CPU=y
 CONFIG_SUSPEND=n
 CONFIG_HIBERNATION=n
 CONFIG_RCU_NOCB_CPU=n

tools/testing/selftests/rcutorture/configs/rcuscale/TREE54

@@ -8,7 +8,7 @@ CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
 CONFIG_RCU_FAST_NO_HZ=n
-CONFIG_HOTPLUG_CPU=n
+CONFIG_HOTPLUG_CPU=y
 CONFIG_SUSPEND=n
 CONFIG_HIBERNATION=n
 CONFIG_RCU_FANOUT=3

tools/testing/selftests/rcutorture/configs/refscale/NOPREEMPT

@@ -7,7 +7,7 @@ CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
 CONFIG_RCU_FAST_NO_HZ=n
-CONFIG_HOTPLUG_CPU=n
+CONFIG_HOTPLUG_CPU=y
 CONFIG_SUSPEND=n
 CONFIG_HIBERNATION=n
 CONFIG_RCU_NOCB_CPU=n

tools/testing/selftests/rcutorture/configs/refscale/PREEMPT

@@ -7,7 +7,7 @@ CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
 CONFIG_RCU_FAST_NO_HZ=n
-CONFIG_HOTPLUG_CPU=n
+CONFIG_HOTPLUG_CPU=y
 CONFIG_SUSPEND=n
 CONFIG_HIBERNATION=n
 CONFIG_RCU_NOCB_CPU=n

tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/locks.h

@@ -174,7 +174,7 @@ static inline bool spin_trylock(spinlock_t *lock)
 }
 
 struct completion {
-	/* Hopefuly this won't overflow. */
+	/* Hopefully this won't overflow. */
 	unsigned int count;
 };