Merge tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:

 - Support for "N" as alias for last bit in bitmap parsing library (eg
   using syntax like "nohz_full=2-N")

 - kvfree_rcu updates

 - mm_dump_obj() updates. (One of these is to mm, but was suggested by
   Andrew Morton.)

 - RCU callback offloading update

 - Polling RCU grace-period interfaces

 - Realtime-related RCU updates

 - Tasks-RCU updates

 - Torture-test updates

 - Torture-test scripting updates

 - Miscellaneous fixes

* tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits)
  rcutorture: Test start_poll_synchronize_rcu() and poll_state_synchronize_rcu()
  rcu: Provide polling interfaces for Tiny RCU grace periods
  torture: Fix kvm.sh --datestamp regex check
  torture: Consolidate qemu-cmd duration editing into kvm-transform.sh
  torture: Print proper vmlinux path for kvm-again.sh runs
  torture: Make TORTURE_TRUST_MAKE available in kvm-again.sh environment
  torture: Make kvm-transform.sh update jitter commands
  torture: Add --duration argument to kvm-again.sh
  torture: Add kvm-again.sh to rerun a previous torture-test
  torture: Create a "batches" file for build reuse
  torture: De-capitalize TORTURE_SUITE
  torture: Make upper-case-only no-dot no-slash scenario names official
  torture: Rename SRCU-t and SRCU-u to avoid lowercase characters
  torture: Remove no-mpstat error message
  torture: Record kvm-test-1-run.sh and kvm-test-1-run-qemu.sh PIDs
  torture: Record jitter start/stop commands
  torture: Extract kvm-test-1-run-qemu.sh from kvm-test-1-run.sh
  torture: Record TORTURE_KCONFIG_GDB_ARG in qemu-cmd
  torture: Abstract jitter.sh start/stop into scripts
  rcu: Provide polling interfaces for Tree RCU grace periods
  ...

Documentation/RCU/RTFP.txt

@@ -847,7 +847,7 @@ Symposium on Distributed Computing}
 	'It's entirely possible that the current user could be replaced
 	by RCU and/or seqlocks, and we could get rid of brlocks entirely.'
 	.
-	Steve Hemminger responds by replacing them with RCU.
+	Stephen Hemminger responds by replacing them with RCU.
 }
 }
 

Documentation/admin-guide/kernel-parameters.rst

@@ -68,6 +68,13 @@ For example one can add to the command line following parameter:
 
 where the final item represents CPUs 100,101,125,126,150,151,...
 
+The value "N" can be used to represent the numerically last CPU on the system,
+i.e "foo_cpus=16-N" would be equivalent to "16-31" on a 32 core system.
+
+Keep in mind that "N" is dynamic, so if system changes cause the bitmap width
+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).
 
 
 This document may not be entirely up to date and comprehensive. The command

Documentation/admin-guide/kernel-parameters.txt

@@ -4077,9 +4077,7 @@
 				see CONFIG_RAS_CEC help text.
 
 	rcu_nocbs=	[KNL]
-			The argument is a cpu list, as described above,
-			except that the string "all" can be used to
-			specify every CPU on the system.
+			The argument is a cpu list, as described above.
 
 			In kernels built with CONFIG_RCU_NOCB_CPU=y, set
 			the specified list of CPUs to be no-callback CPUs.
@@ -4268,6 +4266,18 @@
 	rcuscale.kfree_rcu_test= [KNL]
 			Set to measure performance of kfree_rcu() flooding.
 
+	rcuscale.kfree_rcu_test_double= [KNL]
+			Test the double-argument variant of kfree_rcu().
+			If this parameter has the same value as
+			rcuscale.kfree_rcu_test_single, both the single-
+			and double-argument variants are tested.
+
+	rcuscale.kfree_rcu_test_single= [KNL]
+			Test the single-argument variant of kfree_rcu().
+			If this parameter has the same value as
+			rcuscale.kfree_rcu_test_double, both the single-
+			and double-argument variants are tested.
+
 	rcuscale.kfree_nthreads= [KNL]
 			The number of threads running loops of kfree_rcu().
 

include/linux/mm.h

@@ -3180,7 +3180,11 @@ unsigned long wp_shared_mapping_range(struct address_space *mapping,
 
 extern int sysctl_nr_trim_pages;
 
+#ifdef CONFIG_PRINTK
 void mem_dump_obj(void *object);
+#else
+static inline void mem_dump_obj(void *object) {}
+#endif
 
 #endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */

include/linux/rcu_segcblist.h

@@ -109,7 +109,7 @@ struct rcu_cblist {
  *  |                           SEGCBLIST_KTHREAD_GP                           |
  *  |                                                                          |
  *  |   Kthreads handle callbacks holding nocb_lock, local rcu_core() stops    |
- *  |   handling callbacks.                                                    |
+ *  |   handling callbacks. Enable bypass queueing.                            |
  *  ----------------------------------------------------------------------------
  */
 
@@ -125,7 +125,7 @@ struct rcu_cblist {
  *  |                           SEGCBLIST_KTHREAD_GP                           |
  *  |                                                                          |
  *  |   CB/GP kthreads handle callbacks holding nocb_lock, local rcu_core()    |
- *  |   ignores callbacks.                                                     |
+ *  |   ignores callbacks. Bypass enqueue is enabled.                          |
  *  ----------------------------------------------------------------------------
  *                                      |
  *                                      v
@@ -134,7 +134,8 @@ struct rcu_cblist {
  *  |                           SEGCBLIST_KTHREAD_GP                           |
  *  |                                                                          |
  *  |   CB/GP kthreads and local rcu_core() handle callbacks concurrently      |
- *  |   holding nocb_lock. Wake up CB and GP kthreads if necessary.            |
+ *  |   holding nocb_lock. Wake up CB and GP kthreads if necessary. Disable    |
+ *  |   bypass enqueue.                                                        |
  *  ----------------------------------------------------------------------------
  *                                      |
  *                                      v

include/linux/rculist_nulls.h

@@ -161,7 +161,7 @@ static inline void hlist_nulls_add_fake(struct hlist_nulls_node *n)
  *
  * The barrier() is needed to make sure compiler doesn't cache first element [1],
  * as this loop can be restarted [2]
- * [1] Documentation/core-api/atomic_ops.rst around line 114
+ * [1] Documentation/memory-barriers.txt around line 1533
  * [2] Documentation/RCU/rculist_nulls.rst around line 146
  */
 #define hlist_nulls_for_each_entry_rcu(tpos, pos, head, member)			\

include/linux/rcupdate.h

@@ -882,7 +882,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
  * The BUILD_BUG_ON check must not involve any function calls, hence the
  * checks are done in macros here.
  */
-#define kfree_rcu kvfree_rcu
+#define kfree_rcu(ptr, rhf...) kvfree_rcu(ptr, ## rhf)
 
 /**
  * kvfree_rcu() - kvfree an object after a grace period.

include/linux/rcutiny.h

@@ -17,10 +17,9 @@
 /* Never flag non-existent other CPUs! */
 static inline bool rcu_eqs_special_set(int cpu) { return false; }
 
-static inline unsigned long get_state_synchronize_rcu(void)
-{
-	return 0;
-}
+unsigned long get_state_synchronize_rcu(void);
+unsigned long start_poll_synchronize_rcu(void);
+bool poll_state_synchronize_rcu(unsigned long oldstate);
 
 static inline void cond_synchronize_rcu(unsigned long oldstate)
 {

include/linux/rcutree.h

@@ -41,6 +41,8 @@ void rcu_momentary_dyntick_idle(void);
 void kfree_rcu_scheduler_running(void);
 bool rcu_gp_might_be_stalled(void);
 unsigned long get_state_synchronize_rcu(void);
+unsigned long start_poll_synchronize_rcu(void);
+bool poll_state_synchronize_rcu(unsigned long oldstate);
 void cond_synchronize_rcu(unsigned long oldstate);
 
 void rcu_idle_enter(void);

include/linux/slab.h

@@ -186,8 +186,10 @@ void kfree(const void *);
 void kfree_sensitive(const void *);
 size_t __ksize(const void *);
 size_t ksize(const void *);
+#ifdef CONFIG_PRINTK
 bool kmem_valid_obj(void *object);
 void kmem_dump_obj(void *object);
+#endif
 
 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,

include/linux/vmalloc.h

@@ -241,7 +241,7 @@ pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
 int register_vmap_purge_notifier(struct notifier_block *nb);
 int unregister_vmap_purge_notifier(struct notifier_block *nb);
 
-#ifdef CONFIG_MMU
+#if defined(CONFIG_MMU) && defined(CONFIG_PRINTK)
 bool vmalloc_dump_obj(void *object);
 #else
 static inline bool vmalloc_dump_obj(void *object) { return false; }

include/trace/events/rcu.h

@@ -432,6 +432,34 @@ TRACE_EVENT_RCU(rcu_fqs,
 		  __entry->cpu, __entry->qsevent)
 );
 
+/*
+ * Tracepoint for RCU stall events. Takes a string identifying the RCU flavor
+ * and a string identifying which function detected the RCU stall as follows:
+ *
+ *	"StallDetected": Scheduler-tick detects other CPU's stalls.
+ *	"SelfDetected": Scheduler-tick detects a current CPU's stall.
+ *	"ExpeditedStall": Expedited grace period detects stalls.
+ */
+TRACE_EVENT(rcu_stall_warning,
+
+	TP_PROTO(const char *rcuname, const char *msg),
+
+	TP_ARGS(rcuname, msg),
+
+	TP_STRUCT__entry(
+		__field(const char *, rcuname)
+		__field(const char *, msg)
+	),
+
+	TP_fast_assign(
+		__entry->rcuname = rcuname;
+		__entry->msg = msg;
+	),
+
+	TP_printk("%s %s",
+		  __entry->rcuname, __entry->msg)
+);
+
 #endif /* #if defined(CONFIG_TREE_RCU) */
 
 /*

kernel/rcu/rcu_segcblist.c

@@ -261,8 +261,7 @@ void rcu_segcblist_disable(struct rcu_segcblist *rsclp)
 }
 
 /*
- * Mark the specified rcu_segcblist structure as offloaded.  This
- * structure must be empty.
+ * Mark the specified rcu_segcblist structure as offloaded.
  */
 void rcu_segcblist_offload(struct rcu_segcblist *rsclp, bool offload)
 {

kernel/rcu/rcuscale.c

@@ -625,6 +625,8 @@ rcu_scale_shutdown(void *arg)
 torture_param(int, kfree_nthreads, -1, "Number of threads running loops of kfree_rcu().");
 torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees done in an iteration.");
 torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num allocations and frees.");
+torture_param(bool, kfree_rcu_test_double, false, "Do we run a kfree_rcu() double-argument scale test?");
+torture_param(bool, kfree_rcu_test_single, false, "Do we run a kfree_rcu() single-argument scale test?");
 
 static struct task_struct **kfree_reader_tasks;
 static int kfree_nrealthreads;
@@ -644,10 +646,13 @@ kfree_scale_thread(void *arg)
 	struct kfree_obj *alloc_ptr;
 	u64 start_time, end_time;
 	long long mem_begin, mem_during = 0;
+	bool kfree_rcu_test_both;
+	DEFINE_TORTURE_RANDOM(tr);
 
 	VERBOSE_SCALEOUT_STRING("kfree_scale_thread task started");
 	set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
 	set_user_nice(current, MAX_NICE);
+	kfree_rcu_test_both = (kfree_rcu_test_single == kfree_rcu_test_double);
 
 	start_time = ktime_get_mono_fast_ns();
 
@@ -670,7 +675,15 @@ kfree_scale_thread(void *arg)
 			if (!alloc_ptr)
 				return -ENOMEM;
 
-			kfree_rcu(alloc_ptr, rh);
+			// By default kfree_rcu_test_single and kfree_rcu_test_double are
+			// initialized to false. If both have the same value (false or true)
+			// both are randomly tested, otherwise only the one with value true
+			// is tested.
+			if ((kfree_rcu_test_single && !kfree_rcu_test_double) ||
+					(kfree_rcu_test_both && torture_random(&tr) & 0x800))
+				kfree_rcu(alloc_ptr);
+			else
+				kfree_rcu(alloc_ptr, rh);
 		}
 
 		cond_resched();

kernel/rcu/rcutorture.c

@@ -245,11 +245,11 @@ static const char *rcu_torture_writer_state_getname(void)
 	return rcu_torture_writer_state_names[i];
 }
 
-#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
-#define rcu_can_boost() 1
-#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
-#define rcu_can_boost() 0
-#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
+#if defined(CONFIG_RCU_BOOST) && defined(CONFIG_PREEMPT_RT)
+# define rcu_can_boost() 1
+#else
+# define rcu_can_boost() 0
+#endif
 
 #ifdef CONFIG_RCU_TRACE
 static u64 notrace rcu_trace_clock_local(void)
@@ -494,6 +494,8 @@ static struct rcu_torture_ops rcu_ops = {
 	.sync		= synchronize_rcu,
 	.exp_sync	= synchronize_rcu_expedited,
 	.get_gp_state	= get_state_synchronize_rcu,
+	.start_gp_poll	= start_poll_synchronize_rcu,
+	.poll_gp_state	= poll_state_synchronize_rcu,
 	.cond_sync	= cond_synchronize_rcu,
 	.call		= call_rcu,
 	.cb_barrier	= rcu_barrier,
@@ -923,9 +925,13 @@ static void rcu_torture_enable_rt_throttle(void)
 
 static bool rcu_torture_boost_failed(unsigned long start, unsigned long end)
 {
+	static int dbg_done;
+
 	if (end - start > test_boost_duration * HZ - HZ / 2) {
 		VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
 		n_rcu_torture_boost_failure++;
+		if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg)
+			cur_ops->gp_kthread_dbg();
 
 		return true; /* failed */
 	}
@@ -948,8 +954,8 @@ static int rcu_torture_boost(void *arg)
 	init_rcu_head_on_stack(&rbi.rcu);
 	/* Each pass through the following loop does one boost-test cycle. */
 	do {
-		/* Track if the test failed already in this test interval? */
-		bool failed = false;
+		bool failed = false; // Test failed already in this test interval
+		bool firsttime = true;
 
 		/* Increment n_rcu_torture_boosts once per boost-test */
 		while (!kthread_should_stop()) {
@@ -975,18 +981,17 @@ static int rcu_torture_boost(void *arg)
 
 		/* Do one boost-test interval. */
 		endtime = oldstarttime + test_boost_duration * HZ;
-		call_rcu_time = jiffies;
 		while (time_before(jiffies, endtime)) {
 			/* If we don't have a callback in flight, post one. */
 			if (!smp_load_acquire(&rbi.inflight)) {
 				/* RCU core before ->inflight = 1. */
 				smp_store_release(&rbi.inflight, 1);
-				call_rcu(&rbi.rcu, rcu_torture_boost_cb);
+				cur_ops->call(&rbi.rcu, rcu_torture_boost_cb);
 				/* Check if the boost test failed */
-				failed = failed ||
-					 rcu_torture_boost_failed(call_rcu_time,
-								 jiffies);
+				if (!firsttime && !failed)
+					failed = rcu_torture_boost_failed(call_rcu_time, jiffies);
 				call_rcu_time = jiffies;
+				firsttime = false;
 			}
 			if (stutter_wait("rcu_torture_boost"))
 				sched_set_fifo_low(current);
@@ -999,7 +1004,7 @@ static int rcu_torture_boost(void *arg)
 		 * this case the boost check would never happen in the above
 		 * loop so do another one here.
 		 */
-		if (!failed && smp_load_acquire(&rbi.inflight))
+		if (!firsttime && !failed && smp_load_acquire(&rbi.inflight))
 			rcu_torture_boost_failed(call_rcu_time, jiffies);
 
 		/*
@@ -1025,6 +1030,9 @@ checkwait:	if (stutter_wait("rcu_torture_boost"))
 			sched_set_fifo_low(current);
 	} while (!torture_must_stop());
 
+	while (smp_load_acquire(&rbi.inflight))
+		schedule_timeout_uninterruptible(1); // rcu_barrier() deadlocks.
+
 	/* Clean up and exit. */
 	while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
 		torture_shutdown_absorb("rcu_torture_boost");
@@ -1223,14 +1231,6 @@ rcu_torture_writer(void *arg)
 				WARN_ON_ONCE(1);
 				break;
 			}
-			if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
-				WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE &&
-					  !cur_ops->poll_gp_state(cookie),
-					  "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
-					  __func__,
-					  rcu_torture_writer_state_getname(),
-					  rcu_torture_writer_state,
-					  cookie, cur_ops->get_gp_state());
 		}
 		WRITE_ONCE(rcu_torture_current_version,
 			   rcu_torture_current_version + 1);
@@ -1589,7 +1589,7 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
 	preempt_enable();
 	if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
 		WARN_ONCE(cur_ops->poll_gp_state(cookie),
-			  "%s: Cookie check 3 failed %s(%d) %lu->%lu\n",
+			  "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
 			  __func__,
 			  rcu_torture_writer_state_getname(),
 			  rcu_torture_writer_state,
@@ -1797,7 +1797,7 @@ rcu_torture_stats_print(void)
 		WARN_ON_ONCE(n_rcu_torture_barrier_error);  // rcu_barrier()
 		WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
 		WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio
-		WARN_ON_ONCE(n_rcu_torture_boost_failure); // RCU boost failed
+		WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
 		WARN_ON_ONCE(i > 1); // Too-short grace period
 	}
 	pr_cont("Reader Pipe: ");
@@ -1861,6 +1861,45 @@ rcu_torture_stats(void *arg)
 		torture_shutdown_absorb("rcu_torture_stats");
 	} while (!torture_must_stop());
 	torture_kthread_stopping("rcu_torture_stats");
+
+	{
+		struct rcu_head *rhp;
+		struct kmem_cache *kcp;
+		static int z;
+
+		kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
+		rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
+		pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
+		pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
+		mem_dump_obj(ZERO_SIZE_PTR);
+		pr_alert("mem_dump_obj(NULL):");
+		mem_dump_obj(NULL);
+		pr_alert("mem_dump_obj(%px):", &rhp);
+		mem_dump_obj(&rhp);
+		pr_alert("mem_dump_obj(%px):", rhp);
+		mem_dump_obj(rhp);
+		pr_alert("mem_dump_obj(%px):", &rhp->func);
+		mem_dump_obj(&rhp->func);
+		pr_alert("mem_dump_obj(%px):", &z);
+		mem_dump_obj(&z);
+		kmem_cache_free(kcp, rhp);
+		kmem_cache_destroy(kcp);
+		rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
+		pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
+		pr_alert("mem_dump_obj(kmalloc %px):", rhp);
+		mem_dump_obj(rhp);
+		pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
+		mem_dump_obj(&rhp->func);
+		kfree(rhp);
+		rhp = vmalloc(4096);
+		pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
+		pr_alert("mem_dump_obj(vmalloc %px):", rhp);
+		mem_dump_obj(rhp);
+		pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
+		mem_dump_obj(&rhp->func);
+		vfree(rhp);
+	}
+
 	return 0;
 }
 
@@ -1971,8 +2010,8 @@ static int rcu_torture_stall(void *args)
 			local_irq_disable();
 		else if (!stall_cpu_block)
 			preempt_disable();
-		pr_alert("rcu_torture_stall start on CPU %d.\n",
-			 raw_smp_processor_id());
+		pr_alert("%s start on CPU %d.\n",
+			  __func__, raw_smp_processor_id());
 		while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
 				    stop_at))
 			if (stall_cpu_block)
@@ -1983,7 +2022,7 @@ static int rcu_torture_stall(void *args)
 			preempt_enable();
 		cur_ops->readunlock(idx);
 	}
-	pr_alert("rcu_torture_stall end.\n");
+	pr_alert("%s end.\n", __func__);
 	torture_shutdown_absorb("rcu_torture_stall");
 	while (!kthread_should_stop())
 		schedule_timeout_interruptible(10 * HZ);
@@ -2595,6 +2634,8 @@ static bool rcu_torture_can_boost(void)
 
 	if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
 		return false;
+	if (!cur_ops->call)
+		return false;
 
 	prio = rcu_get_gp_kthreads_prio();
 	if (!prio)

kernel/rcu/tasks.h

@@ -20,7 +20,7 @@ typedef void (*holdouts_func_t)(struct list_head *hop, bool ndrpt, bool *frptp);
 typedef void (*postgp_func_t)(struct rcu_tasks *rtp);
 
 /**
- * Definition for a Tasks-RCU-like mechanism.
+ * 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.
@@ -38,7 +38,7 @@ typedef void (*postgp_func_t)(struct rcu_tasks *rtp);
  * @pregp_func: This flavor's pre-grace-period function (optional).
  * @pertask_func: This flavor's per-task scan function (optional).
  * @postscan_func: This flavor's post-task scan function (optional).
- * @holdout_func: This flavor's holdout-list scan function (optional).
+ * @holdouts_func: This flavor's holdout-list scan function (optional).
  * @postgp_func: This flavor's post-grace-period function (optional).
  * @call_func: This flavor's call_rcu()-equivalent function.
  * @name: This flavor's textual name.
@@ -726,6 +726,42 @@ EXPORT_SYMBOL_GPL(show_rcu_tasks_rude_gp_kthread);
 // flavors, rcu_preempt and rcu_sched.  The fact that RCU Tasks Trace
 // readers can operate from idle, offline, and exception entry/exit in no
 // way allows rcu_preempt and rcu_sched readers to also do so.
+//
+// The implementation uses rcu_tasks_wait_gp(), which relies on function
+// pointers in the rcu_tasks structure.  The rcu_spawn_tasks_trace_kthread()
+// function sets these function pointers up so that rcu_tasks_wait_gp()
+// invokes these functions in this order:
+//
+// rcu_tasks_trace_pregp_step():
+//	Initialize the count of readers and block CPU-hotplug operations.
+// rcu_tasks_trace_pertask(), invoked on every non-idle task:
+//	Initialize per-task state and attempt to identify an immediate
+//	quiescent state for that task, or, failing that, attempt to
+//	set that task's .need_qs flag so that task's next outermost
+//	rcu_read_unlock_trace() will report the quiescent state (in which
+//	case the count of readers is incremented).  If both attempts fail,
+//	the task is added to a "holdout" list.
+// rcu_tasks_trace_postscan():
+//	Initialize state and attempt to identify an immediate quiescent
+//	state as above (but only for idle tasks), unblock CPU-hotplug
+//	operations, and wait for an RCU grace period to avoid races with
+//	tasks that are in the process of exiting.
+// check_all_holdout_tasks_trace(), 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_trace_postgp():
+//	Wait for the count of readers do drop to zero, reporting any stalls.
+//	Also execute full memory barriers to maintain ordering with code
+//	executing after the grace period.
+//
+// The exit_tasks_rcu_finish_trace() synchronizes with exiting tasks.
+//
+// Pre-grace-period update-side code is ordered before the grace
+// period via the ->cbs_lock and barriers in rcu_tasks_kthread().
+// Pre-grace-period read-side code is ordered before the grace period by
+// atomic_dec_and_test() of the count of readers (for IPIed readers) and by
+// scheduler context-switch ordering (for locked-down non-running readers).
 
 // The lockdep state must be outside of #ifdef to be useful.
 #ifdef CONFIG_DEBUG_LOCK_ALLOC

kernel/rcu/tiny.c

@@ -32,12 +32,14 @@ struct rcu_ctrlblk {
 	struct rcu_head *rcucblist;	/* List of pending callbacks (CBs). */
 	struct rcu_head **donetail;	/* ->next pointer of last "done" CB. */
 	struct rcu_head **curtail;	/* ->next pointer of last CB. */
+	unsigned long gp_seq;		/* Grace-period counter. */
 };
 
 /* Definition for rcupdate control block. */
 static struct rcu_ctrlblk rcu_ctrlblk = {
 	.donetail	= &rcu_ctrlblk.rcucblist,
 	.curtail	= &rcu_ctrlblk.rcucblist,
+	.gp_seq		= 0 - 300UL,
 };
 
 void rcu_barrier(void)
@@ -56,6 +58,7 @@ void rcu_qs(void)
 		rcu_ctrlblk.donetail = rcu_ctrlblk.curtail;
 		raise_softirq_irqoff(RCU_SOFTIRQ);
 	}
+	WRITE_ONCE(rcu_ctrlblk.gp_seq, rcu_ctrlblk.gp_seq + 1);
 	local_irq_restore(flags);
 }
 
@@ -177,6 +180,43 @@ void call_rcu(struct rcu_head *head, rcu_callback_t func)
 }
 EXPORT_SYMBOL_GPL(call_rcu);
 
+/*
+ * Return a grace-period-counter "cookie".  For more information,
+ * see the Tree RCU header comment.
+ */
+unsigned long get_state_synchronize_rcu(void)
+{
+	return READ_ONCE(rcu_ctrlblk.gp_seq);
+}
+EXPORT_SYMBOL_GPL(get_state_synchronize_rcu);
+
+/*
+ * Return a grace-period-counter "cookie" and ensure that a future grace
+ * period completes.  For more information, see the Tree RCU header comment.
+ */
+unsigned long start_poll_synchronize_rcu(void)
+{
+	unsigned long gp_seq = get_state_synchronize_rcu();
+
+	if (unlikely(is_idle_task(current))) {
+		/* force scheduling for rcu_qs() */
+		resched_cpu(0);
+	}
+	return gp_seq;
+}
+EXPORT_SYMBOL_GPL(start_poll_synchronize_rcu);
+
+/*
+ * Return true if the grace period corresponding to oldstate has completed
+ * and false otherwise.  For more information, see the Tree RCU header
+ * comment.
+ */
+bool poll_state_synchronize_rcu(unsigned long oldstate)
+{
+	return READ_ONCE(rcu_ctrlblk.gp_seq) != oldstate;
+}
+EXPORT_SYMBOL_GPL(poll_state_synchronize_rcu);
+
 void __init rcu_init(void)
 {
 	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);

kernel/rcu/tree_exp.h

@@ -521,6 +521,7 @@ static void synchronize_rcu_expedited_wait(void)
 		if (rcu_stall_is_suppressed())
 			continue;
 		panic_on_rcu_stall();
+		trace_rcu_stall_warning(rcu_state.name, TPS("ExpeditedStall"));
 		pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {",
 		       rcu_state.name);
 		ndetected = 0;

kernel/rcu/tree_stall.h

@@ -536,6 +536,7 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
 	 * See Documentation/RCU/stallwarn.rst for info on how to debug
 	 * RCU CPU stall warnings.
 	 */
+	trace_rcu_stall_warning(rcu_state.name, TPS("StallDetected"));
 	pr_err("INFO: %s detected stalls on CPUs/tasks:\n", rcu_state.name);
 	rcu_for_each_leaf_node(rnp) {
 		raw_spin_lock_irqsave_rcu_node(rnp, flags);
@@ -606,6 +607,7 @@ static void print_cpu_stall(unsigned long gps)
 	 * See Documentation/RCU/stallwarn.rst for info on how to debug
 	 * RCU CPU stall warnings.
 	 */
+	trace_rcu_stall_warning(rcu_state.name, TPS("SelfDetected"));
 	pr_err("INFO: %s self-detected stall on CPU\n", rcu_state.name);
 	raw_spin_lock_irqsave_rcu_node(rdp->mynode, flags);
 	print_cpu_stall_info(smp_processor_id());

kernel/softirq.c

@@ -423,7 +423,7 @@ static inline void invoke_softirq(void)
 	if (ksoftirqd_running(local_softirq_pending()))
 		return;
 
-	if (!force_irqthreads) {
+	if (!force_irqthreads || !__this_cpu_read(ksoftirqd)) {
 #ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
 		/*
 		 * We can safely execute softirq on the current stack if

kernel/torture.c

@@ -816,9 +816,9 @@ bool torture_init_begin(char *ttype, int v)
 {
 	mutex_lock(&fullstop_mutex);
 	if (torture_type != NULL) {
-		pr_alert("torture_init_begin: Refusing %s init: %s running.\n",
-			 ttype, torture_type);
-		pr_alert("torture_init_begin: One torture test at a time!\n");
+		pr_alert("%s: Refusing %s init: %s running.\n",
+			  __func__, ttype, torture_type);
+		pr_alert("%s: One torture test at a time!\n", __func__);
 		mutex_unlock(&fullstop_mutex);
 		return false;
 	}

lib/bitmap.c

@@ -487,30 +487,25 @@ EXPORT_SYMBOL(bitmap_print_to_pagebuf);
 
 /*
  * Region 9-38:4/10 describes the following bitmap structure:
- * 0	   9  12    18			38
- * .........****......****......****......
- *	    ^  ^     ^			 ^
- *      start  off   group_len	       end
+ * 0	   9  12    18			38	     N
+ * .........****......****......****..................
+ *	    ^  ^     ^			 ^	     ^
+ *      start  off   group_len	       end	 nbits
  */
 struct region {
 	unsigned int start;
 	unsigned int off;
 	unsigned int group_len;
 	unsigned int end;
+	unsigned int nbits;
 };
 
-static int bitmap_set_region(const struct region *r,
-				unsigned long *bitmap, int nbits)
+static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
 {
 	unsigned int start;
 
-	if (r->end >= nbits)
-		return -ERANGE;
-
 	for (start = r->start; start <= r->end; start += r->group_len)
 		bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
-
-	return 0;
 }
 
 static int bitmap_check_region(const struct region *r)
@@ -518,14 +513,23 @@ static int bitmap_check_region(const struct region *r)
 	if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
 		return -EINVAL;
 
+	if (r->end >= r->nbits)
+		return -ERANGE;
+
 	return 0;
 }
 
-static const char *bitmap_getnum(const char *str, unsigned int *num)
+static const char *bitmap_getnum(const char *str, unsigned int *num,
+				 unsigned int lastbit)
 {
 	unsigned long long n;
 	unsigned int len;
 
+	if (str[0] == 'N') {
+		*num = lastbit;
+		return str + 1;
+	}
+
 	len = _parse_integer(str, 10, &n);
 	if (!len)
 		return ERR_PTR(-EINVAL);
@@ -573,7 +577,9 @@ static const char *bitmap_find_region_reverse(const char *start, const char *end
 
 static const char *bitmap_parse_region(const char *str, struct region *r)
 {
-	str = bitmap_getnum(str, &r->start);
+	unsigned int lastbit = r->nbits - 1;
+
+	str = bitmap_getnum(str, &r->start, lastbit);
 	if (IS_ERR(str))
 		return str;
 
@@ -583,7 +589,7 @@ static const char *bitmap_parse_region(const char *str, struct region *r)
 	if (*str != '-')
 		return ERR_PTR(-EINVAL);
 
-	str = bitmap_getnum(str + 1, &r->end);
+	str = bitmap_getnum(str + 1, &r->end, lastbit);
 	if (IS_ERR(str))
 		return str;
 
@@ -593,14 +599,14 @@ static const char *bitmap_parse_region(const char *str, struct region *r)
 	if (*str != ':')
 		return ERR_PTR(-EINVAL);
 
-	str = bitmap_getnum(str + 1, &r->off);
+	str = bitmap_getnum(str + 1, &r->off, lastbit);
 	if (IS_ERR(str))
 		return str;
 
 	if (*str != '/')
 		return ERR_PTR(-EINVAL);
 
-	return bitmap_getnum(str + 1, &r->group_len);
+	return bitmap_getnum(str + 1, &r->group_len, lastbit);
 
 no_end:
 	r->end = r->start;
@@ -627,6 +633,10 @@ static const char *bitmap_parse_region(const char *str, struct region *r)
  * From each group will be used only defined amount of bits.
  * Syntax: range:used_size/group_size
  * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
+ * The value 'N' can be used as a dynamically substituted token for the
+ * maximum allowed value; i.e (nmaskbits - 1).  Keep in mind that it is
+ * dynamic, so if system changes cause the bitmap width to change, such
+ * as more cores in a CPU list, then any ranges using N will also change.
  *
  * Returns: 0 on success, -errno on invalid input strings. Error values:
  *
@@ -640,7 +650,8 @@ int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
 	struct region r;
 	long ret;
 
-	bitmap_zero(maskp, nmaskbits);
+	r.nbits = nmaskbits;
+	bitmap_zero(maskp, r.nbits);
 
 	while (buf) {
 		buf = bitmap_find_region(buf);
@@ -655,9 +666,7 @@ int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
 		if (ret)
 			return ret;
 
-		ret = bitmap_set_region(&r, maskp, nmaskbits);
-		if (ret)
-			return ret;
+		bitmap_set_region(&r, maskp);
 	}
 
 	return 0;

lib/test_bitmap.c

@@ -34,6 +34,8 @@ static const unsigned long exp1[] __initconst = {
 	BITMAP_FROM_U64(0x3333333311111111ULL),
 	BITMAP_FROM_U64(0xffffffff77777777ULL),
 	BITMAP_FROM_U64(0),
+	BITMAP_FROM_U64(0x00008000),
+	BITMAP_FROM_U64(0x80000000),
 };
 
 static const unsigned long exp2[] __initconst = {
@@ -334,15 +336,47 @@ static const struct test_bitmap_parselist parselist_tests[] __initconst = {
 	{0, " ,  ,,  , ,   ",		&exp1[12 * step], 8, 0},
 	{0, " ,  ,,  , ,   \n",		&exp1[12 * step], 8, 0},
 
+	{0, "0-0",			&exp1[0], 32, 0},
+	{0, "1-1",			&exp1[1 * step], 32, 0},
+	{0, "15-15",			&exp1[13 * step], 32, 0},
+	{0, "31-31",			&exp1[14 * step], 32, 0},
+
+	{0, "0-0:0/1",			&exp1[12 * step], 32, 0},
+	{0, "0-0:1/1",			&exp1[0], 32, 0},
+	{0, "0-0:1/31",			&exp1[0], 32, 0},
+	{0, "0-0:31/31",		&exp1[0], 32, 0},
+	{0, "1-1:1/1",			&exp1[1 * step], 32, 0},
+	{0, "0-15:16/31",		&exp1[2 * step], 32, 0},
+	{0, "15-15:1/2",		&exp1[13 * step], 32, 0},
+	{0, "15-15:31/31",		&exp1[13 * step], 32, 0},
+	{0, "15-31:1/31",		&exp1[13 * step], 32, 0},
+	{0, "16-31:16/31",		&exp1[3 * step], 32, 0},
+	{0, "31-31:31/31",		&exp1[14 * step], 32, 0},
+
+	{0, "N-N",			&exp1[14 * step], 32, 0},
+	{0, "0-0:1/N",			&exp1[0], 32, 0},
+	{0, "0-0:N/N",			&exp1[0], 32, 0},
+	{0, "0-15:16/N",		&exp1[2 * step], 32, 0},
+	{0, "15-15:N/N",		&exp1[13 * step], 32, 0},
+	{0, "15-N:1/N",			&exp1[13 * step], 32, 0},
+	{0, "16-N:16/N",		&exp1[3 * step], 32, 0},
+	{0, "N-N:N/N",			&exp1[14 * step], 32, 0},
+
+	{0, "0-N:1/3,1-N:1/3,2-N:1/3",		&exp1[8 * step], 32, 0},
+	{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},
+
 	{-EINVAL, "-1",	NULL, 8, 0},
 	{-EINVAL, "-0",	NULL, 8, 0},
 	{-EINVAL, "10-1", NULL, 8, 0},
-	{-EINVAL, "0-31:", NULL, 8, 0},
-	{-EINVAL, "0-31:0", NULL, 8, 0},
-	{-EINVAL, "0-31:0/", NULL, 8, 0},
-	{-EINVAL, "0-31:0/0", NULL, 8, 0},
-	{-EINVAL, "0-31:1/0", NULL, 8, 0},
-	{-EINVAL, "0-31:10/1", NULL, 8, 0},
+	{-ERANGE, "8-8", NULL, 8, 0},
+	{-ERANGE, "0-31", NULL, 8, 0},
+	{-EINVAL, "0-31:", NULL, 32, 0},
+	{-EINVAL, "0-31:0", NULL, 32, 0},
+	{-EINVAL, "0-31:0/", NULL, 32, 0},
+	{-EINVAL, "0-31:0/0", NULL, 32, 0},
+	{-EINVAL, "0-31:1/0", NULL, 32, 0},
+	{-EINVAL, "0-31:10/1", NULL, 32, 0},
 	{-EOVERFLOW, "0-98765432123456789:10/1", NULL, 8, 0},
 
 	{-EINVAL, "a-31", NULL, 8, 0},

mm/slab.c

@@ -3651,6 +3651,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
 EXPORT_SYMBOL(__kmalloc_node_track_caller);
 #endif /* CONFIG_NUMA */
 
+#ifdef CONFIG_PRINTK
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 {
 	struct kmem_cache *cachep;
@@ -3670,6 +3671,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 	if (DEBUG && cachep->flags & SLAB_STORE_USER)
 		kpp->kp_ret = *dbg_userword(cachep, objp);
 }
+#endif
 
 /**
  * __do_kmalloc - allocate memory

mm/slab.h

@@ -621,6 +621,7 @@ static inline bool slab_want_init_on_free(struct kmem_cache *c)
 	return false;
 }
 
+#ifdef CONFIG_PRINTK
 #define KS_ADDRS_COUNT 16
 struct kmem_obj_info {
 	void *kp_ptr;
@@ -632,5 +633,6 @@ struct kmem_obj_info {
 	void *kp_stack[KS_ADDRS_COUNT];
 };
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page);
+#endif
 
 #endif /* MM_SLAB_H */

mm/slab_common.c

@@ -526,6 +526,7 @@ bool slab_is_available(void)
 	return slab_state >= UP;
 }
 
+#ifdef CONFIG_PRINTK
 /**
  * kmem_valid_obj - does the pointer reference a valid slab object?
  * @object: pointer to query.
@@ -544,6 +545,7 @@ bool kmem_valid_obj(void *object)
 	page = virt_to_head_page(object);
 	return PageSlab(page);
 }
+EXPORT_SYMBOL_GPL(kmem_valid_obj);
 
 /**
  * kmem_dump_obj - Print available slab provenance information
@@ -600,6 +602,8 @@ void kmem_dump_obj(void *object)
 		pr_info("    %pS\n", kp.kp_stack[i]);
 	}
 }
+EXPORT_SYMBOL_GPL(kmem_dump_obj);
+#endif
 
 #ifndef CONFIG_SLOB
 /* Create a cache during boot when no slab services are available yet */

mm/slob.c

@@ -461,11 +461,13 @@ static void slob_free(void *block, int size)
 	spin_unlock_irqrestore(&slob_lock, flags);
 }
 
+#ifdef CONFIG_PRINTK
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 {
 	kpp->kp_ptr = object;
 	kpp->kp_page = page;
 }
+#endif
 
 /*
  * End of slob allocator proper. Begin kmem_cache_alloc and kmalloc frontend.

mm/slub.c

@@ -3964,6 +3964,7 @@ int __kmem_cache_shutdown(struct kmem_cache *s)
 	return 0;
 }
 
+#ifdef CONFIG_PRINTK
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 {
 	void *base;
@@ -4003,6 +4004,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 #endif
 #endif
 }
+#endif
 
 /********************************************************************
  *		Kmalloc subsystem

mm/util.c

@@ -983,6 +983,7 @@ int __weak memcmp_pages(struct page *page1, struct page *page2)
 	return ret;
 }
 
+#ifdef CONFIG_PRINTK
 /**
  * mem_dump_obj - Print available provenance information
  * @object: object for which to find provenance information.
@@ -1013,3 +1014,5 @@ void mem_dump_obj(void *object)
 	}
 	pr_cont(" non-slab/vmalloc memory.\n");
 }
+EXPORT_SYMBOL_GPL(mem_dump_obj);
+#endif

mm/vmalloc.c

@@ -3450,6 +3450,7 @@ void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
 }
 #endif	/* CONFIG_SMP */
 
+#ifdef CONFIG_PRINTK
 bool vmalloc_dump_obj(void *object)
 {
 	struct vm_struct *vm;
@@ -3462,6 +3463,7 @@ bool vmalloc_dump_obj(void *object)
 		vm->nr_pages, (unsigned long)vm->addr, vm->caller);
 	return true;
 }
+#endif
 
 #ifdef CONFIG_PROC_FS
 static void *s_start(struct seq_file *m, loff_t *pos)

tools/testing/selftests/rcutorture/bin/cpus2use.sh

@@ -21,7 +21,6 @@ then
 		awk -v ncpus=$ncpus '{ print ncpus * ($7 + $NF) / 100 }'`
 else
 	# No mpstat command, so use all available CPUs.
-	echo The mpstat command is not available, so greedily using all CPUs.
 	idlecpus=$ncpus
 fi
 awk -v ncpus=$ncpus -v idlecpus=$idlecpus < /dev/null '

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

@@ -5,10 +5,11 @@
 # of this script is to inflict random OS jitter on a concurrently running
 # test.
 #
-# Usage: jitter.sh me duration [ sleepmax [ spinmax ] ]
+# Usage: jitter.sh me jittering-path duration [ sleepmax [ spinmax ] ]
 #
 # me: Random-number-generator seed salt.
 # duration: Time to run in seconds.
+# jittering-path: Path to file whose removal will stop this script.
 # sleepmax: Maximum microseconds to sleep, defaults to one second.
 # spinmax: Maximum microseconds to spin, defaults to one millisecond.
 #
@@ -17,9 +18,10 @@
 # Authors: Paul E. McKenney <paulmck@linux.ibm.com>
 
 me=$(($1 * 1000))
-duration=$2
-sleepmax=${3-1000000}
-spinmax=${4-1000}
+jittering=$2
+duration=$3
+sleepmax=${4-1000000}
+spinmax=${5-1000}
 
 n=1
 
@@ -47,7 +49,7 @@ do
 	fi
 
 	# Check for stop request.
-	if test -f "$TORTURE_STOPFILE"
+	if ! test -f "$jittering"
 	then
 		exit 1;
 	fi
@@ -67,10 +69,10 @@ do
 		srand(n + me + systime());
 		ncpus = split(cpus, ca);
 		curcpu = ca[int(rand() * ncpus + 1)];
-		mask = lshift(1, curcpu);
-		if (mask + 0 <= 0)
-			mask = 1;
-		printf("%#x\n", mask);
+		z = "";
+		for (i = 1; 4 * i <= curcpu; i++)
+			z = z "0";
+		print "0x" 2 ^ (curcpu % 4) z;
 	}' < /dev/null`
 	n=$(($n+1))
 	if ! taskset -p $cpumask $$ > /dev/null 2>&1

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

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Start up the specified number of jitter.sh scripts in the background.
+#
+# Usage: . jitterstart.sh n jittering-dir duration [ sleepmax [ spinmax ] ]
+#
+# n: Number of jitter.sh scripts to start up.
+# jittering-dir: Directory in which to put "jittering" file.
+# duration: Time to run in seconds.
+# sleepmax: Maximum microseconds to sleep, defaults to one second.
+# spinmax: Maximum microseconds to spin, defaults to one millisecond.
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+jitter_n=$1
+if test -z "$jitter_n"
+then
+	echo jitterstart.sh: Missing count of jitter.sh scripts to start.
+	exit 33
+fi
+jittering_dir=$2
+if test -z "$jittering_dir"
+then
+	echo jitterstart.sh: Missing directory in which to place jittering file.
+	exit 34
+fi
+shift
+shift
+
+touch ${jittering_dir}/jittering
+for ((jitter_i = 1; jitter_i <= $jitter_n; jitter_i++))
+do
+	jitter.sh $jitter_i "${jittering_dir}/jittering" "$@" &
+done

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

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Remove the "jittering" file, signaling the jitter.sh scripts to stop,
+# then wait for them to terminate.
+#
+# Usage: . jitterstop.sh jittering-dir
+#
+# jittering-dir: Directory containing "jittering" file.
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+jittering_dir=$1
+if test -z "$jittering_dir"
+then
+	echo jitterstop.sh: Missing directory in which to place jittering file.
+	exit 34
+fi
+
+rm -f ${jittering_dir}/jittering
+wait

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

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Rerun a series of tests under KVM.
+#
+# Usage: kvm-again.sh /path/to/old/run [ options ]
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+scriptname=$0
+args="$*"
+
+T=${TMPDIR-/tmp}/kvm-again.sh.$$
+trap 'rm -rf $T' 0
+mkdir $T
+
+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
+
+oldrun=$1
+shift
+if ! test -d "$oldrun"
+then
+	echo "Usage: $scriptname /path/to/old/run [ options ]"
+	exit 1
+fi
+if ! cp "$oldrun/batches" $T/batches.oldrun
+then
+	# Later on, can reconstitute this from console.log files.
+	echo Prior run batches file does not exist: $oldrun/batches
+	exit 1
+fi
+
+if test -f "$oldrun/torture_suite"
+then
+	torture_suite="`cat $oldrun/torture_suite`"
+elif test -f "$oldrun/TORTURE_SUITE"
+then
+	torture_suite="`cat $oldrun/TORTURE_SUITE`"
+else
+	echo "Prior run torture_suite file does not exist: $oldrun/{torture_suite,TORTURE_SUITE}"
+	exit 1
+fi
+
+KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
+PATH=${KVM}/bin:$PATH; export PATH
+. functions.sh
+
+dryrun=
+dur=
+default_link="cp -R"
+rundir="`pwd`/tools/testing/selftests/rcutorture/res/`date +%Y.%m.%d-%H.%M.%S-again`"
+
+startdate="`date`"
+starttime="`get_starttime`"
+
+usage () {
+	echo "Usage: $scriptname $oldrun [ arguments ]:"
+	echo "       --dryrun"
+	echo "       --duration minutes | <seconds>s | <hours>h | <days>d"
+	echo "       --link hard|soft|copy"
+	echo "       --remote"
+	echo "       --rundir /new/res/path"
+	exit 1
+}
+
+while test $# -gt 0
+do
+	case "$1" in
+	--dryrun)
+		dryrun=1
+		;;
+	--duration)
+		checkarg --duration "(minutes)" $# "$2" '^[0-9][0-9]*\(s\|m\|h\|d\|\)$' '^error'
+		mult=60
+		if echo "$2" | grep -q 's$'
+		then
+			mult=1
+		elif echo "$2" | grep -q 'h$'
+		then
+			mult=3600
+		elif echo "$2" | grep -q 'd$'
+		then
+			mult=86400
+		fi
+		ts=`echo $2 | sed -e 's/[smhd]$//'`
+		dur=$(($ts*mult))
+		shift
+		;;
+	--link)
+		checkarg --link "hard|soft|copy" "$#" "$2" 'hard\|soft\|copy' '^--'
+		case "$2" in
+		copy)
+			arg_link="cp -R"
+			;;
+		hard)
+			arg_link="cp -Rl"
+			;;
+		soft)
+			arg_link="cp -Rs"
+			;;
+		esac
+		shift
+		;;
+	--remote)
+		arg_remote=1
+		default_link="cp -as"
+		;;
+	--rundir)
+		checkarg --rundir "(absolute pathname)" "$#" "$2" '^/' '^error'
+		rundir=$2
+		if test -e "$rundir"
+		then
+			echo "--rundir $2: Already exists."
+			usage
+		fi
+		shift
+		;;
+	*)
+		echo Unknown argument $1
+		usage
+		;;
+	esac
+	shift
+done
+if test -z "$arg_link"
+then
+	arg_link="$default_link"
+fi
+
+echo ---- Re-run results directory: $rundir
+
+# Copy old run directory tree over and adjust.
+mkdir -p "`dirname "$rundir"`"
+if ! $arg_link "$oldrun" "$rundir"
+then
+	echo "Cannot copy from $oldrun to $rundir."
+	usage
+fi
+rm -f "$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
+echo $oldrun > "$rundir/re-run"
+if ! test -d "$rundir/../../bin"
+then
+	$arg_link "$oldrun/../../bin" "$rundir/../.."
+fi
+for i in $rundir/*/qemu-cmd
+do
+	cp "$i" $T
+	qemu_cmd_dir="`dirname "$i"`"
+	kernel_dir="`echo $qemu_cmd_dir | sed -e 's/\.[0-9]\+$//'`"
+	jitter_dir="`dirname "$kernel_dir"`"
+	kvm-transform.sh "$kernel_dir/bzImage" "$qemu_cmd_dir/console.log" "$jitter_dir" $dur < $T/qemu-cmd > $i
+	if test -n "$arg_remote"
+	then
+		echo "# TORTURE_KCONFIG_GDB_ARG=''" >> $i
+	fi
+done
+
+# Extract settings from the last qemu-cmd file transformed above.
+grep '^#' $i | sed -e 's/^# //' > $T/qemu-cmd-settings
+. $T/qemu-cmd-settings
+
+grep -v '^#' $T/batches.oldrun | awk '
+BEGIN {
+	oldbatch = 1;
+}
+
+{
+	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
+}' > $T/runbatches.sh
+
+if test -n "$dryrun"
+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
+fi

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

@@ -30,7 +30,7 @@ do
 			resdir=`echo $i | sed -e 's,/$,,' -e 's,/[^/]*$,,'`
 			head -1 $resdir/log
 		fi
-		TORTURE_SUITE="`cat $i/../TORTURE_SUITE`"
+		TORTURE_SUITE="`cat $i/../torture_suite`"
 		configfile=`echo $i | sed -e 's,^.*/,,'`
 		rm -f $i/console.log.*.diags
 		kvm-recheck-${TORTURE_SUITE}.sh $i

tools/testing/selftests/rcutorture/bin/kvm-test-1-run-batch.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Carry out a kvm-based run for the specified batch of scenarios, which
+# might have been built by --build-only kvm.sh run.
+#
+# Usage: kvm-test-1-run-batch.sh SCENARIO [ SCENARIO ... ]
+#
+# Each SCENARIO is the name of a directory in the current directory
+#	containing a ready-to-run qemu-cmd file.
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+T=${TMPDIR-/tmp}/kvm-test-1-run-batch.sh.$$
+trap 'rm -rf $T' 0
+mkdir $T
+
+echo ---- Running batch $*
+# Check arguments
+runfiles=
+for i in "$@"
+do
+	if ! echo $i | grep -q '^[^/.a-z]\+\(\.[0-9]\+\)\?$'
+	then
+		echo Bad scenario name: \"$i\" 1>&2
+		exit 1
+	fi
+	if ! test -d "$i"
+	then
+		echo Scenario name not a directory: \"$i\" 1>&2
+		exit 2
+	fi
+	if ! test -f "$i/qemu-cmd"
+	then
+		echo Scenario lacks a command file: \"$i/qemu-cmd\" 1>&2
+		exit 3
+	fi
+	rm -f $i/build.*
+	touch $i/build.run
+	runfiles="$runfiles $i/build.run"
+done
+
+# Extract settings from the qemu-cmd file.
+grep '^#' $1/qemu-cmd | sed -e 's/^# //' > $T/qemu-cmd-settings
+. $T/qemu-cmd-settings
+
+# Start up jitter, start each scenario, wait, end jitter.
+echo ---- System running test: `uname -a`
+echo ---- Starting kernels. `date` | tee -a log
+$TORTURE_JITTER_START
+for i in "$@"
+do
+	echo ---- System running test: `uname -a` > $i/kvm-test-1-run-qemu.sh.out
+	echo > $i/kvm-test-1-run-qemu.sh.out
+	kvm-test-1-run-qemu.sh $i >> $i/kvm-test-1-run-qemu.sh.out 2>&1 &
+done
+for i in $runfiles
+do
+	while ls $i > /dev/null 2>&1
+	do
+		:
+	done
+done
+echo ---- All kernel runs complete. `date` | tee -a log
+$TORTURE_JITTER_STOP

tools/testing/selftests/rcutorture/bin/kvm-test-1-run-qemu.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Carry out a kvm-based run for the specified qemu-cmd file, which might
+# have been generated by --build-only kvm.sh run.
+#
+# Usage: kvm-test-1-run-qemu.sh qemu-cmd-dir
+#
+# qemu-cmd-dir provides the directory containing qemu-cmd file.
+#	This is assumed to be of the form prefix/ds/scenario, where
+#	"ds" is the top-level date-stamped directory and "scenario"
+#	is the scenario name.  Any required adjustments to this file
+#	must have been made by the caller.  The shell-command comments
+#	at the end of the qemu-cmd file are not optional.
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+T=${TMPDIR-/tmp}/kvm-test-1-run-qemu.sh.$$
+trap 'rm -rf $T' 0
+mkdir $T
+
+resdir="$1"
+if ! test -d "$resdir"
+then
+	echo $0: Nonexistent directory: $resdir
+	exit 1
+fi
+if ! test -f "$resdir/qemu-cmd"
+then
+	echo $0: Nonexistent qemu-cmd file: $resdir/qemu-cmd
+	exit 1
+fi
+
+echo ' ---' `date`: Starting kernel, PID $$
+
+# Obtain settings from the qemu-cmd file.
+grep '^#' $resdir/qemu-cmd | sed -e 's/^# //' > $T/qemu-cmd-settings
+. $T/qemu-cmd-settings
+
+# Decorate qemu-cmd with redirection, backgrounding, and PID capture
+sed -e 's/$/ 2>\&1 \&/' < $resdir/qemu-cmd > $T/qemu-cmd
+echo 'echo $! > $resdir/qemu_pid' >> $T/qemu-cmd
+
+# In case qemu refuses to run...
+echo "NOTE: $QEMU either did not run or was interactive" > $resdir/console.log
+
+# Attempt to run qemu
+kstarttime=`gawk 'BEGIN { print systime() }' < /dev/null`
+( . $T/qemu-cmd; wait `cat  $resdir/qemu_pid`; echo $? > $resdir/qemu-retval ) &
+commandcompleted=0
+if test -z "$TORTURE_KCONFIG_GDB_ARG"
+then
+	sleep 10 # Give qemu's pid a chance to reach the file
+	if test -s "$resdir/qemu_pid"
+	then
+		qemu_pid=`cat "$resdir/qemu_pid"`
+		echo Monitoring qemu job at pid $qemu_pid
+	else
+		qemu_pid=""
+		echo Monitoring qemu job at yet-as-unknown pid
+	fi
+fi
+if test -n "$TORTURE_KCONFIG_GDB_ARG"
+then
+	base_resdir=`echo $resdir | sed -e 's/\.[0-9]\+$//'`
+	if ! test -f $base_resdir/vmlinux
+	then
+		base_resdir="`cat re-run`/$resdir"
+		if ! test -f $base_resdir/vmlinux
+		then
+			base_resdir=/path/to
+		fi
+	fi
+	echo Waiting for you to attach a debug session, for example: > /dev/tty
+	echo "    gdb $base_resdir/vmlinux" > /dev/tty
+	echo 'After symbols load and the "(gdb)" prompt appears:' > /dev/tty
+	echo "    target remote :1234" > /dev/tty
+	echo "    continue" > /dev/tty
+	kstarttime=`gawk 'BEGIN { print systime() }' < /dev/null`
+fi
+while :
+do
+	if test -z "$qemu_pid" -a -s "$resdir/qemu_pid"
+	then
+		qemu_pid=`cat "$resdir/qemu_pid"`
+	fi
+	kruntime=`gawk 'BEGIN { print systime() - '"$kstarttime"' }' < /dev/null`
+	if test -z "$qemu_pid" || kill -0 "$qemu_pid" > /dev/null 2>&1
+	then
+		if test -n "$TORTURE_KCONFIG_GDB_ARG"
+		then
+			:
+		elif test $kruntime -ge $seconds || test -f "$resdir/../STOP.1"
+		then
+			break;
+		fi
+		sleep 1
+	else
+		commandcompleted=1
+		if test $kruntime -lt $seconds
+		then
+			echo Completed in $kruntime vs. $seconds >> $resdir/Warnings 2>&1
+			grep "^(qemu) qemu:" $resdir/kvm-test-1-run.sh.out >> $resdir/Warnings 2>&1
+			killpid="`sed -n "s/^(qemu) qemu: terminating on signal [0-9]* from pid \([0-9]*\).*$/\1/p" $resdir/Warnings`"
+			if test -n "$killpid"
+			then
+				echo "ps -fp $killpid" >> $resdir/Warnings 2>&1
+				ps -fp $killpid >> $resdir/Warnings 2>&1
+			fi
+		else
+			echo ' ---' `date`: "Kernel done"
+		fi
+		break
+	fi
+done
+if test -z "$qemu_pid" -a -s "$resdir/qemu_pid"
+then
+	qemu_pid=`cat "$resdir/qemu_pid"`
+fi
+if test $commandcompleted -eq 0 -a -n "$qemu_pid"
+then
+	if ! test -f "$resdir/../STOP.1"
+	then
+		echo Grace period for qemu job at pid $qemu_pid
+	fi
+	oldline="`tail $resdir/console.log`"
+	while :
+	do
+		if test -f "$resdir/../STOP.1"
+		then
+			echo "PID $qemu_pid killed due to run STOP.1 request" >> $resdir/Warnings 2>&1
+			kill -KILL $qemu_pid
+			break
+		fi
+		kruntime=`gawk 'BEGIN { print systime() - '"$kstarttime"' }' < /dev/null`
+		if kill -0 $qemu_pid > /dev/null 2>&1
+		then
+			:
+		else
+			break
+		fi
+		must_continue=no
+		newline="`tail $resdir/console.log`"
+		if test "$newline" != "$oldline" && echo $newline | grep -q ' [0-9]\+us : '
+		then
+			must_continue=yes
+		fi
+		last_ts="`tail $resdir/console.log | grep '^\[ *[0-9]\+\.[0-9]\+]' | tail -1 | sed -e 's/^\[ *//' -e 's/\..*$//'`"
+		if test -z "$last_ts"
+		then
+			last_ts=0
+		fi
+		if test "$newline" != "$oldline" -a "$last_ts" -lt $((seconds + $TORTURE_SHUTDOWN_GRACE))
+		then
+			must_continue=yes
+		fi
+		if test $must_continue = no -a $kruntime -ge $((seconds + $TORTURE_SHUTDOWN_GRACE))
+		then
+			echo "!!! PID $qemu_pid hung at $kruntime vs. $seconds seconds" >> $resdir/Warnings 2>&1
+			kill -KILL $qemu_pid
+			break
+		fi
+		oldline=$newline
+		sleep 10
+	done
+elif test -z "$qemu_pid"
+then
+	echo Unknown PID, cannot kill qemu command
+fi
+
+# Tell the script that this run is done.
+rm -f $resdir/build.run
+
+parse-console.sh $resdir/console.log $title

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

@@ -3,7 +3,7 @@
 #
 # Transform a qemu-cmd file to allow reuse.
 #
-# Usage: kvm-transform.sh bzImage console.log < qemu-cmd-in > qemu-cmd-out
+# Usage: kvm-transform.sh bzImage console.log jitter_dir [ seconds ] < qemu-cmd-in > qemu-cmd-out
 #
 #	bzImage: Kernel and initrd from the same prior kvm.sh run.
 #	console.log: File into which to place console output.
@@ -29,20 +29,62 @@ then
 	echo "Need console log file name."
 	exit 1
 fi
+jitter_dir="$3"
+if test -z "$jitter_dir" || ! test -d "$jitter_dir"
+then
+	echo "Need valid jitter directory: '$jitter_dir'"
+	exit 1
+fi
+seconds="$4"
+if test -n "$seconds" && echo $seconds | grep -q '[^0-9]'
+then
+	echo "Invalid duration, should be numeric in seconds: '$seconds'"
+	exit 1
+fi
+
+awk -v image="$image" -v consolelog="$consolelog" -v jitter_dir="$jitter_dir" \
+    -v seconds="$seconds" '
+/^# seconds=/ {
+	if (seconds == "")
+		print $0;
+	else
+		print "# seconds=" seconds;
+	next;
+}
+
+/^# TORTURE_JITTER_START=/ {
+	print "# TORTURE_JITTER_START=\". jitterstart.sh " $4 " " jitter_dir " " $6 " " $7;
+	next;
+}
+
+/^# TORTURE_JITTER_STOP=/ {
+	print "# TORTURE_JITTER_STOP=\". jitterstop.sh " " " jitter_dir " " $5;
+	next;
+}
+
+/^#/ {
+	print $0;
+	next;
+}
 
-awk -v image="$image" -v consolelog="$consolelog" '
 {
 	line = "";
 	for (i = 1; i <= NF; i++) {
-		if (line == "")
+		if ("" seconds != "" && $i ~ /\.shutdown_secs=[0-9]*$/) {
+			sub(/[0-9]*$/, seconds, $i);
+			if (line == "")
+				line = $i;
+			else
+				line = line " " $i;
+		} else if (line == "") {
 			line = $i;
-		else
+		} else {
 			line = line " " $i;
+		}
 		if ($i == "-serial") {
 			i++;
 			line = line " file:" consolelog;
-		}
-		if ($i == "-kernel") {
+		} else if ($i == "-kernel") {
 			i++;
 			line = line " " image;
 		}

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

@@ -29,17 +29,21 @@ PATH=${KVM}/bin:$PATH; export PATH
 TORTURE_ALLOTED_CPUS="`identify_qemu_vcpus`"
 TORTURE_DEFCONFIG=defconfig
 TORTURE_BOOT_IMAGE=""
+TORTURE_BUILDONLY=
 TORTURE_INITRD="$KVM/initrd"; export TORTURE_INITRD
 TORTURE_KCONFIG_ARG=""
 TORTURE_KCONFIG_GDB_ARG=""
 TORTURE_BOOT_GDB_ARG=""
 TORTURE_QEMU_GDB_ARG=""
+TORTURE_JITTER_START=""
+TORTURE_JITTER_STOP=""
 TORTURE_KCONFIG_KASAN_ARG=""
 TORTURE_KCONFIG_KCSAN_ARG=""
 TORTURE_KMAKE_ARG=""
 TORTURE_QEMU_MEM=512
 TORTURE_SHUTDOWN_GRACE=180
 TORTURE_SUITE=rcu
+TORTURE_MOD=rcutorture
 TORTURE_TRUST_MAKE=""
 resdir=""
 configs=""
@@ -100,7 +104,7 @@ do
 		TORTURE_BUILDONLY=1
 		;;
 	--configs|--config)
-		checkarg --configs "(list of config files)" "$#" "$2" '^[^/]\+$' '^--'
+		checkarg --configs "(list of config files)" "$#" "$2" '^[^/.a-z]\+$' '^--'
 		configs="$configs $2"
 		shift
 		;;
@@ -116,7 +120,7 @@ do
 		shift
 		;;
 	--datestamp)
-		checkarg --datestamp "(relative pathname)" "$#" "$2" '^[a-zA-Z0-9._-/]*$' '^--'
+		checkarg --datestamp "(relative pathname)" "$#" "$2" '^[a-zA-Z0-9._/-]*$' '^--'
 		ds=$2
 		shift
 		;;
@@ -215,6 +219,7 @@ do
 	--torture)
 		checkarg --torture "(suite name)" "$#" "$2" '^\(lock\|rcu\|rcuscale\|refscale\|scf\)$' '^--'
 		TORTURE_SUITE=$2
+		TORTURE_MOD="`echo $TORTURE_SUITE | sed -e 's/^\(lock\|rcu\|scf\)$/\1torture/'`"
 		shift
 		if test "$TORTURE_SUITE" = rcuscale || test "$TORTURE_SUITE" = refscale
 		then
@@ -381,6 +386,7 @@ TORTURE_QEMU_GDB_ARG="$TORTURE_QEMU_GDB_ARG"; export TORTURE_QEMU_GDB_ARG
 TORTURE_KCONFIG_KASAN_ARG="$TORTURE_KCONFIG_KASAN_ARG"; export TORTURE_KCONFIG_KASAN_ARG
 TORTURE_KCONFIG_KCSAN_ARG="$TORTURE_KCONFIG_KCSAN_ARG"; export TORTURE_KCONFIG_KCSAN_ARG
 TORTURE_KMAKE_ARG="$TORTURE_KMAKE_ARG"; export TORTURE_KMAKE_ARG
+TORTURE_MOD="$TORTURE_MOD"; export TORTURE_MOD
 TORTURE_QEMU_CMD="$TORTURE_QEMU_CMD"; export TORTURE_QEMU_CMD
 TORTURE_QEMU_INTERACTIVE="$TORTURE_QEMU_INTERACTIVE"; export TORTURE_QEMU_INTERACTIVE
 TORTURE_QEMU_MAC="$TORTURE_QEMU_MAC"; export TORTURE_QEMU_MAC
@@ -399,12 +405,17 @@ echo Results directory: $resdir/$ds
 echo $scriptname $args
 touch $resdir/$ds/log
 echo $scriptname $args >> $resdir/$ds/log
-echo ${TORTURE_SUITE} > $resdir/$ds/TORTURE_SUITE
-pwd > $resdir/$ds/testid.txt
+echo ${TORTURE_SUITE} > $resdir/$ds/torture_suite
+echo Build directory: `pwd` > $resdir/$ds/testid.txt
 if test -d .git
 then
+	echo Current commit: `git rev-parse HEAD` >> $resdir/$ds/testid.txt
+	echo >> $resdir/$ds/testid.txt
+	echo ' ---' Output of "'"git status"'": >> $resdir/$ds/testid.txt
 	git status >> $resdir/$ds/testid.txt
-	git rev-parse HEAD >> $resdir/$ds/testid.txt
+	echo >> $resdir/$ds/testid.txt
+	echo >> $resdir/$ds/testid.txt
+	echo ' ---' Output of "'"git diff HEAD"'": >> $resdir/$ds/testid.txt
 	git diff HEAD >> $resdir/$ds/testid.txt
 fi
 ___EOF___
@@ -434,8 +445,17 @@ function dump(first, pastlast, batchnum)
 	print "echo ----Start batch " batchnum ": `date` | tee -a " rd "log";
 	print "needqemurun="
 	jn=1
+	njitter = 0;
+	split(jitter, ja);
+	if (ja[1] == -1 && ncpus == 0)
+		njitter = 1;
+	else if (ja[1] == -1)
+		njitter = ncpus;
+	else
+		njitter = ja[1];
+	print "TORTURE_JITTER_START=\". jitterstart.sh " njitter " " rd " " dur " " ja[2] " " ja[3] "\"; export TORTURE_JITTER_START";
+	print "TORTURE_JITTER_STOP=\". jitterstop.sh " rd " \"; export TORTURE_JITTER_STOP"
 	for (j = first; j < pastlast; j++) {
-		builddir=KVM "/b" j - first + 1
 		cpusr[jn] = cpus[j];
 		if (cfrep[cf[j]] == "") {
 			cfr[jn] = cf[j];
@@ -444,15 +464,15 @@ function dump(first, pastlast, batchnum)
 			cfrep[cf[j]]++;
 			cfr[jn] = cf[j] "." cfrep[cf[j]];
 		}
+		builddir=rd cfr[jn] "/build";
 		if (cpusr[jn] > ncpus && ncpus != 0)
 			ovf = "-ovf";
 		else
 			ovf = "";
 		print "echo ", cfr[jn], cpusr[jn] ovf ": Starting build. `date` | tee -a " rd "log";
-		print "rm -f " builddir ".*";
-		print "touch " builddir ".wait";
 		print "mkdir " rd cfr[jn] " || :";
-		print "kvm-test-1-run.sh " CONFIGDIR cf[j], builddir, rd cfr[jn], dur " \"" TORTURE_QEMU_ARG "\" \"" TORTURE_BOOTARGS "\" > " rd cfr[jn]  "/kvm-test-1-run.sh.out 2>&1 &"
+		print "touch " builddir ".wait";
+		print "kvm-test-1-run.sh " CONFIGDIR cf[j], rd cfr[jn], dur " \"" TORTURE_QEMU_ARG "\" \"" TORTURE_BOOTARGS "\" > " rd cfr[jn]  "/kvm-test-1-run.sh.out 2>&1 &"
 		print "echo ", cfr[jn], cpusr[jn] ovf ": Waiting for build to complete. `date` | tee -a " rd "log";
 		print "while test -f " builddir ".wait"
 		print "do"
@@ -461,23 +481,21 @@ function dump(first, pastlast, batchnum)
 		print "echo ", cfr[jn], cpusr[jn] ovf ": Build complete. `date` | tee -a " rd "log";
 		jn++;
 	}
+	print "runfiles="
 	for (j = 1; j < jn; j++) {
-		builddir=KVM "/b" j
-		print "rm -f " builddir ".ready"
+		builddir=rd cfr[j] "/build";
+		if (TORTURE_BUILDONLY)
+			print "rm -f " builddir ".ready"
+		else
+			print "mv " builddir ".ready " builddir ".run"
+			print "runfiles=\"$runfiles " builddir ".run\""
+		fi
 		print "if test -f \"" rd cfr[j] "/builtkernel\""
 		print "then"
 		print "\techo ----", cfr[j], cpusr[j] ovf ": Kernel present. `date` | tee -a " rd "log";
 		print "\tneedqemurun=1"
 		print "fi"
 	}
-	njitter = 0;
-	split(jitter, ja);
-	if (ja[1] == -1 && ncpus == 0)
-		njitter = 1;
-	else if (ja[1] == -1)
-		njitter = ncpus;
-	else
-		njitter = ja[1];
 	if (TORTURE_BUILDONLY && njitter != 0) {
 		njitter = 0;
 		print "echo Build-only run, so suppressing jitter | tee -a " rd "log"
@@ -488,19 +506,18 @@ function dump(first, pastlast, batchnum)
 	print "if test -n \"$needqemurun\""
 	print "then"
 	print "\techo ---- Starting kernels. `date` | tee -a " rd "log";
-	print "\techo > " rd "jitter_pids"
-	for (j = 0; j < njitter; j++) {
-		print "\tjitter.sh " j " " dur " " ja[2] " " ja[3] "&"
-		print "\techo $! >> " rd "jitter_pids"
-	}
-	print "\twait"
+	print "\t$TORTURE_JITTER_START";
+	print "\twhile ls $runfiles > /dev/null 2>&1"
+	print "\tdo"
+	print "\t\t:"
+	print "\tdone"
+	print "\t$TORTURE_JITTER_STOP";
 	print "\techo ---- All kernel runs complete. `date` | tee -a " rd "log";
 	print "else"
 	print "\twait"
 	print "\techo ---- No kernel runs. `date` | tee -a " rd "log";
 	print "fi"
 	for (j = 1; j < jn; j++) {
-		builddir=KVM "/b" j
 		print "echo ----", cfr[j], cpusr[j] ovf ": Build/run results: | tee -a " rd "log";
 		print "cat " rd cfr[j]  "/kvm-test-1-run.sh.out | tee -a " rd "log";
 	}
@@ -548,6 +565,18 @@ echo 'ret=$?' >> $T/script
 echo "cat $T/kvm-recheck.sh.out | tee -a $resdir/$ds/log" >> $T/script
 echo 'exit $ret' >> $T/script
 
+# Extract the tests and their batches from the script.
+egrep 'Start batch|Starting build\.' $T/script | grep -v ">>" |
+	sed -e 's/:.*$//' -e 's/^echo //' -e 's/-ovf//' |
+	awk '
+	/^----Start/ {
+		batchno = $3;
+		next;
+	}
+	{
+		print batchno, $1, $2
+	}' > $T/batches
+
 if test "$dryrun" = script
 then
 	cat $T/script
@@ -566,21 +595,14 @@ then
 	exit 0
 elif test "$dryrun" = batches
 then
-	# Extract the tests and their batches from the script.
-	egrep 'Start batch|Starting build\.' $T/script | grep -v ">>" |
-		sed -e 's/:.*$//' -e 's/^echo //' -e 's/-ovf//' |
-		awk '
-		/^----Start/ {
-			batchno = $3;
-			next;
-		}
-		{
-			print batchno, $1, $2
-		}'
+	cat $T/batches
+	exit 0
 else
-	# Not a dryrun, so run the script.
+	# 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
+	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

@@ -374,7 +374,7 @@ done
 if test "$do_kvfree" = "yes"
 then
 	torture_bootargs="rcuscale.kfree_rcu_test=1 rcuscale.kfree_nthreads=16 rcuscale.holdoff=20 rcuscale.kfree_loops=10000 torture.disable_onoff_at_boot"
-	torture_set "rcuscale-kvfree" tools/testing/selftests/rcutorture/bin/kvm.sh --torture rcuscale --allcpus --duration 10 --kconfig "CONFIG_NR_CPUS=$HALF_ALLOTED_CPUS" --trust-make
+	torture_set "rcuscale-kvfree" tools/testing/selftests/rcutorture/bin/kvm.sh --torture rcuscale --allcpus --duration 10 --kconfig "CONFIG_NR_CPUS=$HALF_ALLOTED_CPUS" --memory 1G --trust-make
 fi
 
 echo " --- " $scriptname $args

tools/testing/selftests/rcutorture/configs/rcu/CFLIST

@@ -7,8 +7,8 @@ TREE07
 TREE09
 SRCU-N
 SRCU-P
-SRCU-t
-SRCU-u
+SRCU-T
+SRCU-U
 TINY01
 TINY02
 TASKS01

tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot

@@ -4,3 +4,4 @@ rcutree.gp_init_delay=3
 rcutree.gp_cleanup_delay=3
 rcutree.kthread_prio=2
 threadirqs
+tree.use_softirq=0

tools/testing/selftests/rcutorture/configs/rcu/TREE04.boot

-rcutree.rcu_fanout_leaf=4 nohz_full=1-7
+rcutree.rcu_fanout_leaf=4 nohz_full=1-N

tools/testing/selftests/rcutorture/configs/rcu/TREE08.boot

 rcupdate.rcu_self_test=1
 rcutree.rcu_fanout_exact=1
-rcu_nocbs=0-7
+rcu_nocbs=all

tools/testing/selftests/rcutorture/configs/rcuscale/ver_functions.sh

@@ -12,5 +12,5 @@
 # Adds per-version torture-module parameters to kernels supporting them.
 per_version_boot_params () {
 	echo $1 rcuscale.shutdown=1 \
-		rcuscale.verbose=1
+		rcuscale.verbose=0
 }

tools/testing/selftests/rcutorture/configs/refscale/ver_functions.sh

@@ -12,5 +12,5 @@
 # Adds per-version torture-module parameters to kernels supporting them.
 per_version_boot_params () {
 	echo $1 refscale.shutdown=1 \
-		refscale.verbose=1
+		refscale.verbose=0
 }