Merge branches 'doc.2021.11.30c', 'exp.2021.12.07a', 'fastnohz.2021.11.30c',...

Merge branches 'doc.2021.11.30c', 'exp.2021.12.07a', 'fastnohz.2021.11.30c', 'fixes.2021.11.30c', 'nocb.2021.12.09a', 'nolibc.2021.11.30c', 'tasks.2021.12.09a', 'torture.2021.12.07a' and 'torturescript.2021.11.30c' into HEAD

doc.2021.11.30c: Documentation updates.
exp.2021.12.07a: Expedited-grace-period fixes.
fastnohz.2021.11.30c: Remove CONFIG_RCU_FAST_NO_HZ.
fixes.2021.11.30c: Miscellaneous fixes.
nocb.2021.12.09a: No-CB CPU updates.
nolibc.2021.11.30c: Tiny in-kernel library updates.
tasks.2021.12.09a: RCU-tasks updates, including update-side scalability.
torture.2021.12.07a: Torture-test in-kernel module updates.
torturescript.2021.11.30c: Torture-test scripting updates.

Documentation/RCU/stallwarn.rst

@@ -254,17 +254,6 @@ period (in this case 2603), the grace-period sequence number (7075), and
 an estimate of the total number of RCU callbacks queued across all CPUs
 (625 in this case).
 
-In kernels with CONFIG_RCU_FAST_NO_HZ, more information is printed
-for each CPU::
-
-	0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 softirq=82/543 last_accelerate: a345/d342 dyntick_enabled: 1
-
-The "last_accelerate:" prints the low-order 16 bits (in hex) of the
-jiffies counter when this CPU last invoked rcu_try_advance_all_cbs()
-from rcu_needs_cpu() or last invoked rcu_accelerate_cbs() from
-rcu_prepare_for_idle(). "dyntick_enabled: 1" indicates that dyntick-idle
-processing is enabled.
-
 If the grace period ends just as the stall warning starts printing,
 there will be a spurious stall-warning message, which will include
 the following::

Documentation/admin-guide/kernel-parameters.txt

@@ -4343,19 +4343,30 @@
 				Disable the Correctable Errors Collector,
 				see CONFIG_RAS_CEC help text.
 
-	rcu_nocbs=	[KNL]
-			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.
-			Invocation of these CPUs' RCU callbacks will be
-			offloaded to "rcuox/N" kthreads created for that
-			purpose, where "x" is "p" for RCU-preempt, and
-			"s" for RCU-sched, and "N" is the CPU number.
-			This reduces OS jitter on the offloaded CPUs,
-			which can be useful for HPC and real-time
-			workloads.  It can also improve energy efficiency
-			for asymmetric multiprocessors.
+	rcu_nocbs[=cpu-list]
+			[KNL] The optional argument is a cpu list,
+			as described above.
+
+			In kernels built with CONFIG_RCU_NOCB_CPU=y,
+			enable the no-callback CPU mode, which prevents
+			such CPUs' callbacks from being invoked in
+			softirq context.  Invocation of such CPUs' RCU
+			callbacks will instead be offloaded to "rcuox/N"
+			kthreads created for that purpose, where "x" is
+			"p" for RCU-preempt, "s" for RCU-sched, and "g"
+			for the kthreads that mediate grace periods; and
+			"N" is the CPU number. This reduces OS jitter on
+			the offloaded CPUs, which can be useful for HPC
+			and real-time workloads.  It can also improve
+			energy efficiency for asymmetric multiprocessors.
+
+			If a cpulist is passed as an argument, the specified
+			list of	CPUs is set to no-callback mode from boot.
+
+			Otherwise, if the '=' sign and the cpulist
+			arguments are omitted, no CPU will be set to
+			no-callback mode from boot but the mode may be
+			toggled at runtime via cpusets.
 
 	rcu_nocb_poll	[KNL]
 			Rather than requiring that offloaded CPUs
@@ -4489,10 +4500,6 @@
 			on rcutree.qhimark at boot time and to zero to
 			disable more aggressive help enlistment.
 
-	rcutree.rcu_idle_gp_delay= [KNL]
-			Set wakeup interval for idle CPUs that have
-			RCU callbacks (RCU_FAST_NO_HZ=y).
-
 	rcutree.rcu_kick_kthreads= [KNL]
 			Cause the grace-period kthread to get an extra
 			wake_up() if it sleeps three times longer than
@@ -4603,8 +4610,12 @@
 			in seconds.
 
 	rcutorture.fwd_progress= [KNL]
-			Enable RCU grace-period forward-progress testing
+			Specifies the number of kthreads to be used
+			for  RCU grace-period forward-progress testing
 			for the types of RCU supporting this notion.
+			Defaults to 1 kthread, values less than zero or
+			greater than the number of CPUs cause the number
+			of CPUs to be used.
 
 	rcutorture.fwd_progress_div= [KNL]
 			Specify the fraction of a CPU-stall-warning
@@ -4805,6 +4816,29 @@
 			period to instead use normal non-expedited
 			grace-period processing.
 
+	rcupdate.rcu_task_collapse_lim= [KNL]
+			Set the maximum number of callbacks present
+			at the beginning of a grace period that allows
+			the RCU Tasks flavors to collapse back to using
+			a single callback queue.  This switching only
+			occurs when rcupdate.rcu_task_enqueue_lim is
+			set to the default value of -1.
+
+	rcupdate.rcu_task_contend_lim= [KNL]
+			Set the minimum number of callback-queuing-time
+			lock-contention events per jiffy required to
+			cause the RCU Tasks flavors to switch to per-CPU
+			callback queuing.  This switching only occurs
+			when rcupdate.rcu_task_enqueue_lim is set to
+			the default value of -1.
+
+	rcupdate.rcu_task_enqueue_lim= [KNL]
+			Set the number of callback queues to use for the
+			RCU Tasks family of RCU flavors.  The default
+			of -1 allows this to be automatically (and
+			dynamically) adjusted.	This parameter is intended
+			for use in testing.
+
 	rcupdate.rcu_task_ipi_delay= [KNL]
 			Set time in jiffies during which RCU tasks will
 			avoid sending IPIs, starting with the beginning

Documentation/timers/no_hz.rst

@@ -184,16 +184,12 @@ There are situations in which idle CPUs cannot be permitted to
 enter either dyntick-idle mode or adaptive-tick mode, the most
 common being when that CPU has RCU callbacks pending.
 
-The CONFIG_RCU_FAST_NO_HZ=y Kconfig option may be used to cause such CPUs
-to enter dyntick-idle mode or adaptive-tick mode anyway.  In this case,
-a timer will awaken these CPUs every four jiffies in order to ensure
-that the RCU callbacks are processed in a timely fashion.
-
-Another approach is to offload RCU callback processing to "rcuo" kthreads
+Avoid this by offloading RCU callback processing to "rcuo" kthreads
 using the CONFIG_RCU_NOCB_CPU=y Kconfig option.  The specific CPUs to
 offload may be selected using The "rcu_nocbs=" kernel boot parameter,
 which takes a comma-separated list of CPUs and CPU ranges, for example,
-"1,3-5" selects CPUs 1, 3, 4, and 5.
+"1,3-5" selects CPUs 1, 3, 4, and 5.  Note that CPUs specified by
+the "nohz_full" kernel boot parameter are also offloaded.
 
 The offloaded CPUs will never queue RCU callbacks, and therefore RCU
 never prevents offloaded CPUs from entering either dyntick-idle mode

include/linux/rcu_segcblist.h

@@ -69,7 +69,7 @@ struct rcu_cblist {
  *
  *
  *  ----------------------------------------------------------------------------
- *  |                         SEGCBLIST_SOFTIRQ_ONLY                           |
+ *  |                              SEGCBLIST_RCU_CORE                          |
  *  |                                                                          |
  *  |  Callbacks processed by rcu_core() from softirqs or local                |
  *  |  rcuc kthread, without holding nocb_lock.                                |
@@ -77,7 +77,7 @@ struct rcu_cblist {
  *                                         |
  *                                         v
  *  ----------------------------------------------------------------------------
- *  |                        SEGCBLIST_OFFLOADED                               |
+ *  |       SEGCBLIST_RCU_CORE | SEGCBLIST_LOCKING | SEGCBLIST_OFFLOADED       |
  *  |                                                                          |
  *  | Callbacks processed by rcu_core() from softirqs or local                 |
  *  | rcuc kthread, while holding nocb_lock. Waking up CB and GP kthreads,     |
@@ -89,6 +89,8 @@ struct rcu_cblist {
  *                        |                                 |
  *                        v                                 v
  *  ---------------------------------------  ----------------------------------|
+ *  |        SEGCBLIST_RCU_CORE   |       |  |     SEGCBLIST_RCU_CORE   |      |
+ *  |        SEGCBLIST_LOCKING    |       |  |     SEGCBLIST_LOCKING    |      |
  *  |        SEGCBLIST_OFFLOADED  |       |  |     SEGCBLIST_OFFLOADED  |      |
  *  |        SEGCBLIST_KTHREAD_CB         |  |     SEGCBLIST_KTHREAD_GP        |
  *  |                                     |  |                                 |
@@ -104,9 +106,10 @@ struct rcu_cblist {
  *                                         |
  *                                         v
  *  |--------------------------------------------------------------------------|
+ *  |                           SEGCBLIST_LOCKING    |                         |
  *  |                           SEGCBLIST_OFFLOADED  |                         |
- *  |                           SEGCBLIST_KTHREAD_CB |                         |
- *  |                           SEGCBLIST_KTHREAD_GP                           |
+ *  |                           SEGCBLIST_KTHREAD_GP |                         |
+ *  |                           SEGCBLIST_KTHREAD_CB                           |
  *  |                                                                          |
  *  |   Kthreads handle callbacks holding nocb_lock, local rcu_core() stops    |
  *  |   handling callbacks. Enable bypass queueing.                            |
@@ -120,6 +123,7 @@ struct rcu_cblist {
  *
  *
  *  |--------------------------------------------------------------------------|
+ *  |                           SEGCBLIST_LOCKING    |                         |
  *  |                           SEGCBLIST_OFFLOADED  |                         |
  *  |                           SEGCBLIST_KTHREAD_CB |                         |
  *  |                           SEGCBLIST_KTHREAD_GP                           |
@@ -130,6 +134,22 @@ struct rcu_cblist {
  *                                      |
  *                                      v
  *  |--------------------------------------------------------------------------|
+ *  |                           SEGCBLIST_RCU_CORE   |                         |
+ *  |                           SEGCBLIST_LOCKING    |                         |
+ *  |                           SEGCBLIST_OFFLOADED  |                         |
+ *  |                           SEGCBLIST_KTHREAD_CB |                         |
+ *  |                           SEGCBLIST_KTHREAD_GP                           |
+ *  |                                                                          |
+ *  |   CB/GP kthreads handle callbacks holding nocb_lock, local rcu_core()    |
+ *  |   handles callbacks concurrently. Bypass enqueue is enabled.             |
+ *  |   Invoke RCU core so we make sure not to preempt it in the middle with   |
+ *  |   leaving some urgent work unattended within a jiffy.                    |
+ *  ----------------------------------------------------------------------------
+ *                                      |
+ *                                      v
+ *  |--------------------------------------------------------------------------|
+ *  |                           SEGCBLIST_RCU_CORE   |                         |
+ *  |                           SEGCBLIST_LOCKING    |                         |
  *  |                           SEGCBLIST_KTHREAD_CB |                         |
  *  |                           SEGCBLIST_KTHREAD_GP                           |
  *  |                                                                          |
@@ -143,7 +163,9 @@ struct rcu_cblist {
  *                     |                                 |
  *                     v                                 v
  *  ---------------------------------------------------------------------------|
- *  |                                                                          |
+ *  |                                     |                                    |
+ *  |        SEGCBLIST_RCU_CORE |         |       SEGCBLIST_RCU_CORE |         |
+ *  |        SEGCBLIST_LOCKING  |         |       SEGCBLIST_LOCKING  |         |
  *  |        SEGCBLIST_KTHREAD_CB         |       SEGCBLIST_KTHREAD_GP         |
  *  |                                     |                                    |
  *  | GP kthread woke up and              |   CB kthread woke up and           |
@@ -159,7 +181,7 @@ struct rcu_cblist {
  *                                      |
  *                                      v
  *  ----------------------------------------------------------------------------
- *  |                                   0                                      |
+ *  |                SEGCBLIST_RCU_CORE | SEGCBLIST_LOCKING                    |
  *  |                                                                          |
  *  | Callbacks processed by rcu_core() from softirqs or local                 |
  *  | rcuc kthread, while holding nocb_lock. Forbid nocb_timer to be armed.    |
@@ -168,17 +190,18 @@ struct rcu_cblist {
  *                                      |
  *                                      v
  *  ----------------------------------------------------------------------------
- *  |                         SEGCBLIST_SOFTIRQ_ONLY                           |
+ *  |                         SEGCBLIST_RCU_CORE                               |
  *  |                                                                          |
  *  |  Callbacks processed by rcu_core() from softirqs or local                |
  *  |  rcuc kthread, without holding nocb_lock.                                |
  *  ----------------------------------------------------------------------------
  */
 #define SEGCBLIST_ENABLED	BIT(0)
-#define SEGCBLIST_SOFTIRQ_ONLY	BIT(1)
-#define SEGCBLIST_KTHREAD_CB	BIT(2)
-#define SEGCBLIST_KTHREAD_GP	BIT(3)
-#define SEGCBLIST_OFFLOADED	BIT(4)
+#define SEGCBLIST_RCU_CORE	BIT(1)
+#define SEGCBLIST_LOCKING	BIT(2)
+#define SEGCBLIST_KTHREAD_CB	BIT(3)
+#define SEGCBLIST_KTHREAD_GP	BIT(4)
+#define SEGCBLIST_OFFLOADED	BIT(5)
 
 struct rcu_segcblist {
 	struct rcu_head *head;

include/linux/rcupdate.h

@@ -364,6 +364,12 @@ static inline void rcu_preempt_sleep_check(void) { }
 #define rcu_check_sparse(p, space)
 #endif /* #else #ifdef __CHECKER__ */
 
+#define __unrcu_pointer(p, local)					\
+({									\
+	typeof(*p) *local = (typeof(*p) *__force)(p);			\
+	rcu_check_sparse(p, __rcu);					\
+	((typeof(*p) __force __kernel *)(local)); 			\
+})
 /**
  * unrcu_pointer - mark a pointer as not being RCU protected
  * @p: pointer needing to lose its __rcu property
@@ -371,39 +377,35 @@ static inline void rcu_preempt_sleep_check(void) { }
  * Converts @p from an __rcu pointer to a __kernel pointer.
  * This allows an __rcu pointer to be used with xchg() and friends.
  */
-#define unrcu_pointer(p)						\
-({									\
-	typeof(*p) *_________p1 = (typeof(*p) *__force)(p);		\
-	rcu_check_sparse(p, __rcu);					\
-	((typeof(*p) __force __kernel *)(_________p1)); 		\
-})
+#define unrcu_pointer(p) __unrcu_pointer(p, __UNIQUE_ID(rcu))
 
-#define __rcu_access_pointer(p, space) \
+#define __rcu_access_pointer(p, local, space) \
 ({ \
-	typeof(*p) *_________p1 = (typeof(*p) *__force)READ_ONCE(p); \
+	typeof(*p) *local = (typeof(*p) *__force)READ_ONCE(p); \
 	rcu_check_sparse(p, space); \
-	((typeof(*p) __force __kernel *)(_________p1)); \
+	((typeof(*p) __force __kernel *)(local)); \
 })
-#define __rcu_dereference_check(p, c, space) \
+#define __rcu_dereference_check(p, local, c, space) \
 ({ \
 	/* Dependency order vs. p above. */ \
-	typeof(*p) *________p1 = (typeof(*p) *__force)READ_ONCE(p); \
+	typeof(*p) *local = (typeof(*p) *__force)READ_ONCE(p); \
 	RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_check() usage"); \
 	rcu_check_sparse(p, space); \
-	((typeof(*p) __force __kernel *)(________p1)); \
+	((typeof(*p) __force __kernel *)(local)); \
 })
-#define __rcu_dereference_protected(p, c, space) \
+#define __rcu_dereference_protected(p, local, c, space) \
 ({ \
 	RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_protected() usage"); \
 	rcu_check_sparse(p, space); \
 	((typeof(*p) __force __kernel *)(p)); \
 })
-#define rcu_dereference_raw(p) \
+#define __rcu_dereference_raw(p, local) \
 ({ \
 	/* Dependency order vs. p above. */ \
-	typeof(p) ________p1 = READ_ONCE(p); \
-	((typeof(*p) __force __kernel *)(________p1)); \
+	typeof(p) local = READ_ONCE(p); \
+	((typeof(*p) __force __kernel *)(local)); \
 })
+#define rcu_dereference_raw(p) __rcu_dereference_raw(p, __UNIQUE_ID(rcu))
 
 /**
  * RCU_INITIALIZER() - statically initialize an RCU-protected global variable
@@ -490,7 +492,7 @@ do {									      \
  * when tearing down multi-linked structures after a grace period
  * has elapsed.
  */
-#define rcu_access_pointer(p) __rcu_access_pointer((p), __rcu)
+#define rcu_access_pointer(p) __rcu_access_pointer((p), __UNIQUE_ID(rcu), __rcu)
 
 /**
  * rcu_dereference_check() - rcu_dereference with debug checking
@@ -526,7 +528,8 @@ do {									      \
  * annotated as __rcu.
  */
 #define rcu_dereference_check(p, c) \
-	__rcu_dereference_check((p), (c) || rcu_read_lock_held(), __rcu)
+	__rcu_dereference_check((p), __UNIQUE_ID(rcu), \
+				(c) || rcu_read_lock_held(), __rcu)
 
 /**
  * rcu_dereference_bh_check() - rcu_dereference_bh with debug checking
@@ -541,7 +544,8 @@ do {									      \
  * 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)
+	__rcu_dereference_check((p), __UNIQUE_ID(rcu), \
+				(c) || rcu_read_lock_bh_held(), __rcu)
 
 /**
  * rcu_dereference_sched_check() - rcu_dereference_sched with debug checking
@@ -556,7 +560,8 @@ do {									      \
  * 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(), \
+	__rcu_dereference_check((p), __UNIQUE_ID(rcu), \
+				(c) || rcu_read_lock_sched_held(), \
 				__rcu)
 
 /*
@@ -566,7 +571,8 @@ do {									      \
  * The no-tracing version of rcu_dereference_raw() must not call
  * rcu_read_lock_held().
  */
-#define rcu_dereference_raw_check(p) __rcu_dereference_check((p), 1, __rcu)
+#define rcu_dereference_raw_check(p) \
+	__rcu_dereference_check((p), __UNIQUE_ID(rcu), 1, __rcu)
 
 /**
  * rcu_dereference_protected() - fetch RCU pointer when updates prevented
@@ -585,7 +591,7 @@ do {									      \
  * but very ugly failures.
  */
 #define rcu_dereference_protected(p, c) \
-	__rcu_dereference_protected((p), (c), __rcu)
+	__rcu_dereference_protected((p), __UNIQUE_ID(rcu), (c), __rcu)
 
 
 /**

include/linux/rcutiny.h

@@ -85,7 +85,7 @@ static inline void rcu_irq_enter_irqson(void) { }
 static inline void rcu_irq_exit(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())
+	(is_idle_task(current) && !in_nmi() && !in_hardirq() && !in_serving_softirq())
 static inline void exit_rcu(void) { }
 static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t)
 {

include/linux/srcu.h

@@ -117,7 +117,8 @@ static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
  * lockdep_is_held() calls.
  */
 #define srcu_dereference_check(p, ssp, c) \
-	__rcu_dereference_check((p), (c) || srcu_read_lock_held(ssp), __rcu)
+	__rcu_dereference_check((p), __UNIQUE_ID(rcu), \
+				(c) || srcu_read_lock_held(ssp), __rcu)
 
 /**
  * srcu_dereference - fetch SRCU-protected pointer for later dereferencing

include/linux/torture.h

@@ -38,13 +38,8 @@ do {										\
 		pr_alert("%s" TORTURE_FLAG " %s\n", torture_type, s);		\
 	}									\
 } while (0)
-#define VERBOSE_TOROUT_ERRSTRING(s) \
-do {										\
-	if (verbose) {								\
-		verbose_torout_sleep();						\
-		pr_alert("%s" TORTURE_FLAG "!!! %s\n", torture_type, s);	\
-	}									\
-} while (0)
+#define TOROUT_ERRSTRING(s) \
+	pr_alert("%s" TORTURE_FLAG "!!! %s\n", torture_type, s)
 void verbose_torout_sleep(void);
 
 #define torture_init_error(firsterr)						\

kernel/locking/locktorture.c

@@ -1047,7 +1047,7 @@ static int __init lock_torture_init(void)
 				       sizeof(writer_tasks[0]),
 				       GFP_KERNEL);
 		if (writer_tasks == NULL) {
-			VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
+			TOROUT_ERRSTRING("writer_tasks: Out of memory");
 			firsterr = -ENOMEM;
 			goto unwind;
 		}
@@ -1058,7 +1058,7 @@ static int __init lock_torture_init(void)
 				       sizeof(reader_tasks[0]),
 				       GFP_KERNEL);
 		if (reader_tasks == NULL) {
-			VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
+			TOROUT_ERRSTRING("reader_tasks: Out of memory");
 			kfree(writer_tasks);
 			writer_tasks = NULL;
 			firsterr = -ENOMEM;

kernel/rcu/Kconfig

@@ -112,7 +112,7 @@ config RCU_STALL_COMMON
 	  making these warnings mandatory for the tree variants.
 
 config RCU_NEED_SEGCBLIST
-	def_bool ( TREE_RCU || TREE_SRCU )
+	def_bool ( TREE_RCU || TREE_SRCU || TASKS_RCU_GENERIC )
 
 config RCU_FANOUT
 	int "Tree-based hierarchical RCU fanout value"
@@ -169,24 +169,6 @@ config RCU_FANOUT_LEAF
 
 	  Take the default if unsure.
 
-config RCU_FAST_NO_HZ
-	bool "Accelerate last non-dyntick-idle CPU's grace periods"
-	depends on NO_HZ_COMMON && SMP && RCU_EXPERT
-	default n
-	help
-	  This option permits CPUs to enter dynticks-idle state even if
-	  they have RCU callbacks queued, and prevents RCU from waking
-	  these CPUs up more than roughly once every four jiffies (by
-	  default, you can adjust this using the rcutree.rcu_idle_gp_delay
-	  parameter), thus improving energy efficiency.  On the other
-	  hand, this option increases the duration of RCU grace periods,
-	  for example, slowing down synchronize_rcu().
-
-	  Say Y if energy efficiency is critically important, and you
-	  	don't care about increased grace-period durations.
-
-	  Say N if you are unsure.
-
 config RCU_BOOST
 	bool "Enable RCU priority boosting"
 	depends on (RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT) || PREEMPT_RT

kernel/rcu/rcu_segcblist.c

@@ -261,16 +261,14 @@ void rcu_segcblist_disable(struct rcu_segcblist *rsclp)
 }
 
 /*
- * Mark the specified rcu_segcblist structure as offloaded.
+ * Mark the specified rcu_segcblist structure as offloaded (or not)
  */
 void rcu_segcblist_offload(struct rcu_segcblist *rsclp, bool offload)
 {
-	if (offload) {
-		rcu_segcblist_clear_flags(rsclp, SEGCBLIST_SOFTIRQ_ONLY);
-		rcu_segcblist_set_flags(rsclp, SEGCBLIST_OFFLOADED);
-	} else {
+	if (offload)
+		rcu_segcblist_set_flags(rsclp, SEGCBLIST_LOCKING | SEGCBLIST_OFFLOADED);
+	else
 		rcu_segcblist_clear_flags(rsclp, SEGCBLIST_OFFLOADED);
-	}
 }
 
 /*

kernel/rcu/rcu_segcblist.h

@@ -80,11 +80,14 @@ static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
 	return rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED);
 }
 
-/* Is the specified rcu_segcblist offloaded, or is SEGCBLIST_SOFTIRQ_ONLY set? */
+/*
+ * Is the specified rcu_segcblist NOCB offloaded (or in the middle of the
+ * [de]offloading process)?
+ */
 static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
 {
 	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
-	    !rcu_segcblist_test_flags(rsclp, SEGCBLIST_SOFTIRQ_ONLY))
+	    rcu_segcblist_test_flags(rsclp, SEGCBLIST_LOCKING))
 		return true;
 
 	return false;
@@ -92,9 +95,8 @@ static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
 
 static inline bool rcu_segcblist_completely_offloaded(struct rcu_segcblist *rsclp)
 {
-	int flags = SEGCBLIST_KTHREAD_CB | SEGCBLIST_KTHREAD_GP | SEGCBLIST_OFFLOADED;
-
-	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) && (rsclp->flags & flags) == flags)
+	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
+	    !rcu_segcblist_test_flags(rsclp, SEGCBLIST_RCU_CORE))
 		return true;
 
 	return false;

kernel/rcu/rcuscale.c

@@ -50,8 +50,8 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
 	pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s)
 #define VERBOSE_SCALEOUT_STRING(s) \
 	do { if (verbose) pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s); } while (0)
-#define VERBOSE_SCALEOUT_ERRSTRING(s) \
-	do { if (verbose) pr_alert("%s" SCALE_FLAG "!!! %s\n", scale_type, s); } while (0)
+#define SCALEOUT_ERRSTRING(s) \
+	pr_alert("%s" SCALE_FLAG "!!! %s\n", scale_type, s)
 
 /*
  * The intended use cases for the nreaders and nwriters module parameters
@@ -514,11 +514,11 @@ rcu_scale_cleanup(void)
 	 * during the mid-boot phase, so have to wait till the end.
 	 */
 	if (rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp)
-		VERBOSE_SCALEOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!");
+		SCALEOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!");
 	if (rcu_gp_is_normal() && gp_exp)
-		VERBOSE_SCALEOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!");
+		SCALEOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!");
 	if (gp_exp && gp_async)
-		VERBOSE_SCALEOUT_ERRSTRING("No expedited async GPs, so went with async!");
+		SCALEOUT_ERRSTRING("No expedited async GPs, so went with async!");
 
 	if (torture_cleanup_begin())
 		return;
@@ -845,7 +845,7 @@ rcu_scale_init(void)
 	reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
 			       GFP_KERNEL);
 	if (reader_tasks == NULL) {
-		VERBOSE_SCALEOUT_ERRSTRING("out of memory");
+		SCALEOUT_ERRSTRING("out of memory");
 		firsterr = -ENOMEM;
 		goto unwind;
 	}
@@ -865,7 +865,7 @@ rcu_scale_init(void)
 		kcalloc(nrealwriters, sizeof(*writer_n_durations),
 			GFP_KERNEL);
 	if (!writer_tasks || !writer_durations || !writer_n_durations) {
-		VERBOSE_SCALEOUT_ERRSTRING("out of memory");
+		SCALEOUT_ERRSTRING("out of memory");
 		firsterr = -ENOMEM;
 		goto unwind;
 	}

kernel/rcu/refscale.c

@@ -44,7 +44,10 @@
 	pr_alert("%s" SCALE_FLAG s, scale_type, ## x)
 
 #define VERBOSE_SCALEOUT(s, x...) \
-	do { if (verbose) pr_alert("%s" SCALE_FLAG s, scale_type, ## x); } while (0)
+	do { \
+		if (verbose) \
+			pr_alert("%s" SCALE_FLAG s "\n", scale_type, ## x); \
+	} while (0)
 
 static atomic_t verbose_batch_ctr;
 
@@ -54,12 +57,11 @@ do {											\
 	    (verbose_batched <= 0 ||							\
 	     !(atomic_inc_return(&verbose_batch_ctr) % verbose_batched))) {		\
 		schedule_timeout_uninterruptible(1);					\
-		pr_alert("%s" SCALE_FLAG s, scale_type, ## x);				\
+		pr_alert("%s" SCALE_FLAG s "\n", scale_type, ## x);			\
 	}										\
 } while (0)
 
-#define VERBOSE_SCALEOUT_ERRSTRING(s, x...) \
-	do { if (verbose) pr_alert("%s" SCALE_FLAG "!!! " s, scale_type, ## x); } while (0)
+#define SCALEOUT_ERRSTRING(s, x...) pr_alert("%s" SCALE_FLAG "!!! " s "\n", scale_type, ## x)
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Joel Fernandes (Google) <joel@joelfernandes.org>");
@@ -604,7 +606,7 @@ static u64 process_durations(int n)
 	char *buf;
 	u64 sum = 0;
 
-	buf = kmalloc(128 + nreaders * 32, GFP_KERNEL);
+	buf = kmalloc(800 + 64, GFP_KERNEL);
 	if (!buf)
 		return 0;
 	buf[0] = 0;
@@ -617,13 +619,15 @@ static u64 process_durations(int n)
 
 		if (i % 5 == 0)
 			strcat(buf, "\n");
+		if (strlen(buf) >= 800) {
+			pr_alert("%s", buf);
+			buf[0] = 0;
+		}
 		strcat(buf, buf1);
 
 		sum += rt->last_duration_ns;
 	}
-	strcat(buf, "\n");
-
-	SCALEOUT("%s\n", buf);
+	pr_alert("%s\n", buf);
 
 	kfree(buf);
 	return sum;
@@ -637,7 +641,6 @@ static u64 process_durations(int n)
 // point all the timestamps are printed.
 static int main_func(void *arg)
 {
-	bool errexit = false;
 	int exp, r;
 	char buf1[64];
 	char *buf;
@@ -648,10 +651,10 @@ static int main_func(void *arg)
 
 	VERBOSE_SCALEOUT("main_func task started");
 	result_avg = kzalloc(nruns * sizeof(*result_avg), GFP_KERNEL);
-	buf = kzalloc(64 + nruns * 32, GFP_KERNEL);
+	buf = kzalloc(800 + 64, GFP_KERNEL);
 	if (!result_avg || !buf) {
-		VERBOSE_SCALEOUT_ERRSTRING("out of memory");
-		errexit = true;
+		SCALEOUT_ERRSTRING("out of memory");
+		goto oom_exit;
 	}
 	if (holdoff)
 		schedule_timeout_interruptible(holdoff * HZ);
@@ -663,8 +666,6 @@ static int main_func(void *arg)
 
 	// Start exp readers up per experiment
 	for (exp = 0; exp < nruns && !torture_must_stop(); exp++) {
-		if (errexit)
-			break;
 		if (torture_must_stop())
 			goto end;
 
@@ -698,26 +699,23 @@ static int main_func(void *arg)
 	// Print the average of all experiments
 	SCALEOUT("END OF TEST. Calculating average duration per loop (nanoseconds)...\n");
 
-	if (!errexit) {
-		buf[0] = 0;
-		strcat(buf, "\n");
-		strcat(buf, "Runs\tTime(ns)\n");
-	}
-
+	pr_alert("Runs\tTime(ns)\n");
 	for (exp = 0; exp < nruns; exp++) {
 		u64 avg;
 		u32 rem;
 
-		if (errexit)
-			break;
 		avg = div_u64_rem(result_avg[exp], 1000, &rem);
 		sprintf(buf1, "%d\t%llu.%03u\n", exp + 1, avg, rem);
 		strcat(buf, buf1);
+		if (strlen(buf) >= 800) {
+			pr_alert("%s", buf);
+			buf[0] = 0;
+		}
 	}
 
-	if (!errexit)
-		SCALEOUT("%s", buf);
+	pr_alert("%s", buf);
 
+oom_exit:
 	// This will shutdown everything including us.
 	if (shutdown) {
 		shutdown_start = 1;
@@ -841,12 +839,12 @@ ref_scale_init(void)
 	reader_tasks = kcalloc(nreaders, sizeof(reader_tasks[0]),
 			       GFP_KERNEL);
 	if (!reader_tasks) {
-		VERBOSE_SCALEOUT_ERRSTRING("out of memory");
+		SCALEOUT_ERRSTRING("out of memory");
 		firsterr = -ENOMEM;
 		goto unwind;
 	}
 
-	VERBOSE_SCALEOUT("Starting %d reader threads\n", nreaders);
+	VERBOSE_SCALEOUT("Starting %d reader threads", nreaders);
 
 	for (i = 0; i < nreaders; i++) {
 		firsterr = torture_create_kthread(ref_scale_reader, (void *)i,

kernel/rcu/srcutiny.c

@@ -99,7 +99,7 @@ void __srcu_read_unlock(struct srcu_struct *ssp, int idx)
 	int newval = READ_ONCE(ssp->srcu_lock_nesting[idx]) - 1;
 
 	WRITE_ONCE(ssp->srcu_lock_nesting[idx], newval);
-	if (!newval && READ_ONCE(ssp->srcu_gp_waiting))
+	if (!newval && READ_ONCE(ssp->srcu_gp_waiting) && in_task())
 		swake_up_one(&ssp->srcu_wq);
 }
 EXPORT_SYMBOL_GPL(__srcu_read_unlock);

kernel/rcu/tree.h

@@ -157,7 +157,6 @@ struct rcu_data {
 	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? */
 	bool		cpu_started;	/* RCU watching this onlining CPU. */
 	struct rcu_node *mynode;	/* This CPU's leaf of hierarchy */
 	unsigned long grpmask;		/* Mask to apply to leaf qsmask. */
@@ -189,11 +188,6 @@ struct rcu_data {
 	bool rcu_urgent_qs;		/* GP old need light quiescent state. */
 	bool rcu_forced_tick;		/* Forced tick to provide QS. */
 	bool rcu_forced_tick_exp;	/*   ... provide QS to expedited GP. */
-#ifdef CONFIG_RCU_FAST_NO_HZ
-	unsigned long last_accelerate;	/* Last jiffy CBs were accelerated. */
-	unsigned long last_advance_all;	/* Last jiffy CBs were all advanced. */
-	int tick_nohz_enabled_snap;	/* Previously seen value from sysfs. */
-#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
 
 	/* 4) rcu_barrier(), OOM callbacks, and expediting. */
 	struct rcu_head barrier_head;
@@ -227,8 +221,11 @@ struct rcu_data {
 	struct swait_queue_head nocb_gp_wq; /* For nocb kthreads to sleep on. */
 	bool nocb_cb_sleep;		/* Is the nocb CB thread asleep? */
 	struct task_struct *nocb_cb_kthread;
-	struct rcu_data *nocb_next_cb_rdp;
-					/* Next rcu_data in wakeup chain. */
+	struct list_head nocb_head_rdp; /*
+					 * Head of rcu_data list in wakeup chain,
+					 * if rdp_gp.
+					 */
+	struct list_head nocb_entry_rdp; /* rcu_data node in wakeup chain. */
 
 	/* The following fields are used by CB kthread, hence new cacheline. */
 	struct rcu_data *nocb_gp_rdp ____cacheline_internodealigned_in_smp;
@@ -419,8 +416,6 @@ 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_cleanup_after_idle(void);
-static void rcu_prepare_for_idle(void);
 static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
 static bool rcu_preempt_need_deferred_qs(struct task_struct *t);
 static void rcu_preempt_deferred_qs(struct task_struct *t);
@@ -447,12 +442,16 @@ static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp,
 static void rcu_lockdep_assert_cblist_protected(struct rcu_data *rdp);
 #ifdef CONFIG_RCU_NOCB_CPU
 static void __init rcu_organize_nocb_kthreads(void);
+
+/*
+ * Disable IRQs before checking offloaded state so that local
+ * locking is safe against concurrent de-offloading.
+ */
 #define rcu_nocb_lock_irqsave(rdp, flags)			\
 do {								\
-	if (!rcu_segcblist_is_offloaded(&(rdp)->cblist))		\
 	local_irq_save(flags);					\
-	else								\
-		raw_spin_lock_irqsave(&(rdp)->nocb_lock, (flags));	\
+	if (rcu_segcblist_is_offloaded(&(rdp)->cblist))	\
+		raw_spin_lock(&(rdp)->nocb_lock);		\
 } while (0)
 #else /* #ifdef CONFIG_RCU_NOCB_CPU */
 #define rcu_nocb_lock_irqsave(rdp, flags) local_irq_save(flags)

kernel/rcu/tree_exp.h

@@ -255,7 +255,7 @@ static void rcu_report_exp_cpu_mult(struct rcu_node *rnp,
  */
 static void rcu_report_exp_rdp(struct rcu_data *rdp)
 {
-	WRITE_ONCE(rdp->exp_deferred_qs, false);
+	WRITE_ONCE(rdp->cpu_no_qs.b.exp, false);
 	rcu_report_exp_cpu_mult(rdp->mynode, rdp->grpmask, true);
 }
 
@@ -387,6 +387,7 @@ static void sync_rcu_exp_select_node_cpus(struct work_struct *wp)
 			continue;
 		}
 		if (get_cpu() == cpu) {
+			mask_ofl_test |= mask;
 			put_cpu();
 			continue;
 		}
@@ -506,7 +507,10 @@ static void synchronize_rcu_expedited_wait(void)
 				if (rdp->rcu_forced_tick_exp)
 					continue;
 				rdp->rcu_forced_tick_exp = true;
+				preempt_disable();
+				if (cpu_online(cpu))
 					tick_dep_set_cpu(cpu, TICK_DEP_BIT_RCU_EXP);
+				preempt_enable();
 			}
 		}
 		j = READ_ONCE(jiffies_till_first_fqs);
@@ -655,7 +659,7 @@ static void rcu_exp_handler(void *unused)
 		    rcu_dynticks_curr_cpu_in_eqs()) {
 			rcu_report_exp_rdp(rdp);
 		} else {
-			rdp->exp_deferred_qs = true;
+			WRITE_ONCE(rdp->cpu_no_qs.b.exp, true);
 			set_tsk_need_resched(t);
 			set_preempt_need_resched();
 		}
@@ -677,7 +681,7 @@ static void rcu_exp_handler(void *unused)
 	if (depth > 0) {
 		raw_spin_lock_irqsave_rcu_node(rnp, flags);
 		if (rnp->expmask & rdp->grpmask) {
-			rdp->exp_deferred_qs = true;
+			WRITE_ONCE(rdp->cpu_no_qs.b.exp, true);
 			t->rcu_read_unlock_special.b.exp_hint = true;
 		}
 		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@@ -759,7 +763,7 @@ static void sync_sched_exp_online_cleanup(int cpu)
 	my_cpu = get_cpu();
 	/* Quiescent state either not needed or already requested, leave. */
 	if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) ||
-	    rdp->cpu_no_qs.b.exp) {
+	    READ_ONCE(rdp->cpu_no_qs.b.exp)) {
 		put_cpu();
 		return;
 	}

kernel/rcu/tree_stall.h

@@ -347,26 +347,6 @@ static void rcu_dump_cpu_stacks(void)
 	}
 }
 
-#ifdef CONFIG_RCU_FAST_NO_HZ
-
-static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
-{
-	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
-
-	sprintf(cp, "last_accelerate: %04lx/%04lx dyntick_enabled: %d",
-		rdp->last_accelerate & 0xffff, jiffies & 0xffff,
-		!!rdp->tick_nohz_enabled_snap);
-}
-
-#else /* #ifdef CONFIG_RCU_FAST_NO_HZ */
-
-static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
-{
-	*cp = '\0';
-}
-
-#endif /* #else #ifdef CONFIG_RCU_FAST_NO_HZ */
-
 static const char * const gp_state_names[] = {
 	[RCU_GP_IDLE] = "RCU_GP_IDLE",
 	[RCU_GP_WAIT_GPS] = "RCU_GP_WAIT_GPS",
@@ -408,13 +388,12 @@ static bool rcu_is_gp_kthread_starving(unsigned long *jp)
  * of RCU grace periods that this CPU is ignorant of, for example, "1"
  * if the CPU was aware of the previous grace period.
  *
- * Also print out idle and (if CONFIG_RCU_FAST_NO_HZ) idle-entry info.
+ * Also print out idle info.
  */
 static void print_cpu_stall_info(int cpu)
 {
 	unsigned long delta;
 	bool falsepositive;
-	char fast_no_hz[72];
 	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
 	char *ticks_title;
 	unsigned long ticks_value;
@@ -432,11 +411,10 @@ static void print_cpu_stall_info(int cpu)
 		ticks_title = "ticks this GP";
 		ticks_value = rdp->ticks_this_gp;
 	}
-	print_cpu_stall_fast_no_hz(fast_no_hz, cpu);
 	delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq);
 	falsepositive = rcu_is_gp_kthread_starving(NULL) &&
 			rcu_dynticks_in_eqs(rcu_dynticks_snap(rdp));
-	pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld %s%s\n",
+	pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld %s\n",
 	       cpu,
 	       "O."[!!cpu_online(cpu)],
 	       "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)],
@@ -449,7 +427,6 @@ static void print_cpu_stall_info(int cpu)
 	       rdp->dynticks_nesting, rdp->dynticks_nmi_nesting,
 	       rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu),
 	       data_race(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart,
-	       fast_no_hz,
 	       falsepositive ? " (false positive?)" : "");
 }
 

kernel/scftorture.c

@@ -38,14 +38,10 @@
 #define SCFTORT_STRING "scftorture"
 #define SCFTORT_FLAG SCFTORT_STRING ": "
 
-#define SCFTORTOUT(s, x...) \
-	pr_alert(SCFTORT_FLAG s, ## x)
-
 #define VERBOSE_SCFTORTOUT(s, x...) \
-	do { if (verbose) pr_alert(SCFTORT_FLAG s, ## x); } while (0)
+	do { if (verbose) pr_alert(SCFTORT_FLAG s "\n", ## x); } while (0)
 
-#define VERBOSE_SCFTORTOUT_ERRSTRING(s, x...) \
-	do { if (verbose) pr_alert(SCFTORT_FLAG "!!! " s, ## x); } while (0)
+#define SCFTORTOUT_ERRSTRING(s, x...) pr_alert(SCFTORT_FLAG "!!! " s "\n", ## x)
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Paul E. McKenney <paulmck@kernel.org>");
@@ -587,14 +583,14 @@ static int __init scf_torture_init(void)
 	if (weight_resched1 == 0 && weight_single1 == 0 && weight_single_rpc1 == 0 &&
 	    weight_single_wait1 == 0 && weight_many1 == 0 && weight_many_wait1 == 0 &&
 	    weight_all1 == 0 && weight_all_wait1 == 0) {
-		VERBOSE_SCFTORTOUT_ERRSTRING("all zero weights makes no sense");
+		SCFTORTOUT_ERRSTRING("all zero weights makes no sense");
 		firsterr = -EINVAL;
 		goto unwind;
 	}
 	if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST))
 		scf_sel_add(weight_resched1, SCF_PRIM_RESCHED, false);
 	else if (weight_resched1)
-		VERBOSE_SCFTORTOUT_ERRSTRING("built as module, weight_resched ignored");
+		SCFTORTOUT_ERRSTRING("built as module, weight_resched ignored");
 	scf_sel_add(weight_single1, SCF_PRIM_SINGLE, false);
 	scf_sel_add(weight_single_rpc1, SCF_PRIM_SINGLE_RPC, true);
 	scf_sel_add(weight_single_wait1, SCF_PRIM_SINGLE, true);
@@ -625,12 +621,12 @@ static int __init scf_torture_init(void)
 		nthreads = num_online_cpus();
 	scf_stats_p = kcalloc(nthreads, sizeof(scf_stats_p[0]), GFP_KERNEL);
 	if (!scf_stats_p) {
-		VERBOSE_SCFTORTOUT_ERRSTRING("out of memory");
+		SCFTORTOUT_ERRSTRING("out of memory");
 		firsterr = -ENOMEM;
 		goto unwind;
 	}
 
-	VERBOSE_SCFTORTOUT("Starting %d smp_call_function() threads\n", nthreads);
+	VERBOSE_SCFTORTOUT("Starting %d smp_call_function() threads", nthreads);
 
 	atomic_set(&n_started, nthreads);
 	for (i = 0; i < nthreads; i++) {

kernel/torture.c

@@ -570,7 +570,7 @@ int torture_shuffle_init(long shuffint)
 	shuffle_idle_cpu = -1;
 
 	if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
-		VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
+		TOROUT_ERRSTRING("Failed to alloc mask");
 		return -ENOMEM;
 	}
 
@@ -934,7 +934,7 @@ int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
 	*tp = kthread_run(fn, arg, "%s", s);
 	if (IS_ERR(*tp)) {
 		ret = PTR_ERR(*tp);
-		VERBOSE_TOROUT_ERRSTRING(f);
+		TOROUT_ERRSTRING(f);
 		*tp = NULL;
 	}
 	torture_shuffle_task_register(*tp);

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

@@ -30,9 +30,9 @@ editor=${EDITOR-vi}
 files=
 for i in ${rundir}/*/Make.out
 do
-	if egrep -q "error:|warning:" < $i
+	if egrep -q "error:|warning:|^ld: .*undefined reference to" < $i
 	then
-		egrep "error:|warning:" < $i > $i.diags
+		egrep "error:|warning:|^ld: .*undefined reference to" < $i > $i.diags
 		files="$files $i.diags $i"
 	fi
 done

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

@@ -25,7 +25,7 @@ stopstate="`grep 'End-test grace-period state: g' $i/console.log 2> /dev/null |
 	    tail -1 | sed -e 's/^\[[ 0-9.]*] //' |
 	    awk '{ print \"[\" $1 \" \" $5 \" \" $6 \" \" $7 \"]\"; }' |
 	    tr -d '\012\015'`"
-fwdprog="`grep 'rcu_torture_fwd_prog_cr Duration' $i/console.log 2> /dev/null | sed -e 's/^\[[^]]*] //' | sort -k15nr | head -1 | awk '{ print $14 " " $15 }'`"
+fwdprog="`grep 'rcu_torture_fwd_prog n_max_cbs: ' $i/console.log 2> /dev/null | sed -e 's/^\[[^]]*] //' | sort -k3nr | head -1 | awk '{ print $2 " " $3 }'`"
 if test -z "$ngps"
 then
 	echo "$configfile ------- " $stopstate

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

@@ -144,7 +144,7 @@ do
 	if test "$ret" -ne 0
 	then
 		echo System $i unreachable, giving up. | tee -a "$oldrun/remote-log"
-		exit 4 | tee -a "$oldrun/remote-log"
+		exit 4
 	fi
 done
 
@@ -156,9 +156,16 @@ do
 	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 $i, waiting and then retrying. | tee -a "$oldrun/remote-log"
+		sleep 60
+		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"
+			exit 10
+		fi
 	fi
 done
 
@@ -177,16 +184,16 @@ checkremotefile () {
 		ret=$?
 		if test "$ret" -eq 255
 		then
-			echo " ---" ssh failure to $1 checking for file $2, retry after $sleeptime seconds. `date`
+			echo " ---" ssh failure to $1 checking for file $2, retry after $sleeptime seconds. `date` | tee -a "$oldrun/remote-log"
 		elif test "$ret" -eq 0
 		then
 			return 0
 		elif test "$ret" -eq 1
 		then
-			echo " ---" File \"$2\" not found: ssh $1 test -f \"$2\"
+			echo " ---" File \"$2\" not found: ssh $1 test -f \"$2\" | tee -a "$oldrun/remote-log"
 			return 1
 		else
-			echo " ---" Exit code $ret: ssh $1 test -f \"$2\", retry after $sleeptime seconds. `date`
+			echo " ---" Exit code $ret: ssh $1 test -f \"$2\", retry after $sleeptime seconds. `date` | tee -a "$oldrun/remote-log"
 			return $ret
 		fi
 		sleep $sleeptime
@@ -245,7 +252,7 @@ do
 		sleep 30
 	fi
 done
-echo All batches started. `date`
+echo All batches started. `date` | tee -a "$oldrun/remote-log"
 
 # Wait for all remaining scenarios to complete and collect results.
 for i in $systems
@@ -254,7 +261,7 @@ do
 	do
 		sleep 30
 	done
-	echo " ---" Collecting results from $i `date`
+	echo " ---" Collecting results from $i `date` | tee -a "$oldrun/remote-log"
 	( cd "$oldrun"; ssh $i "cd $rundir; tar -czf - kvm-remote-*.sh.out */console.log */kvm-test-1-run*.sh.out */qemu[_-]pid */qemu-retval */qemu-affinity; rm -rf $T > /dev/null 2>&1" | tar -xzf - )
 done
 

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

@@ -74,7 +74,9 @@ usage () {
 	echo "       --help"
 	echo "       --interactive"
 	echo "       --jitter N [ maxsleep (us) [ maxspin (us) ] ]"
+	echo "       --kasan"
 	echo "       --kconfig Kconfig-options"
+	echo "       --kcsan"
 	echo "       --kmake-arg kernel-make-arguments"
 	echo "       --mac nn:nn:nn:nn:nn:nn"
 	echo "       --memory megabytes|nnnG"
@@ -83,6 +85,7 @@ usage () {
 	echo "       --qemu-cmd qemu-system-..."
 	echo "       --remote"
 	echo "       --results absolute-pathname"
+	echo "       --shutdown-grace seconds"
 	echo "       --torture lock|rcu|rcuscale|refscale|scf"
 	echo "       --trust-make"
 	exit 1
@@ -175,14 +178,14 @@ do
 		jitter="$2"
 		shift
 		;;
+	--kasan)
+		TORTURE_KCONFIG_KASAN_ARG="CONFIG_DEBUG_INFO=y CONFIG_KASAN=y"; export TORTURE_KCONFIG_KASAN_ARG
+		;;
 	--kconfig|--kconfigs)
 		checkarg --kconfig "(Kconfig options)" $# "$2" '^CONFIG_[A-Z0-9_]\+=\([ynm]\|[0-9]\+\)\( CONFIG_[A-Z0-9_]\+=\([ynm]\|[0-9]\+\)\)*$' '^error$'
 		TORTURE_KCONFIG_ARG="`echo "$TORTURE_KCONFIG_ARG $2" | sed -e 's/^ *//' -e 's/ *$//'`"
 		shift
 		;;
-	--kasan)
-		TORTURE_KCONFIG_KASAN_ARG="CONFIG_DEBUG_INFO=y CONFIG_KASAN=y"; export TORTURE_KCONFIG_KASAN_ARG
-		;;
 	--kcsan)
 		TORTURE_KCONFIG_KCSAN_ARG="CONFIG_DEBUG_INFO=y CONFIG_KCSAN=y CONFIG_KCSAN_STRICT=y CONFIG_KCSAN_REPORT_ONCE_IN_MS=100000 CONFIG_KCSAN_VERBOSE=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y"; export TORTURE_KCONFIG_KCSAN_ARG
 		;;

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

@@ -39,7 +39,8 @@ fi
 grep warning: < $F > $T/warnings
 grep "include/linux/*rcu*\.h:" $T/warnings > $T/hwarnings
 grep "kernel/rcu/[^/]*:" $T/warnings > $T/cwarnings
-cat $T/hwarnings $T/cwarnings > $T/rcuwarnings
+grep "^ld: .*undefined reference to" $T/warnings | head -1 > $T/ldwarnings
+cat $T/hwarnings $T/cwarnings $T/ldwarnings > $T/rcuwarnings
 if test -s $T/rcuwarnings
 then
 	print_warning $title build errors:

tools/testing/selftests/rcutorture/configs/rcu/TASKS01.boot

 rcutorture.torture_type=tasks
 rcutree.use_softirq=0
+rcupdate.rcu_task_enqueue_lim=4

tools/testing/selftests/rcutorture/configs/rcu/TRACE01.boot

 rcutorture.torture_type=tasks-tracing
+rcupdate.rcu_task_enqueue_lim=2

tools/testing/selftests/rcutorture/configs/rcu/TRACE02.boot

 rcutorture.torture_type=tasks-tracing
+rcutorture.fwd_progress=2

tools/testing/selftests/rcutorture/configs/rcu/TREE01

@@ -6,7 +6,6 @@ CONFIG_PREEMPT=y
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=y
 CONFIG_RCU_TRACE=y
 CONFIG_HOTPLUG_CPU=y
 CONFIG_MAXSMP=y

tools/testing/selftests/rcutorture/configs/rcu/TREE02

@@ -7,7 +7,6 @@ CONFIG_PREEMPT=y
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_RCU_TRACE=n
 CONFIG_RCU_FANOUT=3
 CONFIG_RCU_FANOUT_LEAF=3

tools/testing/selftests/rcutorture/configs/rcu/TREE02.boot

+rcutorture.fwd_progress=2

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

@@ -7,7 +7,6 @@ CONFIG_PREEMPT=n
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=n
 CONFIG_NO_HZ_FULL=y
-CONFIG_RCU_FAST_NO_HZ=y
 CONFIG_RCU_TRACE=y
 CONFIG_RCU_FANOUT=4
 CONFIG_RCU_FANOUT_LEAF=3

tools/testing/selftests/rcutorture/configs/rcu/TREE05

@@ -7,7 +7,6 @@ CONFIG_PREEMPT=n
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_RCU_TRACE=n
 CONFIG_HOTPLUG_CPU=y
 CONFIG_RCU_FANOUT=6

tools/testing/selftests/rcutorture/configs/rcu/TREE06

@@ -7,7 +7,6 @@ CONFIG_PREEMPT=n
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_RCU_TRACE=n
 CONFIG_RCU_FANOUT=6
 CONFIG_RCU_FANOUT_LEAF=6

tools/testing/selftests/rcutorture/configs/rcu/TREE07

@@ -7,7 +7,6 @@ CONFIG_PREEMPT=n
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=n
 CONFIG_NO_HZ_FULL=y
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_RCU_TRACE=y
 CONFIG_HOTPLUG_CPU=y
 CONFIG_RCU_FANOUT=2

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

@@ -7,7 +7,6 @@ CONFIG_PREEMPT=y
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_RCU_TRACE=n
 CONFIG_RCU_FANOUT=3
 CONFIG_RCU_FANOUT_LEAF=2

tools/testing/selftests/rcutorture/configs/rcu/TREE10

@@ -7,7 +7,6 @@ CONFIG_PREEMPT=n
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_RCU_TRACE=n
 CONFIG_RCU_NOCB_CPU=n
 CONFIG_DEBUG_LOCK_ALLOC=n

tools/testing/selftests/rcutorture/configs/rcu/TREE10.boot

+rcutorture.fwd_progress=2

tools/testing/selftests/rcutorture/configs/rcuscale/TINY

@@ -7,7 +7,6 @@ CONFIG_PREEMPT_DYNAMIC=n
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_RCU_NOCB_CPU=n
 CONFIG_DEBUG_LOCK_ALLOC=n
 CONFIG_PROVE_LOCKING=n

tools/testing/selftests/rcutorture/configs/rcuscale/TRACE01

@@ -5,7 +5,6 @@ CONFIG_PREEMPT=n
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_RCU_NOCB_CPU=n
 CONFIG_DEBUG_LOCK_ALLOC=n
 CONFIG_PROVE_LOCKING=n

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

@@ -6,7 +6,6 @@ CONFIG_PREEMPT=y
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_HOTPLUG_CPU=y
 CONFIG_SUSPEND=n
 CONFIG_HIBERNATION=n

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

@@ -7,7 +7,6 @@ CONFIG_PREEMPT=y
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_HOTPLUG_CPU=y
 CONFIG_SUSPEND=n
 CONFIG_HIBERNATION=n

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

@@ -6,7 +6,6 @@ CONFIG_PREEMPT=n
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_HOTPLUG_CPU=y
 CONFIG_SUSPEND=n
 CONFIG_HIBERNATION=n

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

@@ -6,7 +6,6 @@ CONFIG_PREEMPT=y
 CONFIG_HZ_PERIODIC=n
 CONFIG_NO_HZ_IDLE=y
 CONFIG_NO_HZ_FULL=n
-CONFIG_RCU_FAST_NO_HZ=n
 CONFIG_HOTPLUG_CPU=y
 CONFIG_SUSPEND=n
 CONFIG_HIBERNATION=n

tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt

@@ -15,7 +15,6 @@ CONFIG_PROVE_RCU -- Hardwired to CONFIG_PROVE_LOCKING.
 CONFIG_RCU_BOOST -- one of PREEMPT_RCU.
 CONFIG_RCU_FANOUT -- Cover hierarchy, but overlap with others.
 CONFIG_RCU_FANOUT_LEAF -- Do one non-default.
-CONFIG_RCU_FAST_NO_HZ -- Do one, but not with all nohz_full CPUs.
 CONFIG_RCU_NOCB_CPU -- Do three, one with no rcu_nocbs CPUs, one with
 	rcu_nocbs=0, and one with all rcu_nocbs CPUs.
 CONFIG_RCU_TRACE -- Do half.