Merge tag 'rcu.release.v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

Pull RCU updates from Uladzislau Rezki:
 "Misc fixes:
   - check if IRQs are disabled in rcu_exp_need_qs()
   - instrument KCSAN exclusive-writer assertions
   - add extra WARN_ON_ONCE() check
   - set the cpu_no_qs.b.exp under lock
   - warn if callback enqueued on offline CPU

  Torture-test updates:
   - add rcutorture.preempt_duration kernel module parameter
   - make the TREE03 scenario do preemption
   - improve pooling timeouts for rcu_torture_writer()
   - improve output of "Failure/close-call rcutorture reader segments"
   - add some reader-state debugging checks
   - update doc of polled APIs
   - add extra diagnostics for per-reader-segment preemption
   - add an extra test for sched_clock()
   - improve testing on unresponsive systems

  SRCU updates:
   - improve doc for srcu_read_lock() in terms of return value
   - fix typo in comments
   - remove redundant GP sequence checks in the srcu_funnel_gp_start"

* tag 'rcu.release.v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (31 commits)
  srcu: Remove redundant GP sequence checks in srcu_funnel_gp_start
  srcu: Fix typo s/srcu_check_read_flavor()/__srcu_check_read_flavor()/
  srcu: Guarantee non-negative return value from srcu_read_lock()
  MAINTAINERS: Update RCU git tree
  rcu: Add lockdep_assert_irqs_disabled() to rcu_exp_need_qs()
  rcu: Add KCSAN exclusive-writer assertions for rdp->cpu_no_qs.b.exp
  rcu: Make preemptible rcu_exp_handler() check idempotency
  rcu: Replace open-coded rcu_exp_need_qs() from rcu_exp_handler() with call
  rcu: Move rcu_report_exp_rdp() setting of ->cpu_no_qs.b.exp under lock
  rcu: Make rcu_report_exp_cpu_mult() caller acquire lock
  rcu: Report callbacks enqueued on offline CPU blind spot
  rcutorture: Use symbols for SRCU reader flavors
  rcutorture: Add per-reader-segment preemption diagnostics
  rcutorture: Read CPU ID for decoration protected by both reader types
  rcutorture: Add preempt_count() to rcutorture_one_extend_check() diagnostics
  rcutorture: Add parameters to control polled/conditional wait interval
  rcutorture: Add documentation for recent conditional and polled APIs
  rcutorture: Ignore attempts to test preemption and forward progress
  rcutorture: Make rcutorture_one_extend() check reader state
  rcutorture: Pretty-print rcutorture reader segments
  ...

1 files changed, 89 insertions, 1 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 05f5935eeac8..393563048ab5 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5524,7 +5524,42 @@
 
 	rcutorture.gp_cond= [KNL]
 			Use conditional/asynchronous update-side
-			primitives, if available.
+			normal-grace-period primitives, if available.
+
+	rcutorture.gp_cond_exp= [KNL]
+			Use conditional/asynchronous update-side
+			expedited-grace-period primitives, if available.
+
+	rcutorture.gp_cond_full= [KNL]
+			Use conditional/asynchronous update-side
+			normal-grace-period primitives that also take
+			concurrent expedited grace periods into account,
+			if available.
+
+	rcutorture.gp_cond_exp_full= [KNL]
+			Use conditional/asynchronous update-side
+			expedited-grace-period primitives that also take
+			concurrent normal grace periods into account,
+			if available.
+
+	rcutorture.gp_cond_wi= [KNL]
+			Nominal wait interval for normal conditional
+			grace periods (specified by rcutorture's
+			gp_cond and gp_cond_full module parameters),
+			in microseconds.  The actual wait interval will
+			be randomly selected to nanosecond granularity up
+			to this wait interval.	Defaults to 16 jiffies,
+			for example, 16,000 microseconds on a system
+			with HZ=1000.
+
+	rcutorture.gp_cond_wi_exp= [KNL]
+			Nominal wait interval for expedited conditional
+			grace periods (specified by rcutorture's
+			gp_cond_exp and gp_cond_exp_full module
+			parameters), in microseconds.  The actual wait
+			interval will be randomly selected to nanosecond
+			granularity up to this wait interval.  Defaults to
+			128 microseconds.
 
 	rcutorture.gp_exp= [KNL]
 			Use expedited update-side primitives, if available.
@@ -5533,6 +5568,43 @@
 			Use normal (non-expedited) asynchronous
 			update-side primitives, if available.
 
+	rcutorture.gp_poll= [KNL]
+			Use polled update-side normal-grace-period
+			primitives, if available.
+
+	rcutorture.gp_poll_exp= [KNL]
+			Use polled update-side expedited-grace-period
+			primitives, if available.
+
+	rcutorture.gp_poll_full= [KNL]
+			Use polled update-side normal-grace-period
+			primitives that also take concurrent expedited
+			grace periods into account, if available.
+
+	rcutorture.gp_poll_exp_full= [KNL]
+			Use polled update-side expedited-grace-period
+			primitives that also take concurrent normal
+			grace periods into account, if available.
+
+	rcutorture.gp_poll_wi= [KNL]
+			Nominal wait interval for normal conditional
+			grace periods (specified by rcutorture's
+			gp_poll and gp_poll_full module parameters),
+			in microseconds.  The actual wait interval will
+			be randomly selected to nanosecond granularity up
+			to this wait interval.	Defaults to 16 jiffies,
+			for example, 16,000 microseconds on a system
+			with HZ=1000.
+
+	rcutorture.gp_poll_wi_exp= [KNL]
+			Nominal wait interval for expedited conditional
+			grace periods (specified by rcutorture's
+			gp_poll_exp and gp_poll_exp_full module
+			parameters), in microseconds.  The actual wait
+			interval will be randomly selected to nanosecond
+			granularity up to this wait interval.  Defaults to
+			128 microseconds.
+
 	rcutorture.gp_sync= [KNL]
 			Use normal (non-expedited) synchronous
 			update-side primitives, if available.  If all
@@ -5586,6 +5658,22 @@
 			Set time (jiffies) between CPU-hotplug operations,
 			or zero to disable CPU-hotplug testing.
 
+	rcutorture.preempt_duration= [KNL]
+			Set duration (in milliseconds) of preemptions
+			by a high-priority FIFO real-time task.  Set to
+			zero (the default) to disable.	The CPUs to
+			preempt are selected randomly from the set that
+			are online at a given point in time.  Races with
+			CPUs going offline are ignored, with that attempt
+			at preemption skipped.
+
+	rcutorture.preempt_interval= [KNL]
+			Set interval (in milliseconds, defaulting to one
+			second) between preemptions by a high-priority
+			FIFO real-time task.  This delay is mediated
+			by an hrtimer and is further fuzzed to avoid
+			inadvertent synchronizations.
+
 	rcutorture.read_exit_burst= [KNL]
 			The number of times in a given read-then-exit
 			episode that a set of read-then-exit kthreads