Merge tag 'rcu.6.4.april5.2023.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux

Pull RCU updates from Joel Fernandes:

 - Updates and additions to MAINTAINERS files, with Boqun being added to
   the RCU entry and Zqiang being added as an RCU reviewer.

   I have also transitioned from reviewer to maintainer; however, Paul
   will be taking over sending RCU pull-requests for the next merge
   window.

 - Resolution of hotplug warning in nohz code, achieved by fixing
   cpu_is_hotpluggable() through interaction with the nohz subsystem.

   Tick dependency modifications by Zqiang, focusing on fixing usage of
   the TICK_DEP_BIT_RCU_EXP bitmask.

 - Avoid needless calls to the rcu-lazy shrinker for CONFIG_RCU_LAZY=n
   kernels, fixed by Zqiang.

 - Improvements to rcu-tasks stall reporting by Neeraj.

 - Initial renaming of k[v]free_rcu() to k[v]free_rcu_mightsleep() for
   increased robustness, affecting several components like mac802154,
   drbd, vmw_vmci, tracing, and more.

   A report by Eric Dumazet showed that the API could be unknowingly
   used in an atomic context, so we'd rather make sure they know what
   they're asking for by being explicit:

      https://lore.kernel.org/all/20221202052847.2623997-1-edumazet@google.com/

 - Documentation updates, including corrections to spelling,
   clarifications in comments, and improvements to the srcu_size_state
   comments.

 - Better srcu_struct cache locality for readers, by adjusting the size
   of srcu_struct in support of SRCU usage by Christoph Hellwig.

 - Teach lockdep to detect deadlocks between srcu_read_lock() vs
   synchronize_srcu() contributed by Boqun.

   Previously lockdep could not detect such deadlocks, now it can.

 - Integration of rcutorture and rcu-related tools, targeted for v6.4
   from Boqun's tree, featuring new SRCU deadlock scenarios, test_nmis
   module parameter, and more

 - Miscellaneous changes, various code cleanups and comment improvements

* tag 'rcu.6.4.april5.2023.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux: (71 commits)
  checkpatch: Error out if deprecated RCU API used
  mac802154: Rename kfree_rcu() to kvfree_rcu_mightsleep()
  rcuscale: Rename kfree_rcu() to kfree_rcu_mightsleep()
  ext4/super: Rename kfree_rcu() to kfree_rcu_mightsleep()
  net/mlx5: Rename kfree_rcu() to kfree_rcu_mightsleep()
  net/sysctl: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  lib/test_vmalloc.c: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  tracing: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  misc: vmw_vmci: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  drbd: Rename kvfree_rcu() to kvfree_rcu_mightsleep()
  rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access
  rcu: Avoid stack overflow due to __rcu_irq_enter_check_tick() being kprobe-ed
  rcu-tasks: Report stalls during synchronize_srcu() in rcu_tasks_postscan()
  rcu: Permit start_poll_synchronize_rcu_expedited() to be invoked early
  rcu: Remove never-set needwake assignment from rcu_report_qs_rdp()
  rcu: Register rcu-lazy shrinker only for CONFIG_RCU_LAZY=y kernels
  rcu: Fix missing TICK_DEP_MASK_RCU_EXP dependency check
  rcu: Fix set/clear TICK_DEP_BIT_RCU_EXP bitmask race
  rcu/trace: use strscpy() to instead of strncpy()
  tick/nohz: Fix cpu_is_hotpluggable() by checking with nohz subsystem
  ...

61 files changed, 915 insertions, 342 deletions

diff --git a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.rst b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.rst
index c9c957c85bac..93d899d53258 100644
--- a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.rst
+++ b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.rst
@@ -277,7 +277,7 @@ the following access functions:
 
 Again, only one request in a given batch need actually carry out a
 grace-period operation, which means there must be an efficient way to
-identify which of many concurrent reqeusts will initiate the grace
+identify which of many concurrent requests will initiate the grace
 period, and that there be an efficient way for the remaining requests to
 wait for that grace period to complete. However, that is the topic of
 the next section.
@@ -405,7 +405,7 @@ Use of Workqueues
 In earlier implementations, the task requesting the expedited grace
 period also drove it to completion. This straightforward approach had
 the disadvantage of needing to account for POSIX signals sent to user
-tasks, so more recent implemementations use the Linux kernel's
+tasks, so more recent implementations use the Linux kernel's
 workqueues (see Documentation/core-api/workqueue.rst).
 
 The requesting task still does counter snapshotting and funnel-lock
@@ -465,7 +465,7 @@ corresponding disadvantage that workqueues cannot be used until they are
 initialized, which does not happen until some time after the scheduler
 spawns the first task. Given that there are parts of the kernel that
 really do want to execute grace periods during this mid-boot “dead
-zone”, expedited grace periods must do something else during thie time.
+zone”, expedited grace periods must do something else during this time.
 
 What they do is to fall back to the old practice of requiring that the
 requesting task drive the expedited grace period, as was the case before
diff --git a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst
index 7fdf151a8680..5750f125361b 100644
--- a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst
+++ b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst
@@ -168,7 +168,7 @@ an ``atomic_add_return()`` of zero) to detect idle CPUs.
 +-----------------------------------------------------------------------+
 
 The approach must be extended to handle one final case, that of waking a
-task blocked in ``synchronize_rcu()``. This task might be affinitied to
+task blocked in ``synchronize_rcu()``. This task might be affined to
 a CPU that is not yet aware that the grace period has ended, and thus
 might not yet be subject to the grace period's memory ordering.
 Therefore, there is an ``smp_mb()`` after the return from
diff --git a/Documentation/RCU/RTFP.txt b/Documentation/RCU/RTFP.txt
index 588d97366a46..db8f16b392aa 100644
--- a/Documentation/RCU/RTFP.txt
+++ b/Documentation/RCU/RTFP.txt
@@ -201,7 +201,7 @@ work looked at debugging uses of RCU [Seyster:2011:RFA:2075416.2075425].
 In 2012, Josh Triplett received his Ph.D. with his dissertation
 covering RCU-protected resizable hash tables and the relationship
 between memory barriers and read-side traversal order:  If the updater
-is making changes in the opposite direction from the read-side traveral
+is making changes in the opposite direction from the read-side traversal
 order, the updater need only execute a memory-barrier instruction,
 but if in the same direction, the updater needs to wait for a grace
 period between the individual updates [JoshTriplettPhD].  Also in 2012,
@@ -1245,7 +1245,7 @@ Oregon Health and Sciences University"
 [Viewed September 5, 2005]"
 ,annotation={
 	First posting showing how RCU can be safely adapted for
-	preemptable RCU read side critical sections.
+	preemptible RCU read side critical sections.
 }
 }
 
@@ -1888,7 +1888,7 @@ Revised:
 \url{https://lore.kernel.org/r/20070910183004.GA3299@linux.vnet.ibm.com}
 [Viewed October 25, 2007]"
 ,annotation={
-	Final patch for preemptable RCU to -rt.  (Later patches were
+	Final patch for preemptible RCU to -rt.  (Later patches were
 	to mainline, eventually incorporated.)
 }
 }
@@ -2275,7 +2275,7 @@ lot of {Linux} into your technology!!!"
 \url{https://lore.kernel.org/r/20090724001429.GA17374@linux.vnet.ibm.com}
 [Viewed August 15, 2009]"
 ,annotation={
-	First posting of simple and fast preemptable RCU.
+	First posting of simple and fast preemptible RCU.
 }
 }
 
@@ -2639,7 +2639,7 @@ lot of {Linux} into your technology!!!"
 	RCU-protected hash tables, barriers vs. read-side traversal order.
 	.
 	If the updater is making changes in the opposite direction from
-	the read-side traveral order, the updater need only execute a
+	the read-side traversal order, the updater need only execute a
 	memory-barrier instruction, but if in the same direction, the
 	updater needs to wait for a grace period between the individual
 	updates.
diff --git a/Documentation/RCU/UP.rst b/Documentation/RCU/UP.rst
index 8b20fd45f255..4060d7a2f62a 100644
--- a/Documentation/RCU/UP.rst
+++ b/Documentation/RCU/UP.rst
@@ -107,7 +107,7 @@ UP systems, including PREEMPT SMP builds running on UP systems.
 
 Quick Quiz #3:
 	Why can't synchronize_rcu() return immediately on UP systems running
-	preemptable RCU?
+	preemptible RCU?
 
 .. _answer_quick_quiz_up:
 
@@ -143,7 +143,7 @@ Answer to Quick Quiz #2:
 
 Answer to Quick Quiz #3:
 	Why can't synchronize_rcu() return immediately on UP systems
-	running preemptable RCU?
+	running preemptible RCU?
 
 	Because some other task might have been preempted in the middle
 	of an RCU read-side critical section.  If synchronize_rcu()
diff --git a/Documentation/RCU/checklist.rst b/Documentation/RCU/checklist.rst
index cc361fb01ed4..bd3c58c44bef 100644
--- a/Documentation/RCU/checklist.rst
+++ b/Documentation/RCU/checklist.rst
@@ -70,7 +70,7 @@ over a rather long period of time, but improvements are always welcome!
 	can serve as rcu_read_lock_sched(), but is less readable and
 	prevents lockdep from detecting locking issues.
 
-	Please not that you *cannot* rely on code known to be built
+	Please note that you *cannot* rely on code known to be built
 	only in non-preemptible kernels.  Such code can and will break,
 	especially in kernels built with CONFIG_PREEMPT_COUNT=y.
 
diff --git a/Documentation/RCU/lockdep.rst b/Documentation/RCU/lockdep.rst
index 2749f43ec1b0..69e73a39bd11 100644
--- a/Documentation/RCU/lockdep.rst
+++ b/Documentation/RCU/lockdep.rst
@@ -65,7 +65,7 @@ checking of rcu_dereference() primitives:
 	rcu_access_pointer(p):
 		Return the value of the pointer and omit all barriers,
 		but retain the compiler constraints that prevent duplicating
-		or coalescsing.  This is useful when testing the
+		or coalescing.  This is useful when testing the
 		value of the pointer itself, for example, against NULL.
 
 The rcu_dereference_check() check expression can be any boolean
diff --git a/Documentation/RCU/torture.rst b/Documentation/RCU/torture.rst
index 0316ba0c6922..b3b6dfa85248 100644
--- a/Documentation/RCU/torture.rst
+++ b/Documentation/RCU/torture.rst
@@ -216,7 +216,7 @@ Kernel boot arguments can also be supplied, for example, to control
 rcutorture's module parameters.  For example, to test a change to RCU's
 CPU stall-warning code, use "--bootargs 'rcutorture.stall_cpu=30'".
 This will of course result in the scripting reporting a failure, namely
-the resuling RCU CPU stall warning.  As noted above, reducing memory may
+the resulting RCU CPU stall warning.  As noted above, reducing memory may
 require disabling rcutorture's callback-flooding tests::
 
 	kvm.sh --cpus 448 --configs '56*TREE04' --memory 128M \
@@ -370,5 +370,5 @@ You can also re-run a previous remote run in a manner similar to kvm.sh:
 		tools/testing/selftests/rcutorture/res/2022.11.03-11.26.28-remote \
 		--duration 24h
 
-In this case, most of the kvm-again.sh parmeters may be supplied following
+In this case, most of the kvm-again.sh parameters may be supplied following
 the pathname of the old run-results directory.
diff --git a/Documentation/RCU/whatisRCU.rst b/Documentation/RCU/whatisRCU.rst
index 2c5563a91998..8eddef28d3a1 100644
--- a/Documentation/RCU/whatisRCU.rst
+++ b/Documentation/RCU/whatisRCU.rst
@@ -597,10 +597,10 @@ to avoid having to write your own callback::
 If the occasional sleep is permitted, the single-argument form may
 be used, omitting the rcu_head structure from struct foo.
 
-	kfree_rcu(old_fp);
+	kfree_rcu_mightsleep(old_fp);
 
-This variant of kfree_rcu() almost never blocks, but might do so by
-invoking synchronize_rcu() in response to memory-allocation failure.
+This variant almost never blocks, but might do so by invoking
+synchronize_rcu() in response to memory-allocation failure.
 
 Again, see checklist.rst for additional rules governing the use of RCU.
 
diff --git a/MAINTAINERS b/MAINTAINERS
index 456285afd716..d172ca02a1d5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17636,11 +17636,13 @@ READ-COPY UPDATE (RCU)
 M:	"Paul E. McKenney" <paulmck@kernel.org>
 M:	Frederic Weisbecker <frederic@kernel.org> (kernel/rcu/tree_nocb.h)
 M:	Neeraj Upadhyay <quic_neeraju@quicinc.com> (kernel/rcu/tasks.h)
+M:	Joel Fernandes <joel@joelfernandes.org>
 M:	Josh Triplett <josh@joshtriplett.org>
+M:	Boqun Feng <boqun.feng@gmail.com>
 R:	Steven Rostedt <rostedt@goodmis.org>
 R:	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 R:	Lai Jiangshan <jiangshanlai@gmail.com>
-R:	Joel Fernandes <joel@joelfernandes.org>
+R:	Zqiang <qiang1.zhang@intel.com>
 L:	rcu@vger.kernel.org
 S:	Supported
 W:	http://www.rdrop.com/users/paulmck/RCU/
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index ca6eadeb7d1a..f531da6b362e 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -29,7 +29,6 @@ menuconfig KVM
 	select KVM_MMIO
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select KVM_XFER_TO_GUEST_WORK
-	select SRCU
 	select KVM_VFIO
 	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_IRQFD
diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
index 29e51649203b..a8cdba75f98d 100644
--- a/arch/mips/kvm/Kconfig
+++ b/arch/mips/kvm/Kconfig
@@ -26,7 +26,6 @@ config KVM
 	select HAVE_KVM_VCPU_ASYNC_IOCTL
 	select KVM_MMIO
 	select MMU_NOTIFIER
-	select SRCU
 	select INTERVAL_TREE
 	select KVM_GENERIC_HARDWARE_ENABLING
 	help
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index a9f57dad6d91..902611954200 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -22,7 +22,6 @@ config KVM
 	select PREEMPT_NOTIFIERS
 	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_VCPU_ASYNC_IOCTL
-	select SRCU
 	select KVM_VFIO
 	select IRQ_BYPASS_MANAGER
 	select HAVE_KVM_IRQ_BYPASS
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index d5a658a047a7..5682d8c017b3 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -28,7 +28,6 @@ config KVM
 	select KVM_XFER_TO_GUEST_WORK
 	select HAVE_KVM_VCPU_ASYNC_IOCTL
 	select HAVE_KVM_EVENTFD
-	select SRCU
 	help
 	  Support hosting virtualized guest machines.
 
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 33f4ff909476..45fdf2a9b2e3 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -31,7 +31,6 @@ config KVM
 	select HAVE_KVM_IRQ_ROUTING
 	select HAVE_KVM_INVALID_WAKEUPS
 	select HAVE_KVM_NO_POLL
-	select SRCU
 	select KVM_VFIO
 	select INTERVAL_TREE
 	select MMU_NOTIFIER
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a825bf031f49..947e24714c28 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -283,7 +283,6 @@ config X86
 	select RTC_LIB
 	select RTC_MC146818_LIB
 	select SPARSE_IRQ
-	select SRCU
 	select SYSCTL_EXCEPTION_TRACE
 	select THREAD_INFO_IN_TASK
 	select TRACE_IRQFLAGS_SUPPORT
@@ -1938,7 +1937,6 @@ config X86_SGX
 	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
 	depends on CRYPTO=y
 	depends on CRYPTO_SHA256=y
-	select SRCU
 	select MMU_NOTIFIER
 	select NUMA_KEEP_MEMINFO if NUMA
 	select XARRAY_MULTI
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 8e578311ca9d..89ca7f4c1464 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -46,7 +46,6 @@ config KVM
 	select KVM_XFER_TO_GUEST_WORK
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select KVM_VFIO
-	select SRCU
 	select INTERVAL_TREE
 	select HAVE_KVM_PM_NOTIFIER if PM
 	select KVM_GENERIC_HARDWARE_ENABLING
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 182c6122f815..c1815b9dae68 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -487,7 +487,8 @@ static const struct attribute_group *cpu_root_attr_groups[] = {
 bool cpu_is_hotpluggable(unsigned int cpu)
 {
 	struct device *dev = get_cpu_device(cpu);
-	return dev && container_of(dev, struct cpu, dev)->hotpluggable;
+	return dev && container_of(dev, struct cpu, dev)->hotpluggable
+		&& tick_nohz_cpu_hotpluggable(cpu);
 }
 EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
 
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 60757ac31701..f49f2a5282e1 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1615,7 +1615,7 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
 			drbd_send_sync_param(peer_device);
 	}
 
-	kvfree_rcu(old_disk_conf);
+	kvfree_rcu_mightsleep(old_disk_conf);
 	kfree(old_plan);
 	mod_timer(&device->request_timer, jiffies + HZ);
 	goto success;
@@ -2446,7 +2446,7 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
 
 	mutex_unlock(&connection->resource->conf_update);
 	mutex_unlock(&connection->data.mutex);
-	kvfree_rcu(old_net_conf);
+	kvfree_rcu_mightsleep(old_net_conf);
 
 	if (connection->cstate >= C_WF_REPORT_PARAMS) {
 		struct drbd_peer_device *peer_device;
@@ -2860,7 +2860,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 		new_disk_conf->disk_size = (sector_t)rs.resize_size;
 		rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);
 		mutex_unlock(&device->resource->conf_update);
-		kvfree_rcu(old_disk_conf);
+		kvfree_rcu_mightsleep(old_disk_conf);
 		new_disk_conf = NULL;
 	}
 
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 757f4692b5bd..e197b2a465d2 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3759,7 +3759,7 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in
 		drbd_info(connection, "peer data-integrity-alg: %s\n",
 			  integrity_alg[0] ? integrity_alg : "(none)");
 
-	kvfree_rcu(old_net_conf);
+	kvfree_rcu_mightsleep(old_net_conf);
 	return 0;
 
 disconnect_rcu_unlock:
@@ -4127,7 +4127,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 
 			rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);
 			mutex_unlock(&connection->resource->conf_update);
-			kvfree_rcu(old_disk_conf);
+			kvfree_rcu_mightsleep(old_disk_conf);
 
 			drbd_info(device, "Peer sets u_size to %lu sectors (old: %lu)\n",
 				 (unsigned long)p_usize, (unsigned long)my_usize);
diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
index 75d13ea0024f..2aeea295fa28 100644
--- a/drivers/block/drbd/drbd_state.c
+++ b/drivers/block/drbd/drbd_state.c
@@ -2071,7 +2071,7 @@ static int w_after_conn_state_ch(struct drbd_work *w, int unused)
 		conn_free_crypto(connection);
 		mutex_unlock(&connection->resource->conf_update);
 
-		k