Pull RCU updates from Paul McKenney:

 - Documentation updates

 - Miscellaneous fixes

 - Callback-offload updates, perhaps most notably a new
   RCU_NOCB_CPU_DEFAULT_ALL Kconfig option that causes all CPUs to be
   offloaded at boot time, regardless of kernel boot parameters.

   This is useful to battery-powered systems such as ChromeOS and
   Android. In addition, a new RCU_NOCB_CPU_CB_BOOST kernel boot
   parameter prevents offloaded callbacks from interfering with
   real-time workloads and with energy-efficiency mechanisms

 - Polled grace-period updates, perhaps most notably making these APIs
   account for both normal and expedited grace periods

 - Tasks RCU updates, perhaps most notably reducing the CPU overhead of
   RCU tasks trace grace periods by more than a factor of two on a
   system with 15,000 tasks.

   The reduction is expected to increase with the number of tasks, so it
   seems reasonable to hypothesize that a system with 150,000 tasks
   might see a 20-fold reduction in CPU overhead

 - Torture-test updates

 - Updates that merge RCU's dyntick-idle tracking into context tracking,
   thus reducing the overhead of transitioning to kernel mode from
   either idle or nohz_full userspace execution for kernels that track
   context independently of RCU.

   This is expected to be helpful primarily for kernels built with
   CONFIG_NO_HZ_FULL=y

* tag 'rcu.2022.07.26a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (98 commits)
  rcu: Add irqs-disabled indicator to expedited RCU CPU stall warnings
  rcu: Diagnose extended sync_rcu_do_polled_gp() loops
  rcu: Put panic_on_rcu_stall() after expedited RCU CPU stall warnings
  rcutorture: Test polled expedited grace-period primitives
  rcu: Add polled expedited grace-period primitives
  rcutorture: Verify that polled GP API sees synchronous grace periods
  rcu: Make Tiny RCU grace periods visible to polled APIs
  rcu: Make polled grace-period API account for expedited grace periods
  rcu: Switch polled grace-period APIs to ->gp_seq_polled
  rcu/nocb: Avoid polling when my_rdp->nocb_head_rdp list is empty
  rcu/nocb: Add option to opt rcuo kthreads out of RT priority
  rcu: Add nocb_cb_kthread check to rcu_is_callbacks_kthread()
  rcu/nocb: Add an option to offload all CPUs on boot
  rcu/nocb: Fix NOCB kthreads spawn failure with rcu_nocb_rdp_deoffload() direct call
  rcu/nocb: Invert rcu_state.barrier_mutex VS hotplug lock locking order
  rcu/nocb: Add/del rdp to iterate from rcuog itself
  rcu/tree: Add comment to describe GP-done condition in fqs loop
  rcu: Initialize first_gp_fqs at declaration in rcu_gp_fqs()
  rcu/kvfree: Remove useless monitor_todo flag
  rcu: Cleanup RCU urgency state for offline CPU
  ...

Pull locking updates from Ingo Molnar:
 "This was a fairly quiet cycle for the locking subsystem:

   - lockdep: Fix a handful of the more complex lockdep_init_map_*()
     primitives that can lose the lock_type & cause false reports. No
     such mishap was observed in the wild.

   - jump_label improvements: simplify the cross-arch support of initial
     NOP patching by making it arch-specific code (used on MIPS only),
     and remove the s390 initial NOP patching that was superfluous"

* tag 'locking-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Fix lockdep_init_map_*() confusion
  jump_label: make initial NOP patching the special case
  jump_label: mips: move module NOP patching into arch code
  jump_label: s390: avoid pointless initial NOP patching

With commit d257cc8cb8d5 ("locking/rwsem: Make handoff bit handling more
consistent"), the writer that sets the handoff bit can be interrupted
out without clearing the bit if the wait queue isn't empty. This disables
reader and writer optimistic lock spinning and stealing.

Now if a non-first writer in the queue is somehow woken up or a new
waiter enters the slowpath, it can't acquire the lock.  This is not the
case before commit d257cc8cb8d5 as the writer that set the handoff bit
will clear it when exiting out via the out_nolock path. This is less
efficient as the busy rwsem stays in an unlock state for a longer time.

In some cases, this new behavior may cause lockups as shown in [1] and
[2].

This patch allows a non-first writer to ignore the handoff bit if it
is not originally set or initiated by the first waiter. This patch is
shown to be effective in fixing the lockup problem reported in [1].

[1] https://lore.kernel.org/lkml/20220617134325.GC30825@techsingularity.net/
[2] https://lore.kernel.org/lkml/3f02975c-1a9d-be20-32cf-f1d8e3dfafcc@oracle.com/

Fixes: d257cc8cb8d5 ("locking/rwsem: Make handoff bit handling more consistent")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Donnelly <john.p.donnelly@oracle.com>
Tested-by: Mel Gorman <mgorman@techsingularity.net>
Link: https://lore.kernel.org/r/20220622200419.778799-1-longman@redhat.com

The RCU dynticks counter is going to be merged into the context tracking
subsystem. Start with moving the idle extended quiescent states
entrypoints to context tracking. For now those are dumb redirections to
existing RCU calls.

[ paulmck: Apply kernel test robot feedback. ]

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Cc: Yu Liao <liaoyu15@huawei.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Paul Gortmaker<paul.gortmaker@windriver.com>
Cc: Alex Belits <abelits@marvell.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>

Commit dfd5e3f5fe27 ("locking/lockdep: Mark local_lock_t") added yet
another lockdep_init_map_*() variant, but forgot to update all the
existing users of the most complicated version.

This could lead to a loss of lock_type and hence an incorrect report.
Given the relative rarity of both local_lock and these annotations,
this is unlikely to happen in practise, still, best fix things.

Fixes: dfd5e3f5fe27 ("locking/lockdep: Mark local_lock_t")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YqyEDtoan20K0CVD@worktop.programming.kicks-ass.net

Since the rewrote of prandom_u32(), in the commit mentioned below, the
function uses sleeping locks which extracing random numbers and filling
the batch.
This breaks lockdep on PREEMPT_RT because lock_pin_lock() disables
interrupts while calling __lock_pin_lock(). This can't be moved earlier
because the main user of the function (rq_pin_lock()) invokes that
function after disabling interrupts in order to acquire the lock.

The cookie does not require random numbers as its goal is to provide a
random value in order to notice unexpected "unlock + lock" sites.

Use sched_clock() to provide random numbers.

Fixes: a0103f4d86f88 ("random32: use real rng for non-deterministic randomness")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YoNn3pTkm5+QzE5k@linutronix.de

Pull sysctl updates from Luis Chamberlain:
 "For two kernel releases now kernel/sysctl.c has been being cleaned up
  slowly, since the tables were grossly long, sprinkled with tons of
  #ifdefs and all this caused merge conflicts with one susbystem or
  another.

  This tree was put together to help try to avoid conflicts with these
  cleanups going on different trees at time. So nothing exciting on this
  pull request, just cleanups.

  Thanks a lot to the Uniontech and Huawei folks for doing some of this
  nasty work"

* tag 'sysctl-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (28 commits)
  sched: Fix build warning without CONFIG_SYSCTL
  reboot: Fix build warning without CONFIG_SYSCTL
  kernel/kexec_core: move kexec_core sysctls into its own file
  sysctl: minor cleanup in new_dir()
  ftrace: fix building with SYSCTL=y but DYNAMIC_FTRACE=n
  fs/proc: Introduce list_for_each_table_entry for proc sysctl
  mm: fix unused variable kernel warning when SYSCTL=n
  latencytop: move sysctl to its own file
  ftrace: fix building with SYSCTL=n but DYNAMIC_FTRACE=y
  ftrace: Fix build warning
  ftrace: move sysctl_ftrace_enabled to ftrace.c
  kernel/do_mount_initrd: move real_root_dev sysctls to its own file
  kernel/delayacct: move delayacct sysctls to its own file
  kernel/acct: move acct sysctls to its own file
  kernel/panic: move panic sysctls to its own file
  kernel/lockdep: move lockdep sysctls to its own file
  mm: move page-writeback sysctls to their own file
  mm: move oom_kill sysctls to their own file
  kernel/reboot: move reboot sysctls to its own file
  sched: Move energy_aware sysctls to topology.c
  ...

Queued rwlock was originally named "queue rwlock" which wasn't quite
grammatically correct. However there are still some "queue rwlock"
references in the code. Change those to "queued rwlock" for consistency.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220510192134.434753-1-longman@redhat.com

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong.  The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

All filesystem syctls now get reviewed by fs folks. This commit
follows the commit of fs, move the prove_locking and lock_stat sysctls
to its own file, kernel/lockdep.c.

Signed-off-by: tangmeng <tangmeng@uniontech.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

Have the trace_contention_*() tracepoints consistently include
adaptive spinning. In order to differentiate between the spinning and
non-spinning states add LCB_F_MUTEX and combine with LCB_F_SPIN.

The consequence is that a mutex contention can now triggler multiple
_begin() tracepoints before triggering an _end().

Additionally, this fixes one path where mutex would trigger _end()
without ever seeing a _begin().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>