This commit changes from "%lx" to "%x" and from "0x1ffffL" to "0x1ffff"
to match the change in type between the old field ->state (unsigned long)
and the new field ->__state (unsigned int).

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

Pull RCU updates from Paul McKenney:

 - Bitmap parsing support for "all" as an alias for all bits

 - Documentation updates

 - Miscellaneous fixes, including some that overlap into mm and lockdep

 - kvfree_rcu() updates

 - mem_dump_obj() updates, with acks from one of the slab-allocator
   maintainers

 - RCU NOCB CPU updates, including limited deoffloading

 - SRCU updates

 - Tasks-RCU updates

 - Torture-test updates

* 'core-rcu-2021.07.04' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (78 commits)
  tasks-rcu: Make show_rcu_tasks_gp_kthreads() be static inline
  rcu-tasks: Make ksoftirqd provide RCU Tasks quiescent states
  rcu: Add missing __releases() annotation
  rcu: Remove obsolete rcu_read_unlock() deadlock commentary
  rcu: Improve comments describing RCU read-side critical sections
  rcu: Create an unrcu_pointer() to remove __rcu from a pointer
  srcu: Early test SRCU polling start
  rcu: Fix various typos in comments
  rcu/nocb: Unify timers
  rcu/nocb: Prepare for fine-grained deferred wakeup
  rcu/nocb: Only cancel nocb timer if not polling
  rcu/nocb: Delete bypass_timer upon nocb_gp wakeup
  rcu/nocb: Cancel nocb_timer upon nocb_gp wakeup
  rcu/nocb: Allow de-offloading rdp leader
  rcu/nocb: Directly call __wake_nocb_gp() from bypass timer
  rcu: Don't penalize priority boosting when there is nothing to boost
  rcu: Point to documentation of ordering guarantees
  rcu: Make rcu_gp_cleanup() be noinline for tracing
  rcu: Restrict RCU_STRICT_GRACE_PERIOD to at most four CPUs
  rcu: Make show_rcu_gp_kthreads() dump rcu_node structures blocking GP
  ...

Change the type and name of task_struct::state. Drop the volatile and
shrink it to an 'unsigned int'. Rename it in order to find all uses
such that we can use READ_ONCE/WRITE_ONCE as appropriate.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20210611082838.550736351@infradead.org

bitmaprange.2021.05.10c: Allow "all" for bitmap ranges.
doc.2021.05.10c: Documentation updates.
fixes.2021.05.13a: Miscellaneous fixes.
kvfree_rcu.2021.05.10c: kvfree_rcu() updates.
mmdumpobj.2021.05.10c: mem_dump_obj() updates.
nocb.2021.05.12a: RCU NOCB CPU updates, including limited deoffloading.
srcu.2021.05.12a: SRCU updates.
tasks.2021.05.18a: Tasks-RCU updates.
torture.2021.05.10c: Torture-test updates.

Sparse reports a warning at rcu_print_task_stall():

"warning: context imbalance in rcu_print_task_stall - unexpected unlock"

The root cause is a missing annotation on rcu_print_task_stall().

This commit therefore adds the missing __releases(rnp->lock) annotation.

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

RCU priority boosting cannot do anything unless there is at least one
task blocking the current RCU grace period that was preempted within
the RCU read-side critical section that it still resides in.  However,
the current rcu_torture_boost_failed() code will count this as an RCU
priority-boosting failure if there were no CPUs blocking the current
grace period.  This situation can happen (for example) if the last CPU
blocking the current grace period was subjected to vCPU preemption,
which is always a risk for rcutorture guest OSes.

This commit therefore causes rcu_torture_boost_failed() to refrain from
reporting failure unless there is at least one task blocking the current
RCU grace period that was preempted within the RCU read-side critical
section that it still resides in.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

Currently, show_rcu_gp_kthreads() only dumps rcu_node structures that
have outdated ideas of the current grace-period number.  This commit
also dumps those that are in any way blocking the current grace period.
This helps diagnose RCU priority boosting failures.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

This commit adds each rcu_node structure's ->qsmask and "bBEG" output
indicating whether: (1) There is a boost kthread, (2) A reader needs
to be (or is in the process of being) boosted, (3) A reader is blocking
an expedited grace period, and (4) A reader is blocking a normal grace
period.  This helps diagnose RCU priority boosting failures.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

This commit adds ->gp_max to show_rcu_gp_kthreads() output in order to
better diagnose RCU priority boosting failures.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

This commit adds ->rt_priority and ->gp_start to show_rcu_gp_kthreads()
output in order to better diagnose RCU priority boosting failures.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>