Commit 8cdf2d19038f for kernel

commit 8cdf2d19038fa266806d15603d691dc2fd774858
Merge: 2b5d5f23d405 d8dfba2c606a
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue Nov 19 11:27:07 2024 -0800

    Merge tag 'rcu.release.v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

    Pull RCU updates from Frederic Weisbecker:
     "SRCU:

       - Introduction of the new SRCU-lite flavour with a new pair of
         srcu_read_[un]lock_lite() APIs. In practice the read side using
         this flavour becomes lighter by removing a full memory barrier on
         LOCK and a full memory barrier on UNLOCK. This comes at the expense
         of a higher latency write side with two (in the best case of a
         snaphot of unused read-sides) or more RCU grace periods on the
         update side which now assumes by itself the whole full ordering
         guarantee against the LOCK/UNLOCK counters on both indexes, along
         with the accesses performed inside.

         Uretprobes is a known potential user.

         Note this doesn't replace the default normal flavour of SRCU which
         still behaves the same as usual.

       - Add testing of SRCU-lite through rcutorture and rcuscale

       - Various cleanups on the way.

      Fixes:

       - Allow short-circuiting RCU-TASKS-RUDE grace periods on
         architectures that have sane noinstr boundaries forbidding tracing
         on low-level idle and kernel entry code. RCU-TASKS is enough on
         such configurations because it involves an RCU grace period that
         waits for all idle tasks to either schedule out voluntarily or
         enter into RCU unwatched noinstr code.

       - Allow and test start_poll_synchronize_rcu() with IRQs disabled.

       - Mention rcuog kthreads in relevant documentation and Kconfig help

       - Various fixes and consolidations

      rcutorture:

       - Add --no-affinity on tools to leave the affinity setting of guests
         up to the user.

       - Add guest_os_delay parameter to rcuscale for better warm-up
         control.

       - Fix and improve some rcuscale error handling.

       - Various cleanups and fixes

      stall:

       - Remove dead code

       - Stop dumping tasks if a stalled grace period eventually ended
         midway as that only produces confusing output.

       - Optimize detection of stalling CPUs and avoid useless node locking
         otherwise.

      NOCB:

       - Fix rcu_barrier() hang due to a race against callbacks
         deoffloading. This is not yet used, except by rcutorture, and waits
         for its promised cpusets interface.

       - Remove leftover function declaration"

    * tag 'rcu.release.v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (42 commits)
      rcuscale: Remove redundant WARN_ON_ONCE() splat
      rcuscale: Do a proper cleanup if kfree_scale_init() fails
      srcu: Unconditionally record srcu_read_lock_lite() in ->srcu_reader_flavor
      srcu: Check for srcu_read_lock_lite() across all CPUs
      srcu: Remove smp_mb() from srcu_read_unlock_lite()
      rcutorture: Avoid printing cpu=-1 for no-fault RCU boost failure
      rcuscale: Add guest_os_delay module parameter
      refscale: Correct affinity check
      torture: Add --no-affinity parameter to kvm.sh
      rcu/nocb: Fix missed RCU barrier on deoffloading
      rcu/kvfree: Fix data-race in __mod_timer / kvfree_call_rcu
      rcu/srcutiny: don't return before reenabling preemption
      rcu-tasks: Remove open-coded one-byte cmpxchg() emulation
      doc: Remove kernel-parameters.txt entry for rcutorture.read_exit
      rcutorture: Test start-poll primitives with interrupts disabled
      rcu: Permit start_poll_synchronize_rcu*() with interrupts disabled
      rcu: Allow short-circuiting of synchronize_rcu_tasks_rude()
      doc: Add rcuog kthreads to kernel-per-CPU-kthreads.rst
      rcu: Add rcuog kthreads to RCU_NOCB_CPU help text
      rcu: Use the BITS_PER_LONG macro
      ...