RCU pull request for v6.17

This pull request contains the following branches:
 
 rcu-exp.23.07.2025
 
   - Protect against early RCU exp quiescent state reporting during exp
     grace period initialization.
 
   - Remove superfluous barrier in task unblock path.
 
   - Remove the CPU online quiescent state report optimization, which is
     error prone for certain scenarios.
 
   - Add warning for unexpected pending requested expedited quiescent
     state on dying CPU.
 
 rcu.22.07.2025
 
   - Robustify rcu_is_cpu_rrupt_from_idle() by using more accurate
     indicators of the actual context tracking state of a CPU.
 
   - Handle ->defer_qs_iw_pending field data race.
 
   - Enable rcu_normal_wake_from_gp by default on systems with <= 16 CPUs.
 
   - Fix lockup in rcu_read_unlock() due to recursive irq_exit() calls.
 
   - Refactor expedited handling condition in rcu_read_unlock_special().
 
   - Documentation updates for hotplug and GP init scan ordering,
     separation of rcu_state and rnp's gp_seq states, quiescent state
     reporting for offline CPUs.
 
 torture-scripts.16.07.2025
 
   - Cleanup and improve scripts : remove superfluous warnings for disabled
     tests; better handling of kvm.sh --kconfig arg; suppress some confusing
     diagnostics; tolerate bad kvm.sh args; add new diagnostic for build
     output; fail allmodconfig testing on warnings.
 
   - Include RCU_TORTURE_TEST_CHK_RDR_STATE config for KCSAN kernels.
 
   - Disable default RCU-tasks and clocksource-wdog testing on arm64.
 
   - Add EXPERT Kconfig option for arm64 KCSAN runs.
 
   - Remove SRCU-lite testing.
 
 rcutorture.16.07.2025
 
   - Start torture writer threads creation after reader threads to handle
     race in SRCU-P scenario.
 
   - Add SRCU down_read()/up_read() test.
 
   - Add diagnostics for delayed SRCU up_read(), unmatched up_read(), print
     number of up/down readers and the number of such readers which
     migrated to other CPU.
 
   - Ignore certain unsupported configurations for trivial RCU test.
 
   - Fix splats in RT kernels due to inaccurate checks for BH-disabled
     context.
 
   - Enable checks and logs to capture intentionally exercised unexpected
     scenarios (too short readers) for BUSTED test.
 
   - Remove SRCU-lite testing.
 
 srcu.19.07.2025
 
   - Expedite SRCU-fast grace periods.
 
   - Remove SRCU-lite implementation.
 
   - Add guards for SRCU-fast readers.
 
 rcu.nocb.18.07.2025
 
   - Dump NOCB group leader state on stall detection.
 
   - Robustify nocb_cb_kthread pointer accesses.
 
   - Fix delayed execution of hurry callbacks when LAZY_RCU is enabled.
 
 refscale.07.07.2025
 
   - Fix multiplication overflow in "loops" and "nreaders" calculations.
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Merge tag 'rcu.release.v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

Pull RCU updates from Neeraj Upadhyay:
 "Expedited grace period updates:

   - Protect against early RCU exp quiescent state reporting during exp
     grace period initialization

   - Remove superfluous barrier in task unblock path

   - Remove the CPU online quiescent state report optimization, which is
     error prone for certain scenarios

   - Add warning for unexpected pending requested expedited quiescent
     state on dying CPU

  Core:

   - Robustify rcu_is_cpu_rrupt_from_idle() by using more accurate
     indicators of the actual context tracking state of a CPU

   - Handle ->defer_qs_iw_pending field data race

   - Enable rcu_normal_wake_from_gp by default on systems with <= 16
     CPUs

   - Fix lockup in rcu_read_unlock() due to recursive irq_exit() calls

   - Refactor expedited handling condition in rcu_read_unlock_special()

   - Documentation updates for hotplug and GP init scan ordering,
     separation of rcu_state and rnp's gp_seq states, quiescent state
     reporting for offline CPUs

  torture-scripts:

   - Cleanup and improve scripts : remove superfluous warnings for
     disabled tests; better handling of kvm.sh --kconfig arg; suppress
     some confusing diagnostics; tolerate bad kvm.sh args; add new
     diagnostic for build output; fail allmodconfig testing on warnings

   - Include RCU_TORTURE_TEST_CHK_RDR_STATE config for KCSAN kernels

   - Disable default RCU-tasks and clocksource-wdog testing on arm64

   - Add EXPERT Kconfig option for arm64 KCSAN runs

   - Remove SRCU-lite testing

  rcutorture:

   - Start torture writer threads creation after reader threads to
     handle race in SRCU-P scenario

   - Add SRCU down_read()/up_read() test

   - Add diagnostics for delayed SRCU up_read(), unmatched up_read(),
     print number of up/down readers and the number of such readers
     which migrated to other CPU

   - Ignore certain unsupported configurations for trivial RCU test

   - Fix splats in RT kernels due to inaccurate checks for BH-disabled
     context

   - Enable checks and logs to capture intentionally exercised
     unexpected scenarios (too short readers) for BUSTED test

   - Remove SRCU-lite testing

  srcu:

   - Expedite SRCU-fast grace periods

   - Remove SRCU-lite implementation

   - Add guards for SRCU-fast readers

  rcu nocb:

   - Dump NOCB group leader state on stall detection

   - Robustify nocb_cb_kthread pointer accesses

   - Fix delayed execution of hurry callbacks when LAZY_RCU is enabled

  refscale:

   - Fix multiplication overflow in "loops" and "nreaders" calculations"

* tag 'rcu.release.v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (49 commits)
  rcu: Document concurrent quiescent state reporting for offline CPUs
  rcu: Document separation of rcu_state and rnp's gp_seq
  rcu: Document GP init vs hotplug-scan ordering requirements
  srcu: Add guards for SRCU-fast readers
  rcu: Fix delayed execution of hurry callbacks
  rcu: Refactor expedited handling check in rcu_read_unlock_special()
  checkpatch: Remove SRCU-lite deprecation
  srcu: Remove SRCU-lite implementation
  srcu: Expedite SRCU-fast grace periods
  rcutorture: Remove support for SRCU-lite
  rcutorture: Remove SRCU-lite scenarios
  torture: Remove support for SRCU-lite
  torture: Make torture.sh --allmodconfig testing fail on warnings
  torture: Add "ERROR" diagnostic for testing kernel-build output
  torture: Make torture.sh tolerate runs having bad kvm.sh arguments
  torture: Add textid.txt file to --do-allmodconfig and --do-rcu-rust runs
  torture: Extract testid.txt generation to separate script
  torture: Suppress "find" diagnostics from torture.sh --do-none run
  torture: Provide EXPERT Kconfig option for arm64 KCSAN torture.sh runs
  rcu: Fix rcu_read_unlock() deadloop due to IRQ work
  ...

scripts/checkpatch.pl

@@ -857,8 +857,6 @@ our %deprecated_apis = (
 	"kunmap"				=> "kunmap_local",
 	"kmap_atomic"				=> "kmap_local_page",
 	"kunmap_atomic"				=> "kunmap_local",
-	"srcu_read_lock_lite"			=> "srcu_read_lock_fast",
-	"srcu_read_unlock_lite"			=> "srcu_read_unlock_fast",
 );
 
 #Create a search pattern for all these strings to speed up a loop below