[GIT PULL] RCU changes for v7.0

[Boqun Feng <boqun@kernel.org>]

Hi Linus,

Once the merge window opens, please pull the following changes of RCU.

The following changes since commit 8f0b4cce4481fb22653697cced8d0d04027cb1e8:

  Linux 6.19-rc1 (2025-12-14 16:05:07 +1200)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux.git tags/rcu.release.v7.0

for you to fetch changes up to ed062c41dfda2de8d1712c91e089303dae013bb7:

  Merge branch 'rcu-nocb.20260123a' (2026-01-23 11:15:36 -0800)


(As you may know, I'm switching away from my gmail, so while this
email is by my @kernel.org, all the commits for the PR are signed-off-by
my gmail, JFYI)

Regards,
Boqun

----------------------------------------------------------------
RCU changes for v7.0

RCU Tasks Trace:

Re-implement RCU tasks trace in term of SRCU-fast, not only more than 500 lines
of code are saved because of the reimplementation, a new set of API,
rcu_read_{,un}lock_tasks_trace(), becomes possible as well. Compared to the
previous rcu_read_{,un}lock_trace(), the new API avoid the task_struct accesses
thanks to the SRCU-fast semantics. As a result, the old
rcu_read{,un}lock_trace() API is now deprecated.

RCU Torture Test:

- Multiple improvements on kvm-series.sh (parallel run and progress showing
  metrics)
- Add context checks to rcu_torture_timer().
- Make config2csv.sh properly handle comments in .boot files.
- Include commit discription in testid.txt.

Miscellaneous RCU changes:

- Reduce synchronize_rcu() latency by reporting GP kthread's CPU QS early.
- Use suitable gfp_flags for the init_srcu_struct_nodes().
- Fix rcu_read_unlock() deadloop due to softirq.
- Correctly compute probability to invoke ->exp_current() in rcutorture.
- Make expedited RCU CPU stall warnings detect stall-end races.

RCU nocb:

- Remove unnecessary WakeOvfIsDeferred wake path and callback overload
  handling.
- Extract nocb_defer_wakeup_cancel() helper.

----------------------------------------------------------------
Boqun Feng (4):
      Merge branch 'rcu-tasks-trace.20260101a'
      Merge branch 'rcu-torture.20260104a' into rcu-next
      Merge branch 'rcu-misc.20260111a'
      Merge branch 'rcu-nocb.20260123a'

Joel Fernandes (6):
      rcutorture: Prevent concurrent kvm.sh runs on same source tree
      rcutorture: Add --kill-previous option to terminate previous kvm.sh runs
      rcu: Reduce synchronize_rcu() latency by reporting GP kthread's CPU QS early
      rcu/nocb: Remove unnecessary WakeOvfIsDeferred wake path
      rcu/nocb: Remove dead callback overload handling
      rcu/nocb: Extract nocb_defer_wakeup_cancel() helper

Paul E. McKenney (17):
      rcu: Re-implement RCU Tasks Trace in terms of SRCU-fast
      context_tracking: Remove rcu_task_trace_heavyweight_{enter,exit}()
      rcu: Clean up after the SRCU-fastification of RCU Tasks Trace
      rcu: Move rcu_tasks_trace_srcu_struct out of #ifdef CONFIG_TASKS_RCU_GENERIC
      rcu: Add noinstr-fast rcu_read_{,un}lock_tasks_trace() APIs
      rcu: Update Requirements.rst for RCU Tasks Trace
      checkpatch: Deprecate rcu_read_{,un}lock_trace()
      srcu: Create an rcu_tasks_trace_expedite_current() function
      rcutorture: Test rcu_tasks_trace_expedite_current()
      rcutorture: Add context checks to rcu_torture_timer()
      torture: Parallelize kvm-series.sh guest-OS execution
      torture: Make kvm-series.sh give build numbers and totals
      torture: Make kvm-series.sh give run numbers and totals
      torture: Make config2csv.sh properly handle comments in .boot files
      torture: Include commit discription in testid.txt
      rcu: Make expedited RCU CPU stall warnings detect stall-end races
      rcutorture: Correctly compute probability to invoke ->exp_current()

Yao Kai (1):
      rcu: Fix rcu_read_unlock() deadloop due to softirq

Zqiang (1):
      srcu: Use suitable gfp_flags for the init_srcu_struct_nodes()

 .../RCU/Design/Requirements/Requirements.rst       |  12 +-
 Documentation/admin-guide/kernel-parameters.txt    |  15 -
 include/linux/rcupdate.h                           |  31 +-
 include/linux/rcupdate_trace.h                     | 166 ++++-
 include/linux/sched.h                              |   6 +-
 init/init_task.c                                   |   3 -
 kernel/context_tracking.c                          |  20 -
 kernel/fork.c                                      |   3 -
 kernel/rcu/Kconfig                                 |  43 +-
 kernel/rcu/rcu.h                                   |   9 -
 kernel/rcu/rcuscale.c                              |   7 -
 kernel/rcu/rcutorture.c                            |  10 +-
 kernel/rcu/srcutree.c                              |   2 +-
 kernel/rcu/tasks.h                                 | 708 +--------------------
 kernel/rcu/tree.c                                  |  14 +-
 kernel/rcu/tree.h                                  |   5 +-
 kernel/rcu/tree_exp.h                              |   7 +-
 kernel/rcu/tree_nocb.h                             |  80 +--
 kernel/rcu/tree_plugin.h                           |  15 +-
 scripts/checkpatch.pl                              |   4 +-
 tools/testing/selftests/rcutorture/.gitignore      |   1 +
 .../testing/selftests/rcutorture/bin/config2csv.sh |   2 +-
 .../testing/selftests/rcutorture/bin/kvm-series.sh | 184 +++++-
 tools/testing/selftests/rcutorture/bin/kvm.sh      |  40 ++
 tools/testing/selftests/rcutorture/bin/mktestid.sh |   2 +-
 .../selftests/rcutorture/configs/rcu/TRACE01       |   1 -
 .../selftests/rcutorture/configs/rcu/TRACE02       |   1 -
 27 files changed, 459 insertions(+), 932 deletions(-)