Pull sched_ext fixes from Tejun Heo:

 - The task ownership check in the dispatch queue move operation raced
   against the task exiting or moving to a different sub-scheduler,
   spuriously triggering scheduler aborts. Fix by moving the check under
   the queue lock

 - The cgroup bandwidth change callback runs in a sleepable context but
   sleepable implementations were rejected at load time. Allow them and
   add a marker so userspace can detect the capability

 - Sync tooling headers with the scx repo for accumulated compatibility
   improvements

 - Example scheduler fixes: ignored timer re-arm failures and vtime
   credit loss on cgroup migration

 - Documentation and comment fixes

* tag 'sched_ext-for-7.3-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
  sched_ext: Fix missing @slice and @vtime descriptions in finish_dispatch() kernel-doc
  sched_ext: Fix several comment issues
  sched_ext: Check bpf_timer_start return values in scx_qmap
  sched_ext: Fix vtime delta loss in scx_flatcg cgroup migration
  sched_ext: Fix timer pinning and return value in scx_central
  docs/sched_ext: document that cgroup CPU knobs are scheduler-dependent
  sched_ext: Fix spurious aborts in scx_bpf_dsq_move() on ownership change races
  sched_ext: Sync common and compat headers from the scx repo
  sched_ext: Sync tools autogen enum headers from the scx repo
  Docs/admin-guide/cgroup-v2: document BPF scheduler callbacks for cpu.max and cpu.idle
  sched_ext: Fix nonexistent field in sched-ext.rst example
  sched_ext: Allow ops.cgroup_set_bandwidth() to be sleepable

The scheduler core communicates the initial cpu controller settings
to the BPF scheduler through ops.cgroup_init() and reports subsequent
changes through the corresponding ops.cgroup_set_*() callbacks.
Whether and how a knob takes effect is up to the loaded scheduler:
it may implement the corresponding callback partially or not at all,
so cpu.max, cpu.weight and friends can silently have no effect.

Document this in the basics section of sched-ext.rst.

Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Pull sched_ext updates from Tejun Heo:
 "Most of this cycle completes the enqueue-path support for hierarchical
  sub-scheduling, which makes sub-scheduler support feature complete: a
  root BPF scheduler can now hand a cgroup subtree over to a nested
  sub-scheduler together with revocable CPU grants, and the
  sub-scheduler owns all scheduling decisions for its tasks on those
  CPUs.

  Development volume was high and a number of changes plugging holes in
  the new support landed late in the cycle. Also included are core
  scheduling fixes that were completed too late for the v7.2 release and
  are routed through this pull request.

  Sub-scheduler CPU delegation:

   - Parent schedulers now grant and revoke per-CPU capabilities
     (enqueueing, preemption, CPU frequency control) on their children,
     enforced on every path a scheduler can reach a CPU through.
     Previously only dispatching could be delegated; this lets
     sub-schedulers fully schedule their CPUs.

   - Rescue execution: a task whose scheduler doesn't have access to the
     CPUs the task needs to run on starved until the watchdog ejected
     the whole scheduler. The kernel now runs such tasks directly on a
     small bandwidth budget, turning a scheduler-killing failure into
     bounded degradation.

   - Cgroup integration: tasks migrating across a sub-scheduler boundary
     weren't re-homed to the new owner, causing wrong-scheduler
     scheduling and a use-after-free. Sub-schedulers now take over their
     cgroup subtree and receive its cgroup callbacks.

   - Arena objects now cross the kernel/BPF boundary as typed pointer
     arguments, translated transparently by the BPF tree's new arena
     argument support, replacing untyped arguments with manual
     translation.

   - scx_qmap now demonstrates full hierarchical sub-scheduling.

  Other fixes and updates:

   - Robustness improvements: the abort path is now NMI-safe, fixing
     deadlocks when errors are raised from NMI context and making
     hardlockup recovery direct. Reenqueue loops that could monopolize a
     CPU ahead of the watchdog now eject the offending scheduler, and
     stalls are blamed on the scheduler actually responsible.

   - Hardening: BPF-writable arena memory is validated before kernel
     use, and task slice and vtime writes got explicit synchronization
     rules, closing corruption vectors open to buggy or malicious
     schedulers.

   - Core scheduling: sched_ext dispatching can drop the rq lock inside
     the core-wide pick, which let interleaving selections corrupt each
     other's state and hard-hang the machine. The selection now restarts
     when the lock was released. The task ordering callback was also
     invoked with its arguments swapped, and the default ordering is
     updated to work across sub-scheduler boundaries. The fixes are
     marked for stable.

   - Other fixes headed for stable: a task init leak on fork failure
     during enable, tooling compat macros that silently failed to detect
     newer kernels, and a crash on reenqueueing against a destroyed
     dispatch queue.

   - Tooling: scx_pair moves off deprecated callbacks, and the
     deprecated scx_bpf_cpu_rq() kfunc is removed"

* tag 'sched_ext-for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: (144 commits)
  sched_ext: Drop the dead SCX_DEQ_CORE_SCHED_EXEC test in dequeue_task_scx()
  sched_ext: Make core-sched task ordering hierarchy-aware
  sched_ext: Use runnable_at for the default core-sched task ordering
  sched_ext: Fix inverted ops.core_sched_before() invocation
  sched_ext: Move the config-off sub-cap kfunc stubs into sub.c
  sched_ext: Rename balance-era identifiers to dispatch terms
  sched_ext: Drop the stale keep_prev fixup in dispatch_pick()
  sched_ext: Keep kick_sync waiting on the rq's own CPU
  sched_ext: Make SCHED_CLASS_EXT select GENERIC_ALLOCATOR
  sched_ext/scx_flatcg: Fix cvtime true-up on slice expiry
  sched_ext: Don't BUG_ON a destroyed DSQ in process_deferred_reenq_users
  sched_ext: Fix scx_bpf_dsq_move_to_local___v2 compat detection
  sched_ext: Make scx_bpf_events() read the calling scheduler's counters
  sched_ext: Drop unlocked scx_rq_clock_invalidate() from scx_root_disable()
  selftests/sched_ext: Fix flaky ddsp failure tests on busy systems
  selftests/sched_ext: Make numa idle validation race-free
  sched_ext: Fix scx_bpf_dsq_reenq___compat kfunc extern prototype
  sched_ext/scx_flatcg: expire cached hweights on weight changes
  sched_ext: Fix exit_task leak on fork failure during enable
  sched_ext: fix stale references in doc comments
  ...

Pull documentation updates from Jonathan Corbet:
 "It has been a not-too-busy cycle for docs; here's the highlights:

   - A (hopefully) consensus change to our LLM-attribution requirements,
     removing the specific model name from the Assisted-by tag

   - A couple of new realtime documents

   - Various docs-build-system fixes

   - Ongoing work with the Chinese, Portuguese, and Japanese
     translations

  ...and lots of typo fixes, grammar tweaks, etc"

* tag 'docs-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux: (85 commits)
  Doc: admin-guide: pm: Remove unnecessary backticks and fix a spell
  Documentation: Extend the real-time hardware bits with some firmware bits
  docs: pt_BR: Reorganize process/index.rst to follow english structure
  docs: conf.py: fix the 'utf-8' typo
  doc tools: fix 'path' typos
  Documentation: real-time: Add kernel configuration guide
  docs: python: abi_regex: convert adjacent index placeholders
  docs: python: abi_regex: catch the right exception for a bad regex
  docs: sphinx-build-wrapper: include localversion in kernel version string
  Documentation: html: adjust sidebar section titles styling
  Documentation: html: show sections in the sidebar
  checkpatch.pl: adapt to new Assisted-by: format
  MAINTAINERS: update Traditional Chinese documentation maintainers
  docs: pt_BR: process: Translate CVE documentation
  docs: pt_BR: translate the management-style.rst to Brazilian Portuguese
  docs: xforms_lists: support DEFINE_IDTENTRY_IRQ()
  coding-assistants: simplify attribution
  docs: translations: pt_BR: translate email-clients.rst
  docs: pt_BR: process: Translate the security-bugs.rst
  doc:it_IT: align doc-guide translation
  ...

The ops.exit() example in sched-ext.rst reads ei->type, but
struct scx_exit_info has never had a type field - the exit reason is
exposed as ei->kind since the struct was introduced. A scheduler
written following the example fails to compile with

    error: no member named 'type' in 'struct scx_exit_info'

Use ei->kind.

Fixes: fa48e8d2c7b5 ("sched_ext: Documentation: scheduler: Document extensible scheduler class")
Signed-off-by: Liang Luo <luoliang@kylinos.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>

The events file is under the scheduler's sysfs kobject
(/sys/kernel/sched_ext/root/events for the root scheduler), not the
nonexistent "<scheduler-name>/events" path. Also add the missing "aborting"
line to the scx_show_state.py example.

Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>

Unlike local reenqueues, cap rejections have no repeat limit. A
malfunctioning scheduler can keep re-inserting a task to a cid it lacks caps
on, cycling the task through reject and reenqueue. This was assumed safe
because a task that never runs trips the stall watchdog. However, the
reenqueue irq_work re-arms itself and outranks the timer vector, blocking
everything else on the CPU including stall detection and recovery, until the
NMI hardlockup detector fires.

Local reenqueues already have a repeat cap, SCX_REENQ_LOCAL_MAX_REPEAT,
which needs generalizing to cover all reenqueues. It also has an attribution
problem. Counted per-cpu on root, it tears down the whole hierarchy even
when a sub-scheduler caused the repeated reenqueues.

Generalize by bounding every reenqueue with one per-task counter. reenq_cnt
is bumped in scx_do_enqueue_task() on each SCX_ENQ_REENQ, the single path
every reenqueue producer passes through, and cleared in clr_task_runnable()
when the task is picked to run and in scx_disable_task() when it leaves the
scheduler's control. Past SCX_REENQ_MAX_REPEAT the task's owning scheduler
is ejected with a new SCX_EXIT_ERROR_REENQ and the task is left stranded to
be picked up during sched exit.

The SCX_EV_REENQ_LOCAL_REPEAT event becomes SCX_EV_REENQ_REPEAT, counting
repeat reenqueues from all sources.

v2: Count SCX_EV_REENQ_REPEAT only when a reenqueue leads to another
    reenqueue, not on every reenqueue.

v3: - Also clear reenq_cnt in scx_disable_task() so that the count doesn't
      carry over to the next owner across sched class switches, scheduler
      replacement or sub-scheduler rehoming (Andrea Righi).

    - Update the stale SCX_EV_REENQ_LOCAL_REPEAT references in sched-ext.rst
      (Andrea Righi).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

checkpatch.pl returns 'trailing statements should be on next line'
for this file. Do as told.

Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260703115114.229848-3-manuelebner@mailbox.org>

The scheduler energy-aware placement documentation refers to the
em_pd_energy() API, which was renamed to em_cpu_energy() in commit
f0b5694791ce ("PM / EM: change name of em_pd_energy to em_cpu_energy").
Update the reference to the current name.

em_cpu_energy() is the EM helper that compute_energy() in
kernel/sched/fair.c calls to estimate a performance domain's energy
consumption (defined in include/linux/energy_model.h).

Sync the zh_CN translation, which carries the same stale name.

Signed-off-by: Liang Luo <luoliang@kylinos.cn>
Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Alex Shi <alexs@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260707085335.2942128-1-luoliang@kylinos.cn>

The "Where to Look" and "ABI Instability" sections state that the ops
table is defined in include/linux/sched/ext.h. However, struct
sched_ext_ops is actually defined in kernel/sched/ext/internal.h, along
with the SCX_OPS_* flags; include/linux/sched/ext.h holds the core data
structures (struct sched_ext_entity, struct scx_dispatch_q, ...) and the
DSQ constants. Point the ops table references to the correct header.

Signed-off-by: Liang Luo <luoliang@kylinos.cn>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>