Pull sched_ext fixes from Tejun Heo:

 - Lifecycle fixes for the new sub-scheduler support: two
   use-after-frees and an enable-failure path that left a
   half-initialized sub-scheduler linked.

 - Two dispatch-path locking bugs: a spurious scheduler abort from a
   migration race, and a lockdep splat from stale runqueue-lock
   tracking.

 - Callback and task-state fixes: stale scheduler-owned state on a task
   leaving SCX, a weight callback running after disable, and a bogus
   warning on core-scheduling forced idle.

 - On nohz_full, finite-slice tasks could miss the tick that expires
   their slice. Enable it when such a task is picked, with a selftest.

 - Smaller fixes: userspace CPU-mask helpers, ratelimited deprecation
   warnings, docs and a sparse annotation.

* tag 'sched_ext-for-7.2-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
  sched_ext: Skip ops.set_weight() for disabled tasks
  tools/sched_ext: scx - Fix cmask_subset(), cmask_equal() and cmask_weight()
  sched_ext: Fix premature ops->priv publication in scx_alloc_and_add_sched()
  sched_ext: Record an error on errno-only sub-enable failure
  selftests/sched_ext: Verify nohz_full tick behavior
  sched_ext: Enable tick for finite slices on nohz_full
  sched_ext: Preserve rq tracking across local DSQ dispatch
  sched_ext: Documentation: Fix ops table header reference
  sched_ext: Don't warn on core-sched forced idle in put_prev_task_scx()
  sched_ext: Pin parent scx_sched across a child sub-scheduler's lifetime
  sched_ext: Annotate ksyncs with __rcu in alloc/free_kick_syncs()
  sched_ext: Check remote rq eligibility under task's rq lock
  sched_ext: Reset dsq_vtime and slice when a task leaves SCX
  sched_ext: Avoid flooding the log with deprecation warnings

When switching a task's sched_class away from sched_ext, we get the
following sequence of events in __sched_setscheduler():

sched_change_begin()
  switched_from_scx()
    scx_disable_task(p)
      ops.disable(p)
__setscheduler_params()
  set_load_weight()
    reweight_task_scx(p)
      ops.set_weight(p)
p->sched_class = next_class;
sched_change_end()
  ...

Notably, ops.set_weight() is called _after_ ops.disable().
This violates the expected semantics of the callbacks, the expectation
being that ops.disable() can only be followed by ops.exit_task() or
ops.enable().

Skipping the weight adjustment for disabled tasks should be harmless
since the weight will be recalculated in scx_enable_task() if the task
ever rejoins SCX.

Fixes: 637b0682821b ("sched: Fold sched_class::switch{ing,ed}_{to,from}() into the change pattern")
Cc: stable@vger.kernel.org # v6.19+
Signed-off-by: Kuba Piecuch <jpiecuch@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

scx_alloc_and_add_sched() publishes @sch through ops->priv before allocating
the cgroup path. If that allocation fails, the unwind path clears ops->priv
and frees @sch immediately. scx_prog_sched() callers can dereference
ops->priv from RCU context the moment it is set, so freeing without a grace
period can use-after-free a concurrent kfunc caller.

Move the publication below the cgroup path allocation so that every failure
path after publication frees @sch through kobject_put(), whose release path
defers the freeing by a grace period.

Fixes: 105dcd005be2 ("sched_ext: Introduce scx_prog_sched()")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

scx_sub_enable_workfn() has several failure paths that only return an errno
(e.g. -ENOMEM from an allocation) and jump to err_disable without calling
scx_error(). scx_flush_disable_work() runs the disable, and thus ops.exit(),
only when an error has been recorded, so an errno-only failure leaves the
half-initialized sub-scheduler linked.

Record an error at the err_disable sink so every errno-only failure runs the
disable path.

Fixes: ebeca1f930ea ("sched_ext: Introduce cgroup sub-sched support")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

set_next_task_scx() updates the tick dependency before __schedule()
updates rq->curr. When switching from a non-EXT task, such as idle, to
an EXT task with a finite slice, sched_update_tick_dependency() checks
the outgoing task and can allow the tick to remain stopped.

The dependency can also be lost without a slice-type transition. After a
finite-slice task leaves the CPU idle, the enqueue path can clear the
dependency against the idle rq->curr. SCX_RQ_CAN_STOP_TICK still records
a finite slice, so another finite task skips the transition block and
can run without the ticks needed to expire its slice.

The reverse mismatch can also happen when the last finite-slice EXT task
is dequeued: sub_nr_running() updates the dependency before rq->curr
changes, so the outgoing task state can keep the dependency set after
the CPU goes idle.

Fix this by unconditionally enabling the scheduler tick whenever a
finite-slice EXT task is selected on a nohz_full CPU. Moreover, when the
last runnable EXT task leaves, ignore the outgoing EXT slice state so
the generic scheduler can correctly re-evaluate and clear the tick
dependency.

Fixes: 22a920209ab6 ("sched_ext: Implement tickless support")
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

dispatch_to_local_dsq() can run from scx_bpf_dsq_move_to_local() while
ops.dispatch() has recorded the current rq. Moving a task to a local DSQ
may switch to the source or destination rq before synchronously invoking
ops.dequeue() through the following path:

  SCX_CALL_OP(dispatch, rq)
    ops.dispatch()
      scx_bpf_dsq_move_to_local()
        scx_flush_dispatch_buf()
          finish_dispatch()
            dispatch_to_local_dsq()
              scx_dispatch_enqueue()
                local_dsq_post_enq()
                  call_task_dequeue()
                    SCX_CALL_OP_TASK(dequeue, locked_rq, ...)

The nested callback saves the recorded rq and restores it on return. If
the rq tracking does not follow the lock switch, update_locked_rq() can
trigger the following lockdep assertion while restoring an rq which is
no longer held:

  WARNING: kernel/sched/sched.h:1641 at call_task_dequeue+0x160/0x170
  Call Trace:
    scx_dispatch_enqueue+0x2b0/0x460
    dispatch_to_local_dsq+0x138/0x230
    scx_flush_dispatch_buf+0x1af/0x220
    scx_bpf_dsq_move_to_local___v2+0xe2/0x1c0
    bpf__sched_ext_ops_dispatch+0x4b/0xa7
    do_pick_task_scx+0x3b6/0x910
    __pick_next_task+0x105/0x1f0
    __schedule+0x3e7/0x1980

Introduce switch_rq_lock() to update the tracking state together with
each rq lock handoff. Use it in dispatch_to_local_dsq(),
move_remote_task_to_local_dsq() and the in-balance paths of
scx_dsq_move(), ensuring that scx_locked_rq() consistently refers to the
rq whose lock is actually held throughout the lock dance.

Fixes: 7fb39e4eb4c3 ("sched_ext: Save and restore scx_locked_rq across SCX_CALL_OP")
Cc: stable@vger.kernel.org # 7.1+
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

put_prev_task_scx() warns when a runnable task drops to a lower sched_class
without SCX_OPS_ENQ_LAST, on the assumption that balance_one() would have
kept it running. Core scheduling breaks that: a forced-idle SMT sibling
reschedules through the core_pick fast path in pick_next_task(), which skips
pick_task_scx() and thus balance_one(), so a runnable task can drop to idle
with ENQ_LAST unset.

Gate the warning on sched_cpu_cookie_match(): a cookie mismatch means core
scheduling forced the idle, while a match (or core scheduling off) still
catches a genuine missing-ENQ_LAST drop.

Fixes: 7c65ae81ea86 ("sched_ext: Don't call put_prev_task_scx() before picking the next task")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

A child sub-scheduler dereferences its parent scx_sched throughout its life,
e.g., in scx_sub_disable() which reparents the child's tasks and calls
parent->ops.sub_detach() after unlinking from the parent. However, the
parent is pinned only through parent->sub_kset, which is dropped during
disable. The parent scx_sched can be RCU-freed while a child is still
disabling.

Take a direct reference on the parent in scx_alloc_and_add_sched(), dropped
in scx_sched_free_rcu_work(), so a parent always outlives its descendants.

Signed-off-by: Tejun Heo <tj@kernel.org>

Pull power management fixes from Rafael Wysocki:
 "These fix the schedutil cpufreq governor and drop a bogus warning
  from the cpuidle core:

   - Remove a misguided warning along with an inaccurate comment
     next to it from the cpuidle core (Rafael Wysocki)

   - Clear need_freq_update as appropriate in the .adjust_perf()
     path of the schedutil cpufreq governor to avoid calling
     cpufreq_driver_adjust_perf() unnecessarily on every scheduler
     utilization update (Zhongqiu Han)"

* tag 'pm-7.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpuidle: Allow exit latency to exceed target residency
  cpufreq: schedutil: Fix uncleared need_freq_update on the .adjust_perf() path

Pull block fixes from Jens Axboe:

 - blk-cgroup locking rework and fixes:
      - fix a use-after-free in __blkcg_rstat_flush()
      - defer freeing policy data until after an RCU grace period
      - defer the blkcg css_put until the blkg is unlinked from
        the queue
      - unwind the queue_lock nesting under RCU / blkcg->lock
        across the lookup, create, associate and destroy paths

 - NVMe fixes via Keith:
      - Fix a crash and memory leak during invalid cdev teardown,
        and related cdev cleanups (Maurizio, John)
      - nvmet fixes: handle TCP_CLOSING in the tcp state_change
        handler, reject short AUTH_RECEIVE buffers, handle inline
        data with a nonzero offset in rdma, fix an sq refcount leak,
        and allocate ana_state with the port (Maurizio, Michael,
        Bryam, Wentao, Rosen)
      - nvme-fc fix to not cancel requests on an IO target before it
        is initialized (Mohamed)
      - nvme-apple fix to prevent shared tags across queues on Apple
        A11 (Nick)
      - Various smaller fixes and cleanups (John)

 - MD fixes via Yu Kuai:
      - raid1/raid10 fixes for writes_pending and barrier reference
        leaks on write and discard failures, plus REQ_NOWAIT handling
        fixes (Abd-Alrhman)
      - raid5 discard accounting and validation, and a batch of fixes
        for stripe batch races (Yu Kuai, Chen)
      - Protect raid1 head_position during read balancing (Chen)

 - block bio-integrity fixes: correct an error injection static key
   decrement, fix GFP flag confusion in bio_integrity_alloc_buf(), and
   handle REQ_OP_ZONE_APPEND in __bio_integrity_action() (Christoph)

 - Fixes for bio_iov_iter_bounce_write(): revert the iov_iter after a
   short copy, and respect the iov_iter nofault flag (Qu)

 - Invalidate the cached plug timestamp after a task switch, and clear
   PF_BLOCK_TS in copy_process() (Usama)

 - Fix the IORING_URING_CMD_REISSUE flags check in blkdev_uring_cmd()
   (Yitang)

 - Remove a redundant plug in __submit_bio() (Wen)

 - Don't warn when reclassifying a busy socket lock in nbd (Deepanshu)

* tag 'block-7.2-20260625' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (45 commits)
  block: handle REQ_OP_ZONE_APPEND in __bio_integrity_action
  block: fix GFP_ flags confusion in bio_integrity_alloc_buf
  block, bfq: don't grab queue_lock to initialize bfq
  mm/page_io: don't nest queue_lock under rcu in bio_associate_blkg_from_page()
  blk-cgroup: don't nest queue_lock under blkcg->lock in blkcg_destroy_blkgs()
  blk-cgroup: don't nest queue_lock under rcu in bio_associate_blkg()
  blk-cgroup: don't nest queue_lock under rcu in blkg_lookup_create()
  blk-cgroup: don't nest queue_lock under rcu in blkcg_print_blkgs()
  blk-cgroup: delay freeing policy data after rcu grace period
  blk-cgroup: protect iterating blkgs with blkcg->lock in blkcg_print_stat()
  md/raid5: avoid R5_Overlap races while breaking stripe batches
  md/raid5: use stripe state snapshot in break_stripe_batch_list()
  blk-cgroup: defer blkcg css_put until blkg is unlinked from queue
  blk-cgroup: fix UAF in __blkcg_rstat_flush()
  block, bfq: protect async queue reset with blkcg locks
  nbd: don't warn when reclassifying a busy socket lock
  block: fix incorrect error injection static key decrement
  md/raid5: let stripe batch bm_seq comparison wrap-safe
  md/raid1: protect head_position for read balance
  md/raid1: free r1_bio when REQ_NOWAIT is set and read would block on retry
  ...