Pull locking fixes from Ingo Molnar:

 - Fix a softirq processing delay bug in local_interrupt_disable(),
   which should mostly only affect the Rust runtime (Boqun Feng)

 - Remove the hardirq_disable_count() function which caused the
   previous bug and is now unused & unnecessary (Boqun Feng)

 - lockdep: Invalidate stale class_cache entries for zapped classes
   (Eric Dumazet)

 - Fix rt_mutex specific futex scheduling helpers
   (Sebastian Andrzej Siewior)

 - Fix rcuwait use-after-free race during futex requeue PI (Yao Kai)

* tag 'locking-urgent-2026-09-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Prevent rcuwait use-after-free during requeue PI
  futex: Provide rt_mutex_.*_schedule() equivalents for futex scheduling
  locking/lockdep: Invalidate stale class_cache entries for zapped classes
  preempt: Remove hardirq_disable_count()
  interrupt: Disable interrupt before modifying hardirq_disable counter

This is another run of the Coccinelle script for converting kmalloc()
family of allocations to kmalloc_obj() via the existing rules in
scripts/coccinelle/api/kmalloc_objs.cocci

This catches both the set of kmalloc() uses added since the first
kmalloc_obj() conversions in v7.0 and adds a large group missed in the
first pass due to Coccinelle not interacting well with the cleanup.h
scoped_...() family of macros[1]. I worked around this with spatch's
"--macro-file" argument to a file with all the scoped_...() macros mapped
to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control
flow indicator I could find.

Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc,
riscv, and s390 with no new warnings.

Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1]
Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2]
Signed-off-by: Kees Cook <kees+treewide@kernel.org>

On PREEMPT_RT, FUTEX_CMP_REQUEUE_PI can trigger a KASAN report
(slab-out-of-bounds) in futex_requeue_pi_complete() invocation of
rcuwait_wake_up().

The futex_q used by futex_wait_requeue_pi() is allocated on the waiter's
stack. An early wakeup can race with a PI requeue as follows:

        waiter                          requeue task
        ------                          ------------
futex_wait_requeue_pi()
  futex_do_wait()
    schedule()
                                       futex_requeue
                                         futex_proxy_trylock_atomic()
                                           futex_requeue_pi_prepare()
                                            Q_REQUEUE_PI_NONE -> Q_REQUEUE_PI_IN_PROGRESS
* timeout/ signal wakes waiter *
  futex_requeue_pi_wakeup_sync()
   Q_REQUEUE_PI_IN_PROGRESS -> Q_REQUEUE_PI_WAIT
                                           requeue_pi_wake_futex
                                             futex_requeue_pi_complete()
                                               cmpxchg Q_REQUEUE_PI_WAIT -> Q_REQUEUE_PI_LOCKED
    rcuwait_wait_event()
      if (atomic_read(&q->requeue_state) != Q_REQUEUE_PI_WAIT)
       break /* no schedule() */

 /* q.pi_state->owner == current */
 futex_private_hash_put()
 /* return from syscall */
                                              rcuwait_wake_up(&q->requeue_wait)
                                                /* q is gone */

futex_requeue_pi_complete() publishes Q_REQUEUE_PI_LOCKED before
calling rcuwait_wake_up(). The waiter observes this state in
rcuwait_wait_event() before invoking schedule() in rcuwait_wait_event().
Here, the waiter is free leave the syscall before requeue task can
complete the wake.

To address this race skip rcuwait_wake_up() in the Q_REQUEUE_PI_LOCKED
case.
This state is only published by requeue_pi_wake_futex(), which saves
q->task before futex_requeue_pi_complete() and wakes the waiter via
wake_up_state().

This wake is intended to wake the waiter from its futex_do_wait() sleep.
If the waiter is still sleeping there, it can not get into the
Q_REQUEUE_PI_WAIT state (and require this removed wake).
Should the waiter be woken up from futex_do_wait() by other means (as in
this example) and sleep in futex_requeue_pi_wakeup_sync() then the
wake_up_state() from requeue_pi_wake_futex() will wake it, too.
Should the waiter task terminate before wake_up_state() had a chance to
wake the task then the task pointer does not become invalid because the
futex_hash_bucket::lock is held and the task pointer is RCU protected.

[bigeasy: Updated comment and commit message]

Fixes: 07d91ef510fb1 ("futex: Prevent requeue_pi() lock nesting issue on RT")
Signed-off-by: Yao Kai <yaokai34@huawei.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260901135453.3121948-3-bigeasy@linutronix.de

There is rt_mutex_{pre|post}_schedule() around
rt_mutex_wait_proxy_lock() to ensure that sched_submit_work()/
sched_update_worker() is invoked before we schedule out and block on
rt_mutex while waiting for it become available.

The reason is that blocking on rt_mutex assigns a pi_waiter for the PI
chain and sched_submit_work() will also assign a pi_waiter if it blocks
on lock but a this point we already have a waiter assigned.
We can't skip sched_submit_work() entirely because I/O relies on the
fact that I/O queue is flushed while it blocks on a sleeping lock.
Therefore sched_submit_work() is moved before we block on the lock.

Sleeping lock in this context means mutex or rw_semaphore not spinlock_t
on PREEMPT_RT. Because the mutex abstraction on PREEMPT_RT uses the same
abstraction as the futex proxy lock, the futex code ended up using
rt_mutex_{pre|post}_schedule(), too.
Using it is/ was just to keep the task_struct::sched_rt_mutex assertion
happy. Futex proxy lock is used only in the syscall context of a task.
At this point it never got any I/O that needs to be flushed and it can't
be a workqueue that needs to notify that it will be scheduled out.
Therefore sched_submit_work() does nothing here.

By mistake futex_wait_requeue_pi() -> rt_mutex_wait_proxy_lock() did not
get the rt_mutex_{pre|post}_schedule() annotation. This was not noticed
because in this callchain the lock is (usually) not contended and so
rt_mutex_slowlock_block() does not schedule, triggering the assert.

Adding rt_mutex_pre_schedule() here looks wrong (as noted by PeterZ)
because at this point there is a pi_waiter recorded and invoking
sched_submit_work() with a possible lock contention would be wrong.

Add rt_mutex_futex_{pre|post}_schedule() which toggles the
sched_rt_mutex assert and does not involve sched_submit_work(). Add
asserts here to ensure that sched_submit_work() would do nothing. Use it
only in futex proxy lock case which is rt_mutex_wait_proxy_lock().
Remove it from futex_lock_pi().

Fixes: d14f9e930b90 ("locking/rtmutex: Use rt_mutex specific scheduler helpers")
Reported-by: Yao Kai <yaokai34@huawei.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260901135453.3121948-2-bigeasy@linutronix.de
Closes: https://lore.kernel.org/all/20260717084922.4153317-2-yaokai34@huawei.com

Pull futex fixes from Ingo Molnar:

 - Enforce that the private futex owner shares the mm when attaching
   (Kyle Zeng, Thomas Gleixner)

 - Fix race on the initial mm->futex.phash.ref allocation (Hyunwoo Kim)

 - Fix might_sleep() warning in futex_pivot_pending() (Peter Zijlstra)

* tag 'locking-urgent-2026-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Fix might_sleep() warning in futex_pivot_pending()
  futex: Fix race on the initial mm->futex.phash.ref allocation
  futex: Clean up the redundant exit/exec functions
  futex/pi: Plug private futex exec() race
  futex: Sanitize and document task_struct::futex::state transitions
  futex/pi: Reject cross-mm private futex owners

A younger me put a WARN in might_sleep() to warn about nested sleep loops. This
younger me also build a wait-loop variant that can deal with it. This wait-loop
variant doesn't have all the fancy wrappers, since it isn't used much. It also
lacks wait-bit support.

Add the wait-bit support and use it to fix the nested wait issue.

Fixes: 8e7ff730dd96 ("futex: Fix race in futex_pivot_pending() during private hash resize")
Reported-by: syzbot+350a93852ac854927f45@syzkaller.appspotmail.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260820074927.GH1246887@noisy.programming.kicks-ass.net
Closes: https://syzkaller.appspot.com/bug?extid=350a93852ac854927f45

Pull futex updates from Thomas Gleixner:

 - Improvements to various futex self tests:

    - Conversion to the selftest harness

    - Provide and use thread creation and synchronization helpers to
      reduce the dependency on delays, which tend to fail on loaded test
      systems

    - New tests for validating owner exit scenarios for robust and PI
      futexes

    - Runtime detect supported features and skip the tests if the kernel
      has no support

 - A few minor fixes

* tag 'locking-futex-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  selftests/futex: Give circular-list nodes static storage
  selftests/futex: Use thread synchronization helpers instead of usleep()
  selftests/futex: Provide thread creation and synchronization helpers
  selftests/futex: Dynamically skip unsupported tests
  selftests/futex: Add FUTEX_LOCK_PI owner-exiting coverage
  selftests/futex: Migrate robust_list to harness
  selftests/futex: Migrate futex_priv_hash to harness
  selftests/futex: Migrate futex_numa_mpol to harness
  selftests/futex: Migrate futex_requeue_pi_signal_restart to harness
  selftests/futex: Migrate futex_requeue_pi_mismatched_ops to harness
  selftests/futex: Migrate futex_requeue_pi to harness
  selftests/futex: Migrate futex_requeue to harness
  selftests/futex: Migrate futex_wait_uninitialized_heap to harness
  selftests/futex: Migrate futex_wait_private_mapped_file to harness
  selftests/futex: Migrate futex_wait to harness
  selftests/futex: Correct validation logic in waitv
  selftests/futex: Migrate functional tests to harness
  selftests/futex: Remove static keyword from 'head'
  futex: Remove unnecessary NULL check before kvfree()
  selftests/rseq: Replace glibc-specific __GNUC_PREREQ with portable check

Pull locking updates from Ingo Molnar:
 "Futexes:

   - Use runtime constants for futex_hash computation (K Prateek Nayak,
     Peter Zijlstra)

   - Optimise the size check get_futex_key() (Sebastian Andrzej Siewior)

   - Avoid private hash use-after-free on final put (Felix Hoffmann)

   - Tell kmemleak we're not leaking __futex_queues (Peter Zijlstra)

  Rust integration updates:

   - Implement refcounted interrupt disable and SpinLockIrq for Rust
     (Boqun Feng, Heiko Carstens, Joel Fernandes, Lyude Paul)

   - Rust sync: add helpers for mb, dma_mb and friends; add generic
     memory barriers and use LKMM atomics instead of Rust atomics in the
     revocable code (Gary Guo)

   - Add abstraction and integrate synchronize_rcu() (Philipp Stanner)

  Lock debugging:

   - Add qspinlock contended_release tracepoint (Dmitry Ilvokhin, Peter
     Zijlstra)

   - Enable the printing of held locks of remote running tasks and print
     task CPU (Ingo Molnar)

   - percpu-rwsem: Annotate intentional data race in readers_active_check()
     (Sun Shaojie)

  Misc fixes and updates by Boqun Feng, Peter Zijlstra, Fangrui Song,
  Naveen Kumar Chaudhary and Thomas Huth"

* tag 'locking-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
  rust: sync: Introduce SpinLockIrq::lock_with() and friends
  rust: sync: Add SpinLockIrq
  rust: sync: Use super::* in spinlock.rs
  rust: helper: Add spin_{un,}lock_irq_{enable,disable}() helpers
  rust: Introduce interrupt module
  s390/preempt: Enable HAS_SEPARATE_PREEMPT_RESCHED_BITS
  arm64: sched/preempt: Enable HAS_SEPARATE_PREEMPT_RESCHED_BITS
  preempt: Introduce HAS_SEPARATE_PREEMPT_RESCHED_BITS
  sched: Avoid signed comparison of preempt_count() in __cant_migrate()
  sched: Remove the unused preempt_offset parameter of __cant_sleep()
  locking: Switch to _irq_{disable,enable}() variants in cleanup guards
  irq: Add KUnit test for refcounted interrupt enable/disable
  irq,spin_lock: Add counted interrupt disabling/enabling
  openrisc: Include <linux/cpumask.h> in smp.h
  preempt: Introduce __preempt_count_{sub,add}_return()
  preempt: Introduce HARDIRQ_DISABLE_BITS
  preempt: Track NMI nesting to separate per-CPU counter
  futex: Tell kmemleak we're not leaking __futex_queues
  x86/paravirt: Trace contended_release on unlock
  tracing/lock: Use TRACE_EVENT_FN() for contended_release
  ...

futex_hash_allocate() allocates mm->futex.phash.ref without any locking.
Commit d9b05321e21e ("futex: Move futex_hash_free() back to __mmput()")
moved the allocation here and assumed that the process has just a single
thread at this point.

Commit ee9dce44362b ("futex: Drop CLONE_THREAD requirement for private
default hash alloc") widened need_futex_hash_allocate_default() to cover
any CLONE_VM clone, but left out vfork because the parent is suspended and
cannot race.

That no longer holds once vfork is nested. If a vfork child calls vfork
again and is then killed with SIGKILL, the parent is released from its
vfork wait and runs concurrently with the grandchild in the same mm.
Neither of them went through futex_hash_allocate_default().

When both call prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_SET_SLOTS) at the same
time, each one sees mm->futex.phash.ref as NULL and stores its own percpu
counter. Only the last store survives. The counter stored first is no
longer reachable from the mm, so the references on it are not seen by
__futex_ref_atomic_end(). A private hash that still has references is then
considered dead and freed, and a task that still holds one of its buckets
writes into freed memory in futex_q_lock().

Store the counter once with cmpxchg() and let the loser free_percpu() its
own. The initial reference has to be taken before the store, otherwise
another task can install a private hash while the counter is still 0.

Fixes: d9b05321e21e ("futex: Move futex_hash_free() back to __mmput()")
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/ansrpP4ImE1MaBY9@v4bel

futex_exit_release() and futex_exec_release() are identical now. That means
also exit_mm_release() and exec_mm_release() are identical.

Consolidate the whole lot and remove the redundant copies.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Kyle Zeng <kylebot@openai.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>