linux.git/kernel/irq/internals.h, branch v7.2

Merge tag 'locking-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip

2026-06-15T08:51:14+00:00

Pull locking updates from Ingo Molnar:
 "Futex updates:

   - Optimize futex hash bucket access patterns (Peter Zijlstra)

   - Large series to address the robust futex unlock race for real, by
     Thomas Gleixner:

      "The robust futex unlock mechanism is racy in respect to the
       clearing of the robust_list_head::list_op_pending pointer because
       unlock and clearing the pointer are not atomic.

       The race window is between the unlock and clearing the pending op
       pointer. If the task is forced to exit in this window, exit will
       access a potentially invalid pending op pointer when cleaning up
       the robust list.

       That happens if another task manages to unmap the object
       containing the lock before the cleanup, which results in an UAF.

       In the worst case this UAF can lead to memory corruption when
       unrelated content has been mapped to the same address by the time
       the access happens.

       User space can't solve this problem without help from the kernel.
       This series provides the kernel side infrastructure to help it
       along:

        1) Combined unlock, pointer clearing, wake-up for the
           contended case

        2) VDSO based unlock and pointer clearing helpers with a
           fix-up function in the kernel when user space was interrupted
           within the critical section.

      ... with help by André Almeida:

        - Add a note about robust list race condition (André Almeida)
        - Add self-tests for robust release operations (André Almeida)

  Context analysis updates:

   - Implement context analysis for 'struct rt_mutex'. (Bart Van Assche)
   - Bump required Clang version to 23 (Marco Elver)

  Guard infrastructure updates:

   - Series to remove NULL check from unconditional guards (Dmitry
     Ilvokhin)

  Lockdep updates:

   - Restore self-test migrate_disable() and sched_rt_mutex state on
     PREEMPT_RT (Karl Mehltretter)

  Membarriers updates:

   - Use per-CPU mutexes for targeted commands (Aniket Gattani)
   - Modernize membarrier_global_expedited with cleanup guards (Aniket
     Gattani)
   - Add rseq stress test for CFS throttle interactions (Aniket Gattani)

  percpu-rwsems updates:

   - Extract __percpu_up_read() to optimize inlining overhead (Dmitry
     Ilvokhin)

  Seqlocks updates:

   - Allow UBSAN_ALIGNMENT to fail optimizing (Heiko Carstens)

  Lock tracing:

   - Add contended_release tracepoint to sleepable locks such as
     mutexes, percpu-rwsems, rtmutexes, rwsems and semaphores (Dmitry
     Ilvokhin)

  MAINTAINERS updates:

   - MAINTAINERS: Add RUST [SYNC] entry (Boqun Feng)

  Misc updates and fixes by Randy Dunlap, YE WEI-HONG, Fabricio Parra,
  Dmitry Ilvokhin and Peter Zijlstra"

* tag 'locking-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (36 commits)
  locking: Add contended_release tracepoint to sleepable locks
  locking/percpu-rwsem: Extract __percpu_up_read()
  tracing/lock: Remove unnecessary linux/sched.h include
  futex: Optimize futex hash bucket access patterns
  rust: sync: completion: Mark inline complete_all and wait_for_completion
  MAINTAINERS: Add RUST [SYNC] entry
  cleanup: Specify nonnull argument index
  selftests: futex: Add tests for robust release operations
  Documentation: futex: Add a note about robust list race condition
  x86/vdso: Implement __vdso_futex_robust_try_unlock()
  x86/vdso: Prepare for robust futex unlock support
  futex: Provide infrastructure to plug the non contended robust futex unlock race
  futex: Add robust futex unlock IP range
  futex: Add support for unlocking robust futexes
  futex: Cleanup UAPI defines
  x86: Select ARCH_MEMORY_ORDER_TSO
  uaccess: Provide unsafe_atomic_store_release_user()
  futex: Provide UABI defines for robust list entry modifiers
  futex: Move futex related mm_struct data into a struct
  futex: Make futex_mm_init() void
  ...

genirq: Move NULL check into irqdesc_lock guard unlock expression

2026-06-03T09:38:47+00:00

irqdesc_lock uses __DEFINE_UNLOCK_GUARD() directly with a custom
constructor that can set .lock to NULL.

In preparation for removing the NULL check from __DEFINE_UNLOCK_GUARD(),
move the NULL check into the irqdesc_lock unlock expression, making the
NULL handling explicit at the call site.

No functional change.

Signed-off-by: Dmitry Ilvokhin 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Thomas Gleixner 
Link: https://patch.msgid.link/ab457810653e4356e29b2d74ba616478bd9328ad.1780064327.git.d@ilvokhin.com

genirq/proc: Runtime size the chip name

2026-05-26T14:21:15+00:00

The chip name column in the /proc/interrupt output is 8 characters and
right aligned, which causes visual clutter due to the fixed length and the
alignment. Many interrupt chips, e.g. PCI/MSI[X] have way longer names.

Update the length when a chip is assigned to an interrupt and utilize this
information for the output. Align it left so all chip names start at the
begin of the column.

Update the GDB script as well and disentangle the header maze so it
actually works with all .config combinations.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Reviewed-by: Dmitry Ilvokhin 
Link: https://patch.msgid.link/20260517194932.085786035@kernel.org

genirq: Expose irq_find_desc_at_or_after() in core code

2026-05-26T14:21:15+00:00

... in preparation for a smarter iterator for /proc/interrupts.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Reviewed-by: Dmitry Ilvokhin 
Link: https://patch.msgid.link/20260517194932.005787611@kernel.org

genirq: Add rcuref count to struct irq_desc

2026-05-26T14:21:14+00:00

Prepare for a smarter iterator for /proc/interrupts so that the next
interrupt descriptor can be cached after lookup.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Reviewed-by: Dmitry Ilvokhin 
Link: https://patch.msgid.link/20260517194931.917415190@kernel.org

genirq: Calculate precision only when required

2026-05-26T14:21:14+00:00

Calculating the precision of the interrupt number column on every initial
show_interrupt() invocation is a pointless exercise as the underlying
maximum number of interrupts rarely changes.

Calculate it only when that number is modified and let show_interrupts()
use the cached value.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Reviewed-by: Dmitry Ilvokhin 
Reviewed-by: Radu Rendec 
Link: https://patch.msgid.link/20260517194931.760664517@kernel.org

genirq: Cache the condition for /proc/interrupts exposure

2026-05-26T14:21:13+00:00

show_interrupts() evaluates a boatload of conditions to establish whether
it should expose an interrupt in /proc/interrupts or not.

That can be simplified by caching the condition in an internal status flag,
which is updated when one of the relevant inputs changes.

The irq_desc::kstat_irq check is dropped because visible interrupt
descriptors always have a valid pointer.

As a result the number of instructions and branches for reading
/proc/interrupts is reduced significantly.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Reviewed-by: Dmitry Ilvokhin 
Reviewed-by: Radu Rendec 
Link: https://patch.msgid.link/20260517194931.680943749@kernel.org

genirq: Expose nr_irqs in core code

2026-05-26T14:21:13+00:00

... to avoid function calls in the core code to retrieve the maximum number
of interrupts.

Rename it to 'total_nr_irqs' as 'nr_irqs' is too generic and fix up the
'nr_irqs' reference in the related GDB script as well.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Reviewed-by: Dmitry Ilvokhin 
Reviewed-by: Radu Rendec 
Reviewed-by: Shrikanth Hegde 
Link: https://patch.msgid.link/20260517194931.522168332@kernel.org

genirq/cpuhotplug: Notify about affinity changes breaking the affinity mask

2026-01-13T20:18:16+00:00

During CPU offlining the interrupts affined to that CPU are moved to other
online CPUs, which might break the original affinity mask if the outgoing
CPU was the last online CPU in that mask. This change is not propagated to
irq_desc::affinity_notify(), which leaves users of the affinity notifier
mechanism with stale information.

Avoid this by scheduling affinity change notification work for interrupts
that were affined to the CPU being offlined, if the new target CPU is not
part of the original affinity mask.

Since irq_set_affinity_locked() uses the same logic to schedule affinity
change notification work, split out this logic into a dedicated function
and use that at both places.

[ tglx: Removed the EXPORT(), removed the !SMP stub, moved the prototype,
  	added a lockdep assert instead of a comment, fixed up coding style
  	and name space. Polished and clarified the change log ]

Signed-off-by: Imran Khan 
Signed-off-by: Thomas Gleixner 
Link: https://patch.msgid.link/20260113143727.1041265-1-imran.f.khan@oracle.com

genirq: Remove IRQ timing tracking infrastructure

2025-12-15T21:20:50+00:00

The IRQ timing tracking infrastructure was merged in 2019, but was never
plumbed in, is not selectable, and is therefore never used.

As Daniel agrees that there is little hope for this infrastructure to be
completed in the near term, drop it altogether.

Signed-off-by: Marc Zyngier 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Jinjie Ruan 
Link: https://lore.kernel.org/r/87zf7vex6h.wl-maz@kernel.org
Link: https://patch.msgid.link/20251210082242.360936-2-maz@kernel.org