To avoid a memory leak via mm_alloc() + mmdrop() the futex cleanup code
has been moved to __mmdrop(). This resulted in a warnings if the futex
hash table has been allocated via vmalloc() the mmdrop() was invoked
from atomic context.
The free path must stay in __mmput() to ensure it is invoked from
preemptible context.

In order to avoid the memory leak, delay the allocation of
mm_struct::mm->futex_ref to futex_hash_allocate(). This works because
neither the per-CPU counter nor the private hash has been allocated and
therefore
- futex_private_hash() callers (such as exit_pi_state_list()) don't
  acquire reference if there is no private hash yet. There is also no
  reference put.

- Regular callers (futex_hash()) fallback to global hash. No reference
  counting here.

The futex_ref member can be allocated in futex_hash_allocate() before
the private hash itself is allocated. This happens either while the
first thread is created or on request. In both cases the process has
just a single thread so there can be either futex operation in progress
or the request to create a private hash.

Move futex_hash_free() back to __mmput();
Move the allocation of mm_struct::futex_ref to futex_hash_allocate().

  [ bp: Fold a follow-up fix to prevent a use-after-free:
    https://lore.kernel.org/r/20250830213806.sEKuuGSm@linutronix.de ]

Fixes:  e703b7e247503 ("futex: Move futex cleanup to __mmdrop()")
Closes: https://lore.kernel.org/all/20250821102721.6deae493@kernel.org/
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lkml.kernel.org/r/20250822141238.PfnkTjFb@linutronix.de

Pull locking fix from Borislav Petkov:

 - Prevent a futex hash leak due to different mm lifetimes

* tag 'locking_urgent_for_v6.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Move futex cleanup to __mmdrop()

Pull more MM updates from Andrew Morton:
 "Significant patch series in this pull request:

   - "mseal cleanups" (Lorenzo Stoakes)

     Some mseal cleaning with no intended functional change.

   - "Optimizations for khugepaged" (David Hildenbrand)

     Improve khugepaged throughput by batching PTE operations for large
     folios. This gain is mainly for arm64.

   - "x86: enable EXECMEM_ROX_CACHE for ftrace and kprobes" (Mike Rapoport)

     A bugfix, additional debug code and cleanups to the execmem code.

   - "mm/shmem, swap: bugfix and improvement of mTHP swap in" (Kairui Song)

     Bugfixes, cleanups and performance improvememnts to the mTHP swapin
     code"

* tag 'mm-stable-2025-08-03-12-35' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (38 commits)
  mm: mempool: fix crash in mempool_free() for zero-minimum pools
  mm: correct type for vmalloc vm_flags fields
  mm/shmem, swap: fix major fault counting
  mm/shmem, swap: rework swap entry and index calculation for large swapin
  mm/shmem, swap: simplify swapin path and result handling
  mm/shmem, swap: never use swap cache and readahead for SWP_SYNCHRONOUS_IO
  mm/shmem, swap: tidy up swap entry splitting
  mm/shmem, swap: tidy up THP swapin checks
  mm/shmem, swap: avoid redundant Xarray lookup during swapin
  x86/ftrace: enable EXECMEM_ROX_CACHE for ftrace allocations
  x86/kprobes: enable EXECMEM_ROX_CACHE for kprobes allocations
  execmem: drop writable parameter from execmem_fill_trapping_insns()
  execmem: add fallback for failures in vmalloc(VM_ALLOW_HUGE_VMAP)
  execmem: move execmem_force_rw() and execmem_restore_rox() before use
  execmem: rework execmem_cache_free()
  execmem: introduce execmem_alloc_rw()
  execmem: drop unused execmem_update_copy()
  mm: fix a UAF when vma->mm is freed after vma->vm_refcnt got dropped
  mm/rmap: add anon_vma lifetime debug check
  mm: remove mm/io-mapping.c
  ...

Pull non-MM updates from Andrew Morton:
 "Significant patch series in this pull request:

   - "squashfs: Remove page->mapping references" (Matthew Wilcox) gets
     us closer to being able to remove page->mapping

   - "relayfs: misc changes" (Jason Xing) does some maintenance and
     minor feature addition work in relayfs

   - "kdump: crashkernel reservation from CMA" (Jiri Bohac) switches
     us from static preallocation of the kdump crashkernel's working
     memory over to dynamic allocation. So the difficulty of a-priori
     estimation of the second kernel's needs is removed and the first
     kernel obtains extra memory

   - "generalize panic_print's dump function to be used by other
     kernel parts" (Feng Tang) implements some consolidation and
     rationalization of the various ways in which a failing kernel
     splats information at the operator

* tag 'mm-nonmm-stable-2025-08-03-12-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (80 commits)
  tools/getdelays: add backward compatibility for taskstats version
  kho: add test for kexec handover
  delaytop: enhance error logging and add PSI feature description
  samples: Kconfig: fix spelling mistake "instancess" -> "instances"
  fat: fix too many log in fat_chain_add()
  scripts/spelling.txt: add notifer||notifier to spelling.txt
  xen/xenbus: fix typo "notifer"
  net: mvneta: fix typo "notifer"
  drm/xe: fix typo "notifer"
  cxl: mce: fix typo "notifer"
  KVM: x86: fix typo "notifer"
  MAINTAINERS: add maintainers for delaytop
  ucount: use atomic_long_try_cmpxchg() in atomic_long_inc_below()
  ucount: fix atomic_long_inc_below() argument type
  kexec: enable CMA based contiguous allocation
  stackdepot: make max number of pools boot-time configurable
  lib/xxhash: remove unused functions
  init/Kconfig: restore CONFIG_BROKEN help text
  lib/raid6: update recov_rvv.c zero page usage
  docs: update docs after introducing delaytop
  ...

Enhance the debugging information in check_mm() by including the process
name and PID when reporting bad rss-counter states.  This helps identify
which process is associated with the memory accounting issue.

Link: https://lkml.kernel.org/r/20250723100901.1909683-1-liuqiye2025@163.com
Signed-off-by: Xuanye Liu <liuqiye2025@163.com>
Acked-by: SeongJae Park <sj@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Futex hash allocations are done in mm_init() and the cleanup happens in
__mmput(). That works most of the time, but there are mm instances which
are instantiated via mm_alloc() and freed via mmdrop(), which causes the
futex hash to be leaked.

Move the cleanup to __mmdrop().

Fixes: 56180dd20c19 ("futex: Use RCU-based per-CPU reference counting instead of rcuref_t")
Reported-by: André Draszik <andre.draszik@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: André Draszik <andre.draszik@linaro.org>
Link: https://lore.kernel.org/all/87ldo5ihu0.ffs@tglx
Closes: https://lore.kernel.org/all/0c8cc83bb73abf080faf584f319008b67d0931db.camel@linaro.org

Pull initial deferred unwind infrastructure from Steven Rostedt:
 "This is the core infrastructure for the deferred unwinder that is
  required for sframes[1]. Several other patch series are based on this
  work although those patch series are not dependent on each other. In
  order to simplify the development, having this core series upstream
  will allow the other series to be worked on in parallel. The other
  series are:

    - The two patches to implement x86 support [2] [3]

    - The s390 work [4]

    - The perf work [5]

    - The ftrace work [6]

    - The sframe work [7]

  And more is on the way.

  The core infrastructure adds the following in kernel APIs:

    - int unwind_user_faultable(struct unwind_stacktrace *trace);

        Performs a user space stack trace that may fault user pages in.

    - int unwind_deferred_init(struct unwind_work *work, unwind_callback_t func);

        Allows a tracer to register with the unwind deferred
        infrastructure.

    - int unwind_deferred_request(struct unwind_work *work, u64 *cookie);

        Used when a tracer request a deferred trace. Can be called from
        interrupt or NMI context.

    - void unwind_deferred_cancel(struct unwind_work *work);

        Called by a tracer to unregister from the deferred unwind
        infrastructure.

    - void unwind_deferred_task_exit(struct task_struct *task);

        Called by task exit code to flush any pending unwind requests.

    - void unwind_task_init(struct task_struct *task);

        Called by do_fork() to initialize the task struct for the
        deferred unwinder.

    - void unwind_task_free(struct task_struct *task);

        Called by do_exit() to free up any resources used by the
        deferred unwinder.

    None of the above is actually compiled unless an architecture enables it,
    which none currently do"

Link: https://sourceware.org/binutils/wiki/sframe [1]
Link: https://lore.kernel.org/linux-trace-kernel/20250717004958.260781923@kernel.org/ [2]
Link: https://lore.kernel.org/linux-trace-kernel/20250717004958.432327787@kernel.org/ [3]
Link: https://lore.kernel.org/linux-trace-kernel/20250710163522.3195293-1-jremus@linux.ibm.com/ [4]
Link: https://lore.kernel.org/linux-trace-kernel/20250718164119.089692174@kernel.org/ [5]
Link: https://lore.kernel.org/linux-trace-kernel/20250424192612.505622711@goodmis.org/ [6]
Link: https://lore.kernel.org/linux-trace-kernel/20250717012848.927473176@kernel.org/ [7]

* tag 'trace-deferred-unwind-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  unwind: Finish up unwind when a task exits
  unwind deferred: Use SRCU unwind_deferred_task_work()
  unwind: Add USED bit to only have one conditional on way back to user space
  unwind deferred: Add unwind_completed mask to stop spurious callbacks
  unwind deferred: Use bitmask to determine which callbacks to call
  unwind_user/deferred: Make unwind deferral requests NMI-safe
  unwind_user/deferred: Add deferred unwinding interface
  unwind_user/deferred: Add unwind cache
  unwind_user/deferred: Add unwind_user_faultable()
  unwind_user: Add user space unwinding API with frame pointer support

Pull runtime verification updates from Steven Rostedt:

 - Added Linear temporal logic monitors for RT application

   Real-time applications may have design flaws causing them to have
   unexpected latency. For example, the applications may raise page
   faults, or may be blocked trying to take a mutex without priority
   inheritance.

   However, while attempting to implement DA monitors for these
   real-time rules, deterministic automaton is found to be inappropriate
   as the specification language. The automaton is complicated, hard to
   understand, and error-prone.

   For these cases, linear temporal logic is found to be more suitable.
   The LTL is more concise and intuitive.

 - Make printk_deferred() public

   The new monitors needed access to printk_deferred(). Make them
   visible for the entire kernel.

 - Add a vpanic() to allow for va_list to be passed to panic.

 - Add rtapp container monitor.

   A collection of monitors that check for common problems with
   real-time applications that cause unexpected latency.

 - Add page fault tracepoints to risc-v

   These tracepoints are necessary to for the RV monitor to run on
   risc-v.

 - Fix the behaviour of the rv tool with -s and idle tasks.

 - Allow the rv tool to gracefully terminate with SIGTERM

 - Adjusts dot2c not to create lines over 100 columns

 - Properly order nested monitors in the RV Kconfig file

 - Return the registration error in all DA monitor instead of 0

 - Update and add new sched collection monitors

   Replace tss and sncid monitors with more complete sts:

   Not only prove that switches occur in scheduling context and scheduling
   needs interrupt disabled but also that each call to the scheduler
   disables interrupts to (optionally) switch.

   New monitor: nrp
     Preemption requires need resched which is cleared by any switch
     (includes a non optimal workaround for /nested/ preemptions)

   New monitor: sssw
     suspension requires setting the task to sleepable and, after the
     switch occurs, the task requires a wakeup to come back to runnable

   New monitor: opid
      waking and need-resched operations occur with interrupts and
      preemption disabled or in IRQ without explicitly disabling
      preemption"

* tag 'trace-rv-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (48 commits)
  rv: Add opid per-cpu monitor
  rv: Add nrp and sssw per-task monitors
  rv: Replace tss and sncid monitors with more complete sts
  sched: Adapt sched tracepoints for RV task model
  rv: Retry when da monitor detects race conditions
  rv: Adjust monitor dependencies
  rv: Use strings in da monitors tracepoints
  rv: Remove trailing whitespace from tracepoint string
  rv: Add da_handle_start_run_event_ to per-task monitors
  rv: Fix wrong type cast in reactors_show() and monitor_reactor_show()
  rv: Fix wrong type cast in monitors_show()
  rv: Remove struct rv_monitor::reacting
  rv: Remove rv_reactor's reference counter
  rv: Merge struct rv_reactor_def into struct rv_reactor
  rv: Merge struct rv_monitor_def into struct rv_monitor
  rv: Remove unused field in struct rv_monitor_def
  rv: Return init error when registering monitors
  verification/rvgen: Organise Kconfig entries for nested monitors
  tools/dot2c: Fix generated files going over 100 column limit
  tools/rv: Stop gracefully also on SIGTERM
  ...

Pull sysctl updates from Joel Granados:

 - Move sysctls out of the kern_table array

   This is the final move of ctl_tables into their respective
   subsystems. Only 5 (out of the original 50) will remain in
   kernel/sysctl.c file; these handle either sysctl or common arch
   variables.

   By decentralizing sysctl registrations, subsystem maintainers regain
   control over their sysctl interfaces, improving maintainability and
   reducing the likelihood of merge conflicts.

 - docs: Remove false positives from check-sysctl-docs

   Stopped falsely identifying sysctls as undocumented or unimplemented
   in the check-sysctl-docs script. This script can now be used to
   automatically identify if documentation is missing.

* tag 'sysctl-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl: (23 commits)
  docs: Downgrade arm64 & riscv from titles to comment
  docs: Replace spaces with tabs in check-sysctl-docs
  docs: Remove colon from ctltable title in vm.rst
  docs: Add awk section for ucount sysctl entries
  docs: Use skiplist when checking sysctl admin-guide
  docs: nixify check-sysctl-docs
  sysctl: rename kern_table -> sysctl_subsys_table
  kernel/sys.c: Move overflow{uid,gid} sysctl into kernel/sys.c
  uevent: mv uevent_helper into kobject_uevent.c
  sysctl: Removed unused variable
  sysctl: Nixify sysctl.sh
  sysctl: Remove superfluous includes from kernel/sysctl.c
  sysctl: Remove (very) old file changelog
  sysctl: Move sysctl_panic_on_stackoverflow to kernel/panic.c
  sysctl: move cad_pid into kernel/pid.c
  sysctl: Move tainted ctl_table into kernel/panic.c
  Input: sysrq: mv sysrq into drivers/tty/sysrq.c
  fork: mv threads-max into kernel/fork.c
  parisc/power: Move soft-power into power.c
  mm: move randomize_va_space into memory.c
  ...

Pull scheduler updates from Ingo Molnar:
 "Core scheduler changes:

   - Better tracking of maximum lag of tasks in presence of different
     slices duration, for better handling of lag in the fair scheduler
     (Vincent Guittot)

   - Clean up and standardize #if/#else/#endif markers throughout the
     entire scheduler code base (Ingo Molnar)

   - Make SMP unconditional: build the SMP scheduler's data structures
     and logic on UP kernel too, even though they are not used, to
     simplify the scheduler and remove around 200 #ifdef/[#else]/#endif
     blocks from the scheduler (Ingo Molnar)

   - Reorganize cgroup bandwidth control interface handling for better
     interfacing with sched_ext (Tejun Heo)

  Balancing:

   - Bump sd->max_newidle_lb_cost when newidle balance fails (Chris
     Mason)

   - Remove sched_domain_topology_level::flags to simplify the code
     (Prateek Nayak)

   - Simplify and clean up build_sched_topology() (Li Chen)

   - Optimize build_sched_topology() on large machines (Li Chen)

  Real-time scheduling:

   - Add initial version of proxy execution: a mechanism for
     mutex-owning tasks to inherit the scheduling context of higher
     priority waiters.

     Currently limited to a single runqueue and conditional on
     CONFIG_EXPERT, and other limitations (John Stultz, Peter Zijlstra,
     Valentin Schneider)

   - Deadline scheduler (Juri Lelli):
      - Fix dl_servers initialization order (Juri Lelli)
      - Fix DL scheduler's root domain reinitialization logic (Juri
        Lelli)
      - Fix accounting bugs after global limits change (Juri Lelli)
      - Fix scalability regression by implementing less agressive
        dl_server handling (Peter Zijlstra)

  PSI:

   - Improve scalability by optimizing psi_group_change() cpu_clock()
     usage (Peter Zijlstra)

  Rust changes:

   - Make Task, CondVar and PollCondVar methods inline to avoid
     unnecessary function calls (Kunwu Chan, Panagiotis Foliadis)

   - Add might_sleep() support for Rust code: Rust's "#[track_caller]"
     mechanism is used so that Rust's might_sleep() doesn't need to be
     defined as a macro (Fujita Tomonori)

   - Introduce file_from_location() (Boqun Feng)

  Debugging & instrumentation:

   - Make clangd usable with scheduler source code files again (Peter
     Zijlstra)

   - tools: Add root_domains_dump.py which dumps root domains info (Juri
     Lelli)

   - tools: Add dl_bw_dump.py for printing bandwidth accounting info
     (Juri Lelli)

  Misc cleanups & fixes:

   - Remove play_idle() (Feng Lee)

   - Fix check_preemption_disabled() (Sebastian Andrzej Siewior)

   - Do not call __put_task_struct() on RT if pi_blocked_on is set (Luis
     Claudio R. Goncalves)

   - Correct the comment in place_entity() (wang wei)"

* tag 'sched-core-2025-07-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (84 commits)
  sched/idle: Remove play_idle()
  sched: Do not call __put_task_struct() on rt if pi_blocked_on is set
  sched: Start blocked_on chain processing in find_proxy_task()
  sched: Fix proxy/current (push,pull)ability
  sched: Add an initial sketch of the find_proxy_task() function
  sched: Fix runtime accounting w/ split exec & sched contexts
  sched: Move update_curr_task logic into update_curr_se
  locking/mutex: Add p->blocked_on wrappers for correctness checks
  locking/mutex: Rework task_struct::blocked_on
  sched: Add CONFIG_SCHED_PROXY_EXEC & boot argument to enable/disable
  sched/topology: Remove sched_domain_topology_level::flags
  x86/smpboot: avoid SMT domain attach/destroy if SMT is not enabled
  x86/smpboot: moves x86_topology to static initialize and truncate
  x86/smpboot: remove redundant CONFIG_SCHED_SMT
  smpboot: introduce SDTL_INIT() helper to tidy sched topology setup
  tools/sched: Add dl_bw_dump.py for printing bandwidth accounting info
  tools/sched: Add root_domains_dump.py which dumps root domains info
  sched/deadline: Fix accounting after global limits change
  sched/deadline: Reset extra_bw to max_bw when clearing root domains
  sched/deadline: Initialize dl_servers after SMP
  ...