linux-stable.git/include/linux/uaccess.h, branch v7.1.5

uaccess: minimize INLINE_COPY_USER-related ifdefery

2026-07-24T14:19:24+00:00

[ Upstream commit bd99fcfc6219ebe36ae4d0bf5333b5ecc17b53df ]

Now that we've got the same config selecting inline vs outline
copy_to_user() and copy_from_user(), we can simplify the corresponding
logic in the uaccess.h.

Link: https://lore.kernel.org/20260425020857.356850-4-ynorov@nvidia.com
Fixes: 1f9a8286bc0c ("uaccess: always export _copy_[from|to]_user with CONFIG_RUST")
Signed-off-by: Yury Norov 
Tested-by: Alice Ryhl 
Cc: Arnd Bergmann 
Cc: Christophe Leroy (CS GROUP) 
Cc: Mathieu Desnoyers 
Cc: Peter Zijlstra 
Cc: Randy Dunlap 
Cc: Viktor Malik 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

uaccess: unify inline vs outline copy_{from,to}_user() selection

2026-07-24T14:19:23+00:00

[ Upstream commit c02be2ad2b88c67c5d7c06b6aa7083b5b40e1077 ]

The kernel allows arches to select between inline and outline
implementations of the copy_{from,to}_user() by defining individual
INLINE_COPY_FROM_USER and INLINE_COPY_TO_USER, correspondingly.  However,
all arches enable or disable them always together.

Without the real use-case for one helper being inlined while the other
outlined, having independent controls is excessive and error prone.

Switch the codebase to the single unified INLINE_COPY_USER control.

Link: https://lore.kernel.org/20260425020857.356850-3-ynorov@nvidia.com
Signed-off-by: Yury Norov 
Tested-by: Alice Ryhl 
Cc: Arnd Bergmann 
Cc: Christophe Leroy (CS GROUP) 
Cc: Mathieu Desnoyers 
Cc: Peter Zijlstra 
Cc: Randy Dunlap 
Cc: Viktor Malik 
Signed-off-by: Andrew Morton 
Stable-dep-of: bd99fcfc6219 ("uaccess: minimize INLINE_COPY_USER-related ifdefery")
Signed-off-by: Sasha Levin

uaccess: fix ignored_trailing logic in copy_struct_to_user()

2026-07-24T14:19:11+00:00

[ Upstream commit 4911de3145a797389577abfdf9a5185d36cc18d7 ]

Currently all callers pass ignored_trailing=NULL, but I have
code that will make use of.

Now it actually behaves like documented:

* If @usize < @ksize, then the kernel is trying to pass userspace a newer
  struct than it supports. Thus we only copy the interoperable portions
  (@usize) and ignore the rest (but @ignored_trailing is set to %true if
  any of the trailing (@ksize - @usize) bytes are non-zero).

Fixes: 424a55a4a908 ("uaccess: add copy_struct_to_user helper")
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Dmitry Safonov 
Cc: Francesco Ruggeri 
Cc: Salam Noureddine 
Cc: David Ahern 
Cc: David S. Miller 
Cc: Michal Luczaj 
Cc: David Wei 
Cc: Luiz Augusto von Dentz 
Cc: Luiz Augusto von Dentz 
Cc: Marcel Holtmann 
Cc: Xin Long 
Cc: Eric Dumazet 
Cc: Kuniyuki Iwashima 
Cc: Paolo Abeni 
Cc: Willem de Bruijn 
Cc: Neal Cardwell 
Cc: Jakub Kicinski 
Cc: Simon Horman 
Cc: Aleksa Sarai 
Cc: Christian Brauner 
CC: Kees Cook 
Cc: netdev@vger.kernel.org
Cc: linux-bluetooth@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Stefan Metzmacher 
Link: https://patch.msgid.link/71f69442410c1186ed8ce6d5b4b9d4a5a70edbad.1775576651.git.metze@samba.org
Reviewed-by: Aleksa Sarai 
Signed-off-by: Christian Brauner 
Signed-off-by: Sasha Levin

Merge branch 'nocache-cleanup'

2026-04-13T15:39:51+00:00

This series cleans up some of the special user copy functions naming and
semantics.  In particular, get rid of the (very traditional) double
underscore names and behavior: the whole "optimize away the range check"
model has been largely excised from the other user accessors because
it's so subtle and can be unsafe, but also because it's just not a
relevant optimization any more.

To do that, a couple of drivers that misused the "user" copies as kernel
copies in order to get non-temporal stores had to be fixed up, but that
kind of code should never have been allowed anyway.

The x86-only "nocache" version was also renamed to more accurately
reflect what it actually does.

This was all done because I looked at this code due to a report by Jann
Horn, and I just couldn't stand the inconsistent naming, the horrible
semantics, and the random misuse of these functions.  This code should
probably be cleaned up further, but it's at least slightly closer to
normal semantics.

I had a more intrusive series that went even further in trying to
normalize the semantics, but that ended up hitting so many other
inconsistencies between different architectures in this area (eg
'size_t' vs 'unsigned long' vs 'int' as size arguments, and various
iovec check differences that Vasily Gorbik pointed out) that I ended up
with this more limited version that fixed the worst of the issues.

Reported-by: Jann Horn 
Tested-by: Will Deacon 
Link: https://lore.kernel.org/all/CAHk-=wgg1QVWNWG-UCFo1hx0zqrPnB3qhPzUTrWNft+MtXQXig@mail.gmail.com/

* nocache-cleanup:
  x86-64/arm64/powerpc: clean up and rename __copy_from_user_flushcache
  x86: rename and clean up __copy_from_user_inatomic_nocache()
  x86-64: rename misleadingly named '__copy_user_nocache()' function

x86: rename and clean up __copy_from_user_inatomic_nocache()

2026-03-30T22:05:57+00:00

Similarly to the previous commit, this renames the somewhat confusingly
named function.  But in this case, it was at least less confusing: the
__copy_from_user_inatomic_nocache is indeed copying from user memory,
and it is indeed ok to be used in an atomic context, so it will not warn
about it.

But the previous commit also removed the NTB mis-use of the
__copy_from_user_inatomic_nocache() function, and as a result every
call-site is now _actually_ doing a real user copy.  That means that we
can now do the proper user pointer verification too.

End result: add proper address checking, remove the double underscores,
and change the "nocache" to "nontemporal" to more accurately describe
what this x86-only function actually does.  It might be worth noting
that only the target is non-temporal: the actual user accesses are
normal memory accesses.

Also worth noting is that non-x86 targets (and on older 32-bit x86 CPU's
before XMM2 in the Pentium III) we end up just falling back on a regular
user copy, so nothing can actually depend on the non-temporal semantics,
but that has always been true.

Signed-off-by: Linus Torvalds

Merge tag 'mm-hotfixes-stable-2026-03-09-16-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-03-10T19:47:56+00:00

Pull misc fixes from Andrew Morton:
 "15 hotfixes. 6 are cc:stable. 14 are for MM.

  Singletons, with one doubleton - please see the changelogs for details"

* tag 'mm-hotfixes-stable-2026-03-09-16-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  MAINTAINERS, mailmap: update email address for Lorenzo Stoakes
  mm/mmu_notifier: clean up mmu_notifier.h kernel-doc
  uaccess: correct kernel-doc parameter format
  mm/huge_memory: fix a folio_split() race condition with folio_try_get()
  MAINTAINERS: add co-maintainer and reviewer for SLAB ALLOCATOR
  MAINTAINERS: add RELAY entry
  memcg: fix slab accounting in refill_obj_stock() trylock path
  mm/hugetlb.c: use __pa() instead of virt_to_phys() in early bootmem alloc code
  zram: rename writeback_compressed device attr
  tools/testing: fix testing/vma and testing/radix-tree build
  Revert "ptdesc: remove references to folios from __pagetable_ctor() and pagetable_dtor()"
  mm/cma: move put_page_testzero() out of VM_WARN_ON in cma_release()
  mm/damon/core: clear walk_control on inactive context in damos_walk()
  mm: memfd_luo: always dirty all folios
  mm: memfd_luo: always make all folios uptodate

uaccess: correct kernel-doc parameter format

2026-03-04T17:44:24+00:00

Use the correct kernel-doc function parameter format to avoid kernel-doc
warnings:

Warning: include/linux/uaccess.h:814 function parameter 'uptr' not
 described in 'scoped_user_rw_access_size'
Warning: include/linux/uaccess.h:826 function parameter 'uptr' not
 described in 'scoped_user_rw_access'

Link: https://lkml.kernel.org/r/20260302005229.3471955-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap 
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton

uaccess: Fix scoped_user_read_access() for 'pointer to const'

2026-03-02T17:24:32+00:00

If a 'const struct foo __user *ptr' is used for the address passed to
scoped_user_read_access() then you get a warning/error

  uaccess.h:691:1: error: initialization discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]

for the

  void __user *_tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl)

assignment.

Fix by using 'auto' for both _tmpptr and the redeclaration of uptr.
Replace the CLASS() with explicit __cleanup() functions on uptr.

Fixes: e497310b4ffb ("uaccess: Provide scoped user access regions")
Signed-off-by: David Laight 
Reviewed-and-tested-by: Christophe Leroy (CS GROUP) 
Signed-off-by: Linus Torvalds

Merge tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-12-06T22:01:20+00:00

Pull non-MM updates from Andrew Morton:

 - "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko)
   fixes a build issue and does some cleanup in ib/sys_info.c

 - "Implement mul_u64_u64_div_u64_roundup()" (David Laight)
   enhances the 64-bit math code on behalf of a PWM driver and beefs up
   the test module for these library functions

 - "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich)
   makes BPF symbol names, sizes, and line numbers available to the GDB
   debugger

 - "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang)
   adds a sysctl which can be used to cause additional info dumping when
   the hung-task and lockup detectors fire

 - "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu)
   adds a general base64 encoder/decoder to lib/ and migrates several
   users away from their private implementations

 - "rbree: inline rb_first() and rb_last()" (Eric Dumazet)
   makes TCP a little faster

 - "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin)
   reworks the KEXEC Handover interfaces in preparation for Live Update
   Orchestrator (LUO), and possibly for other future clients

 - "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin)
   increases the flexibility of KEXEC Handover. Also preparation for LUO

 - "Live Update Orchestrator" (Pasha Tatashin)
   is a major new feature targeted at cloud environments. Quoting the
   cover letter:

      This series introduces the Live Update Orchestrator, a kernel
      subsystem designed to facilitate live kernel updates using a
      kexec-based reboot. This capability is critical for cloud
      environments, allowing hypervisors to be updated with minimal
      downtime for running virtual machines. LUO achieves this by
      preserving the state of selected resources, such as memory,
      devices and their dependencies, across the kernel transition.

      As a key feature, this series includes support for preserving
      memfd file descriptors, which allows critical in-memory data, such
      as guest RAM or any other large memory region, to be maintained in
      RAM across the kexec reboot.

   Mike Rappaport merits a mention here, for his extensive review and
   testing work.

 - "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain)
   moves the kexec and kdump sysfs entries from /sys/kernel/ to
   /sys/kernel/kexec/ and adds back-compatibility symlinks which can
   hopefully be removed one day

 - "kho: fixes for vmalloc restoration" (Mike Rapoport)
   fixes a BUG which was being hit during KHO restoration of vmalloc()
   regions

* tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits)
  calibrate: update header inclusion
  Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()"
  vmcoreinfo: track and log recoverable hardware errors
  kho: fix restoring of contiguous ranges of order-0 pages
  kho: kho_restore_vmalloc: fix initialization of pages array
  MAINTAINERS: TPM DEVICE DRIVER: update the W-tag
  init: replace simple_strtoul with kstrtoul to improve lpj_setup
  KHO: fix boot failure due to kmemleak access to non-PRESENT pages
  Documentation/ABI: new kexec and kdump sysfs interface
  Documentation/ABI: mark old kexec sysfs deprecated
  kexec: move sysfs entries to /sys/kernel/kexec
  test_kho: always print restore status
  kho: free chunks using free_page() instead of kfree()
  selftests/liveupdate: add kexec test for multiple and empty sessions
  selftests/liveupdate: add simple kexec-based selftest for LUO
  selftests/liveupdate: add userspace API selftests
  docs: add documentation for memfd preservation via LUO
  mm: memfd_luo: allow preserving memfd
  liveupdate: luo_file: add private argument to store runtime state
  mm: shmem: export some functions to internal.h
  ...

uaccess: gate _copy_[to|from]_user on !INLINE_COPY_FROM_USER

2025-11-20T22:03:44+00:00

These methods only exist when INLINE_COPY_FROM_USER is disabled, so update
the header file to reflect that.

This fixes the following error on builds that enable both RUST and
INLINE_COPY_FROM_USER.

ERROR: modpost: "_copy_from_user" [samples/rust/rust_misc_device.ko] undefined!
ERROR: modpost: "_copy_to_user" [samples/rust/rust_misc_device.ko] undefined!

This error is triggered because when a method is available both as a
rust_helper_* and normal method, Rust will call the normal method.

[akpm@linux-foundation.org: s/INLINE_COPY_FROM_USER/INLINE_COPY_TO_USER/, per Alice]
Link: https://lkml.kernel.org/r/20251118173250.2821388-1-aliceryhl@google.com
Fixes: d99dc586ca7c ("uaccess: decouple INLINE_COPY_FROM_USER and CONFIG_RUST")
Signed-off-by: Alice Ryhl 
Cc: Alex Gaynor 
Cc: Andreas Hindborg 
Cc: Arnd Bergmann 
Cc: Björn Roy Baron 
Cc: Boqun Feng 
Cc: Danilo Krummrich 
Cc: Gary Guo 
Cc: John Hubbard 
Cc: Miguel Ojeda 
Cc: Trevor Gross 
Cc: Yury Norov (NVIDIA) 
Signed-off-by: Andrew Morton