linux-stable.git/tools/testing/selftests/mm/vm_util.h, branch linux-rolling-stable

selftests/mm: add memory failure anonymous page test

2026-02-12T23:43:01+00:00

Patch series "selftests/mm: add memory failure selftests", v4.

Introduce selftests to validate the functionality of memory failure. 
These tests help ensure that memory failure handling for anonymous pages,
pagecaches pages works correctly, including proper SIGBUS delivery to user
processes, page isolation, and recovery paths.

Currently madvise syscall is used to inject memory failures.  And only
anonymous pages and pagecaches are tested.  More test scenarios, e.g. 
hugetlb, shmem, thp, will be added.  Also more memory failure injecting
methods will be supported, e.g.  APEI Error INJection, if required.


This patch (of 3):

This patch adds a new kselftest to validate memory failure handling for
anonymous pages. The test performs the following operations:
1. Allocates anonymous pages using mmap().
2. Injects memory failure via madvise syscall.
3. Verifies expected error handling behavior.
4. Unpoison memory.

This test helps ensure that memory failure handling for anonymous pages
works correctly, including proper SIGBUS delivery to user processes, page
isolation and recovery paths.

Link: https://lkml.kernel.org/r/20260206031639.2707102-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20260206031639.2707102-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: David Hildenbrand 
Cc: Liam Howlett 
Cc: Lorenzo Stoakes 
Cc: Mark Brown 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Naoya Horiguchi 
Cc: Shuah Khan 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Cc: kernel test robot 
Signed-off-by: Andrew Morton

selftests/mm: introduce helper to read every page

2026-01-31T22:22:41+00:00

FORCE_READ(*addr) ensures that the compiler will emit a load from addr. 
Several tests need to trigger such a load for a range of pages, ensuring
that every page is faulted in, if it wasn't already.

Introduce a new helper force_read_pages() that does exactly that and
replace existing loops with a call to it.

The step size (regular/huge page size) is preserved for all loops, except
in split_huge_page_test.  Reading every byte is unnecessary; we now read
every huge page, matching the following call to check_huge_file().

Link: https://lkml.kernel.org/r/20260122170224.4056513-7-kevin.brodsky@arm.com
Signed-off-by: Kevin Brodsky 
Reviewed-by: Dev Jain 
Reviewed-by: Muhammad Usama Anjum 
Acked-by: David Hildenbrand (Red Hat) 
Cc: Jason Gunthorpe 
Cc: John Hubbard 
Cc: Lorenzo Stoakes 
Cc: Mark Brown 
Cc: Paolo Abeni 
Cc: Ryan Roberts 
Cc: SeongJae Park 
Cc: Shuah Khan 
Cc: wang lian 
Cc: Yunsheng Lin 
Signed-off-by: Andrew Morton

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
  ...

selftests: complete kselftest include centralization

2025-11-27T22:24:31+00:00

This follow-up patch completes centralization of kselftest.h and
ksefltest_harness.h includes in remaining seltests files, replacing all
relative paths with a non-relative paths using shared -I include path in
lib.mk

Tested with gcc-13.3 and clang-18.1, and cross-compiled successfully on
riscv, arm64, x86_64 and powerpc arch.

[reddybalavignesh9979@gmail.com: add selftests include path for kselftest.h]
  Link: https://lkml.kernel.org/r/20251017090201.317521-1-reddybalavignesh9979@gmail.com
Link: https://lkml.kernel.org/r/20251016104409.68985-1-reddybalavignesh9979@gmail.com
Signed-off-by: Bala-Vignesh-Reddy 
Suggested-by: Andrew Morton 
Link: https://lore.kernel.org/lkml/20250820143954.33d95635e504e94df01930d0@linux-foundation.org/
Reviewed-by: Wei Yang 
Cc: David Hildenbrand 
Cc: David S. Miller 
Cc: Eric Dumazet 
Cc: Günther Noack 
Cc: Jakub Kacinski 
Cc: Liam Howlett 
Cc: Lorenzo Stoakes 
Cc: Michal Hocko 
Cc: Mickael Salaun 
Cc: Ming Lei 
Cc: Paolo Abeni 
Cc: Shuah Khan 
Cc: Simon Horman 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

tools/testing/selftests/mm: add smaps visibility guard region test

2025-11-20T21:43:58+00:00

Assert that we observe guard regions appearing in /proc/$pid/smaps as
expected, and when split/merge is performed too (with expected sticky
behaviour).

Also add handling for file systems which don't sanely handle mmap() VMA
merging so we don't incorrectly encounter a test failure in this
situation.

Link: https://lkml.kernel.org/r/059e62b8c67e55e6d849878206a95ea1d7c1e885.1763460113.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes 
Cc: Andrei Vagin 
Cc: Baolin Wang 
Cc: Barry Song 
Cc: David Hildenbrand (Red Hat) 
Cc: Dev Jain 
Cc: Jann Horn 
Cc: Jonathan Corbet 
Cc: Lance Yang 
Cc: Liam Howlett 
Cc: "Masami Hiramatsu (Google)" 
Cc: Mathieu Desnoyers 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Nico Pache 
Cc: Pedro Falcato 
Cc: Ryan Roberts 
Cc: Steven Rostedt 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

selftests/mm: skip soft-dirty tests when CONFIG_MEM_SOFT_DIRTY is disabled

2025-09-23T21:14:16+00:00

The madv_populate and soft-dirty kselftests currently fail on systems
where CONFIG_MEM_SOFT_DIRTY is disabled.

Introduce a new helper softdirty_supported() into vm_util.c/h to ensure
tests are properly skipped when the feature is not enabled.

Link: https://lkml.kernel.org/r/20250917133137.62802-1-lance.yang@linux.dev
Fixes: 9f3265db6ae8 ("selftests: vm: add test for Soft-Dirty PTE bit")
Signed-off-by: Lance Yang 
Acked-by: David Hildenbrand 
Suggested-by: David Hildenbrand 
Cc: Lorenzo Stoakes 
Cc: Shuah Khan 
Cc: Gabriel Krisman Bertazi 
Cc: 
Signed-off-by: Andrew Morton

selftests/mm: put general ksm operation into vm_util

2025-09-13T23:55:13+00:00

Patch series "test that rmap behaves as expected", v4.

As David suggested, currently we don't have a high level test case to
verify the behavior of rmap. This patch set introduce the verification
on rmap by migration.

Patch 1 is a preparation to move ksm related operations into vm_util.
Patch 2 is the new test case for rmap.

Currently it covers following four scenarios:

  * anonymous page
  * shmem page
  * pagecache page
  * ksm page


This patch (of 2):

There are some general ksm operations could be used by other related
test cases. Put them into vm_util for common use.

This is a preparation patch for later use.

Link: https://lkml.kernel.org/r/20250819080047.10063-1-richard.weiyang@gmail.com
Link: https://lkml.kernel.org/r/20250819080047.10063-2-richard.weiyang@gmail.com
Signed-off-by: Wei Yang 
Suggested-by: David Hildenbrand 
Cc: David Hildenbrand 
Cc: Lorenzo Stoakes 
Cc: Rik van Riel 
Cc: Liam R. Howlett 
Cc: Vlastimil Babka 
Cc: Harry Yoo 
Signed-off-by: Andrew Morton

selftests/mm: reimplement is_backed_by_thp() with more precise check

2025-09-13T23:55:12+00:00

and rename it to is_backed_by_folio().

is_backed_by_folio() checks if the given vaddr is backed a folio with
a given order. It does so by:
1. getting the pfn of the vaddr;
2. checking kpageflags of the pfn;

if order is greater than 0:
3. checking kpageflags of the head pfn;
4. checking kpageflags of all tail pfns.

pmd_order is added to split_huge_page_test.c and replaces max_order.

[ziy@nvidia.com: reduce code duplication, per David]
  Link: https://lkml.kernel.org/r/F54782D6-65A3-4D35-AE03-8ADE636EE258@nvidia.com
Link: https://lkml.kernel.org/r/20250818184622.1521620-4-ziy@nvidia.com
Signed-off-by: Zi Yan 
Reviewed-by: Wei Yang 
Reviewed-by: wang lian 
Acked-by: David Hildenbrand 
Cc: Baolin Wang 
Cc: Barry Song 
Cc: Dev Jain 
Cc: Donet Tom 
Cc: Liam Howlett 
Cc: Lorenzo Stoakes 
Cc: Mariano Pache 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Ryan Roberts 
Cc: Shuah Khan 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

selftest/mm: extract sz2ord function into vm_util.h

2025-09-13T23:55:06+00:00

The function already has 2 uses and will have a 3rd one in prctl
selftests.  The pagesize argument is added into the function, as it's not
a global variable anymore.  No functional change intended with this patch.

Link: https://lkml.kernel.org/r/20250815135549.130506-6-usamaarif642@gmail.com
Suggested-by: David Hildenbrand 
Signed-off-by: Usama Arif 
Reviewed-by: Lorenzo Stoakes 
Reviewed-by: Zi Yan 
Cc: Arnd Bergmann 
Cc: Baolin Wang 
Cc: Barry Song 
Cc: Dev Jain 
Cc: Jann Horn 
Cc: Johannes Weiner 
Cc: Jonathan Corbet 
Cc: Liam Howlett 
Cc: Mariano Pache 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Rik van Riel 
Cc: Ryan Roberts 
Cc: SeongJae Park 
Cc: Shakeel Butt 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Cc: Yafang 
Signed-off-by: Andrew Morton

mm/selftests: fix split_huge_page_test failure on systems with 64KB page size

2025-09-13T23:55:03+00:00

The split_huge_page_test fails on systems with a 64KB base page size. 
This is because the order of a 2MB huge page is different:

On 64KB systems, the order is 5.

On 4KB systems, it's 9.

The test currently assumes a maximum huge page order of 9, which is only
valid for 4KB base page systems.  On systems with 64KB pages, attempting
to split huge pages beyond their actual order (5) causes the test to fail.

In this patch, we calculate the huge page order based on the system's base
page size.  With this change, the tests now run successfully on both 64KB
and 4KB page size systems.

Link: https://lkml.kernel.org/r/20250816040113.760010-5-aboorvad@linux.ibm.com
Fixes: fa6c02315f74 ("mm: huge_memory: a new debugfs interface for splitting THP tests")
Co-developed-by: Aboorva Devarajan 
Signed-off-by: Aboorva Devarajan 
Signed-off-by: Donet Tom 
Reviewed-by: Dev Jain 
Reviewed-by: Zi Yan 
Reviewed-by: Wei Yang 
Cc: Baolin Wang 
Cc: Barry Song 
Cc: David Hildenbrand 
Cc: Liam Howlett 
Cc: Lorenzo Stoakes 
Cc: Mariano Pache 
Cc: "Ritesh Harjani (IBM)" 
Cc: Ryan Roberts 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton