kernel/linux.git/tools/testing/selftests/mm/vm_util.c, branch v7.1

selftests/mm/vm_util: robust write_file()

2026-04-18T07:10:54+00:00

Add three more checks for buflen and numwritten. The buflen should be at least two, that means at least one char and the null-end. The error case check is added by checking numwriten < 0 instead of numwritten < 1. And the truncate case is checked. The test will exit if any of these conditions aren't met. Additionally, add more print information when a write failure occurs or a truncated write happens, providing clearer diagnostics. Link: https://lore.kernel.org/20260402014543.1671131-5-chuhu@redhat.com Signed-off-by: Chunyu Hu Acked-by: David Hildenbrand (Arm) Reviewed-by: Lorenzo Stoakes Cc: Nico Pache Signed-off-by: Andrew Morton

selftests/mm: move write_file helper to vm_util

2026-04-18T07:10:54+00:00

thp_settings provides write_file() helper for safely writing to a file and exit when write failure happens. It's a very low level helper and many sub tests need such a helper, not only thp tests. split_huge_page_test also defines a write_file locally. The two have minior differences in return type and used exit api. And there would be conflicts if split_huge_page_test wanted to include thp_settings.h because of different prototype, making it less convenient. It's possisble to merge the two, although some tests don't use the kselftest infrastrucutre for testing. It would also work when using the ksft_exit_msg() to exit in my test, as the counters are all zero. Output will be like: TAP version 13 1..62 Bail out! /proc/sys/vm/drop_caches1 open failed: No such file or directory # Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0 So here we just keep the version in split_huge_page_test, and move it into the vm_util. This makes it easy to maitain and user could just include one vm_util.h when they don't need thp setting helpers. Keep the prototype of void return as the function will exit on any error, return value is not necessary, and will simply the callers like write_num() and write_string(). Link: https://lore.kernel.org/20260402014543.1671131-4-chuhu@redhat.com Signed-off-by: Chunyu Hu Reviewed-by: Lorenzo Stoakes (Oracle) Acked-by: David Hildenbrand (Arm) Reviewed-by: Zi Yan Acked-by: Mike Rapoport (Microsoft) Suggested-by: Mike Rapoport Cc: Nico Pache Signed-off-by: Andrew Morton

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

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

selftests/mm: pass filename as input param to VM_PFNMAP tests

2025-09-13T23:54:43+00:00

Enable these tests to be run on other pfnmap'ed memory like NVIDIA's EGM. Add '--' as a separator to pass in file path. This allows passing of cmd line arguments to kselftest_harness. Use '/dev/mem' as default filename. Existing test passes: pfnmap TAP version 13 1..6 # Starting 6 tests from 1 test cases. # PASSED: 6 / 6 tests passed. # Totals: pass:6 fail:0 xfail:0 xpass:0 skip:0 error:0 Pass params to kselftest_harness: pfnmap -r pfnmap:mremap_fixed TAP version 13 1..1 # Starting 1 tests from 1 test cases. # RUN pfnmap.mremap_fixed ... # OK pfnmap.mremap_fixed ok 1 pfnmap.mremap_fixed # PASSED: 1 / 1 tests passed. # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0 Pass non-existent file name as input: pfnmap -- /dev/blah TAP version 13 1..6 # Starting 6 tests from 1 test cases. # RUN pfnmap.madvise_disallowed ... # SKIP Cannot open '/dev/blah' Pass non pfnmap'ed file as input: pfnmap -r pfnmap.madvise_disallowed -- randfile.txt TAP version 13 1..1 # Starting 1 tests from 1 test cases. # RUN pfnmap.madvise_disallowed ... # SKIP Invalid file: 'randfile.txt'. Not pfnmap'ed Link: https://lkml.kernel.org/r/20250805013629.47629-1-sudarsanm@google.com Signed-off-by: Sudarsan Mahendran Acked-by: David Hildenbrand Cc: Axel Rasmussen Cc: Shuah Khan Signed-off-by: Andrew Morton