kernel/tools/testing/selftests/mm/ksm_functional_tests.c, branch linux-rolling-stable

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

2025-12-06T22:01:20Z

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

2025-11-27T22:24:31Z

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

selftests: update ksm inheritance tests for prctl fork/exec

2025-11-17T01:27:55Z

To reproduce the issue mentioned by [1], this add a setting of pages_to_scan and sleep_millisecs at the start of test_prctl_fork_exec(). The main change is just raise the scanning frequency of ksmd. [1] https://lore.kernel.org/all/202510012256278259zrhgATlLA2C510DMD3qI@zte.com.cn/ Link: https://lkml.kernel.org/r/20251007182935207jm31wCIgLpZg5XbXQY64S@zte.com.cn Signed-off-by: xu xin Cc: David Hildenbrand Cc: Jinjiang Tu Cc: Stefan Roesch Cc: Wang Yaxin Cc: Yang Yang Signed-off-by: Andrew Morton

selftests/mm: add fork inheritance test for ksm_merging_pages counter

2025-09-28T18:51:32Z

Add a new selftest to verify whether the `ksm_merging_pages` counter in `mm_struct` is not inherited by a child process after fork. This helps ensure correctness of KSM accounting across process creation. Link: https://lkml.kernel.org/r/e7bb17d374133bd31a3e423aa9e46e1122e74971.1758648700.git.donettom@linux.ibm.com Signed-off-by: Donet Tom Acked-by: David Hildenbrand Cc: Aboorva Devarajan Cc: Chengming Zhou Cc: "Ritesh Harjani (IBM)" Cc: Wei Yang Cc: xu xin Signed-off-by: Andrew Morton

selftests/mm: put general ksm operation into vm_util

2025-09-13T23:55:13Z

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: fix child process exit codes in ksm_functional_tests

2025-09-13T23:55:04Z

In ksm_functional_tests, test_child_ksm() returned negative values to indicate errors. However, when passed to exit(), these were interpreted as large unsigned values (e.g, -2 became 254), leading to incorrect handling in the parent process. As a result, some tests appeared to be skipped or silently failed. This patch changes test_child_ksm() to return positive error codes (1, 2, 3) and updates test_child_ksm_err() to interpret them correctly. Additionally, test_prctl_fork_exec() now uses exit(4) after a failed execv() to clearly signal exec failures. This ensures the parent accurately detects and reports child process failures. -------------- Before patch: -------------- - [RUN] test_unmerge ok 1 Pages were unmerged ... - [RUN] test_prctl_fork - No pages got merged - [RUN] test_prctl_fork_exec ok 7 PR_SET_MEMORY_MERGE value is inherited ... Bail out! 1 out of 8 tests failed - Planned tests != run tests (9 != 8) - Totals: pass:7 fail:1 xfail:0 xpass:0 skip:0 error:0 -------------- After patch: -------------- - [RUN] test_unmerge ok 1 Pages were unmerged ... - [RUN] test_prctl_fork - No pages got merged not ok 7 Merge in child failed - [RUN] test_prctl_fork_exec ok 8 PR_SET_MEMORY_MERGE value is inherited ... Bail out! 2 out of 9 tests failed - Totals: pass:7 fail:2 xfail:0 xpass:0 skip:0 error:0 Link: https://lkml.kernel.org/r/20250816040113.760010-6-aboorvad@linux.ibm.com Fixes: 6c47de3be3a0 ("selftest/mm: ksm_functional_tests: extend test case for ksm fork/exec") Co-developed-by: Donet Tom Signed-off-by: Donet Tom Signed-off-by: Aboorva Devarajan Acked-by: David Hildenbrand Reviewed-by: Wei Yang Cc: Baolin Wang Cc: Barry Song Cc: Dev Jain Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Mariano Pache Cc: "Ritesh Harjani (IBM)" Cc: Ryan Roberts Cc: Shuah Khan Cc: Zi Yan Signed-off-by: Andrew Morton

selftest/mm: fix ksm_funtional_test failures

2025-09-13T23:55:03Z

This patch fixes 2 issues. 1) After fork() in test_prctl_fork, the child process uses the file descriptors from the parent process to read ksm_stat and ksm_merging_pages. This results in incorrect values being read (parent process ksm_stat and ksm_merging_pages will be read in child), causing the test to fail. This patch calls init_global_file_handles() in the child process to ensure that the current process's file descriptors are used to read ksm_stat and ksm_merging_pages. 2) All tests currently call ksm_merge to trigger page merging. To ensure the system remains in a consistent state for subsequent tests, it is better to call ksm_unmerge during the test cleanup phase In the test_prctl_fork test, after a fork(), reading ksm_merging_pages in the child process returns a non-zero value because a previous test performed a merge, and the child's memory state is inherited from the parent. Although the child process calls ksm_unmerge, the ksm_merging_pages counter in the parent is reset to zero, while the child's counter remains unchanged. This discrepancy causes the test to fail. To avoid this issue, each test should call ksm_unmerge during cleanup to ensure the counter is reset and the system is in a clean state for subsequent tests. execv argument is an array of pointers to null-terminated strings. In this patch we also added NULL in the execv argument. Link: https://lkml.kernel.org/r/20250816040113.760010-4-aboorvad@linux.ibm.com Fixes: 6c47de3be3a0 ("selftest/mm: ksm_functional_tests: extend test case for ksm fork/exec") Co-developed-by: Aboorva Devarajan Signed-off-by: Aboorva Devarajan Signed-off-by: Donet Tom Reviewed-by: Wei Yang Cc: Baolin Wang Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Mariano Pache Cc: "Ritesh Harjani (IBM)" Cc: Ryan Roberts Cc: Shuah Khan Cc: Zi Yan Signed-off-by: Andrew Morton

selftests/mm: fix UFFDIO_API usage with proper two-step feature negotiation

2025-07-10T05:42:23Z

The current implementation of test_unmerge_uffd_wp() explicitly sets `uffdio_api.features = UFFD_FEATURE_PAGEFAULT_FLAG_WP` before calling UFFDIO_API. This can cause the ioctl() call to fail with EINVAL on kernels that do not support UFFD-WP, leading the test to fail unnecessarily: # ------------------------------ # running ./ksm_functional_tests # ------------------------------ # TAP version 13 # 1..9 # # [RUN] test_unmerge # ok 1 Pages were unmerged # # [RUN] test_unmerge_zero_pages # ok 2 KSM zero pages were unmerged # # [RUN] test_unmerge_discarded # ok 3 Pages were unmerged # # [RUN] test_unmerge_uffd_wp # not ok 4 UFFDIO_API failed <----- # # [RUN] test_prot_none # ok 5 Pages were unmerged # # [RUN] test_prctl # ok 6 Setting/clearing PR_SET_MEMORY_MERGE works # # [RUN] test_prctl_fork # # No pages got merged # # [RUN] test_prctl_fork_exec # ok 7 PR_SET_MEMORY_MERGE value is inherited # # [RUN] test_prctl_unmerge # ok 8 Pages were unmerged # Bail out! 1 out of 8 tests failed # # Planned tests != run tests (9 != 8) # # Totals: pass:7 fail:1 xfail:0 xpass:0 skip:0 error:0 # [FAIL] This patch improves compatibility and robustness of the UFFD-WP test (test_unmerge_uffd_wp) by correctly implementing the UFFDIO_API two-step handshake as recommended by the userfaultfd(2) man page. Key changes: 1. Use features=0 in the initial UFFDIO_API call to query supported feature bits, rather than immediately requesting WP support. 2. Skip the test gracefully if: - UFFDIO_API fails with EINVAL (e.g. unsupported API version), or - UFFD_FEATURE_PAGEFAULT_FLAG_WP is not advertised by the kernel. 3. Close the initial userfaultfd and create a new one before enabling the required feature, since UFFDIO_API can only be called once per fd. 4. Improve diagnostics by distinguishing between expected and unexpected failures, using strerror() to report errors. This ensures the test behaves correctly across a wider range of kernel versions and configurations, while preserving the intended behavior on kernels that support UFFD-WP. [liwang@redhat.com: fail the test if sys_userfaultfd() fails, per David] Link: https://lkml.kernel.org/r/20250625004645.400520-1-liwang@redhat.com Link: https://lkml.kernel.org/r/20250624042411.395285-1-liwang@redhat.com Signed-off-by: Li Wang Suggested-by: David Hildenbrand Acked-by: David Hildenbrand Cc: Aruna Ramakrishna Cc: Bagas Sanjaya Cc: Catalin Marinas Cc: Dave Hansen Cc: Joey Gouly Cc: Johannes Weiner Cc: Keith Lucas Cc: Ryan Roberts Cc: Shuah Khan Cc: Axel Rasmussen Cc: Li Wang Cc: Mike Rapoport Cc: Nadav Amit Cc: Peter Xu Signed-off-by: Andrew Morton

Revert "selftests/mm: remove local __NR_* definitions"

2025-03-06T05:36:12Z

This reverts commit a5c6bc590094a1a73cf6fa3f505e1945d2bf2461. The general approach described in commit e076eaca5906 ("selftests: break the dependency upon local header files") was taken one step too far here: it should not have been extended to include the syscall numbers. This is because doing so would require per-arch support in tools/include/uapi, and no such support exists. This revert fixes two separate reports of test failures, from Dave Hansen[1], and Li Wang[2]. An excerpt of Dave's report: Before this commit (a5c6bc590094a1a73cf6fa3f505e1945d2bf2461) things are fine. But after, I get: running PKEY tests for unsupported CPU/OS An excerpt of Li's report: I just found that mlock2_() return a wrong value in mlock2-test [1] https://lore.kernel.org/dc585017-6740-4cab-a536-b12b37a7582d@intel.com [2] https://lore.kernel.org/CAEemH2eW=UMu9+turT2jRie7+6ewUazXmA6kL+VBo3cGDGU6RA@mail.gmail.com Link: https://lkml.kernel.org/r/20250214033850.235171-1-jhubbard@nvidia.com Fixes: a5c6bc590094 ("selftests/mm: remove local __NR_* definitions") Signed-off-by: John Hubbard Cc: Dave Hansen Cc: Li Wang Cc: David Hildenbrand Cc: Jeff Xu Cc: Andrei Vagin Cc: Axel Rasmussen Cc: Christian Brauner Cc: Kees Cook Cc: Kent Overstreet Cc: Liam R. Howlett Cc: Muhammad Usama Anjum Cc: Peter Xu Cc: Rich Felker Cc: Shuah Khan Cc: Signed-off-by: Andrew Morton

selftests/mm: remove local __NR_* definitions

2024-07-04T02:30:16Z

This continues the work on getting the selftests to build without requiring people to first run "make headers" [1]. Now that the system call numbers are in the correct, checked-in locations in the kernel tree (./tools/include/uapi/asm/unistd*.h), make sure that the mm selftests include that file (indirectly). Doing so provides guaranteed definitions at build time, so remove all of the checks for "ifdef __NR_xxx" in the mm selftests, because they will always be true (defined). [1] commit e076eaca5906 ("selftests: break the dependency upon local header files") Link: https://lkml.kernel.org/r/20240618022422.804305-7-jhubbard@nvidia.com Signed-off-by: John Hubbard Acked-by: David Hildenbrand Cc: Jeff Xu Cc: Andrei Vagin Cc: Axel Rasmussen Cc: Christian Brauner Cc: Kees Cook Cc: Kent Overstreet Cc: Liam R. Howlett Cc: Muhammad Usama Anjum Cc: Peter Xu Cc: Rich Felker Cc: Shuah Khan Signed-off-by: Andrew Morton