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

selftests/mm/uffd: remove static address usage in shmem_allocate_area()

2025-11-20T21:44:00Z

The current shmem_allocate_area() implementation uses a hardcoded virtual base address (BASE_PMD_ADDR) as a hint for mmap() when creating shmem-backed test areas. This approach is fragile and may fail on systems with ASLR or different virtual memory layouts, where the chosen address is unavailable. Replace the static base address with a dynamically reserved address range obtained via mmap(NULL, ..., PROT_NONE). The memfd-backed areas and their alias are then mapped into that reserved region using MAP_FIXED, preserving the original layout and aliasing semantics while avoiding collisions with unrelated mappings. This change improves robustness and portability of the test suite without altering its behavior or coverage. [mehdi.benhadjkhelifa@gmail.com: make cleanup code more clear, per Mike] Link: https://lkml.kernel.org/r/20251113142050.108638-1-mehdi.benhadjkhelifa@gmail.com Link: https://lkml.kernel.org/r/20251111205739.420009-1-mehdi.benhadjkhelifa@gmail.com Signed-off-by: Mehdi Ben Hadj Khelifa Suggested-by: Mike Rapoport Reviewed-by: Mike Rapoport (Microsoft) Cc: David Hildenbrand Cc: David Hunter Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Peter Xu Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

selftests/mm/uffd: refactor non-composite global vars into struct

2025-09-21T21:21:59Z

Refactor macros and non-composite global variable definitions into a struct that is defined at the start of a test and is passed around instead of relying on global vars. Link: https://lkml.kernel.org/r/20250829155600.2000-1-ujwal.kundur@gmail.com Signed-off-by: Ujwal Kundur Acked-by: Peter Xu Reviewed-by: Brendan Jackman Cc: David Hildenbrand Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

selftests/mm/uffd: rename nr_cpus -> nr_parallel

2025-03-17T05:06:38Z

A later commit will bound this variable so it no longer necessarily matches the number of CPUs. Rename it appropriately. Link: https://lkml.kernel.org/r/20250311-mm-selftests-v4-4-dec210a658f5@google.com Signed-off-by: Brendan Jackman Reviewed-by: Dev Jain Cc: Lorenzo Stoakes Cc: Mateusz Guzik Cc: Shuah Khan Signed-off-by: Andrew Morton

selftests/mm: fix spelling

2025-03-17T05:06:23Z

Fix misspelling flagged by codespell. Link: https://lkml.kernel.org/r/20250215081803.1793-1-ujwal.kundur@gmail.com Signed-off-by: Ujwal Kundur Signed-off-by: Andrew Morton

selftests: mm: fix typo

2025-03-17T05:06:11Z

Fix misspelling. Link: https://lkml.kernel.org/r/77e0e915-36c3-4c95-84b8-0b73aaa17951@gmail.com Signed-off-by: Eric Salem 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

Revert "selftests/mm: replace atomic_bool with pthread_barrier_t"

2024-10-29T04:40:41Z

This reverts commit e61ef21e27e8deed8c474e9f47f4aa7bc37e138c. uffd_poll_thread may be called by other tests that do not initialize the pthread_barrier, so this approach is not correct. This will revert to using atomic_bool instead. Link: https://lkml.kernel.org/r/20241018171734.2315053-3-edliaw@google.com Fixes: e61ef21e27e8 ("selftests/mm: replace atomic_bool with pthread_barrier_t") Signed-off-by: Edward Liaw Cc: Ryan Roberts Cc: Peter Xu Cc: Shuah Khan Cc: Signed-off-by: Andrew Morton

selftests/mm: replace atomic_bool with pthread_barrier_t

2024-10-17T07:28:06Z

Patch series "selftests/mm: fix deadlock after pthread_create". On Android arm, pthread_create followed by a fork caused a deadlock in the case where the fork required work to be completed by the created thread. Update the synchronization primitive to use pthread_barrier instead of atomic_bool. Apply the same fix to the wp-fork-with-event test. This patch (of 2): Swap synchronization primitive with pthread_barrier, so that stdatomic.h does not need to be included. The synchronization is needed on Android ARM64; we see a deadlock with pthread_create when the parent thread races forward before the child has a chance to start doing work. Link: https://lkml.kernel.org/r/20241003211716.371786-1-edliaw@google.com Link: https://lkml.kernel.org/r/20241003211716.371786-2-edliaw@google.com Fixes: cff294582798 ("selftests/mm: extend and rename uffd pagemap test") Signed-off-by: Edward Liaw Cc: Lokesh Gidra Cc: Peter Xu 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

selftests/mm: fix ARM related issue with fork after pthread_create

2024-03-26T18:14:12Z

Following issue was observed while running the uffd-unit-tests selftest on ARM devices. On x86_64 no issues were detected: pthread_create followed by fork caused deadlock in certain cases wherein fork required some work to be completed by the created thread. Used synchronization to ensure that created thread's start function has started before invoking fork. [edliaw@google.com: refactored to use atomic_bool] Link: https://lkml.kernel.org/r/20240325194100.775052-1-edliaw@google.com Fixes: 760aee0b71e3 ("selftests/mm: add tests for RO pinning vs fork()") Signed-off-by: Lokesh Gidra Signed-off-by: Edward Liaw Cc: Peter Xu Cc: Signed-off-by: Andrew Morton