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

selftests/mm/uffd: initialize char variable to Null

2025-11-29T18:41:09Z

In "uffd-stress.c" & "uffd-unit-tests.c". address of char variable having garbage value (uninitialized) is passed to 'write' syscall triggers warning. uffd-stress.c:246:39: warning: variable 'c' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer] uffd-unit-tests.c:581:31: warning: variable 'c' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer] so the fix is to assign char variable to '\0' to prevent writing of garbage value. Link: https://lkml.kernel.org/r/20251126160830.52124-1-ankitkhushwaha.linux@gmail.com Signed-off-by: Ankit Khushwaha Reviewed-by: Mike Rapoport (Microsoft) Cc: Bill Wendling Cc: Justin Stitt Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Nathan Chancellor 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-stress: stricten constraint on free hugepages needed before the test

2025-09-13T23:55:19Z

The test requires at least 2 * (bytes/page_size) hugetlb memory, since we require identical number of hugepages for src and dst location. Fix this. Along with the above, as explained in patch "selftests/mm/uffd-stress: Make test operate on less hugetlb memory", the racy nature of the test requires that we have some extra number of hugepages left beyond what is required. Therefore, stricten this constraint. Link: https://lkml.kernel.org/r/20250909061531.57272-3-dev.jain@arm.com Fixes: 5a6aa60d1823 ("selftests/mm: skip uffd hugetlb tests with insufficient hugepages") Signed-off-by: Dev Jain Cc: David Hildenbrand 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: use __auto_type in swap() macro

2025-09-13T23:54:44Z

Replace typeof() with __auto_type in the swap() macro in uffd-stress.c. __auto_type was introduced in GCC 4.9 and reduces the compile time for all compilers. No functional changes intended. Link: https://lkml.kernel.org/r/20250730142301.6754-1-pranav.tyagi03@gmail.com Signed-off-by: Pranav Tyagi Reviewed-by: Joshua Hahn Cc: Peter Xu Cc: Shuah Khan Signed-off-by: Andrew Morton

selftests/mm: don't fail uffd-stress if too many CPUs

2025-03-17T05:06:38Z

This calculation divides a fixed parameter by an environment-dependent parameter i.e. the number of CPUs. The simple way to avoid machine-specific failures here is to just put a cap on the max value of the latter. Link: https://lkml.kernel.org/r/20250311-mm-selftests-v4-6-dec210a658f5@google.com Signed-off-by: Brendan Jackman Suggested-by: Mateusz Guzik Cc: Dev Jain Cc: Lorenzo Stoakes Cc: Shuah Khan Signed-off-by: Andrew Morton

selftests/mm: print some details when uffd-stress gets bad params

2025-03-17T05:06:38Z

So this can be debugged more easily. Link: https://lkml.kernel.org/r/20250311-mm-selftests-v4-5-dec210a658f5@google.com Signed-off-by: Brendan Jackman Cc: Dev Jain Cc: Lorenzo Stoakes Cc: Mateusz Guzik Cc: Shuah Khan 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: skip uffd-stress if userfaultfd not available

2025-03-17T05:06:37Z

It's pretty obvious that the test wouldn't work if you don't have the feature enabled. But, it's still useful to SKIP instead of failing so the reader can immediately tell that this is the reason why. Link: https://lkml.kernel.org/r/20250311-mm-selftests-v4-2-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

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

mm: turn off test_uffdio_wp if CONFIG_PTE_MARKER_UFFD_WP is not configured.

2024-07-05T01:05:58Z

If CONFIG_PTE_MARKER_UFFD_WP is disabled, then we turn off three features in userfaultfd_api (UFFD_FEATURE_WP_HUGETLBFS_SHMEM, UFFD_FEATURE_WP_UNPOPULATED, and UFFD_FEATURE_WP_ASYNC). Currently this test always will call uffdio_regsiter with the flag UFFDIO_REGISTER_MODE_WP. However, the kernel ensures in vma_can_userfault that if the feature UFFD_FEATURE_WP_HUGETLBFS_SHMEM is disabled, only allow the VM_UFFD_WP on anonymous vmas, meaning our call to uffdio_regsiter will fail. We still want to be able to run the test even if we have CONFIG_PTE_MARKER_UFFD_WP disabled, so check to see if the feature UFFD_FEATURE_WP_HUGETLBFS_SHMEM has been turned off in the test and if so, disable us from calling uffdio_regsiter with the flag UFFDIO_REGISTER_MODE_WP. Link: https://lkml.kernel.org/r/20240626130513.120193-3-audra@redhat.com Signed-off-by: Audra Mitchell Reviewed-by: Peter Xu Cc: Al Viro Cc: Andrea Arcangeli Cc: Christian Brauner Cc: Jan Kara Cc: Mike Rapoport Cc: Rafael Aquini Cc: Shaohua Li Cc: Shuah Khan Signed-off-by: Andrew Morton