kernel/linux.git/tools/testing/selftests/mm, branch v7.1.7

selftests/mm: fix exclusive_cow test fork() handling

2026-07-24T14:20:22+00:00

[ Upstream commit cea5702144615878600d3a39b5d8b3cc34719012 ] The test ignores the return value of fork(), so both the parent and the (newly created) child run the COW verification loops and then call hmm_buffer_free() before returning into the kselftest harness, which _exit()s each side. This duplicated teardown sequence has been observed to manifest as a SIGSEGV in the test child, e.g.: hmm-tests[360141]: segfault (11) at 0 nip 10006964 lr 1000ac3c code 1 in hmm-tests[6964,10000000+30000] Fix this by adopting the same fork()-then-wait pattern already used by the nearby anon_write_child / anon_write_child_shared tests in this file: the child performs the COW verification and then _exit(0)s so it does not run the test teardown, while the parent independently verifies COW, waits for the child, and only then frees the buffer. Link: https://lore.kernel.org/20260611034102.1030738-4-aboorvad@linux.ibm.com Fixes: b659baea75469 ("mm: selftests for exclusive device memory") Signed-off-by: Aboorva Devarajan Cc: Alex Sierra Cc: Alistair Popple Cc: Balbir Singh Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: Leon Romanovsky Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Brost Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Ralph Campbell Cc: Sayali Patil Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

selftests/mm: remove hardcoded THP sizing assumptions in hmm tests

2026-07-24T14:20:22+00:00

[ Upstream commit 8edb0e769ce2a996774df83485781dd9f4bc2d44 ] migrate_partial_unmap_fault() and migrate_remap_fault() use hardcoded offsets based on a 2MB PMD size. Similarly, benchmark_thp_migration() assumes a fixed 2MB THP size when generating test buffer sizes. Derive offsets and test sizes from the runtime PMD page size returned by read_pmd_pagesize(). If unavailable, fall back to TWOMEG. This allows the tests to adapt correctly on systems where PMD-sized THP differs from 2MB. Also replace the fixed 1MB unmap size with a PMD-relative value derived from the runtime PMD size. On systems with larger PMD sizes, computed test buffer sizes can exceed INT_MAX. Skip such test cases to avoid overflow. Link: https://lore.kernel.org/20260611034102.1030738-3-aboorvad@linux.ibm.com Fixes: 24c2c5b8ffbd ("selftests/mm/hmm-tests: partial unmap, mremap and anon_write tests") Fixes: 271a7b2e3c13 ("selftests/mm/hmm-tests: new throughput tests including THP") Signed-off-by: Sayali Patil Signed-off-by: Aboorva Devarajan Acked-by: Balbir Singh Cc: Alex Sierra Cc: Alistair Popple Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: Leon Romanovsky Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Brost Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Ralph Campbell Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

selftests/mm: allow PUD-level entries in compound testcase of hmm tests

2026-07-24T14:20:22+00:00

[ Upstream commit 224ed0e019b122d08580362abe57574a78f2b5fa ] Patch series "selftests/mm: assorted fixes for hmm-tests", v3. This series fixes a few issues in hmm-tests that show up when page-size and huge-page configuration differ from the hardcoded assumptions the tests were written for (PMD/THP sizing, default hugepage size, and related cases). It also includes a fix to exclusive_cow: the test ignored the return value of fork(), so both parent and child ran the same teardown path. This patch (of 3): The HMM compound testcase currently assumes only PMD-level mappings and fails on systems where default_hugepagesz=1G is set, because the region is then reported by the device at PUD level. Determine the mapping level (PMD or PUD) the device reports for the first page of the range and require every page to match that level exactly via ASSERT_EQ(). This accepts PUD-level mappings while preserving the expected/observed protection values printed on failure, and rejects a fragmented mapping that mixes PMD- and PUD-level entries within the same range (which a per-page OR check would have let pass). Link: https://lore.kernel.org/20260611034102.1030738-1-aboorvad@linux.ibm.com Link: https://lore.kernel.org/20260611034102.1030738-2-aboorvad@linux.ibm.com Fixes: e478425bec93 ("mm/hmm: add tests for hmm_pfn_to_map_order()") Signed-off-by: Sayali Patil Co-developed-by: Aboorva Devarajan Signed-off-by: Aboorva Devarajan Cc: Alex Sierra Cc: Alistair Popple Cc: Balbir Singh Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: Leon Romanovsky Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Brost Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Ralph Campbell Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

selftests/mm: clarify alternate unmapping in compaction_test

2026-07-24T14:20:22+00:00

[ Upstream commit 69ba1d76d93ab818245333cf400928477ba72053 ] Add a comment explaining that every other entry in the list is unmapped to intentionally create fragmentation with locked pages before invoking check_compaction(). Link: https://lore.kernel.org/da5e0a8d5152e54152c0d2f456aac2fac35af291.1779296493.git.sayalip@linux.ibm.com Fixes: bd67d5c15cc1 ("Test compaction of mlocked memory") Signed-off-by: Sayali Patil Tested-by: Venkat Rao Bagalkote Cc: David Hildenbrand (Arm) Cc: Dev Jain Cc: Liam Howlett Cc: Miaohe Lin Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Cc: Zi Yan Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

selftests/mm: move hwpoison setup into run_test() and silence modprobe output for memory-failure category

2026-07-24T14:20:22+00:00

[ Upstream commit 90c132f8379b788a0482dbeabc884d3ae5d82205 ] run_vmtests.sh contains special handling to ensure the hwpoison_inject module is available for the memory-failure tests. This logic was implemented outside of run_test(), making the setup category-specific but managed globally. Move the hwpoison_inject handling into run_test() and restrict it to the memory-failure category so that: 1. the module is checked and loaded only when memory-failure tests run, 2. the test is skipped if the module or the debugfs interface (/sys/kernel/debug/hwpoison/) is not available. 3. the module is unloaded after the test if it was loaded by the script. This localizes category-specific setup and makes the test flow consistent with other per-category preparations. While updating this logic, fix the module availability check. The script previously used: modprobe -R hwpoison_inject The -R option prints the resolved module name to stdout, causing every run to print: hwpoison_inject in the test output, even when no action is required, introducing unnecessary noise. Replace this with: modprobe -n hwpoison_inject which verifies that the module is loadable without producing output, keeping the selftest logs clean and consistent. Also, ensure that skipped tests do not override a previously recorded failure. A skipped test currently sets exitcode to ksft_skip even if a prior test has failed, which can mask failures in the final exit status. Update the logic to only set exitcode to ksft_skip when no failure has been recorded. Link: https://lore.kernel.org/93441f34f7ef5add47d1a130d03daa79e21b5050.1779296493.git.sayalip@linux.ibm.com Fixes: ff4ef2fbd101 ("selftests/mm: add memory failure anonymous page test") Signed-off-by: Sayali Patil Reviewed-by: Miaohe Lin Tested-by: Venkat Rao Bagalkote Cc: David Hildenbrand (Arm) Cc: Dev Jain Cc: Liam Howlett Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Cc: Zi Yan Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

selftests/mm: run_vmtests.sh: free memory if available memory is low

2026-07-24T14:20:22+00:00

[ Upstream commit 157adc22f01cdd0c0dc1b9e4389ed2377d9b69d3 ] Currently when running THP and HugeTLB tests, if HAVE_HUGEPAGES is set run_test() drops caches, compacts memory and runs the test. But if HAVE_HUGEPAGES is not set it skips the tests entirely, even if THP tests have nothing to do with HAVE_HUGEPAGES. Replace the check if HAVE_HUGEPAGES is set with a check of how much memory is available. If there is less than 256 MB of available memory, drop caches and run compaction and then continue to run a test regardless of HAVE_HUGEPAGES value. Link: https://lore.kernel.org/20260511162840.375890-55-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Tested-by: Luiz Capitulino Tested-by: Sarthak Sharma Cc: Baolin Wang Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Donet Tom Cc: Jason Gunthorpe Cc: John Hubbard Cc: Lance Yang Cc: Leon Romanovsky Cc: Liam Howlett Cc: Li Wang Cc: Lorenzo Stoakes Cc: Mark Brown Cc: Michal Hocko Cc: Nico Pache Cc: Peter Xu Cc: Ryan Roberts Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Zi Yan Signed-off-by: Andrew Morton Stable-dep-of: 90c132f8379b ("selftests/mm: move hwpoison setup into run_test() and silence modprobe output for memory-failure category") Signed-off-by: Sasha Levin

selftests/mm: skip uffd-stress test when nr_pages_per_cpu is zero

2026-07-24T14:20:22+00:00

[ Upstream commit f3bd00507f226a419125df6064632bcbd47d8e70 ] uffd-stress currently fails when the computed nr_pages_per_cpu evaluates to zero: nr_pages_per_cpu = bytes / page_size / nr_parallel This can occur on systems with large hugepage sizes (e.g. 1GB) and a high number of CPUs, where the total allocated memory is sufficient overall but not enough to provide at least one page per cpu. In such cases, the failure is due to insufficient test resources rather than incorrect kernel behaviour. Update the test to treat this condition as a test skip instead of reporting an error. [sayalip@linux.ibm.com: use ksft_exit_skip() instead of KSFT_SKIP] Link: https://lore.kernel.org/88202b56-1dc5-43e2-9d1f-a0823a9531f0@linux.ibm.com Link: https://lore.kernel.org/0707e9a0f1b3dd904c4a069b91db317f9c160faa.1779296493.git.sayalip@linux.ibm.com Fixes: db0f1c138f18 ("selftests/mm: print some details when uffd-stress gets bad params") Signed-off-by: Sayali Patil Acked-by: Zi Yan Acked-by: David Hildenbrand (Arm) Tested-by: Venkat Rao Bagalkote Cc: Dev Jain Cc: Liam Howlett Cc: Miaohe Lin Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

selftests/mm: ensure destination is hugetlb-backed in hugetlb-mremap

2026-07-24T14:20:22+00:00

[ Upstream commit f20ca8972e83f111c4300c60d74314568c8964bc ] The hugetlb-mremap selftest reserves the destination address using a anonymous base-page mapping before calling mremap() with MREMAP_FIXED, while the source region is hugetlb-backed. When remapping a hugetlb mapping into a base-page VMA may fail with: mremap: Device or resource busy This is observed on powerpc hash MMU systems where slice constraints and page size incompatibilities prevent the remap. Ensure the destination region is created using MAP_HUGETLB so that both source and destination VMAs are hugetlb-backed and compatible. Update the FLAGS macro to include MAP_HUGETLB | MAP_SHARED so that both mappings are hugetlb-backed and compatible. Also use the macro for the mmap() calls to avoid repeating the flag combination. This ensures the test reliably exercises hugetlb mremap instead of failing due to VMA type mismatch. Link: https://lore.kernel.org/367644df45c65098f23e3945c6a80f4b8a8964a6.1779296493.git.sayalip@linux.ibm.com Fixes: 12b613206474 ("mm, hugepages: add hugetlb vma mremap() test") Signed-off-by: Sayali Patil Tested-by: Venkat Rao Bagalkote Cc: David Hildenbrand (Arm) Cc: Dev Jain Cc: Liam Howlett Cc: Miaohe Lin Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Cc: Zi Yan Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

selftest/mm: register existing mapping with userfaultfd in hugetlb-mremap

2026-07-24T14:20:22+00:00

[ Upstream commit 1df31d5ef58dc6bdf0f2a8b809152d835c60b28e ] Previously, register_region_with_uffd() created a new anonymous mapping and overwrote the address supplied by the caller before registering the range with userfaultfd. As a result, userfaultfd was applied to an unrelated anonymous mapping instead of the hugetlb region used by the test. Remove the extra mmap() and register the caller-provided address range directly using UFFDIO_REGISTER_MODE_MISSING, so that faults are generated for the hugetlb mapping used by the test. This ensures userfaultfd operates on the actual hugetlb test region and validates the expected fault handling. Before patch: running ./hugetlb-mremap ------------------------- TAP version 13 1..1 Map haddr: Returned address is 0x7eaa40000000 Map daddr: Returned address is 0x7daa40000000 Map vaddr: Returned address is 0x7faa40000000 Address returned by mmap() = 0x7fff9d000000 Mremap: Returned address is 0x7faa40000000 First hex is 0 First hex is 3020100 ok 1 Read same data Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0 [PASS] ok 1 hugetlb-mremap After patch: running ./hugetb-mremap ------------------------- TAP version 13 1..1 Map haddr: Returned address is 0x7eaa40000000 Map daddr: Returned address is 0x7daa40000000 Map vaddr: Returned address is 0x7faa40000000 Registered memory at address 0x7eaa40000000 with userfaultfd Mremap: Returned address is 0x7faa40000000 First hex is 0 First hex is 3020100 ok 1 Read same data Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0 [PASS] ok 1 hugetlb-mremap Link: https://lore.kernel.org/13845da872ed174316173e8996dbb5f181994017.1779296493.git.sayalip@linux.ibm.com Fixes: 12b613206474 ("mm, hugepages: add hugetlb vma mremap() test") Signed-off-by: Sayali Patil Acked-by: David Hildenbrand (Arm) Tested-by: Venkat Rao Bagalkote Cc: Dev Jain Cc: Liam Howlett Cc: Miaohe Lin Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Cc: Zi Yan Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

selftests/mm: free dynamically allocated PMD-sized buffers in split_huge_page_test

2026-07-24T14:20:21+00:00

[ Upstream commit e5d3e1422e92d54e28e81fad8bfc7c1ecb41a353 ] Dynamically allocated buffers of PMD size for file-backed THP operations (file_buf1 and file_buf2) were not freed on the success path and some failure paths. Since the function is called repeatedly in a loop for each split order, this can cause significant memory leaks. On architectures with large PMD sizes, repeated leaks could exhaust system memory and trigger the OOM killer during test execution. Ensure all allocated buffers are freed to maintain stable repeated test runs. Link: https://lore.kernel.org/060c673b376bbeeed2b1fb1d48a825e846654191.1779296493.git.sayalip@linux.ibm.com Fixes: 035a112e5fd5 ("selftests/mm: make file-backed THP split work by writing PMD size data") Signed-off-by: Sayali Patil Reviewed-by: Zi Yan Tested-by: Venkat Rao Bagalkote Cc: David Hildenbrand (Arm) Cc: Dev Jain Cc: Liam Howlett Cc: Miaohe Lin Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin