kernel/linux.git/tools/testing/selftests/mm, branch v6.12.98

selftests/mm: fix exclusive_cow test fork() handling

2026-07-24T14:11:12+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: allow PUD-level entries in compound testcase of hmm tests

2026-07-24T14:11:12+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

2026-07-24T14:11:12+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: ensure destination is hugetlb-backed in hugetlb-mremap

2026-07-24T14:11:12+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

2026-07-24T14:11:12+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: restore default nr_hugepages value via exit trap in charge_reserved_hugetlb.sh

2026-07-24T14:11:12+00:00

[ Upstream commit a3f66e9b6e4dad38444656ffc28c28c33a4d4e1f ] Patch series "selftests/mm: fix failures and robustness improvements", v7. Powerpc systems with a 64K base page size exposed several issues while running mm selftests. Some tests assume specific hugetlb configurations, use incorrect interfaces, or fail instead of skipping when the required kernel features are not available. This series fixes these issues and improves test robustness. This patch (of 13): cleanup() resets nr_hugepages to 0 on every invocation, while the test reconfigures it again in the next iteration. This leads to repeated allocation and freeing of large numbers of hugepages, especially when the original value is high. Additionally, with set -e, failures in earlier cleanup steps (e.g., rmdir or umount returning EBUSY while background activity is still ongoing) can cause the script to exit before restoring the original value, leaving the system in a modified state. Introduce a trap on EXIT, INT, and TERM to restore the original nr_hugepages value once at script termination. This avoids unnecessary allocation churn and ensures the original value is reliably restored on all exit paths. Link: https://lore.kernel.org/cover.1779296493.git.sayalip@linux.ibm.com Link: https://lore.kernel.org/5b8fbb29cd6ceffe6752e0af104f60cec072aa10.1779296493.git.sayalip@linux.ibm.com Fixes: 7d695b1c3695 ("selftests/mm: save and restore nr_hugepages value") Signed-off-by: Sayali Patil Acked-by: Zi Yan Tested-by: Venkat Rao Bagalkote Cc: David Hildenbrand 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: Fix resv_sz when parsing arm64 signal frame

2026-07-24T14:10:47+00:00

[ Upstream commit c364aa56d6738c8759e88941d7a45a1d6b4c52d0 ] get_header() wants the size of the reserved area in struct sigcontext, but instead we pass it the size of the entire struct. This could in theory result in an out-of-bounds read (if the signal frame is malformed). Fix this using one of the existing macros from tools/testing/selftests/arm64/signal/testcases/testcases.h. This issue was reported by Sashiko on a patch that copied this portion of the code. Link: https://sashiko.dev/#/patchset/20260421144252.1440365-1-kevin.brodsky%40arm.com Fixes: f5b5ea51f78f ("selftests: mm: make protection_keys test work on arm64") Signed-off-by: Kevin Brodsky Reviewed-by: Mark Brown Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

selftests/mm: pagemap_ioctl: use the correct page size for transact_test()

2026-07-18T14:52:14+00:00

commit dccf636bf1e68c3fda92f0c9e1018ab7e0ac8b2c upstream. There are several places in transact_test() where we use the hardcoded 0x1000 (4k) as page size, which is not always correct for architectures supporting multiple page sizes. Switch to use the correct page size. Otherwise ./ksft_pagemap.sh on a 16k-page-size arm64 box fails with $ ./ksft_pagemap.sh [...] # ok 96 mprotect_tests Both pages written after remap and mprotect # ok 97 mprotect_tests Clear and make the pages written # Bail out! ioctl failed # # Planned tests != run tests (117 != 97) # # Totals: pass:97 fail:0 xfail:0 xpass:0 skip:0 error:0 # [FAIL] not ok 1 pagemap_ioctl # exit=1 # SUMMARY: PASS=0 SKIP=0 FAIL=1 1..1 Link: https://lore.kernel.org/20260628101118.35861-1-zenghui.yu@linux.dev Fixes: 46fd75d4a3c9 ("selftests: mm: add pagemap ioctl tests") Signed-off-by: Zenghui Yu Cc: Muhammad Usama Anjum Cc: David Hildenbrand Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Zenghui Yu Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

selftests: mm: fix and speedup "droppable" test

2026-07-18T14:52:14+00:00

commit cc13a7a618fe8354f16d74c06aaf9565a68e9ebd upstream. The droppable test currently relies on creating memory pressure in a child process to trigger dropping the droppable pages. That not only takes a long time on some machines (allocating and filling all that memory), on large machines this will not work as we hardcode the area size to 134217728 bytes. ... further, we rely on timeouts to detect that memory was not dropped, which is really suboptimal. Instead, let's just use MADV_PAGEOUT on a 2 MiB region. MADV_PAGEOUT works with droppable memory even without swap. There is the low chance of MADV_PAGEOUT failing to drop a page because of speculative references. We'll wait 1s and retry 10 times to rule that unlikely case out as best as we can. On a machine without swap: $ ./droppable TAP version 13 1..1 ok 1 madvise(MADV_PAGEOUT) behavior # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0 Link: https://lore.kernel.org/20260611-droppable_test-v1-1-b6a73d99f658@kernel.org Fixes: 9651fcedf7b9 ("mm: add MAP_DROPPABLE for designating always lazily freeable mappings") Signed-off-by: David Hildenbrand (Arm) Reported-by: Aishwarya TCV Tested-by: Sarthak Sharma Tested-by: Lance Yang Reviewed-by: Dev Jain Reviewed-by: SeongJae Park Tested-by: Lorenzo Stoakes Reviewed-by: Lorenzo Stoakes Reviewed-by: Jason A. Donenfeld Cc: Anthony Yznaga Cc: Liam R. Howlett Cc: Mark Brown Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/memory: fix spurious warning when unmapping device-private/exclusive pages

2026-06-09T10:26:02+00:00

[ Upstream commit be3f38d05cc5a7c3f13e51994c5dd043ab604d28 ] Device private and exclusive entries are only supported for anonymous folios. This condition is tested in __migrate_device_pages() and make_device_exclusive() using folio_test_anon(). However the unmap path tests this assumption using vma_is_anonymous(). This is wrong because whilst anonymous VMAs can only contain folios where folio_test_anon() is true the opposite relation does not hold. A folio for which folio_test_anon() is true does not imply vma_is_anonymous() is true. Such a condition can occur if for example a folio is part of a private filebacked mapping. In this case vma_is_anonymous() is false as the mapping is filebacked, but folio_test_anon() may be true, thus permitting devices to migrate the folio to device private memory. This can lead to the following spurious warnings during process teardown: [ 772.737706] ------------[ cut here ]------------ [ 772.739201] WARNING: mm/memory.c:1754 at unmap_page_range.cold+0x26/0x18a, CPU#17: hmm-tests/2041 [ 772.742050] Modules linked in: test_hmm nvidia_uvm(O) nvidia(O) [ 772.743959] CPU: 17 UID: 0 PID: 2041 Comm: hmm-tests Tainted: G W O 7.0.0+ #387 PREEMPT(full) [ 772.747104] Tainted: [W]=WARN, [O]=OOT_MODULE [ 772.748509] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 772.752117] RIP: 0010:unmap_page_range.cold+0x26/0x18a [ 772.753780] Code: 7e fe ff ff 48 89 4c 24 78 4c 89 44 24 38 e8 f2 ff b1 00 48 8b 4c 24 78 4c 8b 44 24 38 48 8b 44 24 18 48 83 78 48 00 74 04 90 <0f> 0b 90 48 89 ca b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 2a 80 3c 02 [ 772.759602] RSP: 0018:ffff888112607550 EFLAGS: 00010286 [ 772.761310] RAX: ffff88811bbf4dc0 RBX: dffffc0000000000 RCX: ffffea03e9bfffd8 [ 772.763583] RDX: 1ffff1102377e9c1 RSI: 0000000000000008 RDI: ffff88811bbf4e08 [ 772.765914] RBP: 0000000000000006 R08: ffff8881059f7448 R09: ffffed10224c0e68 [ 772.768184] R10: ffff888112607347 R11: 0000000000000001 R12: 0000000000000001 [ 772.770461] R13: ffffea03e9bfffc0 R14: ffff888112607908 R15: ffffea03e9bfffc0 [ 772.772782] FS: 00007f327caa2780(0000) GS:ffff888427b7d000(0000) knlGS:0000000000000000 [ 772.775328] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 772.777187] CR2: 00007f327ca89000 CR3: 00000001994d5000 CR4: 00000000000006f0 [ 772.779135] Call Trace: [ 772.779792] [ 772.780317] ? dmirror_interval_invalidate+0x1a3/0x290 [test_hmm] [ 772.781873] ? vm_normal_page_pud+0x2b0/0x2b0 [ 772.782992] ? __rwlock_init+0x150/0x150 [ 772.784006] ? lock_release+0x216/0x2b0 [ 772.785008] ? __mmu_notifier_invalidate_range_start+0x505/0x6e0 [ 772.786522] ? lock_release+0x216/0x2b0 [ 772.787498] ? unmap_single_vma+0xb6/0x210 [ 772.788573] unmap_vmas+0x27d/0x520 [ 772.789506] ? unmap_single_vma+0x210/0x210 [ 772.790607] ? mas_update_gap.part.0+0x620/0x620 [ 772.791834] unmap_region+0x19e/0x350 [ 772.792769] ? remove_vma+0x130/0x130 [ 772.793684] ? mas_alloc_nodes+0x1f2/0x300 [ 772.794730] vms_complete_munmap_vmas+0x8c1/0xe20 [ 772.795926] ? unmap_region+0x350/0x350 [ 772.796917] do_vmi_align_munmap+0x36a/0x4e0 [ 772.798018] ? lock_release+0x216/0x2b0 [ 772.799024] ? vma_shrink+0x620/0x620 [ 772.799983] do_vmi_munmap+0x150/0x2c0 [ 772.800939] __vm_munmap+0x161/0x2c0 [ 772.801872] ? expand_downwards+0xd60/0xd60 [ 772.802948] ? clockevents_program_event+0x1ef/0x540 [ 772.804217] ? lock_release+0x216/0x2b0 [ 772.805158] __x64_sys_munmap+0x59/0x80 [ 772.805776] do_syscall_64+0xfc/0x670 [ 772.806336] ? irqentry_exit+0xda/0x580 [ 772.806976] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 772.807772] RIP: 0033:0x7f327cbb2717 [ 772.808323] Code: 73 01 c3 48 8b 0d f9 76 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c9 76 0d 00 f7 d8 64 89 01 48 [ 772.811337] RSP: 002b:00007ffde7f57d38 EFLAGS: 00000202 ORIG_RAX: 000000000000000b [ 772.812564] RAX: ffffffffffffffda RBX: 00007f327cc9c000 RCX: 00007f327cbb2717 [ 772.813733] RDX: 0000000000000000 RSI: 0000000000400000 RDI: 00007f327c289000 [ 772.814867] RBP: 0000000000421360 R08: 000000000000001a R09: 0000000000000000 [ 772.815991] R10: 0000000000000003 R11: 0000000000000202 R12: 00007ffde7f57d74 [ 772.817121] R13: 00007f327c689010 R14: 0000000000100000 R15: 00007f327c289000 [ 772.818272] [ 772.818614] irq event stamp: 0 [ 772.819159] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [ 772.820174] hardirqs last disabled at (0): [] copy_process+0x19f3/0x6440 [ 772.821511] softirqs last enabled at (0): [] copy_process+0x1a40/0x6440 [ 772.822869] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 772.823871] ---[ end trace 0000000000000000 ]--- Fix this by using the same check for folio_test_anon() in zap_nonpresent_ptes(). Also add a hmm-test case for this. Link: https://lore.kernel.org/20260501065116.2057242-1-apopple@nvidia.com Fixes: 999dad824c39 ("mm/shmem: persist uffd-wp bit across zapping for file-backed") Signed-off-by: Alistair Popple Reported-by: Arsen Arsenović Reviewed-by: Balbir Singh Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: John Hubbard Cc: Leon Romanovsky Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Peter Xu Cc: Matthew Brost Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Thomas Hellström Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton [ applied the change in `zap_pte_range()` instead of `zap_nonpresent_ptes()` ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman