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charset="utf-8" From: Sayali Patil The HMM compound testcase currently assume only PMD-level mappings and fail on systems when default_hugepagesz=3D1G is set. Extend the checks to accept PUD-level protections as well, avoiding false failures. Fixes: e478425bec93 ("mm/hmm: add tests for hmm_pfn_to_map_order()") Signed-off-by: Sayali Patil Signed-off-by: Aboorva Devarajan --- tools/testing/selftests/mm/hmm-tests.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftes= ts/mm/hmm-tests.c index e1c8a679a4cf3..3d0da4dff85bc 100644 --- a/tools/testing/selftests/mm/hmm-tests.c +++ b/tools/testing/selftests/mm/hmm-tests.c @@ -1602,8 +1602,8 @@ TEST_F(hmm2, snapshot) } =20 /* - * Test the hmm_range_fault() HMM_PFN_PMD flag for large pages that - * should be mapped by a large page table entry. + * Test the hmm_range_fault() handling of large pages (PMD or PUD) + * that should be mapped by a large page table entry. */ TEST_F(hmm, compound) { @@ -1651,8 +1651,8 @@ TEST_F(hmm, compound) /* Check what the device saw. */ m =3D buffer->mirror; for (i =3D 0; i < npages; ++i) - ASSERT_EQ(m[i], HMM_DMIRROR_PROT_WRITE | - HMM_DMIRROR_PROT_PMD); + ASSERT_TRUE((m[i] =3D=3D (HMM_DMIRROR_PROT_WRITE | HMM_DMIRROR_PROT_PMD)= ) || + (m[i] =3D=3D (HMM_DMIRROR_PROT_WRITE | HMM_DMIRROR_PROT_PUD))); 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charset="utf-8" From: Sayali Patil 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. Fixes: 24c2c5b8ffbd ("selftests/mm/hmm-tests: partial unmap, mremap and ano= n_write tests") Fixes: 271a7b2e3c13 ("selftests/mm/hmm-tests: new throughput tests includin= g THP") Signed-off-by: Sayali Patil Signed-off-by: Aboorva Devarajan --- tools/testing/selftests/mm/hmm-tests.c | 62 ++++++++++++++++++-------- 1 file changed, 43 insertions(+), 19 deletions(-) diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftes= ts/mm/hmm-tests.c index 3d0da4dff85bc..1d49d9e919c1f 100644 --- a/tools/testing/selftests/mm/hmm-tests.c +++ b/tools/testing/selftests/mm/hmm-tests.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -2334,12 +2335,21 @@ TEST_F(hmm, migrate_partial_unmap_fault) struct hmm_buffer *buffer; unsigned long npages; unsigned long size =3D read_pmd_pagesize(); + unsigned long unmap_size; + unsigned long offsets[3]; unsigned long i; void *old_ptr; void *map; int *ptr; int ret, j, use_thp; - int offsets[] =3D { 0, 512 * ONEKB, ONEMEG }; + + if (!size) + size =3D TWOMEG; + + unmap_size =3D size / 2; + offsets[0] =3D 0; + offsets[1] =3D size / 4; + offsets[2] =3D size / 2; =20 for (use_thp =3D 0; use_thp < 2; ++use_thp) { for (j =3D 0; j < ARRAY_SIZE(offsets); ++j) { @@ -2381,12 +2391,12 @@ TEST_F(hmm, migrate_partial_unmap_fault) for (i =3D 0, ptr =3D buffer->mirror; i < size / sizeof(*ptr); ++i) ASSERT_EQ(ptr[i], i); =20 - munmap(buffer->ptr + offsets[j], ONEMEG); + munmap(buffer->ptr + offsets[j], unmap_size); =20 /* Fault pages back to system memory and check them. */ for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) if (i * sizeof(int) < offsets[j] || - i * sizeof(int) >=3D offsets[j] + ONEMEG) + i * sizeof(int) >=3D offsets[j] + unmap_size) ASSERT_EQ(ptr[i], i); =20 buffer->ptr =3D old_ptr; @@ -2400,12 +2410,19 @@ TEST_F(hmm, migrate_remap_fault) struct hmm_buffer *buffer; unsigned long npages; unsigned long size =3D read_pmd_pagesize(); + unsigned long offsets[3]; unsigned long i; void *old_ptr, *new_ptr =3D NULL; void *map; int *ptr; int ret, j, use_thp, dont_unmap, before; - int offsets[] =3D { 0, 512 * ONEKB, ONEMEG }; + + if (!size) + size =3D TWOMEG; + + offsets[0] =3D 0; + offsets[1] =3D size / 4; + offsets[2] =3D size / 2; =20 for (before =3D 0; before < 2; ++before) { for (dont_unmap =3D 0; dont_unmap < 2; ++dont_unmap) { @@ -2808,38 +2825,45 @@ static inline int run_migration_benchmark(int fd, i= nt use_thp, size_t buffer_siz TEST_F_TIMEOUT(hmm, benchmark_thp_migration, 120) { struct benchmark_results thp_results, regular_results; - size_t thp_size =3D 2 * 1024 * 1024; /* 2MB - typical THP size */ + size_t thp_size =3D read_pmd_pagesize(); int iterations =3D 5; =20 + if (!thp_size) + thp_size =3D TWOMEG; + printf("\nHMM THP Migration Benchmark\n"); printf("---------------------------\n"); printf("System page size: %ld bytes\n", sysconf(_SC_PAGESIZE)); =20 /* Test different buffer sizes */ size_t test_sizes[] =3D { - thp_size / 4, /* 512KB - smaller than THP */ - thp_size / 2, /* 1MB - half THP */ - thp_size, /* 2MB - single THP */ - thp_size * 2, /* 4MB - two THPs */ - thp_size * 4, /* 8MB - four THPs */ - thp_size * 8, /* 16MB - eight THPs */ - thp_size * 128, /* 256MB - one twenty eight THPs */ + thp_size / 4, /* quarter THP */ + thp_size / 2, /* half THP */ + thp_size, /* single THP */ + thp_size * 2, /* two THPs */ + thp_size * 4, /* four THPs */ + thp_size * 8, /* eight THPs */ + thp_size * 128, /* one twenty eight THPs */ }; =20 static const char *const test_names[] =3D { - "Small Buffer (512KB)", - "Half THP Size (1MB)", - "Single THP Size (2MB)", - "Two THP Size (4MB)", - "Four THP Size (8MB)", - "Eight THP Size (16MB)", - "One twenty eight THP Size (256MB)" + "Small Buffer", + "Half THP Size", + "Single THP Size", + "Two THP Size", + "Four THP Size", + "Eight THP Size", + "One twenty eight THP Size" }; =20 int num_tests =3D ARRAY_SIZE(test_sizes); =20 /* Run all tests */ for (int i =3D 0; i < num_tests; i++) { + /* Skip test sizes exceeding INT_MAX to avoid overflow */ + if (test_sizes[i] > INT_MAX) + break; + /* Test with THP */ ASSERT_EQ(run_migration_benchmark(self->fd, 1, test_sizes[i], iterations, &thp_results), 0); --=20 2.54.0 From nobody Mon May 25 03:32:23 2026 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF36C2F8EA0; 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charset="utf-8" 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. Fixes: b659baea75469 ("mm: selftests for exclusive device memory") Signed-off-by: Aboorva Devarajan --- tools/testing/selftests/mm/hmm-tests.c | 30 +++++++++++++++++++++++--- 1 file changed, 27 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftes= ts/mm/hmm-tests.c index 1d49d9e919c1f..48834e7d1d984 100644 --- a/tools/testing/selftests/mm/hmm-tests.c +++ b/tools/testing/selftests/mm/hmm-tests.c @@ -1868,6 +1868,8 @@ TEST_F(hmm, exclusive_cow) unsigned long i; int *ptr; int ret; + pid_t pid; + int status; =20 npages =3D ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift; ASSERT_NE(npages, 0); @@ -1896,14 +1898,36 @@ TEST_F(hmm, exclusive_cow) ASSERT_EQ(ret, 0); ASSERT_EQ(buffer->cpages, npages); =20 - fork(); + pid =3D fork(); + if (pid =3D=3D -1) + ASSERT_EQ(pid, 0); =20 - /* Fault pages back to system memory and check them. */ + if (pid =3D=3D 0) { + /* + * Child: fault pages back and verify COW, then _exit(). + * On ASSERT failure the harness calls abort(); the parent + * reports it via the WIFEXITED/WEXITSTATUS checks below. + */ + for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i]++, i); + + for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i + 1); + + _exit(0); + } + + /* Parent: also increment to verify COW works for both processes. */ for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) ASSERT_EQ(ptr[i]++, i); =20 for (i =3D 0, ptr =3D buffer->ptr; i < size / sizeof(*ptr); ++i) - ASSERT_EQ(ptr[i], i+1); + ASSERT_EQ(ptr[i], i + 1); + + /* Parent: wait for child and then free the buffer. */ + ASSERT_EQ(waitpid(pid, &status, 0), pid); + ASSERT_TRUE(WIFEXITED(status)); + ASSERT_EQ(WEXITSTATUS(status), 0); =20 hmm_buffer_free(buffer); } --=20 2.54.0