ksm_tests was previously mmapping a region of memory, aligning the returned pointer to a PMD boundary, then setting MADV_HUGEPAGE, but was setting it past the end of the mmapped area due to not taking the pointer alignment into consideration. Fix this behaviour.

Up until commit efa7df3e3bb5 ("mm: align larger anonymous mappings on THP boundaries"), this buggy behavior was (usually) masked because the alignment difference was always less than PMD-size. But since the mentioned commit, `ksm_tests -H -s 100` started failing.

Fixes: 325254899684 ("selftests: vm: add KSM huge pages merging time test") Cc: stable@vger.kernel.org Signed-off-by: Ryan Roberts ryan.roberts@arm.com --- Applies on top of mm-unstable.

Thanks, Ryan

tools/testing/selftests/mm/ksm_tests.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c index 380b691d3eb9..b748c48908d9 100644 --- a/tools/testing/selftests/mm/ksm_tests.c +++ b/tools/testing/selftests/mm/ksm_tests.c @@ -566,7 +566,7 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot, if (map_ptr_orig == MAP_FAILED) err(2, "initial mmap");

- if (madvise(map_ptr, len + HPAGE_SIZE, MADV_HUGEPAGE)) + if (madvise(map_ptr, len, MADV_HUGEPAGE)) err(2, "MADV_HUGEPAGE");

pagemap_fd = open("/proc/self/pagemap", O_RDONLY); -- 2.25.1