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@xxxxxxxxxxxxxxx
Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx>
---
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
