selftests/mm: ksm_tests should only MADV_HUGEPAGE valid memory

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.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 325254899684 ("selftests: vm: add KSM huge pages merging time test")
Signed-off-by: Ryan Roberts <[email protected]>
Cc: Pedro Demarchi Gomes <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions