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large folio after our large folio in > physical memory, our "pfn_flags & (KPF_THP | KPF_COMPOUND_TAIL" would > trigger even though it's actually a head page of the next folio. > > If is_backed_by_folio() returns a wrong result, split_pte_mapped_thp() > can fail with "Some THPs are missing during mremap". > > Fix it by checking for head/tail pages of folios properly. Add > folio_tail_flags/folio_head_flags to improve readability and use these > masks also when just testing for any compound page. > > Fixes: 169b456b0162 ("selftests/mm: reimplement is_backed_by_thp() with= more precise check") > Signed-off-by: David Hildenbrand > --- > tools/testing/selftests/mm/split_huge_page_test.c | 15 +++++++--------= > 1 file changed, 7 insertions(+), 8 deletions(-) > LGTM. Thanks for fixing it. Reviewed-by: Zi Yan Best Regards, Yan, Zi