Both uniform and non uniform split check missed the check to prevent splitting anon folios in swapcache to non-zero order. Fix the check.

Fixes: 58729c04cf10 ("mm/huge_memory: add buddy allocator like (non-uniform) folio_split()") Reported-by: "David Hildenbrand (Red Hat)" david@kernel.org Closes: https://lore.kernel.org/all/dc0ecc2c-4089-484f-917f-920fdca4c898@kernel.org/ Cc: stable@vger.kernel.org Signed-off-by: Zi Yan ziy@nvidia.com --- mm/huge_memory.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 36fc4ff002c9..595811c78f42 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3674,7 +3674,8 @@ bool non_uniform_split_supported(struct folio *folio, unsigned int new_order, /* order-1 is not supported for anonymous THP. */ VM_WARN_ONCE(warns && new_order == 1, "Cannot split to order-1 folio"); - return new_order != 1; + if (new_order == 1) + return false; } else if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !mapping_large_folio_support(folio->mapping)) { /* @@ -3705,7 +3706,8 @@ bool uniform_split_supported(struct folio *folio, unsigned int new_order, if (folio_test_anon(folio)) { VM_WARN_ONCE(warns && new_order == 1, "Cannot split to order-1 folio"); - return new_order != 1; + if (new_order == 1) + return false; } else if (new_order) { if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !mapping_large_folio_support(folio->mapping)) {