When an after-split folio is large and needs to be dropped due to EOF, folio_put_refs(folio, folio_nr_pages(folio)) should be used to drop all page cache refs. Otherwise, the folio will not be freed, causing memory leak.
This leak would happen on a filesystem with blocksize > page_size and a truncate is performed, where the blocksize makes folios split to
0 order ones, causing truncated folios not being freed.
Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages") Reported-by: Hugh Dickins hughd@google.com Closes: https://lore.kernel.org/all/fcbadb7f-dd3e-21df-f9a7-2853b53183c4@google.com/ Cc: stable@vger.kernel.org Signed-off-by: Zi Yan ziy@nvidia.com --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 3d3ebdc002d5..373781b21e5c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3304,7 +3304,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, folio_account_cleaned(tail, inode_to_wb(folio->mapping->host)); __filemap_remove_folio(tail, NULL); - folio_put(tail); + folio_put_refs(tail, folio_nr_pages(tail)); } else if (!folio_test_anon(folio)) { __xa_store(&folio->mapping->i_pages, tail->index, tail, 0);