On Jan 13, 2024, at 02:08, Sidhartha Kumar sidhartha.kumar@oracle.com wrote:
has_extra_refcount() makes the assumption that the page cache adds a ref count of 1 and subtracts this in the extra_pins case. Commit a08c7193e4f1 (mm/filemap: remove hugetlb special casing in filemap.c) modifies __filemap_add_folio() by calling folio_ref_add(folio, nr); for all cases (including hugtetlb) where nr is the number of pages in the folio. We should adjust the number of references coming from the page cache by subtracing the number of pages rather than 1.
In hugetlbfs_read_iter(), folio_test_has_hwpoisoned() is testing the wrong flag as, in the hugetlb case, memory-failure code calls folio_test_set_hwpoison() to indicate poison. folio_test_hwpoison() is the correct function to test for that flag.
After these fixes, the hugetlb hwpoison read selftest passes all cases.
Fixes: a08c7193e4f1 ("mm/filemap: remove hugetlb special casing in filemap.c") Closes: https://lore.kernel.org/linux-mm/20230713001833.3778937-1-jiaqiyan@google.co... Cc: stable@vger.kernel.org # 6.7+ Signed-off-by: Sidhartha Kumar sidhartha.kumar@oracle.com Reported-by: Muhammad Usama Anjum usama.anjum@collabora.com
Acked-by: Muchun Song muchun.song@linux.dev
Thanks.