6.7-stable review patch. If anyone has any objections, please let me know.
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From: Sidhartha Kumar sidhartha.kumar@oracle.com
commit 19d3e221807772f8443e565234a6fdc5a2b09d26 upstream.
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.
Link: https://lkml.kernel.org/r/20240112180840.367006-1-sidhartha.kumar@oracle.com Fixes: a08c7193e4f1 ("mm/filemap: remove hugetlb special casing in filemap.c") Signed-off-by: Sidhartha Kumar sidhartha.kumar@oracle.com Closes: https://lore.kernel.org/linux-mm/20230713001833.3778937-1-jiaqiyan@google.co... Reported-by: Muhammad Usama Anjum usama.anjum@collabora.com Tested-by: Muhammad Usama Anjum usama.anjum@collabora.com Acked-by: Miaohe Lin linmiaohe@huawei.com Acked-by: Muchun Song muchun.song@linux.dev Cc: James Houghton jthoughton@google.com Cc: Jiaqi Yan jiaqiyan@google.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Naoya Horiguchi naoya.horiguchi@nec.com Cc: stable@vger.kernel.org [6.7+] Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/hugetlbfs/inode.c | 2 +- mm/memory-failure.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
--- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -340,7 +340,7 @@ static ssize_t hugetlbfs_read_iter(struc } else { folio_unlock(folio);
- if (!folio_test_has_hwpoisoned(folio)) + if (!folio_test_hwpoison(folio)) want = nr; else { /* --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -976,7 +976,7 @@ static bool has_extra_refcount(struct pa int count = page_count(p) - 1;
if (extra_pins) - count -= 1; + count -= folio_nr_pages(page_folio(p));
if (count > 0) { pr_err("%#lx: %s still referenced by %d users\n",