The patch titled Subject: fs/hugetlbfs/inode.c: mm/memory-failure.c: fix hugetlbfs hwpoison handling has been added to the -mm mm-hotfixes-unstable branch. Its filename is fs-hugetlbfs-inodec-mm-memory-failurec-fix-hugetlbfs-hwpoison-handling.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Sidhartha Kumar sidhartha.kumar@oracle.com Subject: fs/hugetlbfs/inode.c: mm/memory-failure.c: fix hugetlbfs hwpoison handling Date: Fri, 12 Jan 2024 10:08:40 -0800

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 Cc: James Houghton jthoughton@google.com Cc: Jiaqi Yan jiaqiyan@google.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Miaohe Lin linmiaohe@huawei.com Cc: Muchun Song muchun.song@linux.dev Cc: Naoya Horiguchi naoya.horiguchi@nec.com Cc: stable@vger.kernel.org [6.7+] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/hugetlbfs/inode.c | 2 +- mm/memory-failure.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/fs/hugetlbfs/inode.c~fs-hugetlbfs-inodec-mm-memory-failurec-fix-hugetlbfs-hwpoison-handling +++ a/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~fs-hugetlbfs-inodec-mm-memory-failurec-fix-hugetlbfs-hwpoison-handling +++ a/mm/memory-failure.c @@ -982,7 +982,7 @@ 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", _

Patches currently in -mm which might be from sidhartha.kumar@oracle.com are

fs-hugetlbfs-inodec-mm-memory-failurec-fix-hugetlbfs-hwpoison-handling.patch maple_tree-fix-comment-describing-mas_node_count_gfp.patch