The patch titled Subject: mm/memory-failure: fix missing ->mf_stats count in hugetlb poison has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-memory-failure-fix-missing-mf_stats-count-in-hugetlb-poison.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: Jane Chu jane.chu@oracle.com Subject: mm/memory-failure: fix missing ->mf_stats count in hugetlb poison Date: Fri, 19 Dec 2025 12:15:58 -0700

When a newly poisoned subpage ends up in an already poisoned hugetlb folio, 'num_poisoned_pages' is incremented, but the per node ->mf_stats is not. Fix the inconsistency by designating action_result() to update them both.

While at it, define __get_huge_page_for_hwpoison() return values in terms of symbol names for better readibility. Also rename folio_set_hugetlb_hwpoison() to hugetlb_update_hwpoison() since the function does more than the conventional bit setting and the fact three possible return values are expected.

Link: https://lkml.kernel.org/r/20251219191559.2962716-1-jane.chu@oracle.com Fixes: 18f41fa616ee4 ("mm: memory-failure: bump memory failure stats to pglist_data") Signed-off-by: Jane Chu jane.chu@oracle.com Cc: "David Hildenbrand (Red Hat)" david@kernel.org Cc: David Rientjes rientjes@google.com Cc: Jiaqi Yan jiaqiyan@google.com Cc: Liam Howlett liam.howlett@oracle.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Miaohe Lin linmiaohe@huawei.com Cc: Michal Hocko mhocko@suse.com Cc: Mike Rapoport rppt@kernel.org Cc: Muchun Song muchun.song@linux.dev Cc: Oscar Salvador osalvador@suse.de Cc: Suren Baghdasaryan surenb@google.com Cc: William Roche william.roche@oracle.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/memory-failure.c | 56 ++++++++++++++++++++++++------------------ 1 file changed, 33 insertions(+), 23 deletions(-)

--- a/mm/memory-failure.c~mm-memory-failure-fix-missing-mf_stats-count-in-hugetlb-poison +++ a/mm/memory-failure.c @@ -1883,12 +1883,18 @@ static unsigned long __folio_free_raw_hw return count; }

-static int folio_set_hugetlb_hwpoison(struct folio *folio, struct page *page) +#define MF_HUGETLB_ALREADY_POISONED 3 /* already poisoned */ +#define MF_HUGETLB_ACC_EXISTING_POISON 4 /* accessed existing poisoned page */ +/* + * Set hugetlb folio as hwpoisoned, update folio private raw hwpoison list + * to keep track of the poisoned pages. + */ +static int hugetlb_update_hwpoison(struct folio *folio, struct page *page) { struct llist_head *head; struct raw_hwp_page *raw_hwp; struct raw_hwp_page *p; - int ret = folio_test_set_hwpoison(folio) ? -EHWPOISON : 0; + int ret = folio_test_set_hwpoison(folio) ? MF_HUGETLB_ALREADY_POISONED : 0;

/* * Once the hwpoison hugepage has lost reliable raw error info, @@ -1896,20 +1902,18 @@ static int folio_set_hugetlb_hwpoison(st * so skip to add additional raw error info. */ if (folio_test_hugetlb_raw_hwp_unreliable(folio)) - return -EHWPOISON; + return MF_HUGETLB_ALREADY_POISONED; + head = raw_hwp_list_head(folio); llist_for_each_entry(p, head->first, node) { if (p->page == page) - return -EHWPOISON; + return MF_HUGETLB_ACC_EXISTING_POISON; }

raw_hwp = kmalloc(sizeof(struct raw_hwp_page), GFP_ATOMIC); if (raw_hwp) { raw_hwp->page = page; llist_add(&raw_hwp->node, head); - /* the first error event will be counted in action_result(). */ - if (ret) - num_poisoned_pages_inc(page_to_pfn(page)); } else { /* * Failed to save raw error info. We no longer trace all @@ -1955,32 +1959,30 @@ void folio_clear_hugetlb_hwpoison(struct folio_free_raw_hwp(folio, true); }

+#define MF_HUGETLB_FREED 0 /* freed hugepage */ +#define MF_HUGETLB_IN_USED 1 /* in-use hugepage */ +#define MF_NOT_HUGETLB 2 /* not a hugepage */ + /* * Called from hugetlb code with hugetlb_lock held. - * - * Return values: - * 0 - free hugepage - * 1 - in-use hugepage - * 2 - not a hugepage - * -EBUSY - the hugepage is busy (try to retry) - * -EHWPOISON - the hugepage is already hwpoisoned */ int __get_huge_page_for_hwpoison(unsigned long pfn, int flags, bool *migratable_cleared) { struct page *page = pfn_to_page(pfn); struct folio *folio = page_folio(page); - int ret = 2; /* fallback to normal page handling */ + int ret = MF_NOT_HUGETLB; bool count_increased = false; + int rc;

if (!folio_test_hugetlb(folio)) goto out;

if (flags & MF_COUNT_INCREASED) { - ret = 1; + ret = MF_HUGETLB_IN_USED; count_increased = true; } else if (folio_test_hugetlb_freed(folio)) { - ret = 0; + ret = MF_HUGETLB_FREED; } else if (folio_test_hugetlb_migratable(folio)) { ret = folio_try_get(folio); if (ret) @@ -1991,8 +1993,9 @@ int __get_huge_page_for_hwpoison(unsigne goto out; }

- if (folio_set_hugetlb_hwpoison(folio, page)) { - ret = -EHWPOISON; + rc = hugetlb_update_hwpoison(folio, page); + if (rc >= MF_HUGETLB_ALREADY_POISONED) { + ret = rc; goto out; }

@@ -2029,22 +2032,29 @@ static int try_memory_failure_hugetlb(un *hugetlb = 1; retry: res = get_huge_page_for_hwpoison(pfn, flags, &migratable_cleared); - if (res == 2) { /* fallback to normal page handling */ + switch (res) { + case MF_NOT_HUGETLB: /* fallback to normal page handling */ *hugetlb = 0; return 0; - } else if (res == -EHWPOISON) { + case MF_HUGETLB_ALREADY_POISONED: + case MF_HUGETLB_ACC_EXISTING_POISON: if (flags & MF_ACTION_REQUIRED) { folio = page_folio(p); res = kill_accessing_process(current, folio_pfn(folio), flags); } - action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED); + if (res == MF_HUGETLB_ALREADY_POISONED) + action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED); + else + action_result(pfn, MF_MSG_HUGE, MF_FAILED); return res; - } else if (res == -EBUSY) { + case -EBUSY: if (!(flags & MF_NO_RETRY)) { flags |= MF_NO_RETRY; goto retry; } return action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED); + default: + break; }

folio = page_folio(p); _

Patches currently in -mm which might be from jane.chu@oracle.com are

mm-memory-failure-fix-missing-mf_stats-count-in-hugetlb-poison.patch