mm-hugetlb-fix-resv_huge_pages-double-decrement-in-memfd-error-path.patch removed from -mm tree

The quilt patch titled
Subject: mm/hugetlb: fix resv_huge_pages double decrement in memfd error path
has been removed from the -mm tree. Its filename was
mm-hugetlb-fix-resv_huge_pages-double-decrement-in-memfd-error-path.patch

This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Hongfu Li <[email protected]>
Subject: mm/hugetlb: fix resv_huge_pages double decrement in memfd error path
Date: Tue, 25 Aug 2026 10:10:13 +0800

alloc_hugetlb_folio_reserve() decrements h->resv_huge_pages when dequeuing a folio, but unlike the use_global_reservation handling in hugetlb_alloc_folio(), it does not set HPageRestoreReserve on the folio.

Its sole caller memfd_alloc_folio() pre-allocates a reservation via hugetlb_reserve_pages() before allocating. When hugetlb_add_to_page_cache() fails, folio_put() drops the folio without HPageRestoreReserve set, so free_huge_folio() does not restore the reservation. The subsequent hugetlb_unreserve_pages() on the err_unresv path decrements the counter a second time, leaving resv_huge_pages off by one for every failed allocation.

Set HPageRestoreReserve when consuming the reservation in alloc_hugetlb_folio_reserve(). On the error path, free_huge_folio() then restores the reservation before hugetlb_unreserve_pages() releases it. The success path is unaffected, as hugetlb_add_to_page_cache() clears the flag once the folio is added to the page cache.

---

 mm/hugetlb.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

@@ -2187,8 +2187,10 @@ struct folio *alloc_hugetlb_folio_reserv
 
 	folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask, preferred_nid,
 					       nmask);
-	if (folio)
+	if (folio) {
+		folio_set_hugetlb_restore_reserve(folio);
 		h->resv_huge_pages--;
+	}
 
 	spin_unlock_irq(&hugetlb_lock);
 	return folio;

_

Patches currently in -mm which might be from [email protected] are

mm-page_owner-preserve-original-free_pid-free_tgid-during-folio-migration.patch mm-memfd-fix-hugetlb-reservation-accounting-in-error-paths.patch selftests-mm-fix-ptrace-peekdata-check-in-memfd_secret-test.patch mm-hugetlb_cgroup-move-per-node-usage-on-cross-node-migration.patch mm-hugetlb_cgroup-move-per-node-usage-on-cgroup-reparenting.patch mm-hugetlb-account-migration-target-folio-in-per-node-nr_hugetlb-vmstat.patch mm-memcg-migrate-per-node-hugetlb-lruvec-stat-together-with-hugetlb-folio.patch