The quilt patch titled Subject: mm/hugetlb: fix memfd_pin_folios resv_huge_pages leak has been removed from the -mm tree. Its filename was mm-hugetlb-fix-memfd_pin_folios-resv_huge_pages-leak.patch

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

------------------------------------------------------ From: Steve Sistare steven.sistare@oracle.com Subject: mm/hugetlb: fix memfd_pin_folios resv_huge_pages leak Date: Tue, 3 Sep 2024 07:25:19 -0700

memfd_pin_folios followed by unpin_folios leaves resv_huge_pages elevated if the pages were not already faulted in. During a normal page fault, resv_huge_pages is consumed here:

hugetlb_fault() alloc_hugetlb_folio() dequeue_hugetlb_folio_vma() dequeue_hugetlb_folio_nodemask() dequeue_hugetlb_folio_node_exact() free_huge_pages-- resv_huge_pages--

During memfd_pin_folios, the page is created by calling alloc_hugetlb_folio_nodemask instead of alloc_hugetlb_folio, and resv_huge_pages is not modified:

memfd_alloc_folio() alloc_hugetlb_folio_nodemask() dequeue_hugetlb_folio_nodemask() dequeue_hugetlb_folio_node_exact() free_huge_pages--

alloc_hugetlb_folio_nodemask has other callers that must not modify resv_huge_pages. Therefore, to fix, define an alternate version of alloc_hugetlb_folio_nodemask for this call site that adjusts resv_huge_pages.

Link: https://lkml.kernel.org/r/1725373521-451395-4-git-send-email-steven.sistare@... Fixes: 89c1905d9c14 ("mm/gup: introduce memfd_pin_folios() for pinning memfd folios") Signed-off-by: Steve Sistare steven.sistare@oracle.com Acked-by: Vivek Kasireddy vivek.kasireddy@intel.com Cc: David Hildenbrand david@redhat.com Cc: Jason Gunthorpe jgg@nvidia.com Cc: Matthew Wilcox willy@infradead.org Cc: Muchun Song muchun.song@linux.dev Cc: Peter Xu peterx@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

include/linux/hugetlb.h | 10 ++++++++++ mm/hugetlb.c | 17 +++++++++++++++++ mm/memfd.c | 9 ++++----- 3 files changed, 31 insertions(+), 5 deletions(-)

--- a/include/linux/hugetlb.h~mm-hugetlb-fix-memfd_pin_folios-resv_huge_pages-leak +++ a/include/linux/hugetlb.h @@ -692,6 +692,9 @@ struct folio *alloc_hugetlb_folio(struct struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid, nodemask_t *nmask, gfp_t gfp_mask, bool allow_alloc_fallback); +struct folio *alloc_hugetlb_folio_reserve(struct hstate *h, int preferred_nid, + nodemask_t *nmask, gfp_t gfp_mask); + int hugetlb_add_to_page_cache(struct folio *folio, struct address_space *mapping, pgoff_t idx); void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma, @@ -1058,6 +1061,13 @@ static inline struct folio *alloc_hugetl { return NULL; } + +static inline struct folio * +alloc_hugetlb_folio_reserve(struct hstate *h, int preferred_nid, + nodemask_t *nmask, gfp_t gfp_mask) +{ + return NULL; +}

static inline struct folio * alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid, --- a/mm/hugetlb.c~mm-hugetlb-fix-memfd_pin_folios-resv_huge_pages-leak +++ a/mm/hugetlb.c @@ -2390,6 +2390,23 @@ struct folio *alloc_buddy_hugetlb_folio_ return folio; }

+struct folio *alloc_hugetlb_folio_reserve(struct hstate *h, int preferred_nid, + nodemask_t *nmask, gfp_t gfp_mask) +{ + struct folio *folio; + + spin_lock_irq(&hugetlb_lock); + folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask, preferred_nid, + nmask); + if (folio) { + VM_BUG_ON(!h->resv_huge_pages); + h->resv_huge_pages--; + } + + spin_unlock_irq(&hugetlb_lock); + return folio; +} + /* folio migration callback function */ struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid, nodemask_t *nmask, gfp_t gfp_mask, bool allow_alloc_fallback) --- a/mm/memfd.c~mm-hugetlb-fix-memfd_pin_folios-resv_huge_pages-leak +++ a/mm/memfd.c @@ -82,11 +82,10 @@ struct folio *memfd_alloc_folio(struct f gfp_mask = htlb_alloc_mask(hstate_file(memfd)); gfp_mask &= ~(__GFP_HIGHMEM | __GFP_MOVABLE);

- folio = alloc_hugetlb_folio_nodemask(hstate_file(memfd), - numa_node_id(), - NULL, - gfp_mask, - false); + folio = alloc_hugetlb_folio_reserve(hstate_file(memfd), + numa_node_id(), + NULL, + gfp_mask); if (folio && folio_try_get(folio)) { err = hugetlb_add_to_page_cache(folio, memfd->f_mapping, _

Patches currently in -mm which might be from steven.sistare@oracle.com are