From: Steve Sistare <steven.sistare@xxxxxxxxxx> commit 9289f020da47ef04b28865589eeee3d56d4bafea upstream. When memfd_pin_folios -> memfd_alloc_folio creates a hugetlb page, the index is wrong. The subsequent call to filemap_get_folios_contig thus cannot find it, and fails, and memfd_pin_folios loops forever. To fix, adjust the index for the huge_page_order. memfd_alloc_folio also forgets to unlock the folio, so the next touch of the page calls hugetlb_fault which blocks forever trying to take the lock. Unlock it. Link: https://lkml.kernel.org/r/1725373521-451395-5-git-send-email-steven.sistare@xxxxxxxxxx Fixes: 89c1905d9c14 ("mm/gup: introduce memfd_pin_folios() for pinning memfd folios") Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx> Acked-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Muchun Song <muchun.song@xxxxxxxxx> Cc: Peter Xu <peterx@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/memfd.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/memfd.c b/mm/memfd.c index bfe0e7189a37..bcb131db829d 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -79,10 +79,13 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx) * alloc from. Also, the folio will be pinned for an indefinite * amount of time, so it is not expected to be migrated away. */ - gfp_mask = htlb_alloc_mask(hstate_file(memfd)); - gfp_mask &= ~(__GFP_HIGHMEM | __GFP_MOVABLE); + struct hstate *h = hstate_file(memfd); - folio = alloc_hugetlb_folio_reserve(hstate_file(memfd), + gfp_mask = htlb_alloc_mask(h); + gfp_mask &= ~(__GFP_HIGHMEM | __GFP_MOVABLE); + idx >>= huge_page_order(h); + + folio = alloc_hugetlb_folio_reserve(h, numa_node_id(), NULL, gfp_mask); @@ -95,6 +98,7 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx) free_huge_folio(folio); return ERR_PTR(err); } + folio_unlock(folio); return folio; } return ERR_PTR(-ENOMEM); -- 2.46.2 Patches currently in stable-queue which might be from steven.sistare@xxxxxxxxxx are queue-6.11/mm-gup-fix-memfd_pin_folios-alloc-race-panic.patch queue-6.11/mm-hugetlb-fix-memfd_pin_folios-resv_huge_pages-leak.patch queue-6.11/mm-hugetlb-simplify-refs-in-memfd_alloc_folio.patch queue-6.11/mm-hugetlb-fix-memfd_pin_folios-free_huge_pages-leak.patch queue-6.11/mm-filemap-fix-filemap_get_folios_contig-thp-panic.patch queue-6.11/mm-gup-fix-memfd_pin_folios-hugetlb-page-allocation.patch
