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authorSteve Sistare <steven.sistare@oracle.com>2024-09-03 16:25:20 +0200
committerAndrew Morton <akpm@linux-foundation.org>2024-09-26 23:01:43 +0200
commit9289f020da47ef04b28865589eeee3d56d4bafea (patch)
treeae6d67b30630c49d5633035711789164ebde35f4
parentmm/hugetlb: fix memfd_pin_folios resv_huge_pages leak (diff)
downloadlinux-9289f020da47ef04b28865589eeee3d56d4bafea.tar.xz
linux-9289f020da47ef04b28865589eeee3d56d4bafea.zip
mm/gup: fix memfd_pin_folios hugetlb page allocation
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@oracle.com 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>
-rw-r--r--mm/memfd.c8
1 files changed, 6 insertions, 2 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));
+ struct hstate *h = 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(hstate_file(memfd),
+ 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);