Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: fix memfd_pin_folios free_huge_pages leak memfd_pin_folios followed by unpin_folios fails to restore free_huge_pages if the pages were not already faulted in, because the folio refcount for pages created by memfd_alloc_folio never goes to 0. memfd_pin_folios needs another folio_put to undo the folio_try_get below: memfd_alloc_folio() alloc_hugetlb_folio_nodemask() dequeue_hugetlb_folio_nodemask() dequeue_hugetlb_folio_node_exact() folio_ref_unfreeze(folio, 1); ; adds 1 refcount folio_try_get() ; adds 1 refcount hugetlb_add_to_page_cache() ; adds 512 refcount (on x86) With the fix, after memfd_pin_folios + unpin_folios, the refcount for the (unfaulted) page is 512, which is correct, as the refcount for a faulted unpinned page is 513.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 89c1905d9c140372b7f50ef48f42378cf85d9bc5 before 59e081ff2e91bbf19b8c1ecb75b031f778858383; affected 89c1905d9c140372b7f50ef48f42378cf85d9bc5 before c56b6f3d801d7ec8965993342bdd9e2972b6cb8e |
| Linux / Linux | affected 6.11; unaffected 0 before 6.11; unaffected 6.11.3 through 6.11.*; unaffected 6.12 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/59e081ff2e91bbf19b8c1ecb75b031f778858383
- https://git.kernel.org/stable/c/c56b6f3d801d7ec8965993342bdd9e2972b6cb8e
ADP enrichment
No English description supplied.
No references supplied.