PT-2026-52250 · Linux · Linux

Publicado

2026-06-25

·

Atualizado

2026-06-25

·

CVE-2026-53154

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In the Linux kernel, the following vulnerability has been resolved:
mm/hugetlb: restore reservation on error in hugetlb folio copy paths
Two sites in mm/hugetlb.c allocate a hugetlb folio via alloc hugetlb folio() (consuming a VMA reservation) and then call copy user large folio(), which became int-returning in commit 1cb9dc4b475c ("mm: hwpoison: support recovery from HugePage copy-on-write faults") and can now fail (e.g. -EHWPOISON on a hwpoisoned source page). On the failure path, folio put() restores the global hugetlb pool count through free huge folio(), but the per-VMA reservation map entry is left marked consumed:
  • hugetlb mfill atomic pte() resubmission path (UFFDIO COPY)
  • copy hugetlb page range() fork-time CoW path when hugetlb try dup anon rmap() fails (rare: pinned hugetlb anon folio under fork)
User-visible effect: on UFFDIO COPY into a private hugetlb VMA where the resubmission copy fails, the reservation for that address is leaked from the VMA's reserve map. A subsequent fault at the same address takes the no-reservation path, and under hugetlb pool pressure the task is SIGBUSed at an address it had previously reserved. The fork-time CoW path leaks the same way in the child VMA's reserve map, though it requires the much rarer combination of pinned hugetlb anon page + hwpoisoned source.
Add the missing restore reserve on error() call before folio put() on both error paths.
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Identificadores relacionados

CVE-2026-53154

Produtos afetados

Linux