Bug 2395380 (CVE-2022-50285)

Summary: CVE-2022-50285 kernel: mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-09-15 15:10:44 UTC 
In the Linux kernel, the following vulnerability has been resolved:

mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages

The h->*_huge_pages counters are protected by the hugetlb_lock, but
alloc_huge_page has a corner case where it can decrement the counter
outside of the lock.

This could lead to a corrupted value of h->resv_huge_pages, which we have
observed on our systems.

Take the hugetlb_lock before decrementing h->resv_huge_pages to avoid a
potential race.
Comment 1 Jon Moroney 2025-09-15 18:57:40 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025091507-CVE-2022-50285-955c@gregkh/T