CVE-2026-72213

Description

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: fix hugetlb cgroup rsvd charge/uncharge mismatch In alloc_hugetlb_folio(), a single h_cg pointer is used for both the rsvd and non-rsvd hugetlb cgroup charges. When map_chg is set, hugetlb_cgroup_charge_cgroup_rsvd() stores the charged cgroup in h_cg, but the immediately following hugetlb_cgroup_charge_cgroup() overwrites h_cg with the non-rsvd cgroup pointer. As a result, hugetlb_cgroup_commit_charge_rsvd() stores the wrong (non-rsvd) cgroup pointer into the folio's rsvd slot. When the folio is later freed, free_huge_folio() unconditionally calls both hugetlb_cgroup_uncharge_folio() and hugetlb_cgroup_uncharge_folio_rsvd(). The rsvd uncharge reads back the wrong cgroup from the folio and decrements a counter that was never charged for that cgroup, causing a page_counter underflow: page_counter underflow: -512 nr_pages=512 WARNING: mm/page_counter.c:61 at page_counter_cancel Fix this by introducing a separate h_cg_rsvd pointer exclusively for the rsvd charge path, keeping the rsvd and non-rsvd charges fully independent through their charge, commit, and error uncharge paths.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

References

• https://git.kernel.org/stable/c/f8dfdf725bccb0ae41eead2f6da8183727218855 ↗
• https://git.kernel.org/stable/c/043c509f2488033c68c46d2de2af082fcd568612 ↗
• https://git.kernel.org/stable/c/5c32ae4a91fb5f4941328e0c1720a7fa4189c3bd ↗
• https://git.kernel.org/stable/c/1697d253f51cf5e3825a3423ff49e128a3502ab2 ↗
• https://git.kernel.org/stable/c/b785f2bd9496facedc0a031be09cddcd1d3c84d3 ↗
• https://git.kernel.org/stable/c/15807d0ddde37407af72859426b654f3d1972b00 ↗