---
id: "CVE-2026-98729"
kind: "vulnerability"
aliases: ["CVE-2026-98729"]
title: "Linux kernel: hugetlb mappings on AMD F15h can trigger teardown crash"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["amd-f15h", "hugetlbfs", "infrastructure", "linux-kernel", "x86"]
not_affected_if: ["no-hugetlbfs-use", "non-amd-f15h-cpu"]
published_at: "2026-10-18T16:17:26+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:17:15+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98729", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux kernel: hugetlb mappings on AMD F15h can trigger teardown crash

On AMD F15h x86 systems, the kernel applies a randomised alignment to hugetlbfs mappings, so mapped addresses fall off the huge page boundary. Teardown then hits a BUG_ON in __unmap_hugepage_range, which crashes the kernel.

_Summary, check and fix written by a model from the sources; labelled as such._

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98729

## From the sources

In the Linux kernel, the following vulnerability has been resolved:

x86/mm: Don't apply va_align to hugetlb mappings on AMD F15h

get_align_mask() returns huge_page_mask_align() for hugetlbfs, but get_align_bits()
adds va_align.bits regardless, so vm_unmapped_area() returns an address off the huge
page boundary and __unmap_hugepage_range() hits BUG_ON(start & ~huge_page_mask(h)) at
teardown.

This can be triggered on Carrizo and FX-8370E, both hstates.

Pass the file to get_align_bits() and skip the randomisation for hugetlbfs.

  [ bp: Massage commit message. ]

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