---
id: CVE-2026-98177
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  drm/amdkfd: Avoid integer underflow in EOP ring size calculation.

  The low 6 bits of cp_hqd_eop_control store the base-2 logarithm
  of the EOP ring size
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  drm/amdkfd: Avoid integer underflow in EOP ring size calculation.

  The low 6 bits of cp_hqd_eop_control store the base-2 logarithm
  of the EOP ring size. This was calcul…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    287a34c4d712e0bdb67751e21316d9c8d75a528a
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    8ee521b8b189799e361d4233c5180ba56656d4d4
  - Linux < 7.2.8
  - Linux (all versions)
published: '2026-10-06'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T09:17:59.787'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98177'
references:
  - url: 'https://git.kernel.org/stable/c/287a34c4d712e0bdb67751e21316d9c8d75a528a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8ee521b8b189799e361d4233c5180ba56656d4d4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-06T08:50:17.456Z'
---

## Overview

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

drm/amdkfd: Avoid integer underflow in EOP ring size calculation.

The low 6 bits of cp_hqd_eop_control store the base-2 logarithm
of the EOP ring size. This was calculated as

order_base_2(q->eop_ring_buffer_size / 4) - 1

But order_base_2 can in theory return 0, so this could underflow
(although in practice the ring buffer size cannot be less than 4096).

Change this to

order_base_2(q->eop_ring_buffer_size / 8)

using properties of logarithms.

Also add to the above comment to make the mathematics more clear.

(cherry picked from commit f0f43fcf8b2b3a924cad9444340921c96ed5f634)

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.