---
id: CVE-2026-98176
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  drm/amdkfd: Avoid integer underflow with ffs in EOP ring size calc

  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 with ffs in EOP ring size calc

  The low 6 bits of cp_hqd_eop_control store the base-2 logarithm
  of the EOP ring size. This was calcu…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    82e1b8299c6da02ce02185c208d2fdf7572b5ea1
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    c883d0a132d430ef7ebb23fd94323be94d0fbdb8
  - Linux < 7.2.8
  - Linux (all versions)
published: '2026-10-06'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T09:17:59.653'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98176'
references:
  - url: 'https://git.kernel.org/stable/c/82e1b8299c6da02ce02185c208d2fdf7572b5ea1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c883d0a132d430ef7ebb23fd94323be94d0fbdb8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-06T08:50:17.453Z'
---

## Overview

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

drm/amdkfd: Avoid integer underflow with ffs in EOP ring size calc

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

ffs(q->eop_ring_buffer_size / sizeof(unsigned int)) - 1 - 1

But ffs can in theory return 1 or 0, so this could underflow
(although in practice the ring buffer size cannot be less than 4096).

Change this to

ffs(q->eop_ring_buffer_size / sizeof(unsigned int) / 4)

using properties of logarithms.

(cherry picked from commit 4f18c56630383c14bfc6b2d65f88f2f895d2121a)

## Remediation

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