---
id: CVE-2026-97587
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  perf: RISC-V: store available counter mask as bitmap

  The available-counter mask was a single unsigned long, but iteration
  uses RISCV_MAX_COUNTERS, which is 64
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  perf: RISC-V: store available counter mask as bitmap

  The available-counter mask was a single unsigned long, but iteration
  uses RISCV_MAX_COUNTERS, which is 64. On RV32…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= e9991434596f5373dfd75857b445eb92a9253c56 <
    143668c424772979a45118dc9cc9c2c13a35f41d
  - >-
    Linux >= e9991434596f5373dfd75857b445eb92a9253c56 <
    9bec7beaed074bcae4181fde9ff9dfbe4e7b0957
  - >-
    Linux >= e9991434596f5373dfd75857b445eb92a9253c56 <
    e5481db31f4654e9a1254d5d467d9b1ff2f8b1cb
  - >-
    Linux >= e9991434596f5373dfd75857b445eb92a9253c56 <
    6809da6e9c08ccc9a09cb0a48c61471679274aaa
  - Linux 5.18
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:09.880'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97587'
references:
  - url: 'https://git.kernel.org/stable/c/143668c424772979a45118dc9cc9c2c13a35f41d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6809da6e9c08ccc9a09cb0a48c61471679274aaa'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9bec7beaed074bcae4181fde9ff9dfbe4e7b0957'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e5481db31f4654e9a1254d5d467d9b1ff2f8b1cb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.906Z'
---

## Overview

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

perf: RISC-V: store available counter mask as bitmap

The available-counter mask was a single unsigned long, but iteration
uses RISCV_MAX_COUNTERS, which is 64. On RV32 that reads past the object.
Filling with an unsigned-long bit at index 32 and above is also wrong.

Use DECLARE_BITMAP and set_bit/bitmap helpers. Walk each bitmap word
into CFG_MATCH when checking events, when allocating an index, and when
stopping all counters. Set the counter base to i times BITS_PER_LONG.
Share the CFG_MATCH ecall through a small helper so the 32-bit argument
split is not duplicated. On qemu-system-riscv32 the probe bitmap has bits
above XLEN set, so the first word alone is not enough.

[pjw@kernel.org: updated to apply; fixed checkpatch.pl issues]

## Remediation

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