---
id: CVE-2026-98552
title: 'perf/core: Fix a refcount leak in attach_perf_ctx_data()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  perf/core: Fix a refcount leak in attach_perf_ctx_data()

  The attach_perf_ctx_data() can race on global and !global cases.  The
  global case is protected by global_ctx_d…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 506e64e710ff9573fd2b86686528762b7901b5e4 <
    23250517cd475367653f1e99396967f54c6f1b7c
  - >-
    Linux >= 506e64e710ff9573fd2b86686528762b7901b5e4 <
    5286d4eb5cd7e10d7d93c3cc596e18bc8ad80f72
  - >-
    Linux >= 506e64e710ff9573fd2b86686528762b7901b5e4 <
    cca4980630b3c7a85f53cb43c6018184ce5d4e37
  - Linux 6.15
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:18:19.810Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98552'
references:
  - url: 'https://git.kernel.org/stable/c/23250517cd475367653f1e99396967f54c6f1b7c'
  - url: 'https://git.kernel.org/stable/c/5286d4eb5cd7e10d7d93c3cc596e18bc8ad80f72'
  - url: 'https://git.kernel.org/stable/c/cca4980630b3c7a85f53cb43c6018184ce5d4e37'
tags:
  - cve.org
ingestedAt: '2026-10-18T15:45:12.264Z'
---

## Overview

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

perf/core: Fix a refcount leak in attach_perf_ctx_data()

The attach_perf_ctx_data() can race on global and !global cases.  The
global case is protected by global_ctx_data_rwsem and shares a single
reference count using perf_ctx_data.global field.

But when it races with !global case, it may miss to set the global field
and result in a reference count leak.

 CPU1                                  CPU2
 ----------------------------------------------------------------
 attach_task_ctx_data(.global=1)       attach_task_ctx_data(.global=0)
   cd1 = alloc_perf_ctx_data();          cd2 = alloc_perf_ctx_data();
                                         //    { .global = 0, .refcount = 1 };

                                         try_cmpxchg(); // success,
                                         // task->perf_ctx_data = cd2
   try_cmpxhg(); // fail; old = cd2
   refcount_inc_not_zero(&old->refcount); // success
     // old.refcount = 2
   free_perf_ctx_data(cd1);

Then later detach_global_ctx_data() will see the data but it's not
marked as global, so it won't call detach_task_ctx_data().

## Affected

- `Linux >= 506e64e710ff9573fd2b86686528762b7901b5e4 < 23250517cd475367653f1e99396967f54c6f1b7c`
- `Linux >= 506e64e710ff9573fd2b86686528762b7901b5e4 < 5286d4eb5cd7e10d7d93c3cc596e18bc8ad80f72`
- `Linux >= 506e64e710ff9573fd2b86686528762b7901b5e4 < cca4980630b3c7a85f53cb43c6018184ce5d4e37`
- `Linux 6.15`

## Remediation

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