---
id: CVE-2026-93795
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  blk-cgroup: fix leaks and online flag on radix_tree_insert failure

  When radix_tree_insert() fails in blkg_create(), the error path has two
  issues:

  1
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  blk-cgroup: fix leaks and online flag on radix_tree_insert failure

  When radix_tree_insert() fails in blkg_create(), the error path has two
  issues:

  1. blkg->online is …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    6e85f02d45b5977c0326a8d854c6db878aa6b34a
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    4c0d150fb98ea40760611979f4e664c244b20966
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    dbbca20764382b4d411ec2918f4e278ffe547acc
  - Linux < 6.12.111
  - Linux < 6.18.53
  - Linux (all versions)
published: '2026-09-24'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T13:17:20.097'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93795'
references:
  - url: 'https://git.kernel.org/stable/c/4c0d150fb98ea40760611979f4e664c244b20966'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6e85f02d45b5977c0326a8d854c6db878aa6b34a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dbbca20764382b4d411ec2918f4e278ffe547acc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-24T16:47:15.900Z'
epss: 0.00166
epssPercentile: 0.05196
---

## Overview

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

blk-cgroup: fix leaks and online flag on radix_tree_insert failure

When radix_tree_insert() fails in blkg_create(), the error path has two
issues:

1. blkg->online is set to true unconditionally, even when the blkg was
   never fully inserted.  Move the assignment inside the success block.

2. The error path calls blkg_put() without first calling
   percpu_ref_kill().  Because the refcount is still in percpu mode,
   percpu_ref_put() only does this_cpu_sub() without checking for zero,
   so blkg_release() is never triggered.  This permanently leaks the
   blkg memory, its percpu iostat, policy data, the parent blkg
   reference, and the cgroup css reference — the latter preventing the
   cgroup from ever being destroyed.

Fix by replacing blkg_put() with percpu_ref_kill(), matching the pattern
used in blkg_destroy().

## Remediation

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