---
id: CVE-2022-50103
title: 'sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed

  With cgroup v2, the cpuset's cpus_allowed mask can be empty indicating
  that the cpuset will just u…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 7f51412a415d87ea8598d14722fb31e4f5701257 <
    336626564b58071b8980a4e6a31a8f5d92705d9b
  - >-
    Linux >= 7f51412a415d87ea8598d14722fb31e4f5701257 <
    147f66d22f58712dce7ccdd6a1f6cb3ee8042df4
  - >-
    Linux >= 7f51412a415d87ea8598d14722fb31e4f5701257 <
    357f3f0e522a6ce1ce4a571cb780d9861d53bec7
  - >-
    Linux >= 7f51412a415d87ea8598d14722fb31e4f5701257 <
    f56607b44c9896e51678a7e8cdd3a5479f4b4548
  - >-
    Linux >= 7f51412a415d87ea8598d14722fb31e4f5701257 <
    b6e8d40d43ae4dec00c8fea2593eeea3114b8f44
  - Linux 3.19
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T19:54:25.132451Z'
published: '2025-06-18'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T20:00:16.912Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2022-50103'
references:
  - url: 'https://git.kernel.org/stable/c/336626564b58071b8980a4e6a31a8f5d92705d9b'
  - url: 'https://git.kernel.org/stable/c/147f66d22f58712dce7ccdd6a1f6cb3ee8042df4'
  - url: 'https://git.kernel.org/stable/c/357f3f0e522a6ce1ce4a571cb780d9861d53bec7'
  - url: 'https://git.kernel.org/stable/c/f56607b44c9896e51678a7e8cdd3a5479f4b4548'
  - url: 'https://git.kernel.org/stable/c/b6e8d40d43ae4dec00c8fea2593eeea3114b8f44'
tags:
  - cve.org
epss: 0.00198
epssPercentile: 0.0966
ingestedAt: '2026-11-05T22:38:31.660Z'
---

## Overview

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

sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed

With cgroup v2, the cpuset's cpus_allowed mask can be empty indicating
that the cpuset will just use the effective CPUs of its parent. So
cpuset_can_attach() can call task_can_attach() with an empty mask.
This can lead to cpumask_any_and() returns nr_cpu_ids causing the call
to dl_bw_of() to crash due to percpu value access of an out of bound
CPU value. For example:

	[80468.182258] BUG: unable to handle page fault for address: ffffffff8b6648b0
	  :
	[80468.191019] RIP: 0010:dl_cpu_busy+0x30/0x2b0
	  :
	[80468.207946] Call Trace:
	[80468.208947]  cpuset_can_attach+0xa0/0x140
	[80468.209953]  cgroup_migrate_execute+0x8c/0x490
	[80468.210931]  cgroup_update_dfl_csses+0x254/0x270
	[80468.211898]  cgroup_subtree_control_write+0x322/0x400
	[80468.212854]  kernfs_fop_write_iter+0x11c/0x1b0
	[80468.213777]  new_sync_write+0x11f/0x1b0
	[80468.214689]  vfs_write+0x1eb/0x280
	[80468.215592]  ksys_write+0x5f/0xe0
	[80468.216463]  do_syscall_64+0x5c/0x80
	[80468.224287]  entry_SYSCALL_64_after_hwframe+0x44/0xae

Fix that by using effective_cpus instead. For cgroup v1, effective_cpus
is the same as cpus_allowed. For v2, effective_cpus is the real cpumask
to be used by tasks within the cpuset anyway.

Also update task_can_attach()'s 2nd argument name to cs_effective_cpus to
reflect the change. In addition, a check is added to task_can_attach()
to guard against the possibility that cpumask_any_and() may return a
value >= nr_cpu_ids.

## Affected

- `Linux >= 7f51412a415d87ea8598d14722fb31e4f5701257 < 336626564b58071b8980a4e6a31a8f5d92705d9b`
- `Linux >= 7f51412a415d87ea8598d14722fb31e4f5701257 < 147f66d22f58712dce7ccdd6a1f6cb3ee8042df4`
- `Linux >= 7f51412a415d87ea8598d14722fb31e4f5701257 < 357f3f0e522a6ce1ce4a571cb780d9861d53bec7`
- `Linux >= 7f51412a415d87ea8598d14722fb31e4f5701257 < f56607b44c9896e51678a7e8cdd3a5479f4b4548`
- `Linux >= 7f51412a415d87ea8598d14722fb31e4f5701257 < b6e8d40d43ae4dec00c8fea2593eeea3114b8f44`
- `Linux 3.19`

## Remediation

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