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

sched/ext: Prevent update_locked_rq() calls with NULL rq

Avoid invoking update_locked_rq() when the runqueue (rq) pointer is NULL
in the SCX_CALL_OP and SCX_CALL_OP_RET macros.

Previously, calling update_locked_rq(NULL) with preemption enabled could
trigger the following warning:

BUG: using __this_cpu_write() in preemptible [00000000]

This happens because __this_cpu_write() is unsafe to use in preemptible
context.

rq is NULL when an ops invoked from an unlocked context. In such cases, we
don't need to store any rq, since the value should already be NULL
(unlocked). Ensure that update_locked_rq() is only called when rq is
non-NULL, preventing calling __this_cpu_write() on preemptible context.
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 19 Aug 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Mon, 18 Aug 2025 21:00:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Sat, 16 Aug 2025 11:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: sched/ext: Prevent update_locked_rq() calls with NULL rq Avoid invoking update_locked_rq() when the runqueue (rq) pointer is NULL in the SCX_CALL_OP and SCX_CALL_OP_RET macros. Previously, calling update_locked_rq(NULL) with preemption enabled could trigger the following warning: BUG: using __this_cpu_write() in preemptible [00000000] This happens because __this_cpu_write() is unsafe to use in preemptible context. rq is NULL when an ops invoked from an unlocked context. In such cases, we don't need to store any rq, since the value should already be NULL (unlocked). Ensure that update_locked_rq() is only called when rq is non-NULL, preventing calling __this_cpu_write() on preemptible context.
Title sched/ext: Prevent update_locked_rq() calls with NULL rq
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-08-16T11:12:11.304Z

Reserved: 2025-04-16T04:51:24.023Z

Link: CVE-2025-38522

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-08-16T12:15:27.523

Modified: 2025-08-18T20:16:28.750

Link: CVE-2025-38522

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-08-16T00:00:00Z

Links: CVE-2025-38522 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-08-18T20:50:04Z