U.S. flag   An official website of the United States government
Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock (Dot gov) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2025-21767 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: clocksource: Use migrate_disable() to avoid calling get_random_u32() in atomic context The following bug report happened with a PREEMPT_RT kernel: BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2012, name: kwatchdog preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 get_random_u32+0x4f/0x110 clocksource_verify_choose_cpus+0xab/0x1a0 clocksource_verify_percpu.part.0+0x6b/0x330 clocksource_watchdog_kthread+0x193/0x1a0 It is due to the fact that clocksource_verify_choose_cpus() is invoked with preemption disabled. This function invokes get_random_u32() to obtain random numbers for choosing CPUs. The batched_entropy_32 local lock and/or the base_crng.lock spinlock in driver/char/random.c will be acquired during the call. In PREEMPT_RT kernel, they are both sleeping locks and so cannot be acquired in atomic context. Fix this problem by using migrate_disable() to allow smp_processor_id() to be reliably used without introducing atomic context. preempt_disable() is then called after clocksource_verify_choose_cpus() but before the clocksource measurement is being run to avoid introducing unexpected latency.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to [email protected].

URL Source(s) Tag(s)
https://cert-portal.siemens.com/productcert/html/ssa-082556.html siemens-SADP
https://git.kernel.org/stable/c/0fb534187d2355f6c8f995321e76d1ccd1262ac1 kernel.org Patch 
https://git.kernel.org/stable/c/60f54f0d4ea530950549a8263e6fdd70a40490a4 kernel.org Patch 
https://git.kernel.org/stable/c/6bb05a33337b2c842373857b63de5c9bf1ae2a09 kernel.org Patch 
https://git.kernel.org/stable/c/852805b6cbdb69c298a8fc9fbe79994c95106e04 kernel.org Patch 
https://git.kernel.org/stable/c/8783ceeee797d9aa9cfe150690fb9d0bac8cc459 kernel.org Patch 
https://git.kernel.org/stable/c/cc3d79e7c806cb57d71c28a4a35e7d7fb3265faa kernel.org Patch 
https://git.kernel.org/stable/c/d9c217fadfcff7a8df58567517d1e4253f3fd243 kernel.org Patch 
https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html CVE
https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html CVE

Weakness Enumeration

CWE-ID CWE Name Source
CWE-667 Improper Locking cwe source acceptance level NIST  

Known Affected Software Configurations Switch to CPE 2.2

CPEs loading, please wait.

Denotes Vulnerable Software
Are we missing a CPE here? Please let us know.

Change History

7 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2025-21767
NVD Published Date:
02/26/2025
NVD Last Modified:
06/17/2026
Source:
kernel.org