Bug 2532254 (CVE-2026-89501)

Summary:	CVE-2026-89501 kernel: ring-buffer: Hold cpu_buffer::lock when resizing a subbuf
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's ring-buffer component. A race condition occurs when resizing a sub-buffer without properly holding the `cpu_buffer::lock`. This oversight can lead to concurrency issues with memory allocation and deallocation operations, potentially resulting in system instability or a denial of service.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-11 21:44:16 UTC

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

ring-buffer: Hold cpu_buffer::lock when resizing a subbuf

Because, ring_buffer_subbuf_order_set() can clear cpu_buffer->free_page,
hold cpu_buffer->lock to prevent races with
ring_buffer_alloc_read_page() and ring_buffer_free_read_page().

Comment 1 Keith Grant 2026-09-18 11:51:45 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89501.mbox