Bug 2540459 (CVE-2026-97521)

Summary:	CVE-2026-97521 kernel: gfs2: fix quota init duplicate scan
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
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 GFS2 (Global File System 2) file system, which can lead to a Denial of Service (DoS). In real-time kernel configurations, the quota initialization routine improperly invokes a sleeping function while holding an atomic lock. A local user capable of triggering GFS2 quota operations could exploit this behavior to cause a kernel crash and system unresponsiveness.	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 2026-09-24 16:54:33 UTC

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

gfs2: fix quota init duplicate scan

gfs2_quota_init() checks for duplicate quota_change IDs while holding
qd_lock and the quota hash bucket bitlock. That path used
gfs2_qd_search_bucket(), which takes a lockref reference via
lockref_get_not_dead().

On PREEMPT_RT this may sleep, which is not allowed under the bucket
bitlock, triggering "sleeping function called from invalid context".

Use a no-ref bucket lookup in this path, then continue duplicate
handling without taking a lockref there.

Refactor gfs2_qd_search_bucket() to build on top of the no-ref helper
so lookup traversal stays in one place.

This patch fixes a bug reported by syzbot.

Comment 1 gkamathe 2026-09-28 17:58:16 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97521.mbox