Bug 2495952 (CVE-2026-53327)

Summary:	CVE-2026-53327 kernel: debugobjects: Do not fill_pool() if pi_blocked_on
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	rhel-process-autobot, 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 debugobjects functionality. On systems with Real-Time (RT) enabled kernels, the `fill_pool()` function can lead to a system assertion if a task is already blocked on a lock, causing corruption of the priority inheritance chain. This issue can result in a Denial of Service (DoS) due to the system asserting.	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 2026-07-01 14:03:17 UTC

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

debugobjects: Do not fill_pool() if pi_blocked_on

On RT enabled kernels, fill_pool() ends up calling rtlock_lock(), which
asserts if current::pi_blocked_on is set, because a task can obviously only
block on one lock as otherwise the priority inheritenace chain gets
corrupted.

Prevent this by expanding the conditional to take current::pi_blocked_on
into account.

Comment 1 Mauro Matteo Cascella 2026-07-01 16:28:34 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026070141-CVE-2026-53327-9db6@gregkh/T