Bug 2559664 (CVE-2026-98926)

Summary:	CVE-2026-98926 kernel: drm/amd/display: Remove sink usage from DPMS
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 AMD display driver. During Display Power Management Signaling (DPMS) sequences, the driver attempts to access a display sink pointer without verifying whether it is null. A local user could exploit this flaw during display power state transitions, triggering a null pointer dereference that crashes the system and results in a Denial of Service (DoS).	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 2026-10-23 12:56:43 UTC

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

drm/amd/display: Remove sink usage from DPMS

[Why]
stream->sink is optional and can be null, so should always be checked
before dereference. Additionally, most of its usage in DPMS sequences
is for stream->sink->link, which can be replaced with stream->link,
as the two should always be the same.

[How]
* Replace stream->sink->link in DPMS on/off
* Add assert to USB4 BW allocation where sink is required
* Avoid inconsistencies in resource access, e.g. don't repeat
stream->link after it was already saved to a local variable
* Pull out effective VPG calculation to helper getter
* Formatting fixes