Bug 2535375 (CVE-2026-89814)

Summary:	CVE-2026-89814 kernel: drm/amdgpu: clamp the isolation index for rings outside a partition
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 `drm/amdgpu` component. This vulnerability occurs when a graphics ring is not assigned to a partition, leading to an out-of-bounds array access during SDMA submissions. A local attacker could potentially exploit this to cause a system crash, resulting in a denial of service (DoS).	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
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Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-16 12:24:22 UTC

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

drm/amdgpu: clamp the isolation index for rings outside a partition

adev->isolation[] has one slot per partition, but a ring that is not
assigned to one keeps AMDGPU_XCP_NO_PARTITION, which is ~0, so indexing
the array with it is out of bounds. SDMA submissions hit this on both
the isolation enforcement and the VM flush path and trip UBSAN.

Fall back to the first slot the way the cleaner shader path already
does, and stop taking the address before the ring type check that makes
it relevant.

Comment 1 Mauro Matteo Cascella 2026-09-21 16:13:58 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89814.mbox