Bug 2540525 (CVE-2026-93284)

Summary:	CVE-2026-93284 kernel: drm/pagemap: dma-unmap pages before handling migration errors
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 (Direct Rendering Manager) pagemap subsystem. During page migration error handling, the kernel clears the page tracking array before finishing Direct Memory Access (DMA) unmapping operations. A local user could exploit this flaw by triggering migration failures, causing improper memory unmapping and leading to a system crash and 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 2026-09-24 17:06:42 UTC

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

drm/pagemap: dma-unmap pages before handling migration errors

drm_pagemap_migrate_unmap_pages() relies on the pages array to determine
which pages require DMA unmapping. However,
drm_pagemap_migration_unlock_put_pages() clears the array as part of its
cleanup, leaving drm_pagemap_migrate_unmap_pages() with no valid page
information if it is called afterward.

Call drm_pagemap_migrate_unmap_pages() before
drm_pagemap_migration_unlock_put_pages() so the pages array remains
valid during DMA unmapping.

Comment 1 gkamathe 2026-09-28 14:13:05 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93284.mbox