Bug 2482607 (CVE-2026-46220)

Summary: CVE-2026-46220 kernel: drm/amdgpu/sdma4: replace BUG_ON with WARN_ON in fence emission
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: unspecifiedCC: 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 AMDGPU graphics driver (drm/amdgpu/sdma4). An unprivileged local user could exploit this vulnerability by submitting specially crafted DRM_IOCTL_AMDGPU_CS commands with misaligned fence writeback addresses. This could trigger a BUG_ON assertion, leading to a fatal kernel panic and causing a Denial of Service (DoS) on the system.
 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 2026-05-28 11:05:33 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu/sdma4: replace BUG_ON with WARN_ON in fence emission

sdma_v4_0_ring_emit_fence() contains two BUG_ON(addr & 0x3) assertions
that verify fence writeback addresses are dword-aligned.  These
assertions can be reached from unprivileged userspace via crafted
DRM_IOCTL_AMDGPU_CS submissions, causing a fatal kernel panic in a
scheduler worker thread.

Replace both BUG_ON() calls with WARN_ON() to log the condition without
crashing the kernel.  A misaligned fence address at this point indicates
a driver bug, but crashing the kernel is never the correct response when
the assertion is reachable from userspace.

The CS IOCTL path is the correct place to filter invalid submissions;
the ring emission callback is too late to do anything about it.

(cherry picked from commit b90250bd933afd1ba94d86d6b13821997b22b18e)
Comment 1 Keith Grant 2026-05-28 12:48:44 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052837-CVE-2026-46220-457f@gregkh/T