Bug 2440642 (CVE-2026-23213)

Summary: CVE-2026-23213 kernel: drm/amd/pm: Disable MMIO access during SMU Mode 1 reset
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: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
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 2026-02-18 15:03:27 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/amd/pm: Disable MMIO access during SMU Mode 1 reset

During Mode 1 reset, the ASIC undergoes a reset cycle and becomes
temporarily inaccessible via PCIe. Any attempt to access MMIO registers
during this window (e.g., from interrupt handlers or other driver threads)
can result in uncompleted PCIe transactions, leading to NMI panics or
system hangs.

To prevent this, set the `no_hw_access` flag to true immediately after
triggering the reset. This signals other driver components to skip
register accesses while the device is offline.

A memory barrier `smp_mb()` is added to ensure the flag update is
globally visible to all cores before the driver enters the sleep/wait
state.

(cherry picked from commit 7edb503fe4b6d67f47d8bb0dfafb8e699bb0f8a4)
Comment 1 Alexander B 2026-02-18 17:54:11 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026021800-CVE-2026-23213-c699@gregkh/T