The Linux kernel’s Coresight subsystem failed to preserve system register ETMs and the External Trace Enabler (ETE) across CPU power‑down events. This is inferred from the patch notes, which hard‑code the sysreg ETM setting and switch to a local variable for the save_state flag to guard against concurrent probing failures. The vulnerability manifested as warnings like “coresight ete0: External agent took claim tag,” indicating trace context loss during a power cycle. The absence of a documented ACPI binding (arm,coresight‑loses‑context‑with‑cpu) implies that users could not resolve this issue without kernel changes.

The affected product is the Linux kernel. No specific version numbers are enumerated, so all kernel releases before the patch that implemented the hard‑coded sysreg ETM setting are potentially impacted. Products that combine Coresight hardware tracing with ACPI powered‑down handling are within scope.

No CVSS or EPSS score is provided, and the vulnerability is not listed in the CISA KEV catalog. Because the flaw is in privileged kernel code, the attack surface is a local privileged context; an adversary who can invoke a CPU power‑down cycle could induce trace state loss, impairing the reliability of hardware diagnostics. The impact primarily concerns the confidentiality and integrity of monitoring data rather than enabling remote code execution or direct denial of service.