The coresight tmc‑etr subsystem contains a race condition that occurs when sysfs mode and perf mode are enabled simultaneously. In this situation the tmc_etr_enable_hw function may be called while the buffer pointer is uninitialized or already allocated, causing a WARN_ON warning in the kernel log. The warning indicates a potential misuse of the hardware enable routine, but the description does not mention a crash or data corruption.

All Linux kernels that include the coresight_tmc driver and are built with tracepoint support are affected. Every build released prior to the commit that adds the double‑check is potentially vulnerable. This encompasses mainstream distributions with the default kernel configuration and custom kernels that enable coresight_tmc.

The advisory reports a CVSS score of 4.7 and an EPSS score of < 1%, and the vulnerability is not listed in CISA’s KEV catalog. An attacker would need local or privileged access to write to the relevant sysfs entries and enable perf on the same device, making the threat vector local. Because the issue manifests as a WARN_ON warning rather than a documented crash or denial‑of‑service, the risk to system availability is low unless additional weaknesses are present.