CVE-2026-64211

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An issue exists in the Sleepable Read-Copy Update (SRCU) mechanism where an srcu struct structure, while transitioning from CPU-0 to all-CPUs state, may attempt to invoke callbacks on CPUs that have never been online or are not within the cpu possible mask. This behavior can lead to system hangs on s390 architectures. To prevent this, the system must refrain from queueing workqueue handlers on CPUs that are not online. Additionally, invoking call srcu(), synchronize srcu(), or synchronize srcu expedited() on a CPU that is not yet fully online is considered an error; in such cases, callbacks are redirected to the boot CPU.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.