Linux Kernel Vulnerability in LoongArch CPU Handling

CVE-2026-64250

What is CVE-2026-64250?

The vulnerability involves improper handling of CPU states in the Linux kernel for the LoongArch architecture. Specifically, when a CPU is marked as offline using the smp_send_stop() function, the RCU subsystem is not informed about this change. This leads to RCU expecting a quiescent state from CPUs that have been disabled, causing potential hangs during reboot or shutdown processes. Although typically harmless, it may become problematic in specific scenarios, particularly with the use of irq_work_sync() which relies on completion of RCU grace periods. Implementing proper reporting of dead CPUs helps mitigate this issue.

References