Linux Kernel Vulnerability Affecting PowerPC Machine Check Exception Handling

CVE-2026-64214

What is CVE-2026-64214?

A vulnerability in the Linux kernel affects the handling of machine check exceptions for PowerPC systems, resulting in periodic kernel panics. This issue occurs specifically in the arch_irq_work_raise() function where preempt_disable() and preempt_enable() calls are deemed redundant. As these calls were initially implemented to prevent race conditions while raisingirq work from exception contexts, they are unnecessary due to preemption protection introduced in related functions. Consequently, the presence of these calls leads to faulting when accessing preempt_count, culminating in a kernel panic when machine check exceptions are processed in real mode. The vulnerability highlights the importance of updating to the latest kernel versions that remove these redundant function calls to ensure system stability.

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