Linux Kernel Vulnerability in Arch CPU Idle Function Affecting IBM z/VM

CVE-2023-53859

What is CVE-2023-53859?

A vulnerability has been identified in the Linux kernel related to the arch_cpu_idle function within IBM's z/VM environment. This issue emerges from RCU (Read-Copy-Update) not being active during the execution of arch_cpu_idle, leading to potential instability warnings in the kernel. The commit that addresses this issue marks arch_cpu_idle as noinstr, aligning it with best practices across other architectures that implement CONFIG_ARCH_WANTS_NO_INSTR. Patch the system to ensure enhanced stability and compliance with kernel standards.

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