CVE-2025-71132

Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 6.18.0

Description The Linux kernel contains an issue within the smc91x driver when built with PREEMPT RT. A broken interrupt request (IRQ) context occurs due to improper handling of IRQ disabling and restoration within the smc special trylock() and smc special unlock() functions. Specifically, smc special trylock() disables IRQs even in PREEMPT RT mode, while smc special unlock() fails to restore them correctly. This leads to a workqueue leak and potential system instability, as demonstrated by a splat observed in FVP RevC. The root cause is related to the interaction between spin unlock irqrestore() and rcu read unlock bh() within the Real-Time (RT) preemptive kernel.

Recommendations Update to Linux kernel version 6.18.0 or later.