System Hang Vulnerability in Linux Kernel Affecting x86 Architecture

CVE-2025-38047

What is CVE-2025-38047?

A vulnerability exists in the Linux kernel affecting x86 architectures, specifically when resuming from S4 sleep state with FRED (Fast Restore Device) enabled. When the system wakes up, the restore kernel initializes FRED MSRs (Model-Specific Registers) but may not synchronize their values correctly with those expected by the image kernel. This inconsistency can lead to system hangs during the wakeup process, as the image kernel takes control while relying on outdated or mismatched FRED MSR values. Proper recalibration of these registers is crucial to prevent system instability and ensure smooth operation after hibernation.

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