Linux Kernel Vulnerability in nios2 Configuration Affecting Memory Management

CVE-2025-40245

What is CVE-2025-40245?

A vulnerability in the Linux kernel's nios2 architecture configuration can lead to improper memory management, resulting in kernel paging failures. Specifically, when CONFIG_FLATMEM is set, the kernel relies on memblock_get_current_limit() for determining memory mapping limits. If not properly initialized, this can cause max_low_pfn to exceed max_pfn, leading to persistent kernel panic errors. The introduced patch rectifies the issue by adjusting memblock.current_limit based on upper memory limits, thus preventing unintended memory access and ensuring system stability.

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