Soft Lockup in Linux Kernel due to Memory Size Configuration

CVE-2025-21851

Summary

A vulnerability exists in the Linux kernel related to the handling of memory size configurations for AArch64 architecture. Specifically, in scenarios where CONFIG_PAGE_SIZE_64KB is enabled, a segmentation fault may occur during the execution of arena_map_free(), leading to a soft lockup. This issue arises when an unaligned address is passed to apply_to_pte_range(), disrupting the memory management flow. The vulnerability has been addressed by ensuring that the address returned by bpf_arena_get_kern_vm_start() is properly aligned according to the page size, preventing such failures and enhancing system stability.

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