Local Kernel Memory Mapping Vulnerability in Linux Kernel

CVE-2022-49081

Summary

A vulnerability exists in the Linux kernel's handling of high memory mapping, specifically in the _kmap_local_sched{in,out} functions. When CONFIG_DEBUG_KMAP_LOCAL is enabled, improper checks allow uninitialized memory slots to lead to runtime warnings and potential system instability. The flawed check compares pteval against pte_none, which can yield false results, particularly on architectures like xtensa, threatening the integrity of kernel operations and potentially leading to unforeseen behaviors.

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