Kernel Vulnerability in Linux Hyper-V Clocksource Implementation

CVE-2022-49726

Summary

A vulnerability exists in the Linux kernel related to the improper use of the EXPORT_SYMBOL and __init annotations in the Hyper-V clocksource implementation. This design flaw allows symbols marked as __init, which are from a section that is released after initialization, to be mistakenly accessed by modules. This could lead to kernel panic if these freed symbols are used. The issue was identified following a revision of modpost tool, which highlighted previously undetected incidents in linux-next builds. To mitigate this vulnerability, the recommended actions include either removing the __init annotation or avoiding the EXPORT_SYMBOL in the affected code.

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