CONFIG_ARM_DEBUG_WX: Warn on W+X mappings at boot

General informations

The Linux kernel configuration item CONFIG_ARM_DEBUG_WX:

• prompt: Warn on W+X mappings at boot
• type: bool
• depends on: CONFIG_MMU
• defined in arch/arm/Kconfig.debug
• found in Linux kernels: 6.9–6.12

Help text

Generate a warning if any W+X mappings are found at boot.

This is useful for discovering cases where the kernel is leaving W+X mappings after applying NX, as such mappings are a security risk.

Look for a message in dmesg output like this:

arm/mm: Checked W+X mappings: passed, no W+X pages found.

or like this, if the check failed:

arm/mm: Checked W+X mappings: FAILED, <N> W+X pages found.

Note that even if the check fails, your kernel is possibly still fine, as W+X mappings are not a security hole in themselves, what they do is that they make the exploitation of other unfixed kernel bugs easier.

There is no runtime or memory usage effect of this option once the kernel has booted up - it's a one time check.

If in doubt, say "Y".

Hardware

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The data is retrived from:

• Linux kernel
• Linux Kernel Driver DataBase (LKDDb)

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