CONFIG_PAGE_POISONING: Poison pages after freeing

General informations

The Linux kernel configuration item CONFIG_PAGE_POISONING has multiple definitions:

Poison pages after freeing found in mm/Kconfig.debug

The configuration item CONFIG_PAGE_POISONING:

• prompt: Poison pages after freeing
• type: bool
• depends on: (none)
• defined in mm/Kconfig.debug
• found in Linux kernels: 4.6–4.20, 5.0–5.19, 6.0–6.8, 6.9-rc+HEAD

Help text

Fill the pages with poison patterns after free_pages() and verify the patterns before alloc_pages. The filling of the memory helps reduce the risk of information leaks from freed data. This does have a potential performance impact if enabled with the "page_poison=1" kernel boot option.

Note that "poison" here is not the same thing as the "HWPoison" for MEMORY_FAILURE. This is software poisoning only.

If you are only interested in sanitization of freed pages without checking the poison pattern on alloc, you can boot the kernel with "init_on_free=1" instead of enabling this.

If unsure, say N

found in mm/Kconfig.debug

The configuration item CONFIG_PAGE_POISONING:

• prompt:
• type: bool
• depends on: (none)
• defined in mm/Kconfig.debug
• found in Linux kernels: 2.6.39, 3.0–3.19, 4.0–4.5

Help text

(none)

Debug page memory allocations found in mm/Kconfig.debug

The configuration item CONFIG_PAGE_POISONING:

• prompt: Debug page memory allocations
• type: bool
• depends on: ( CONFIG_DEBUG_KERNEL && ! CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC ) && (! CONFIG_HIBERNATION )
• defined in mm/Kconfig.debug
• found in Linux kernels: 2.6.30–2.6.38

Help text

Fill the pages with poison patterns after free_pages() and verify the patterns before alloc_pages(). This results in a large slowdown, but helps to find certain types of memory corruption.

This option cannot be enabled in combination with hibernation as that would result in incorrect warnings of memory corruption after a resume because free pages are not saved to the suspend image.

Hardware

LKDDb

Raw data from LKDDb:

• (none)

Sources

This page is automaticly generated with free (libre, open) software lkddb(see lkddb-sources).

The data is retrived from:

• Linux kernel
• Linux Kernel Driver DataBase (LKDDb)

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