CONFIG_KASAN_VMALLOC: Check accesses to vmalloc allocations

General informations

The Linux kernel configuration item CONFIG_KASAN_VMALLOC has multiple definitions:

Check accesses to vmalloc allocations found in lib/Kconfig.kasan

The configuration item CONFIG_KASAN_VMALLOC:

• prompt: Check accesses to vmalloc allocations
• type: bool
• depends on: CONFIG_HAVE_ARCH_KASAN_VMALLOC
• defined in lib/Kconfig.kasan
• found in Linux kernels: 5.18-rc+HEAD

Help text

This mode makes KASAN check accesses to vmalloc allocations for validity.

With software KASAN modes, checking is done for all types of vmalloc allocations. Enabling this option leads to higher memory usage.

With hardware tag-based KASAN, only VM_ALLOC mappings are checked. There is no additional memory usage.

Back mappings in vmalloc space with real shadow memory found in lib/Kconfig.kasan

The configuration item CONFIG_KASAN_VMALLOC:

• prompt: Back mappings in vmalloc space with real shadow memory
• type: bool
• depends on: CONFIG_KASAN_GENERIC && CONFIG_HAVE_ARCH_KASAN_VMALLOC
• defined in lib/Kconfig.kasan
• found in Linux kernels: 5.5–5.17, 5.17+HEAD

Help text

By default, the shadow region for vmalloc space is the read-only zero page. This means that KASAN cannot detect errors involving vmalloc space.

Enabling this option will hook in to vmap/vmalloc and back those mappings with real shadow memory allocated on demand. This allows for KASAN to detect more sorts of errors (and to support vmapped stacks), but at the cost of higher memory usage.

Hardware

LKDDb

Raw data from LKDDb:

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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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