CONFIG_KASAN_STACK: Stack instrumentation (unsafe)

General informations

The Linux kernel configuration item CONFIG_KASAN_STACK has multiple definitions:

Stack instrumentation (unsafe) found in lib/Kconfig.kasan

The configuration item CONFIG_KASAN_STACK:

• prompt: Stack instrumentation (unsafe)
• type: bool
• depends on: ( CONFIG_CC_IS_CLANG && ! CONFIG_COMPILE_TEST ) && ( CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS ) && (! CONFIG_ARCH_DISABLE_KASAN_INLINE ) && ( CONFIG_CC_IS_GCC )
• defined in lib/Kconfig.kasan
• found in Linux kernels: 5.19, 6.0–6.8, 6.9-rc+HEAD

Help text

Disables stack instrumentation and thus KASAN's ability to detect out-of-bounds bugs in stack variables.

With Clang, stack instrumentation has a problem that causes excessive stack usage, see https://llvm.org/pr38809. Thus, with Clang, this option is deemed unsafe.

This option is always disabled when compile-testing with Clang to avoid cluttering the log with stack overflow warnings.

With GCC, enabling stack instrumentation is assumed to be safe.

If the architecture disables inline instrumentation via ARCH_DISABLE_KASAN_INLINE, stack instrumentation gets disabled as well, as it adds inline-style instrumentation that is run unconditionally.

Enable stack instrumentation (unsafe) found in lib/Kconfig.kasan

The configuration item CONFIG_KASAN_STACK:

• prompt: Enable stack instrumentation (unsafe)
• type: bool
• depends on: ( CONFIG_CC_IS_CLANG && ! CONFIG_COMPILE_TEST ) && ( CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS ) && (! CONFIG_ARCH_DISABLE_KASAN_INLINE ) && ( CONFIG_CC_IS_GCC )
• defined in lib/Kconfig.kasan
• found in Linux kernels: 5.12–5.18, 5.18+HEAD

Help text

The LLVM stack address sanitizer has a know problem that causes excessive stack usage in a lot of functions, see https://bugs.llvm.org/show_bug.cgi?id=38809 Disabling asan-stack makes it safe to run kernels build with clang-8 with KASAN enabled, though it loses some of the functionality. This feature is always disabled when compile-testing with clang to avoid cluttering the output in stack overflow warnings, but clang users can still enable it for builds without COMPILE_TEST. On gcc it is assumed to always be safe to use and enabled by default. If the architecture disables inline instrumentation, stack instrumentation is also disabled as it adds inline-style instrumentation that is run unconditionally.

found in lib/Kconfig.kasan

The configuration item CONFIG_KASAN_STACK:

• prompt:
• type: int
• depends on: CONFIG_KASAN_STACK_ENABLE || CONFIG_CC_IS_GCC
• defined in lib/Kconfig.kasan
• found in Linux kernels: 5.0–5.11

Help text

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Hardware

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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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