linux/lib/Kconfig.kasan
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   1config HAVE_ARCH_KASAN
   2        bool
   3
   4if HAVE_ARCH_KASAN
   5
   6config KASAN
   7        bool "KASan: runtime memory debugger"
   8        depends on SLUB || (SLAB && !DEBUG_SLAB)
   9        select CONSTRUCTORS
  10        select STACKDEPOT
  11        help
  12          Enables kernel address sanitizer - runtime memory debugger,
  13          designed to find out-of-bounds accesses and use-after-free bugs.
  14          This is strictly a debugging feature and it requires a gcc version
  15          of 4.9.2 or later. Detection of out of bounds accesses to stack or
  16          global variables requires gcc 5.0 or later.
  17          This feature consumes about 1/8 of available memory and brings about
  18          ~x3 performance slowdown.
  19          For better error detection enable CONFIG_STACKTRACE.
  20          Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
  21          (the resulting kernel does not boot).
  22
  23choice
  24        prompt "Instrumentation type"
  25        depends on KASAN
  26        default KASAN_OUTLINE
  27
  28config KASAN_OUTLINE
  29        bool "Outline instrumentation"
  30        help
  31          Before every memory access compiler insert function call
  32          __asan_load*/__asan_store*. These functions performs check
  33          of shadow memory. This is slower than inline instrumentation,
  34          however it doesn't bloat size of kernel's .text section so
  35          much as inline does.
  36
  37config KASAN_INLINE
  38        bool "Inline instrumentation"
  39        help
  40          Compiler directly inserts code checking shadow memory before
  41          memory accesses. This is faster than outline (in some workloads
  42          it gives about x2 boost over outline instrumentation), but
  43          make kernel's .text size much bigger.
  44          This requires a gcc version of 5.0 or later.
  45
  46endchoice
  47
  48config TEST_KASAN
  49        tristate "Module for testing kasan for bug detection"
  50        depends on m && KASAN
  51        help
  52          This is a test module doing various nasty things like
  53          out of bounds accesses, use after free. It is useful for testing
  54          kernel debugging features like kernel address sanitizer.
  55
  56endif
  57