lib/Kconfig.kasan

   1 config HAVE_ARCH_KASAN
   2         bool
   3
   4 if HAVE_ARCH_KASAN
   5
   6 config KASAN
   7         bool "KASan: runtime memory debugger"
   8         depends on SLUB_DEBUG
   9         select CONSTRUCTORS
  10         help
  11           Enables kernel address sanitizer - runtime memory debugger,
  12           designed to find out-of-bounds accesses and use-after-free bugs.
  13           This is strictly a debugging feature and it requires a gcc version
  14           of 4.9.2 or later. Detection of out of bounds accesses to stack or
  15           global variables requires gcc 5.0 or later.
  16           This feature consumes about 1/8 of available memory and brings about
  17           ~x3 performance slowdown.
  18           For better error detection enable CONFIG_STACKTRACE,
  19           and add slub_debug=U to boot cmdline.
  20
  21 config KASAN_SHADOW_OFFSET
  22         hex
  23         default 0xdffffc0000000000 if X86_64
  24
  25 choice
  26         prompt "Instrumentation type"
  27         depends on KASAN
  28         default KASAN_OUTLINE
  29
  30 config KASAN_OUTLINE
  31         bool "Outline instrumentation"
  32         help
  33           Before every memory access compiler insert function call
  34           __asan_load*/__asan_store*. These functions performs check
  35           of shadow memory. This is slower than inline instrumentation,
  36           however it doesn't bloat size of kernel's .text section so
  37           much as inline does.
  38
  39 config KASAN_INLINE
  40         bool "Inline instrumentation"
  41         help
  42           Compiler directly inserts code checking shadow memory before
  43           memory accesses. This is faster than outline (in some workloads
  44           it gives about x2 boost over outline instrumentation), but
  45           make kernel's .text size much bigger.
  46           This requires a gcc version of 5.0 or later.
  47
  48 endchoice
  49
  50 config TEST_KASAN
  51         tristate "Module for testing kasan for bug detection"
  52         depends on m && KASAN
  53         help
  54           This is a test module doing various nasty things like
  55           out of bounds accesses, use after free. It is useful for testing
  56           kernel debugging features like kernel address sanitizer.
  57
  58 endif