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 || (SLAB && !DEBUG_SLAB)
   9         select SLUB_DEBUG if SLUB
  10         select CONSTRUCTORS
  11         select STACKDEPOT
  12         help
  13           Enables kernel address sanitizer - runtime memory debugger,
  14           designed to find out-of-bounds accesses and use-after-free bugs.
  15           This is strictly a debugging feature and it requires a gcc version
  16           of 4.9.2 or later. Detection of out of bounds accesses to stack or
  17           global variables requires gcc 5.0 or later.
  18           This feature consumes about 1/8 of available memory and brings about
  19           ~x3 performance slowdown.
  20           For better error detection enable CONFIG_STACKTRACE.
  21           Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
  22           (the resulting kernel does not boot).
  23
  24 config KASAN_EXTRA
  25         bool "KAsan: extra checks"
  26         depends on KASAN && DEBUG_KERNEL && !COMPILE_TEST
  27         help
  28           This enables further checks in the kernel address sanitizer, for now
  29           it only includes the address-use-after-scope check that can lead
  30           to excessive kernel stack usage, frame size warnings and longer
  31           compile time.
  32           https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
  33
  34
  35 choice
  36         prompt "Instrumentation type"
  37         depends on KASAN
  38         default KASAN_OUTLINE
  39
  40 config KASAN_OUTLINE
  41         bool "Outline instrumentation"
  42         help
  43           Before every memory access compiler insert function call
  44           __asan_load*/__asan_store*. These functions performs check
  45           of shadow memory. This is slower than inline instrumentation,
  46           however it doesn't bloat size of kernel's .text section so
  47           much as inline does.
  48
  49 config KASAN_INLINE
  50         bool "Inline instrumentation"
  51         help
  52           Compiler directly inserts code checking shadow memory before
  53           memory accesses. This is faster than outline (in some workloads
  54           it gives about x2 boost over outline instrumentation), but
  55           make kernel's .text size much bigger.
  56           This requires a gcc version of 5.0 or later.
  57
  58 endchoice
  59
  60 config TEST_KASAN
  61         tristate "Module for testing kasan for bug detection"
  62         depends on m && KASAN
  63         help
  64           This is a test module doing various nasty things like
  65           out of bounds accesses, use after free. It is useful for testing
  66           kernel debugging features like kernel address sanitizer.
  67
  68 endif