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 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
  23 choice
  24         prompt "Instrumentation type"
  25         depends on KASAN
  26         default KASAN_OUTLINE
  27
  28 config 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
  37 config 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
  46 endchoice
  47
  48 config 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
  56 endif