Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1config HAVE_ARCH_KASAN
2 bool
3
4if HAVE_ARCH_KASAN
5
6config KASAN
7 bool "KASan: runtime memory debugger"
8 depends on (SLUB && SYSFS) || (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
24config 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
35choice
36 prompt "Instrumentation type"
37 depends on KASAN
38 default KASAN_OUTLINE
39
40config 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
49config 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
58endchoice
59
60config KASAN_S390_4_LEVEL_PAGING
61 bool "KASan: use 4-level paging"
62 depends on KASAN && S390
63 help
64 Compiling the kernel with KASan disables automatic 3-level vs
65 4-level paging selection. 3-level paging is used by default (up
66 to 3TB of RAM with KASan enabled). This options allows to force
67 4-level paging instead.
68
69config TEST_KASAN
70 tristate "Module for testing kasan for bug detection"
71 depends on m && KASAN
72 help
73 This is a test module doing various nasty things like
74 out of bounds accesses, use after free. It is useful for testing
75 kernel debugging features like kernel address sanitizer.
76
77endif