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config HAVE_ARCH_KASAN
bool
if HAVE_ARCH_KASAN
config KASAN
bool "KASan: runtime memory debugger"
depends on SLUB || (SLAB && !DEBUG_SLAB)
select CONSTRUCTORS
select STACKDEPOT
help
Enables kernel address sanitizer - runtime memory debugger,
designed to find out-of-bounds accesses and use-after-free bugs.
This is strictly a debugging feature and it requires a gcc version
of 4.9.2 or later. Detection of out of bounds accesses to stack or
global variables requires gcc 5.0 or later.
This feature consumes about 1/8 of available memory and brings about
~x3 performance slowdown.
For better error detection enable CONFIG_STACKTRACE.
See KASAN_SANITIZE_ALL for selectively compiling files and directories
with this compiler feature enabled.
Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
(the resulting kernel does not boot).
choice
prompt "Instrumentation type"
depends on KASAN
default KASAN_OUTLINE
config KASAN_OUTLINE
bool "Outline instrumentation"
help
Before every memory access compiler insert function call
__asan_load*/__asan_store*. These functions performs check
of shadow memory. This is slower than inline instrumentation,
however it doesn't bloat size of kernel's .text section so
much as inline does.
config KASAN_INLINE
bool "Inline instrumentation"
help
Compiler directly inserts code checking shadow memory before
memory accesses. This is faster than outline (in some workloads
it gives about x2 boost over outline instrumentation), but
make kernel's .text size much bigger.
This requires a gcc version of 5.0 or later.
endchoice
config KASAN_SANITIZE_ALL
bool "KASan: Enable Instrumentation for entire kernel"
depends on KASAN
default y
help
Enable compilation with $(CFLAGS_KASAN) by default.
KASAN_SANITIZE := n - exclude all files in a directory
KASAN_SANITIZE_file_name.o := n - exclude a single file
Setting KASAN_SANITIZE_ALL to 'n' allows enabling kasan in
only certain files or directories.
KASAN_SANITIZE := y - include all files in a directory
KASAN_SANITIZE_file_name.o := y - include single file
KASAN_SANITIZE does not affect subdirectories.
KASAN_SANITIZE_file_name.o has priority over KASAN_SANITIZE.
config TEST_KASAN
tristate "Module for testing kasan for bug detection"
depends on m && KASAN
help
This is a test module doing various nasty things like
out of bounds accesses, use after free. It is useful for testing
kernel debugging features like kernel address sanitizer.
endif
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