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03758dbbe2
Building with KASAN and SLUB but without sysfs now results in a
build-time error:
WARNING: unmet direct dependencies detected for SLUB_DEBUG
Depends on [n]: SLUB [=y] && SYSFS [=n]
Selected by [y]:
- KASAN [=y] && HAVE_ARCH_KASAN [=y] && (SLUB [=y] || SLAB [=n] && !DEBUG_SLAB [=n]) && SLUB [=y]
mm/slub.c:4565:12: error: 'list_locations' defined but not used [-Werror=unused-function]
static int list_locations(struct kmem_cache *s, char *buf,
^~~~~~~~~~~~~~
mm/slub.c:4406:13: error: 'validate_slab_cache' defined but not used [-Werror=unused-function]
static long validate_slab_cache(struct kmem_cache *s)
This disallows that broken configuration in Kconfig.
Link: http://lkml.kernel.org/r/20180709154019.1693026-1-arnd@arndb.de
Fixes: dd275caf4a ("kasan: depend on CONFIG_SLUB_DEBUG")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
69 lines
2.2 KiB
Plaintext
69 lines
2.2 KiB
Plaintext
config HAVE_ARCH_KASAN
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bool
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if HAVE_ARCH_KASAN
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config KASAN
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bool "KASan: runtime memory debugger"
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depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
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select SLUB_DEBUG if SLUB
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select CONSTRUCTORS
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select STACKDEPOT
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help
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Enables kernel address sanitizer - runtime memory debugger,
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designed to find out-of-bounds accesses and use-after-free bugs.
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This is strictly a debugging feature and it requires a gcc version
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of 4.9.2 or later. Detection of out of bounds accesses to stack or
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global variables requires gcc 5.0 or later.
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This feature consumes about 1/8 of available memory and brings about
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~x3 performance slowdown.
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For better error detection enable CONFIG_STACKTRACE.
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Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
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(the resulting kernel does not boot).
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config KASAN_EXTRA
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bool "KAsan: extra checks"
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depends on KASAN && DEBUG_KERNEL && !COMPILE_TEST
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help
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This enables further checks in the kernel address sanitizer, for now
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it only includes the address-use-after-scope check that can lead
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to excessive kernel stack usage, frame size warnings and longer
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compile time.
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
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choice
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prompt "Instrumentation type"
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depends on KASAN
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default KASAN_OUTLINE
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config KASAN_OUTLINE
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bool "Outline instrumentation"
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help
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Before every memory access compiler insert function call
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__asan_load*/__asan_store*. These functions performs check
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of shadow memory. This is slower than inline instrumentation,
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however it doesn't bloat size of kernel's .text section so
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much as inline does.
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config KASAN_INLINE
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bool "Inline instrumentation"
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help
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Compiler directly inserts code checking shadow memory before
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memory accesses. This is faster than outline (in some workloads
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it gives about x2 boost over outline instrumentation), but
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make kernel's .text size much bigger.
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This requires a gcc version of 5.0 or later.
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endchoice
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config TEST_KASAN
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tristate "Module for testing kasan for bug detection"
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depends on m && KASAN
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help
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This is a test module doing various nasty things like
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out of bounds accesses, use after free. It is useful for testing
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kernel debugging features like kernel address sanitizer.
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endif
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