![Jason A. Donenfeld](/assets/img/avatar_default.png)
KASAN depends on having access to some of the accounting that SLUB_DEBUG
does; without it, there are immediate crashes [1]. So, the natural
thing to do is to make KASAN select SLUB_DEBUG.
[1] http://lkml.kernel.org/r/CAHmME9rtoPwxUSnktxzKso14iuVCWT7BE_-_8PAC=pGw1iJnQg@mail.gmail.com
Link: http://lkml.kernel.org/r/20180622154623.25388-1-Jason@zx2c4.com
Fixes: f9e13c0a5a
("slab, slub: skip unnecessary kasan_cache_shutdown()")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: <stable@vger.kernel.org>
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 || (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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