Re: [PATCH v2 5/5] arm64: add KASan support

On 05/26/2015 04:35 PM, Linus Walleij wrote:

On Fri, May 15, 2015 at 3:59 PM, Andrey Ryabinin [off-list ref] wrote:

And then at boot I just get this:

kasan test: kmalloc_oob_right out-of-bounds to right
kasan test: kmalloc_oob_left out-of-bounds to left
kasan test: kmalloc_node_oob_right kmalloc_node(): out-of-bounds to right
kasan test: kmalloc_large_oob_rigth kmalloc large allocation:
out-of-bounds to right
kasan test: kmalloc_oob_krealloc_more out-of-bounds after krealloc more
kasan test: kmalloc_oob_krealloc_less out-of-bounds after krealloc less
kasan test: kmalloc_oob_16 kmalloc out-of-bounds for 16-bytes access
kasan test: kmalloc_oob_in_memset out-of-bounds in memset
kasan test: kmalloc_uaf use-after-free
kasan test: kmalloc_uaf_memset use-after-free in memset
kasan test: kmalloc_uaf2 use-after-free after another kmalloc
kasan test: kmem_cache_oob out-of-bounds in kmem_cache_alloc
kasan test: kasan_stack_oob out-of-bounds on stack
kasan test: kasan_global_oob out-of-bounds global variable

W00t no nice KASan warnings (which is what I expect).

This is my compiler by the way:
$ arm-linux-gnueabihf-gcc --version
arm-linux-gnueabihf-gcc (crosstool-NG linaro-1.13.1-4.9-2014.09 -
Linaro GCC 4.9-2014.09) 4.9.2 20140904 (prerelease)

I did the same exercise on the foundation model (FVP) and I guess
that is what you developed the patch set on because there I got
nice KASan dumps:

That's not kasan dumps. That is slub debug output.
KASan warnings starts with
	"BUG: KASan: use after free/out of bounds access "
line.

I wonder were the problem lies, any hints where to start looking
to fix this?

I suspect that your compiler lack -fsantize=kernel-address support.
It seems that GCC 4.9.2 doesn't supports -fsanitize=address/kernel-address on aarch64.

I tested this patchset on Cavium Thunder-x and on FVP also and didn't observe any problems.

Yours,
Linus Walleij

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