Re: [PATCH v3 00/13] Kernel address sanitizer - runtime memory debugger.

[Andrey Ryabinin]

2014-09-26 21:01 GMT+04:00 Sasha Levin <sasha.levin@xxxxxxxxxx>:
> On 09/24/2014 08:43 AM, Andrey Ryabinin wrote:
>> Hi.
>>
>> This is a third iteration of kerenel address sanitizer (KASan).
>>
>> KASan is a runtime memory debugger designed to find use-after-free
>> and out-of-bounds bugs.
>>
>> Currently KASAN supported only for x86_64 architecture and requires kernel
>> to be build with SLUB allocator.
>> KASAN uses compile-time instrumentation for checking every memory access, therefore you
>> will need a fresh GCC >= v5.0.0.
>
> Hi Andrey,
>
> I tried this patchset, with the latest gcc, and I'm seeing the following:
>
> arch/x86/kernel/head.o: In function `_GLOBAL__sub_I_00099_0_reserve_ebda_region':
> /home/sasha/linux-next/arch/x86/kernel/head.c:71: undefined reference to `__asan_init_v4'
> init/built-in.o: In function `_GLOBAL__sub_I_00099_0___ksymtab_system_state':
> /home/sasha/linux-next/init/main.c:1034: undefined reference to `__asan_init_v4'
> init/built-in.o: In function `_GLOBAL__sub_I_00099_0_init_uts_ns':
> /home/sasha/linux-next/init/version.c:50: undefined reference to `__asan_init_v4'
> init/built-in.o: In function `_GLOBAL__sub_I_00099_0_root_mountflags':
> /home/sasha/linux-next/init/do_mounts.c:638: undefined reference to `__asan_init_v4'
> init/built-in.o: In function `_GLOBAL__sub_I_00099_0_rd_prompt':
> /home/sasha/linux-next/init/do_mounts_rd.c:361: undefined reference to `__asan_init_v4'
> init/built-in.o:/home/sasha/linux-next/init/do_mounts_md.c:312: more undefined references to `__asan_init_v4' follow
>
>
> What am I missing?
>

__asan_init_v* is a version of compiler's api. Recently it was changed
in gcc - https://gcc.gnu.org/ml/gcc-patches/2014-09/msg01872.html

To fix this, just add:

void __asan_init_v4(void) {}
EXPORT_SYMBOL(__asan_init_v4);

 to the mm/kasan/kasan.c

I'll fix this in next spin.

>
> Thanks,
> Sasha
>
> --



-- 
Best regards,
Andrey Ryabinin
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