Re: [dpdk-dev] [PATCH] Enable AddressSanitizer feature on DPDK

[David Christensen <drc@linux.vnet.ibm.com>]

On 9/18/21 12:21 AM, Peng, ZhihongX wrote:
>> -----Original Message-----
>> From: David Christensen <drc@linux.vnet.ibm.com>
>> Sent: Saturday, September 18, 2021 4:51 AM
>> To: Peng, ZhihongX <zhihongx.peng@intel.com>; Burakov, Anatoly
>> <anatoly.burakov@intel.com>; Ananyev, Konstantin
>> <konstantin.ananyev@intel.com>; stephen@networkplumber.org
>> Cc: dev@dpdk.org; Lin, Xueqin <xueqin.lin@intel.com>
>> Subject: Re: [dpdk-dev] [PATCH] Enable AddressSanitizer feature on DPDK
>>
>>>>> If you want to use this feature,
>>>>> you need to add below compilation options when compiling code:
>>>>> -Dbuildtype=debug -Db_lundef=false -Db_sanitize=address
>>>>> "-Dbuildtype=debug": Display code information when coredump occurs
>>>>> in the program.
>>>>> "-Db_lundef=false": It is enabled by default, and needs to be
>>>>> disabled when using asan.
>>>>
>>>> On initial inspection, it appears ASAN functionality doesn't work
>>>> with DPDK on PPC architecture.  I tested the patch with several
>>>> compiler versions (gcc
>>>> 8.3.1 from RHEL 8.3 through gcc 11.2.1 from the IBM Advanced
>>>> Toolchain 15.0) and observed the following error when running testpmd
>> with ASAN enabled:
>>>>
>>>> AddressSanitizer:DEADLYSIGNAL
>>>>
>> ==========================================================
>>>> =======
>>>> ==49246==ERROR: AddressSanitizer: SEGV on unknown address
>>>> 0x0000a0077bd0 (pc 0x000010b4eca4 bp 0x7fffffffe150 sp 0x7fffffffe150
>>>> T0) ==49246==The signal is caused by a UNKNOWN memory access.
>>>>        #0 0x10b4eca4 in
>> asan_set_shadow ../lib/eal/common/malloc_elem.h:120
>>>>        #1 0x10b4ed68 in
>> asan_set_zone ../lib/eal/common/malloc_elem.h:135
>>>>        #2 0x10b4ee90 in asan_clear_split_alloczone
>>>> ../lib/eal/common/malloc_elem.h:162
>>>>        #3 0x10b51f84 in malloc_elem_alloc
>>>> ../lib/eal/common/malloc_elem.c:477
>>>> ...
>>>>
>>>> Can you incorporate an exception for PPC architecture with this patch
>>>> while I look into the problem further?
>>>>
>>>> Dave
>>>
>>> We do not have a ppc platform, so there is no adaptation.
>>> doc/guides/prog_guide/asan.rst has stated that we currently only
>>> support Linux x86_64. You can adapt according to the following documents,
>> the main work is to modify the base address according to the platform.
>>> Documents:
>>> https://github.com/google/sanitizers/wiki/AddressSanitizer
>>> https://github.com/llvm/llvm-project/tree/main/compiler-rt
>>
>> Understand you don't have such a platform.  I looked into it and suggest the
>> following change in lib/eal/common/malloc_elem.h:
>>
>> #define ASAN_SHADOW_GRAIN_SIZE  8
>> #define ASAN_SHADOW_SCALE       3
>> #ifdef RTE_ARCH_PPC_64
>> #define ASAN_SHADOW_OFFSET 0x020000000000 #else #define
>> ASAN_SHADOW_OFFSET 0x00007fff8000 #endif
>> #define ASAN_MEM_FREE_FLAG      0xfd
>> #define ASAN_MEM_REDZONE_FLAG   0xfa
>> #define ASAN_MEM_TO_SHADOW(mem) (((mem) >>
>> ASAN_SHADOW_SCALE) +
>> ASAN_SHADOW_OFFSET)
>>
>>
>> This resolves the segmentation error I receive.
>>
>> Dave
>>
> 
> Great, good information for dpdk asan tool. Because we can't do many tests,
> so when this patch is merged into the main line, you can submit the ppc
> architecture patch.

If your argument is that this is x86 only then please ensure it can't be 
enabled on non-x86 platforms such as ARM and PPC.  I can then easily 
submit a follow-on patch to enable for PPC.

As the patch currently stands it enables ASAN on a non-tested platform 
and provides an unexpected error for some users when it can easily be 
avoided.  I'd advise not accepting the patch as currently presented.

Dave