Re: [boost] UBSan question

Subject: Re: [boost] UBSan question
From: Raffi Enficiaud (raffi.enficiaud_at_[hidden])
Date: 2019-01-25 18:56:18

On 16.01.19 02:00, Raffi Enficiaud via Boost wrote:
> Hi,
> 
> I am trying to correct for the errors reported by UBSAN in boost.test. A
> lot of them were false positive, as ... in boost.test, we check the
> capacity of the framework to catch various errors in the program.
> 
> I compile/run the tests with the following:
> 
> .../../../b2 \
>     --toolset=clang \
>     cxxflags=-std=c++11 \
>     cxxflags=-fno-omit-frame-pointer \
>     cxxflags=-fsanitize=undefined \
>     cxxflags=-fno-sanitize-recover=undefined \
>     cxxflags=-fsanitize-recover=integer-divide-by-zero \
>     cxxflags=-fsanitize-recover=float-divide-by-zero \
>     linkflags=-fsanitize=undefined \
>     linkflags=-fno-sanitize-recover=undefined \
>     linkflags=-fsanitize-recover=integer-divide-by-zero \
>     linkflags=-fsanitize-recover=float-divide-by-zero \
>     linkflags=-fuse-ld=gold \
>     variant=debug
> 
> I have an exception that is failing the tests on clang-6/ubuntu18.04
> (UBSAN exiting the process), but not on gcc-8/ubuntu18.04 (full log below).
> 
> UndefinedBehaviorSanitizer:DEADLYSIGNAL
> ==8303==ERROR: UndefinedBehaviorSanitizer: FPE on unknown address
> 
> This FPE is happening for instance after reading from a null pointer.
> 
> I've searched on how to silence/blacklist this, but none of the
> approaches worked so far, and I am not sure what is provoking this FPE.
> 
> Is there any UBsan specialist? Does anyone have an idea?
> 
> Thanks,
> Raffi
> 

I am a bit blocked by this now, any specialist in the room or should I
just discard ubsan with clang 6?

Thanks!
Raffi