[jira] [Resolved] (AVRO-2202) Use of -fstack-protector or -D_GLIBCXX_DEBUG causes memory corruption when combined with musl libc static builds

["Daniel Kulp (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AVRO-2202?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Daniel Kulp resolved AVRO-2202.
-------------------------------
    Resolution: Fixed
      Assignee: Daniel Kulp  (was: Thiruvalluvan M. G.)

I'm not able to reproduce any crash with "normal" libc setups.   However, I did update the CMakeLists.txt to do two things:

1) Make sure we preserve existing CMAKE_CXX_FLAGS and CMAKE_CXX_FLAGS_DEBUG so things like the -g are not removed.   This is definitely important in trying to debug things.

2) Only add the above problematic flags if AVRO_ADD_PROTECTOR_FLAGS is set which should only be set for our "build.sh test" runs.   It's not set for all Debug builds so you should be able to do your own build without those flags and hopefully then not have your crash.

> Use of -fstack-protector or -D_GLIBCXX_DEBUG causes memory corruption when combined with musl libc static builds
> ----------------------------------------------------------------------------------------------------------------
>
>                 Key: AVRO-2202
>                 URL: https://issues.apache.org/jira/browse/AVRO-2202
>             Project: Apache Avro
>          Issue Type: Bug
>          Components: c++
>    Affects Versions: 1.8.2
>         Environment: OS: Gentoo Linux
> Compiler: Gcc 6.4.0 targeting musl libc 1.19 with stdlibc++ in a static build
>            Reporter: Josh Scoggins
>            Assignee: Daniel Kulp
>            Priority: Major
>             Fix For: 1.9.0
>
>
> Observed with master and version 1.8.2. Inside of the C++ implementation's CMakeLists.txt the lines 56-60 were added sometime in 2016 which activate features inside of libstdc++ to help find errors. This change has two side effects:
>  # -g is eliminated from the build so debugging gdb becomes harder as source position data has been removed
>  # The safety containers that implicitly wrap all standard containers somehow (I can't figure out exactly how) cause memory corruption when setMetadata is called (in version 1.8.2) or when a Writer object is destroyed (on master). Since our software uses musl libc with libstdc++ I believe that it is an interaction with these debugging features which cause memory corruption (as I said, I have no clue _why_ it is happening, only that these features _cause_ it :()
> Previously, we were using 1.7.7 which did not have these lines in its CMakeLists.txt and thus did not exhibit any sort of memory corruption. I was able to work around this by removing lines 56-60 from CMakeLists.txt so our static libs could be built and our unit tests not crash by writing to memory it did not own. There should be a toggle or something similar to turn off these features for debug builds as they are for developers of avro only. 



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