[Buildroot] glibc link fails on x86_64 with fPIC error

[Romain Naour <romain.naour@gmail.com>]

Hi,

Le 06/11/2018 ? 21:35, mws a ?crit?:
> Thanks Matt and also Roman. In meantime I discovered something interesting:
> with libc=musl the build succeeds, but with libc=uClibc-ng it fails in a way
> similar to glibc, which I think exonerates glibc.  Here is the ucLibC
> failure with the similar linking error:
> 
> $ tail -20 tools.log
>  AR cr libc/libc_so.a
>  STRIP -x -R .note -R .comment libc/libc_so.a
>  CC libpthread/nptl/pthread_atfork.oS
>  AR cr lib/libpthread_nonshared.a
>  STRIP -x -R .note -R .comment lib/libpthread_nonshared.a
>  LD libuClibc-1.0.30.so
> ./lib/ld64-uClibc.so.1: warning: multiple common of
> `_dl_internal_error_number'
> libc/libc_so.a(libdl.oS): warning: previous common is here
> ./lib/ld64-uClibc.so.1: warning: multiple common of `_dl_error_number'
> libc/libc_so.a(libdl.oS): warning: previous common is here
> ./lib/ld64-uClibc.so.1: warning: multiple common of `_dl_free_function'
> libc/libc_so.a(libdl.oS): warning: previous common is here
> ./lib/ld64-uClibc.so.1: warning: multiple common of `_dl_malloc_function'
> libc/libc_so.a(libdl.oS): warning: previous common is here
> /home/build/src/docker/buildroot/host/lib/gcc/x86_64-buildroot-linux-uclibc/7.3.0/../../../../x86_64-buildroot-linux-uclibc/bin/ld:

Can you try outside of docker ?
Also, we don't recommend to run the build as root.

Best regards,
Romain

> libc/libc_so.a(libc-cancellation.oS): relocation R_X86_64_PC32 against
> symbol `__pthread_unwind' can not be used when making a shared object;
> recompile with -fPIC
> /home/build/src/docker/buildroot/host/lib/gcc/x86_64-buildroot-linux-uclibc/7.3.0/../../../../x86_64-buildroot-linux-uclibc/bin/ld:
> final link failed: Bad value
> collect2: error: ld returned 1 exit status
> make[2]: *** [lib/libc.so] Error 1
> make[1]: ***
> [/home/build/src/docker/buildroot/build/uclibc-1.0.30/.stamp_built] Error 2
> make: *** [_all] Error 2
> 
> So my hypothesis is that something about my build system environment is
> causing a misconfiguration of the toolchain with respect to gcc's defaults. 
> I am thinking maybe the pic/PIC default or the mcmodel default is somehow
> different from what glibc or uClibc-ng Makefiles expect it to be, and they
> are not setting those options to be explicitly the way they should be in
> their respective Makefiles.
> 
> So I need to figure out what part of the toolchain build is looking at the
> system itself to determine defaults in this area, or alternatively find the
> specific gcc setting and change its default manually in buildroot's config.
> 
> 
> 
> 
> --
> Sent from: http://buildroot-busybox.2317881.n4.nabble.com/
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