[Buildroot] glibc link fails on x86_64 with fPIC error

[Buildroot] glibc link fails on x86_64 with fPIC error

[mws]

I'm using buildroot-2018.08.2 to build for x86_64 using essentially the
defaults for that release (glibc 2.27, gcc 7.3.0) but enabling glibc for the
toolchain.  The toolchain build goes very well until it gets to glibc in the
elf/ subdirectory at which point it blows up with an fPIC error on the link
test shown below.

I've tried varying gcc version, binutils version to see if this is some
defaults problem with no luck.  Has anyone else seen this before or have
advice on fixing?  Fundamentally it seems like basic out-of-the-box x86_64 +
glibc is not able to build with this buildroot release.

---

buildroot/host/bin/x86_64-buildroot-linux-gnu-gcc   -nostdlib -nostartfiles
-r -o
buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os
'-Wl,-('
buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/dl-allobjs.os
buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/rtld-libc.a
-lgcc '-Wl,-)' \
         
-Wl,-Map,buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os.map
buildroot/host/bin/x86_64-buildroot-linux-gnu-gcc   -nostdlib -nostartfiles
-shared -o
buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/ld.so.new               
\
          -Wl,-z,combreloc -Wl,-z,relro -Wl,--hash-style=both -Wl,-z,defs      
\
         
buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os
-Wl,--version-script=buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/ld.map           
\
          -Wl,-soname=ld-linux-x86-64.so.2                      \
          -Wl,-defsym=_begin=0
buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os:
In function `dl_main':
rtld.c:(.text+0x25ab): undefined reference to `__open'
rtld.c:(.text+0x2b19): undefined reference to `__access'
rtld.c:(.text+0x442c): undefined reference to `__access'
buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os:
In function `lose.isra.5':
dl-load.c:(.text+0x486a): undefined reference to `__close'
buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os:
In function `_dl_map_object_from_fd':
dl-load.c:(.text+0x491c): undefined reference to `__GI___fxstat64'
buildroot/host/lib/gcc/x86_64-buildroot-linux-gnu/7.3.0/../../../../x86_64-buildroot-linux-gnu/bin/ld:
buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os:
relocation R_X86_64_PC32 against undefined symbol `__GI___fxstat64' can not
be used when making a shared object; recompile with -fPIC
buildroot/host/lib/gcc/x86_64-buildroot-linux-gnu/7.3.0/../../../../x86_64-buildroot-linux-gnu/bin/ld:
final link failed: Bad value
collect2: error: ld returned 1 exit status
make[4]: ***
[buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/ld.so]
Error 1
make[3]: *** [elf/subdir_lib] Error 2
make[2]: *** [all] Error 2
make[1]: ***
[buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/.stamp_built]
Error 2
make: *** [_all] Error 2



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[Buildroot] glibc link fails on x86_64 with fPIC error

[Matthew Weber]

Mike,

On Tue, Nov 6, 2018 at 10:09 AM mws <mike.w.shapiro+buildroot@gmail.com> wrote:
>
> I'm using buildroot-2018.08.2 to build for x86_64 using essentially the
> defaults for that release (glibc 2.27, gcc 7.3.0) but enabling glibc for the
> toolchain.  The toolchain build goes very well until it gets to glibc in the
> elf/ subdirectory at which point it blows up with an fPIC error on the link
> test shown below.
>

If looks like some of the hardening features are turned on like relro.
Would you mind doing a savedefconfig and provide that defconfig
(should be small so just inline here in a response is fine)?

> I've tried varying gcc version, binutils version to see if this is some
> defaults problem with no luck.  Has anyone else seen this before or have
> advice on fixing?  Fundamentally it seems like basic out-of-the-box x86_64 +
> glibc is not able to build with this buildroot release.
>
> ---
>
> buildroot/host/bin/x86_64-buildroot-linux-gnu-gcc   -nostdlib -nostartfiles
> -r -o
> buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os
> '-Wl,-('
> buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/dl-allobjs.os
> buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/rtld-libc.a
> -lgcc '-Wl,-)' \
>
> -Wl,-Map,buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os.map
> buildroot/host/bin/x86_64-buildroot-linux-gnu-gcc   -nostdlib -nostartfiles
> -shared -o
> buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/ld.so.new
> \
>           -Wl,-z,combreloc -Wl,-z,relro -Wl,--hash-style=both -Wl,-z,defs
> \
>
> buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os
> -Wl,--version-script=buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/ld.map
> \
>           -Wl,-soname=ld-linux-x86-64.so.2                      \
>           -Wl,-defsym=_begin=0
> buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os:
> In function `dl_main':
> rtld.c:(.text+0x25ab): undefined reference to `__open'
> rtld.c:(.text+0x2b19): undefined reference to `__access'
> rtld.c:(.text+0x442c): undefined reference to `__access'
> buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os:
> In function `lose.isra.5':
> dl-load.c:(.text+0x486a): undefined reference to `__close'
> buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os:
> In function `_dl_map_object_from_fd':
> dl-load.c:(.text+0x491c): undefined reference to `__GI___fxstat64'
> buildroot/host/lib/gcc/x86_64-buildroot-linux-gnu/7.3.0/../../../../x86_64-buildroot-linux-gnu/bin/ld:
> buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/librtld.os:
> relocation R_X86_64_PC32 against undefined symbol `__GI___fxstat64' can not
> be used when making a shared object; recompile with -fPIC
> buildroot/host/lib/gcc/x86_64-buildroot-linux-gnu/7.3.0/../../../../x86_64-buildroot-linux-gnu/bin/ld:
> final link failed: Bad value
> collect2: error: ld returned 1 exit status
> make[4]: ***
> [buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/build/elf/ld.so]
> Error 1
> make[3]: *** [elf/subdir_lib] Error 2
> make[2]: *** [all] Error 2
> make[1]: ***
> [buildroot/build/glibc-glibc-2.27-57-g6c99e37f6fb640a50a3113b2dbee5d5389843c1e/.stamp_built]
> Error 2
> make: *** [_all] Error 2
>
>
>
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[Buildroot] glibc link fails on x86_64 with fPIC error

[mws]

$ cat defconfig
BR2_x86_64=y
BR2_x86_core_avx2=y
BR2_JLEVEL=1
BR2_TOOLCHAIN_BUILDROOT_GLIBC=y
BR2_KERNEL_HEADERS_4_9=y
BR2_PACKAGE_BUSYBOX_SHOW_OTHERS=y
BR2_PACKAGE_PCIUTILS=y
BR2_PACKAGE_LIBXML2=y
BR2_PACKAGE_ELFUTILS=y
BR2_PACKAGE_LIBCAP=y
BR2_PACKAGE_BASH=y

$ grep -i relro .config
BR2_RELRO_NONE=y
# BR2_RELRO_PARTIAL is not set
# BR2_RELRO_FULL is not set

Thanks for any ideas.



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[Buildroot] glibc link fails on x86_64 with fPIC error

[Romain Naour]

Hi,

Le 06/11/2018 ? 17:49, mws a ?crit?:
> $ cat defconfig
> BR2_x86_64=y
> BR2_x86_core_avx2=y
> BR2_JLEVEL=1
> BR2_TOOLCHAIN_BUILDROOT_GLIBC=y
> BR2_KERNEL_HEADERS_4_9=y
> BR2_PACKAGE_BUSYBOX_SHOW_OTHERS=y
> BR2_PACKAGE_PCIUTILS=y
> BR2_PACKAGE_LIBXML2=y
> BR2_PACKAGE_ELFUTILS=y
> BR2_PACKAGE_LIBCAP=y
> BR2_PACKAGE_BASH=y

With this defconfig, the toolchain build fine here.

Can you share the full build log ?

Best regards,
Romain

> 
> $ grep -i relro .config
> BR2_RELRO_NONE=y
> # BR2_RELRO_PARTIAL is not set
> # BR2_RELRO_FULL is not set
> 
> Thanks for any ideas.
> 
> 
> 
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> Sent from: http://buildroot-busybox.2317881.n4.nabble.com/
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> 

[Buildroot] glibc link fails on x86_64 with fPIC error

[Matthew Weber]

Mike,

On Tue, Nov 6, 2018 at 10:48 AM Mike Shapiro <mike.w.shapiro@gmail.com> wrote:
>
>
> $ cat defconfig
> BR2_x86_64=y
> BR2_x86_core_avx2=y
> BR2_JLEVEL=1
> BR2_TOOLCHAIN_BUILDROOT_GLIBC=y
> BR2_KERNEL_HEADERS_4_9=y
> BR2_PACKAGE_BUSYBOX_SHOW_OTHERS=y
> BR2_PACKAGE_PCIUTILS=y
> BR2_PACKAGE_LIBXML2=y
> BR2_PACKAGE_ELFUTILS=y
> BR2_PACKAGE_LIBCAP=y
> BR2_PACKAGE_BASH=y
>

I was able to checkout 2018.08.2, use your defconfig but with
BR2_JLEVEL set to 0 and the build was successful.  I had the following
host machine:
gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.4)

Matt

[Buildroot] glibc link fails on x86_64 with fPIC error

[mws]

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:
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.




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[Buildroot] glibc link fails on x86_64 with fPIC error

[Romain Naour]

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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> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot
>