Re: vdso_standalone_test_x86.c build failure on Linus' tree

[Chuck Ebbert <cebbert.lkml@gmail.com>]

On Wed, 8 Oct 2014 12:16:11 -0700
Andy Lutomirski <luto@amacapital.net> wrote:

> On Wed, Oct 8, 2014 at 11:52 AM, Josh Boyer <jwboyer@fedoraproject.org> wrote:
> > I'm seeing the following build failure on a 32-bit x86 build in Fedora
> > based on Linux v3.17-2860-gef0625b70dac:
> >
> > Documentation/vDSO/vdso_standalone_test_x86.o: In function `to_base10':
> > vdso_standalone_test_x86.c:(.text+0xcc): undefined reference to `__umoddi3'
> > vdso_standalone_test_x86.c:(.text+0xea): undefined reference to `__udivdi3'
> > collect2: error: ld returned 1 exit status
> > scripts/Makefile.host:100: recipe for target
> > 'Documentation/vDSO/vdso_standalone_test_x86' failed
> > make[2]: *** [Documentation/vDSO/vdso_standalone_test_x86] Error 1
> > scripts/Makefile.build:404: recipe for target 'Documentation/vDSO' failed
> > make[1]: *** [Documentation/vDSO] Error 2
> > make[1]: *** Waiting for unfinished jobs....
> > Makefile:922: recipe for target 'vmlinux' failed
> > make: *** [vmlinux] Error 2
> >
> It should build and work on 32-bit.
> 
> Except that the makefile is totally bogus.  vdso_standalone_test isn't
> a hostprog at all.  It's a target prog.  But kbuild doesn't understand
> that, so I have no idea what, if anything, that makefile is supposed
> to do.

Heh, I was wondering why I got a 64-bit program with ARCH=i386
 
> I would argue that the whole documentation build system should be
> fixed to cross-compile or should just be disabled for cross-builds if
> glibc isn't available.
> 

Fedora doesn't cross-compile i686 builds because of problems like
this. It sets up an i386 chroot and runs all native tools inside of
it.