Re: [PATCH v12 00/21] Compile-time stack metadata validation

[Josh Poimboeuf <jpoimboe@redhat.com>]

On Tue, Sep 15, 2015 at 11:57:00AM -0500, Chris J Arges wrote:
> I got the following compiler error when building v12 of this patchset:
> 
>   DESCEND  stacktool
>   CC       stacktool.o
>   CC       elf.o
>   CC       special.o
>   CC       arch/x86/decode.o
>   LD       arch/x86/stacktool-in.o
>   LD       stacktool-in.o
> Warning: stacktool: x86 instruction decoder differs from kernel
>   LINK     stacktool
> stacktool-in.o: In function `elf_close':
> (.text+0xe7c): undefined reference to `elf_end'
> stacktool-in.o: In function `elf_open':
> (.text+0xec7): undefined reference to `elf_version'
> stacktool-in.o: In function `elf_open':
> (.text+0xf29): undefined reference to `elf_begin'
> stacktool-in.o: In function `elf_open':
> (.text+0xf42): undefined reference to `gelf_getehdr'
> stacktool-in.o: In function `elf_open':
> (.text+0xf59): undefined reference to `elf_getshdrnum'
> stacktool-in.o: In function `elf_open':
> (.text+0xf6f): undefined reference to `elf_getshdrstrndx'
> stacktool-in.o: In function `elf_open':
> (.text+0xfc9): undefined reference to `elf_getscn'
> stacktool-in.o: In function `elf_open':
> (.text+0xfdd): undefined reference to `elf_ndxscn'
> stacktool-in.o: In function `elf_open':
> (.text+0xff2): undefined reference to `gelf_getshdr'
> stacktool-in.o: In function `elf_open':
> (.text+0x100e): undefined reference to `elf_strptr'
> stacktool-in.o: In function `elf_open':
> (.text+0x1029): undefined reference to `elf_getdata'
> stacktool-in.o: In function `elf_open':
> (.text+0x1101): undefined reference to `elf_nextscn'
> stacktool-in.o: In function `elf_open':
> (.text+0x119e): undefined reference to `gelf_getsym'
> stacktool-in.o: In function `elf_open':
> (.text+0x11b8): undefined reference to `elf_strptr'
> stacktool-in.o: In function `elf_open':
> (.text+0x13d4): undefined reference to `gelf_getrela'
> collect2: error: ld returned 1 exit status
> Makefile:33: recipe for target 'stacktool' failed
> make[2]: *** [stacktool] Error 1
> Makefile:53: recipe for target 'stacktool' failed
> make[1]: *** [stacktool] Error 2
> Makefile:1502: recipe for target 'tools/stacktool' failed
> make: *** [tools/stacktool] Error 2
> 
> The patch below addresses this issue for me.
> 
> --
> 
> From 9ec5827aa726300394c0155657820f2595008116 Mon Sep 17 00:00:00 2001
> From: Chris J Arges <chris.j.arges@canonical.com>
> Date: Tue, 15 Sep 2015 16:45:27 +0000
> Subject: [PATCH] x86/stacktool: Fix LDFLAGS order in Makefile
> 
> When building tools/stacktool I get a compiler error which causes libelf to not
> properly link. This patch adjusts the LDFLAG after the object file, which
> allows gcc to properly link.
> 
> Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>

Makes sense (after reading the part in the ld man page about how the
order matters for '-l' arguments).  Not sure yet why it works for me
without the patch.

To avoid breaking bisection, this patch should be folded into patch 4 of
the series (which I will do, if a v13 is necessary).

Thanks!

-- 
Josh