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Symbol redefinition building 2.6.6 UML kernel

I'm trying to help some members of the LFS team debug a problem building a 2.6.6-based UML kernel. At this time, we cannot determine whether the problem is actually the fault of "ld" or if we have a toolchain build quality problem. The testing has been done with FSF 2.15 binutils and HJL binutils.

Here is the scenario:

- unpack a linux-2.6.6 kernel tarball
- apply the 2.6.6 UML kernel patch (from
- run "make ARCH=um menuconfig" and turn off UML Networking Multicast support
- run "make ARCH=um linux"

On some of our systems, during the final link of vmlinux, there are symbol redefinitions of the common functions from glibc that are also present in the kernel. Primarily this includes the string functions, but there are others.

I have followed this down to the object file "unmap_fin.o" (from arch/um/kernel/tt) that is built; this object file is made by linking "unmap.o" with the system's libc (glibc-CVS in our case) but producing a relocatable object. This relocatable object is then linked into vmlinux using the linker script at arch/um/, which appears to just "force" the contents of this file into the resulting kernel image as raw data.

As best I can tell, during this final link step the linker should not be paying attention to any exported symbols from this object file, but it does. When it works properly, the symbol redefinitions do not occur and the final link proceeds to completion.

We are concerned that we may be providing faulty toolchain build instructions to our users, although we have not had problems building hundreds of other packages. In fact, these same build instructions work fine for the UML kernel on some of our testers' systems, just not all of them.

Can anyone provide some assistance to us to try to isolate this problem? Thanks in advance :-)

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