Re: [Qemu-devel] Problems compiling qemu-snapshot

[Grzegorz Kulewski]

On Wed, 1 Jun 2005, bent jakobsen wrote:

> Hi,
>
> When I try to compile the lastest qemu-snapshot (2005-05-31_23) I get
> the following error:
>
> gcc -g -Wl,-shared -o qemu-i386 elfload.o main.o syscall.o mmap.o
> signal.o path.o osdep.o thunk.o vm86.o libqemu.a gdbstub.o -lm
> /usr/bin/ld: errno: TLS definition in /lib/libc.so.6 section .tbss
> mismatches non-TLS reference in libqemu.a(helper2.o)
> /lib/libc.so.6: could not read symbols: Bad value
> collect2: ld returned 1 exit status
>
>
> Has anyone seen this before ?  Or am I the only one who has seen this ?
>
> I think this started to happen when I updated the Linux kernel (to
> 2.6.11.11), or perhaps when I updated to glibc version 2.3.5

Probably glibc...

TLS = mechanizm for having some variables per-thread. It requires new gcc, 
binutils and maybe glibc.

errno = global variable (or macro or something - differs from one compiler 
to another...) that was defined in ancient days of early UNIXes ('70 
probably) to hold last error after syscall. But when you have multiple 
threads this variable must be par-thread to actually mean something (if it 
would be global you would never know if it holds last error for your 
thread or some other thread in your app). So newer glibcs set it probably 
as per-thread rather than global.

Are you absolutely sure that you have compatible and well compiled set of 
kernel, kernel headers, gcc, glibc? Because it looks like something could 
be broken here. How did you upgrade your glibc? What is your 
distributions? What are your versions of above core packages?


Grzegorz Kulewski