Bug#211610: gcc-3.3: Simple TLS code segfaults

[GOTO Masanori <gotom@debian.or.jp>]

severity 211610 wishlist
reassign 211610 glibc
thanks

At Thu, 18 Sep 2003 18:17:42 -0500,
Andr�Rold�wrote:
> When trying to executing a binary with the __thread keywork, the program
> segfaults. Below is the output.
> 
> [pts/0]
> aroldan@volatile:~$ cat tls.c
> __thread int a;
> 
> int 
> main (void)
> {
>         return a;
> }
> [pts/0]
> aroldan@volatile:~$ gcc-3.3 -Wall -o tls tls.c
> [pts/0]
> aroldan@volatile:~$ ./tls
> Segmentation fault (core dumped)
> [pts/0]
> aroldan@volatile:~$ gdb tls core
> GNU gdb 5.3.90_2003-08-24-cvs-debian
> Copyright 2003 Free Software Foundation, Inc.
> GDB is free software, covered by the GNU General Public License, and you are
> welcome to change it and/or distribute copies of it under certain conditions.
> Type "show copying" to see the conditions.
> There is absolutely no warranty for GDB.  Type "show warranty" for details.
> This GDB was configured as "i386-linux"...(no debugging symbols found)...
> Core was generated by `./tls'.
> Program terminated with signal 11, Segmentation fault.
> Reading symbols from /lib/libc.so.6...(no debugging symbols found)...done.
> Loaded symbols for /lib/libc.so.6
> Reading symbols from /lib/ld-linux.so.2...(no debugging symbols found)...done.
> Loaded symbols for /lib/ld-linux.so.2
> #0  0x08048344 in main ()
> (gdb) disas main
> Dump of assembler code for function main:
> 0x08048334 <main+0>:    push   %ebp
> 0x08048335 <main+1>:    mov    %esp,%ebp
> 0x08048337 <main+3>:    sub    $0x8,%esp
> 0x0804833a <main+6>:    and    $0xfffffff0,%esp
> 0x0804833d <main+9>:    mov    $0x0,%eax
> 0x08048342 <main+14>:   sub    %eax,%esp
> 0x08048344 <main+16>:   mov    %gs:0x0,%eax

This is because glibc's dl does not support tls currently on i386, so
%gs:0 does not setup correctly for this purpose.

Regards,
-- gotom