$ qemu-system-i386 -kernel bzImage -m 128 -s

qemu

sd@tbox:~/src/lll-project/test-qemu$ LANG=C gdb vmlinux
GNU gdb (GDB) 7.2-debian
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i486-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/sd/src/lll-project/test-qemu/vmlinux...(no debugging symbols found)...done.
(gdb) target remote localhost:1234
Remote debugging using localhost:1234
0xc11be5e5 in ?? ()
(gdb) backtrace full
#0  0xc11be5e5 in ?? ()
No symbol table info available.
#1  0xc103a0f3 in ?? ()
No symbol table info available.
#2  0xc132c413 in ?? ()
No symbol table info available.
#3  0xc10215a0 in ?? ()
No symbol table info available.
#4  0xc102195a in ?? ()
No symbol table info available.
#5  0xc1021225 in ?? ()
No symbol table info available.
#6  0xc132ddb5 in ?? ()
No symbol table info available.
#7  <signal handler called>
No symbol table info available.
#8  0xc11bee37 in ?? ()
No symbol table info available.
#9  0xc14d1399 in ?? ()
No symbol table info available.
#10 0xc14a5e21 in ?? ()
No symbol table info available.
#11 0xc14a342e in ?? ()
No symbol table info available.
#12 0x00000000 in ?? ()
No symbol table info available.
(gdb)