GDB

what to expect...

(gdb) gdb vmlinux
GNU gdb 5.0
Copyright 2000 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-redhat-linux"...
(gdb) 
(gdb) disassemble create_virtual_node
Dump of assembler code for function create_virtual_node:
0xc017d2f0 <create_virtual_node>:       push   %ebp
0xc017d2f1 <create_virtual_node+1>:     push   %edi
0xc017d2f2 <create_virtual_node+2>:     push   %esi
0xc017d2f3 <create_virtual_node+3>:     push   %ebx

......and so on

(gdb) info scope create_virtual_node
Scope for create_virtual_node:
Symbol tb is an argument at stack/frame offset 36, length 4.
Symbol h is an argument at stack/frame offset 40, length 4.
Symbol h is a local variable in register $ebx, length 4.
Symbol ih is a local variable at frame offset 12, length 4.
Symbol vn is a local variable in register $esi, length 4.
Symbol new_num is a local variable in register $ebp, length 4.
Symbol Sh is a local variable at frame offset 8, length 4.
(gdb) 

Can run gdb on a running kernel
(include debugging symbols, that's -g in CFLAGS)

> gdb -q vmlinux /proc/kcore