i'm getting regularly
fxp1: device timeout (sometimes fxp0 too)

on one machine.

machine sometimes crashes like freezeing or getting into ddb.

in ddb even disk syncing doesn't work but i was able to show where it 
stopped:

fxp_add_rfabuf+0x28


i have kernel with debug symbols - but i know almost nothing about using 
gdb

how to translate it to exact (near exact) instruction in C?