Since I was unable to use gdb with the mipsel cores, I has written an small library that loads with LD_PRELOAD and intercepts the signals SIGSEGV, SIGBUS and SIGILL and shows the direction where the signal was raised.
This is a real example on my Asus WL-500gx:
[unai@perseida root]$ lua
Lua 5.0.2 Copyright (C) 1994-2004 Tecgraf, PUC-Rio
> require("socket")
Uncaught fatal signal 11 raised at 0x2ACC4BFC:/lib/libc.so.0+0x2CBFC[_cs_close+0x1C] (address 0)
Segmentation fault (core dumped)
I don't have a better place to put this utility, so I attach it here.