Re: shellcoding on gentoo

[nonexistent () fake com]

Try initializing the upper 3 MSB's of the eax register before trapping. This seems like a really common error amongst 
new shellcode writers. It's probably that eax has already been initalized with a value and you're only setting the LSB. 
Then when you trap the wrong (or completely invalid) systemcall is being called, fails, and since you don't exit() 
after the trap it crashes. If you use something like strace, you'll be able to confirm what systemcall (if any) is 
actually being called on the trap.