How to reproduce:
- Create file on a mounted (harddisk) file system (tested on XFS):
  touch test

- Check extended attributes:
  attr -l test

As soon as you try to copy that file on a system without the SMACK patch, cp
crashes with a segmentation fault.

lsetxattr("../test", "security.SMACK64", "_", 2, 0) = -1 EPERM (Operation not
permitted)
--- SIGSEGV (Segmentation fault) @ 0 (0) ---

Removing that SMACK attribute fixes the problem.