I couldn't reproduce it on my laptop. (uname -rv: 3.11.0-14-generic #21-Ubuntu SMP Tue Nov 12 17:04:55 UTC 2013)
on my machines I had to try with n from 10 to 100 (in increments of 10) to get the segfault. The few bad values of n differed in each machine. Also the ubuntu I used were 12.x instead, if that matters.
But GC is indeed buggy, and it is enormously hard to make a reasonably small test case that will fail on most machines :(
the cases I was aware of were rather due to GC being overly conservative. This bug seems more serious and I haven't seen such kind yet. It also disappears if we refactor code to use string instead of DirEntry (ie only maintain the entry.name field)