To debug fakeroot, one may try: Start faked in xterm 1: $ faked --foreground --debug 51452231:280 # First number here is the 'FAKEROOTKEY', second is the pid of # faked. Both to be used later. # Later, when programs go using faked, a _lot_ of debug output # will be shown here. Send signals to faked in xterm 2: #Whenever you want to get info about the internal inode data #faked is keeping, do: kill -s USR1 280 And the 'real' program runs (at your choise) in another xterm [3], or gdb In an xterm, do: $ LD_PRELOAD=/usr/lib/libfakeroot/libfakeroot.so.0 $ FAKEROOTKEY=51452231 # number output by faked, xterm 1 $ export LD_PRELOAD FAKEROOTKEY $ my-prog #start anything you like. Or, if you want to run the programme in a gdb session: To make specifying the paths easier, put libfakeroot.c, libfakeroot.so.0.0.1 and the binary you want to run in the same directory (libfakeroot.so.0.0.1 is put in ./.libs/libfakeroot.so.0.0.1 by libtool during compilation, copy it out there). Then, in gdb do: $ gdb ./ls #as an example, I run 'ls'. (gdb) set env LD_PRELOAD=/home/joost/maintain/vpathlib/libfakeroot-0.1/libfakeroot.so.0.0.1 (gdb) set env FAKEROOTKEY=51452231 #number from xterm 1. # Or wherever you've got your libfakeroot.so.0.0.1 (gdb) break libfakeroot.c:181 Breakpoint 1 at 0x4000ecc8: file libfakeroot.c, line 181. (gdb) run -al Starting program: /home/joost/maintain/vpathlib/libfakeroot-0.1/ls -al Temporarily disabling shared library breakpoints: 1 Breakpoint 1, __lxstat (ver=134556187, file_name=0x0, statbuf=0x80529c8) at libfakeroot.c:208 208 struct stat *statbuf){ # OK, and there I've found a bug -- ver can only be '0' in the # current libc6 (glibc2). Unfortunately, it didn't reproduce.