On Mon, Feb 23, 2015 at 02:08:10PM +1100, Aleksa Sarai wrote:

NOTE: I'm not sure if I'm doing enough cleanup inside copy_process(),
because a bunch of stuff happens between the last valid goto to the
bad_fork_free_pid label and cgroup_post_fork().

What is the correct way of doing cleanup this late inside
copy_process()?

Its not; you're past the point of fail. You've already exposed the new
process.

If you want to allow fail, you'll have to do it earlier.