I'm not sure where to report it.
$ chroot /usr
Segmentation fault (core dumped)
First, in MSYS by default /usr is mounted to /. In few days we stop using it but it not solve your problem.
I only reported a crash. I was not solving any problems with chroot /usr. I just typed a command and got a segfault. So the discussion of how useless chroot under Cygwin is is irrelevant.
Are there reasons (other than low priority of the problem) to believe that this segfault cannot be fixed and replaced with an error message?
The new layout will fix this problem:
chroot: failed to run command ‘/usr/bin/bash’: No such file or directory
We will release it ASAP.
Fixed in todays (2014-06-24) snapshots and installers.