Well, that's most likely the problem. The home directory to which you chroot the user MUST be owned by root with permissions of 755. I'm pretty sure the same rules apply to any directories above that one. Therefore, I would not be using /tmp as your test as you need to take away write permissions for everyone except for root for the chroot directory and every directory above it all the way up to root. Other users or programs may be writing to /tmp. I would recommend creating a /chroot directory, then another directory below that with the same permissions, modifying your /etc/ssh/sshd_config file with those changes, restart the sshd process and try it again.
Here's what worked for me, in case someone else is having issues with this.
There are multiple scenarios:
If you keep the chroot_list empty then the configuration will work.
BUT if you start adding users in chroot_list, then it will have the opposite effect, those users are users that are not jailed.
With this config you can add users in chroot_list, which will contain a list with users that are jailed to their home directories.