Modifying /etc/systemd/system.conf to read like this: DefaultTasksMax=infinity
does also fix the issue, which seems related to recent kernels (>= 4.3) and systemd: http://unix.stackexchange.com/questions/253903/creating-threads-fails-with-resource-temporarily-unavailable-with-4-3-kernel This is probably why it fails for me on a virtual machine running stretch and it does not fail on another virtual machine running stretch with a kernel from jessie. So: Could you please try to reproduce this on a system running stretch, including linux-image-4.5.0-1-amd64? (i.e. not just the chroot). Thanks.
