warning: pthread_create failed for timer: Invalid argument, scheduling broken

[floehopper]

I think the following warning started to occur when I added the CLONE_NEWPID flag to the call to unshare. It doesn't seem to cause a problem at the moment, but it may well be a hidden danger.

root@ubuntu-xenial:/vagrant# ./container run /bin/bash
run: Running ["/bin/bash"]
child: Running ["/bin/bash"]
/var/lib/gems/2.4.0/gems/childprocess-0.8.0/lib/childprocess/unix/fork_exec_process.rb:20: warning: pthread_create failed for timer: Invalid argument, scheduling broken
root@container:/# 

[floehopper]

Maybe this is related: jemalloc/jemalloc#1006

It might be worth upgrading Ruby to v2.5 when the Brightbox package is available.