Worker children not killed immediately when reaching --kill-after

[ryanwitt]

Observed in production that child processes do not exit and become orphaned once --kill-after is reached. Saw this on the command line.

Also see separate orphaned child processes on some production machines.

Theory on what's happening:

qdone uses child_process.exec (not to be confused with exec(3)) to execute children within a shell.

It seems like exec's timeout option (that we use to send SIGTERM to the child if it reaches the timeout) does not actually kill the child of the shell (observed on Ubuntu 16.04).

Seems like a fairly useless option for exec. Maybe a better option for execFile?

Workarounds:

1. Kill the qdone process group?
2. Find the PID of the child (not the child shell, but shell's child) and manually signal that.

I'm starting this ticket to record my findings, but it may be worth checking node issues as well to see if anybody has run into this strange design on exec.