child_process.exec hangs without executing command #27937

• Version: v8.10.0
• Platform: Linux 4.4.0-17763-Microsoft docs: Fix mixed content issues #379-Microsoft Wed Mar 06 19:16:00 PST 2019 x86_64 x86_64 x86_64 GNU/Linux
• Subsystem: child_process.exec
  Software spec:

1. Windows 10 WSL running Ubuntu 18.04.2 LTS
2. Apache Server 2.4.29 (Ubuntu)
3. Xming X Server 6.9.0.31 (Windows 10)
4. Firefox Quantum 67.0 (64-bit for Ubuntu)
5. Node.js v8.10.0 for Ubuntu

The attached TestExec.html file runs TestExec.js, which executes TestExec.bash.
The user enters a string, which is written to TestExec.txt by the Bash script.
TestExec.bash is executed via child_process.exec.
TestExec2.js is a modified form of TestExec.js, with no dependencies on the HTML document.
TestExec2.js runs correctly from the command line, "node TestExec2.js".
However, TestExec.js hangs indefinitely, when child_process.exec("bash TestExec.bash arg") is called from Firefox.
(Note that the "puts called" message is never displayed in Firefox, indicating that puts() is never executed from child_process.exec [see TestExec_run.jpg screenshot])
Therefore, child_process.exec works at the command line, but not from Firefox, via the
TestExec.js script.
See 4 attached files: