Deadlock possible on JIRA startup if a 401 / 403 response is returned when PICO is not fully initialised

Summary.

A deadlock possible on JIRA startup if a 401 / 403 response is returned when PICO is not fully initialised.

This is because the page displayed on that response code displayError.jsp assumes the PICO container is up and attempts to retrieve components from it in an unsafe way.

Steps to Reproduce.

• Start JIRA.
• Immediately after, attempt to navigate to displayError.jsp or /display-error before PICO is up.

Actual Results

• A deadlock will occur on the PICO container.

Expected Results

• The error page is displayed succesfully.

Workaround

• Block requests to JIRA at the apache level until it has been fully started.

Notes

Please verify that DisplayErrorServlet does not have any unsafe usages of PICO either.