Maven occasionally hangs within Surefire

I'm trying to fix a build issue where Maven hangs running tests. This
happens about 30% of the time on our Travis builds.

It never happens on our Jenkins cluster, but it happens occasionally on
some of our local machines. We were able to capture a jstack and lsof from
the process after it hung.

Any tips on how to debug? Relevant captured data is here:

https://gist.github.com/tpetr/1bdd2cfd362f125b4f06

I can't file an issue here [1] as I don't have an account.

Thanks;

-Whitney

[1] -
http://jira.codehaus.org/browse/SUREFIRE#selectedTab=com.atlassian.jira.plugin.system.project%3Aissues-panel