We've noticed that the /tmp directory on our slaves is filling up with directories with names beginning with "resource-" (ex. "resource-504258138138001911").
I was able to narrow down how to reproduce the issue. Most of our jobs are "Freestyle" projects, but one is a "Maven Project"; and whenever that job runs, it creates a /tmp/resources-xxx temp directory but never deletes it. The Freestyle projects that run the exact same "mvn clean install" command using the Execute shell plugin don't experience this issue.
If you want to reproduce it, create a Maven Project, clone a git repo that has a maven project that has some JUnit tests. Run "ls -al /tmp" before and after executing the "clean install" maven goal. You will see 2 new /tmp/resource directories after running the Maven goal (which should also run some tests).
My guess as to the problem is someone is probably calling Files.createTempDirectory("resource-") without calling File.deleteOnExit() afterwards.