pfSense

At least with some wireless devices, they send a link up event to the OS when they associate successfully. This triggers rc.linkup which in turn calls interface_configure(). For wireless interfaces, this also calls interface_wireless_configure() which tears down and rebuilds the wireless interface, which then associates again, triggers another link up event, and so on in an endless loop.

This at least affects ralink USB wifi devices with the run(4) driver.

To me, I have a fix.