Comment 5 for bug 1508424

Without the lock if you don't pass authenticated=False when making an auth call you will end up in an infinite loop of the session trying to authenticate the request from the plugin with the plugin, so the lock is preventing a stacktrace there but shouldn't be affecting regular traffic.

There is really no reason that the same thread should trigger that lock twice (infinite loop) it's foreseeable if the token fetch is taking a long time then other threads will be blocked waiting on it - but this should take the same amount of time as if they all did their own fetch.

Have you got a backtrace or something of what's happening?