gst-launch { priority=3 fakesrc num-buffers=1 ! fakesink }

will probably run into a trace/breakpoint trap.
In my gdb it locks forever.
On some rare occasisons it might even work.
On the multi-CPU Solaris machine it's doing some weird mad stuff I don't
even understand.

I'm opening this as bug, because I want to have a general consensus on how
we handle access to members of different objects. Particularly interesting
are element->current_state and element->pending_state for this case.

I'd propose to clearly define who may read/write to each member of each
element or which lock is needed to access it.