internal-error inferior_thread(): Assertion `tp' failed

One of my main uses of gdb is to attach to multithreaded valgrind processes run as `valgrind --vgdb=yes --vgdb-error=0` 

With recent builds of gdb I have started to encounter this assertion when the valgrind process is creating new threads.

    thread.c:89: internal-error: thread_info* inferior_thread(): Assertion `tp' failed.

I suspect that this has something to do with my environment (I’m configuring and running from a $HOME relative prefix), but the assertion itself doesn’t given me much information to go on, google has been unhelpful, and I’m not aware of any specific changes that I’ve made to my environment.

Does anyone have experience with this problem?

Thanks,
Luke