I don't know why this doesn't hit the STM32F4 but when bringing up the K10 I was hitting busfaults during L4_Map, the code in root_thread.c calls L4_Map before a stack has been set for given thread. So, do_ipc should not try to dereference a non-existing stack pointer. My guess with the STM is that the busfault is being treated as a memfault and being handled by the memmanage_handler (incorrectly).
I don't know why this doesn't hit the STM32F4 but when bringing up the K10 I was hitting busfaults during L4_Map, the code in root_thread.c calls L4_Map before a stack has been set for given thread. So, do_ipc should not try to dereference a non-existing stack pointer. My guess with the STM is that the busfault is being treated as a memfault and being handled by the memmanage_handler (incorrectly).