In methodDataOop.hpp

  void set_trap_state(int new_state) {
    assert(ProfileTraps, "used only under +ProfileTraps");
    uint old_flags = (_header._struct._flags & flag_mask);
    _header._struct._flags = (new_state << trap_shift) | old_flags;
    assert(trap_state() == new_state, "sanity");
  }

the assertion

assert(trap_state() == new_state, "sanity");

can fail if the trap state is being set simultaneously by another
thread.