What kind of meat? How was it prepared to smoke it? Exactly how frozen. Rock hard or partially frozen?
Strictly by USDA Guidelines, you need to Thaw first to avoid the center of the meat being in the danger zone too long. However that is a general statement and overly broad. We know that Bacteria is ONLY on the surface of intact meat. With an all natural Butt or Brisket, as long as the Surface is heated above 140, we don't care how long it takes the center to heat up. 2, 4 or 24 hours, there no bacteria to kill or worry about.
A Frozen Meatloaf or Enhanced Turkey, Injected with broth, is a whole different story and would be dangerous if smoked partially frozen. In a similar train of thought, every authority on Sous Vide Cooking, has instructions to cook Frozen Meat. So... Can you Smoke Partially Frozen Meat? That depends on the type of meat and how it was treated before smoking...JJ