When trying to allocate a PnP BIOS memory resource, the code loops trying

to move up the start address until the allocation succeeds.  If the
alignment of the resource was 0, then the code would keep trying the same
request in an infinite loop and hang.  Force the request to always move
start up by at least 1 byte each time through the loop.

sys/isa/isa_common.c

@@ -147,7 +147,7 @@ isa_find_memory(device_t child, struct isa_config *config,
 			     end = config->ic_mem[i].ir_end,
 			     align = config->ic_mem[i].ir_align;
 		     start + size - 1 <= end && start + size > start;
-		     start += align) {
+		     start += MAX(align, 1)) {
 			bus_set_resource(child, SYS_RES_MEMORY, i,
 					 start, size);
 			res[i] = bus_alloc_resource(child,