The phrase "to fill the hole" means to fix or solve a problem or a need that exists. It refers to taking action or providing something that is missing or lacking in a particular situation. Full definition
They and other service - oriented companies currently are doing most of the work in filling the hole in gross domestic product left by the Great Recession. (canadianbusiness.com)
Put the legs into the ground and then fill the holes with concrete until the holes are three - quarters of the way full. (thefashionablehousewife.com)
What the legislature actually did was provide enough additional revenue to fill the hole left by the absent stimulus fund. (educationnext.org)