This is currently considered the most effective "patch" for many players. You can opt-in by going to Steam > Settings > Interface > Client Beta Participation and selecting "Steam Beta Update"
However, in the original PC release (2012). The error persisted for years. This is currently considered the most effective "patch"
The “Failed to allocate from state pool” error is a memory allocation crash that has affected PC players of Call of Duty: Black Ops 2 for years. It typically occurs when the game engine attempts to reserve memory for graphical assets (textures, shaders, models) but cannot find a sufficiently large contiguous block of memory in the state pool —a reserved portion of RAM or VRAM used for rendering states. This is currently considered the most effective "patch"