I'm guessing here based on how they're implemented on Windows, and someone should correct me if I'm wrong, but I would think it's meant to guard against consumi

I'm guessing here based on how they're implemented on Windows, and someone should correct me if I'm wrong, but I would think it's meant to guard against consuming (comparatively expensive) kernel-mode memory. Expensive because they can't be paged to disk [1], and thus actually consume RAM, thus allowing even lowly-privileged applications to completely exhaust physical RAM and thus make the system unusable. FWIW, I don't think Windows has such a limit, so this makes me wonder if this is really the concern. I'm not aware of a better reason. [1] AFAIK, on Windows, kernel objects (which the kernel cares about) use the non-paged pool, but handles to them (which user-mode cares about) use the paged pool. So you don't technically need to limit the number of handles per se, but it seems like a convenient proxy.