The Linux kernel uses a:

"Dual architecture" is not a recognized classification for kernel designs.

While Linux is predominantly monolithic, this term alone doesn't fully account for its significant modularity through loadable kernel modules, which leads to the "hybrid" classification by some.

The Linux kernel, while largely monolithic in nature, is often categorized as having a hybrid microkernel architecture due to its extensive use of dynamically loadable kernel modules. This modularity allows drivers and other functionalities to be loaded and unloaded on demand, combining the performance advantages of a monolithic kernel with the flexibility and maintainability characteristics found in microkernel designs.