Isn’t there a part of the data segment that is writable? Initialized vs uninitialized data segment right?

You're right, I know mutable and read-only are separates, I know I seen gcc and clang put static int and global int in the same page, and I know I heard people say global variables are on the heap thousands of times. I guess I forgot global writable data doesn't necessarily mean heap nor the read-only section of memory