I'm developer and works on my own library. The library is using by my program. I checked system monitor about memory usage. One section takes my attention. It's section with flags/right p. It cannot be read and write ant cannot be executed, I think.
That's the line
7ffff7bd9000-7ffff7dd8000 ---p 2044 KB 0 KB 0 KB 0 KB 0 KB 0 KB 0 KB 0 KB 0 KB 0 KB 0 KB 0 KB /usr/lib64/libgreattao.so.2.0

What's it means?

I think "p" character maybe means it would be copy on write operation, but why it don't have read rights?

"*P*rivate" in contrast to "*S*hared" - By 99.9% chance this is a non-const static member in the library that you application set to a new value.
It therefore needs a local copy of the memory (or all other application linking the same library would suddenly have that value there as well)