How do you step into plugins with gdb?
Let's say you wrote a new local planner plugin for the move_base node. I can step through the move_base code just fine, but when I try to follow the plugin pointer into my local planner, I end up in a boost wrapper that only checks that the pointer is not null. So, how do you use gdb to debug plugins?
You say you want to follow the code execution into your plugin, but it sounds like you're doing it by reading memory instead of following code execution. I'd start by setting a breakpoint inside your plugin, and wait for gdb to hit it.
If that gives you trouble, please edit your question with the output from GDB.