How to solve “ptrace operation not permitted” when trying to attach GDB to a process?

Question

I\'m trying to attach a program with gdb but it returns:

Attaching to process 29139
Could not attach to process. If your uid matches the ui

Answer 1

Not really addressing the above use-case but I had this problem:

Problem: It happened that I started my program with sudo, so when launching gdb it was giving me ptrace: Operation not permitted.

Solution: sudo gdb ...