For instance I see
Reading symbols from /lib/libc.so.6...(no debugging symbols found)...done
That implies that your GDB is not searching /usr/lib/debug. One way that could happen is if you set debug-file-directory in your .gdbinit incorrectly.
Here is the default setting:
(gdb) show debug-file-directory
The directory where separate debug symbols are searched for is “/usr/lib/debug”.
https://stackoverflow.com/questions/10000335/how-to-use-debug-version-of-libc