gdm outputs many lines with "[Thread debugging using libthread_db enabled]"

Issue

• gdm outputs many lines as follows:

gdm[38314]: ******************* START **********************************
gdm[38314]: [Thread debugging using libthread_db enabled]
gdm[38314]: 0x000000373100f33e in waitpid () from /lib64/libpthread.so.0
gdm[38314]: #0  0x000000373100f33e in waitpid () from /lib64/libpthread.so.0
gdm[38314]: #1  0x000000000040e9db in ?? ()
gdm[38314]: #2  0x000000000040ea87 in ?? ()
gdm[38314]: #3  <signal handler called>
gdm[38314]: #4  0x000000332660610d in pam_set_item () from /lib64/libpam.so.0
gdm[38314]: #5  0x000000000040b6c7 in ?? ()
gdm[38314]: #6  0x0000003732440642 in g_main_context_dispatch () from /lib64/libglib-2.0.so.0
gdm[38314]: #7  0x0000003732444c98 in ?? () from /lib64/libglib-2.0.so.0
gdm[38314]: #8  0x00000037324451a5 in g_main_loop_run () from /lib64/libglib-2.0.so.0
gdm[38314]: #9  0x0000000000405688 in ?? ()
gdm[38314]: #10 0x000000373081ed1d in __libc_start_main () from /lib64/libc.so.6
gdm[38314]: #11 0x00000000004053e9 in ?? ()
gdm[38314]: #12 0x00007ffeee1c2238 in ?? ()
gdm[38314]: #13 0x000000000000001c in ?? ()
gdm[38314]: #14 0x0000000000000001 in ?? ()
gdm[38314]: #15 0x00007ffeee1c3c82 in ?? ()
gdm[38314]: #16 0x0000000000000000 in ?? ()
gdm[38314]: 
gdm[38314]: Thread 1 (Thread 0x7fae2e52e7a0 (LWP 38234)):
gdm[38314]: #0  0x000000373100f33e in waitpid () from /lib64/libpthread.so.0
gdm[38314]: No symbol table info available.
gdm[38314]: #1  0x000000000040e9db in ?? ()
gdm[38314]: No symbol table info available.
gdm[38314]: #2  0x000000000040ea87 in ?? ()
gdm[38314]: No symbol table info available.
gdm[38314]: #3  <signal handler called>
gdm[38314]: No symbol table info available.
gdm[38314]: #4  0x000000332660610d in pam_set_item () from /lib64/libpam.so.0
gdm[38314]: No symbol table info available.
gdm[38314]: #5  0x000000000040b6c7 in ?? ()
gdm[38314]: No symbol table info available.
gdm[38314]: #6  0x0000003732440642 in g_main_context_dispatch () from /lib64/libglib-2.0.so.0
gdm[38314]: No symbol table info available.
gdm[38314]: #7  0x0000003732444c98 in ?? () from /lib64/libglib-2.0.so.0
gdm[38314]: No symbol table info available.
gdm[38314]: #8  0x00000037324451a5 in g_main_loop_run () from /lib64/libglib-2.0.so.0
gdm[38314]: No symbol table info available.
gdm[38314]: No symbol table info available.
gdm[38314]: A debugging session is active.
gdm[38314]: 
gdm[38314]: #011Inferior 1 [process 38234] will be detached.
gdm[38314]: 
gdm[38314]: Quit anyway? (y or n) [answered Y; input not from terminal]
gdm[38314]: ******************* END **********************************