Comment 1 for bug 1380697

I see xtrabackup issuing select sys calls on the fd that is not open according to /proc file system

here is an output snippet:

root@node-11:~# ps aux | grep mysql
mysql 7036 0.0 0.0 4408 612 ? S 15:18 0:00 sh -c wsrep_sst_xtrabackup-v2 --role 'joiner' --address '192.168.0.4' --auth 'wsrep_sst:password' --datadir '/var/lib/mysql/' --defaults-file '/etc/my.cnf' --parent '7019' ''
mysql 7037 0.0 0.0 9712 1740 ? S 15:18 0:00 /bin/bash -ue /usr//bin/wsrep_sst_xtrabackup-v2 --role joiner --address 192.168.0.4 --auth wsrep_sst:password --datadir /var/lib/mysql/ --defaults-file /etc/my.cnf --parent 7019
mysql 7323 0.0 0.0 26220 1768 ? S 15:18 0:00 socat -u TCP-LISTEN:4444,reuseaddr,nodelay,sndbuf=1048576,rcvbuf=1048576 stdio
mysql 7324 0.0 0.0 84696 1852 ? S 15:18 0:00 xbstream -x
root 19155 0.0 0.0 12708 1940 ? S 15:42 0:00 /bin/bash /usr/lib/ocf/resource.d/mirantis/mysql-wss start
root 21767 0.0 0.0 9396 928 pts/3 S+ 15:45 0:00 grep --color=auto mysql
root@node-11:~# netstat -ntlp | grep 7323
root@node-11:~# ps aux | grep socat
mysql 7323 0.0 0.0 26220 1768 ? S 15:18 0:00 socat -u TCP-LISTEN:4444,reuseaddr,nodelay,sndbuf=1048576,rcvbuf=1048576 stdio
root 22040 0.0 0.0 9396 928 pts/3 S+ 15:46 0:00 grep --color=auto socat
root@node-11:~# netstat -nlp | grep 4444
root@node-11:~# ps aux | grpe 4444
No command 'grpe' found, did you mean:
 Command 'grape' from package 'groovy' (universe)
 Command 'grpn' from package 'grpn' (universe)
 Command 'gpre' from package 'firebird2.5-super' (universe)
 Command 'gpre' from package 'firebird2.1-classic' (universe)
 Command 'gpre' from package 'firebird2.5-classic-common' (universe)
 Command 'gpre' from package 'firebird2.1-super' (universe)
 Command 'grep' from package 'grep' (main)
 Command 'gvpe' from package 'gvpe' (universe)
 Command 'nrpe' from package 'nagios-nrpe-server' (main)
grpe: command not found
root@node-11:~# strace -f -p 7323
Process 7323 attached - interrupt to quit
select(12, [11], [], [], NULL^C <unfinished ...>
Process 7323 detached
root@node-11:~# cat /proc/7323/fd
fd/ fdinfo/
root@node-11:~# cat /proc/7323/fd
fd/ fdinfo/
root@node-11:~# cat /proc/7323/fd/
0 1 10 11 14 15 2 3 5 6 7 8 9

As you can see, xtrabackup is running select() syscall on non-existing socket