I have a problem with vsftpd that replies "500 OOPS: priv_sock_get_int" when i do command "ls". following is a snip of ftp client console running on osx. And I'm using test account that has home directory on the ftp server, not virtual account.

Connected to 192.0.0.20.
220 satellite
Name (192.0.0.20:john): test_account
331 Please specify the password.
Password: 
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ls
500 OOPS: priv_sock_get_int
421 Service not available, remote server has closed connection.

and my vsftpd.conf

local_enable=YES
write_enable=YES
#local_umask=022
local_umask=002
#anon_upload_enable=YES
#anon_mkdir_write_enable=YES
#dirmessage_enable=YES
#xferlog_enable=YES
connect_from_port_20=YES
#chown_uploads=YES
#chown_username=whoever
#xferlog_file=/var/log/vsftpd.log
#xferlog_std_format=YES
#idle_session_timeout=600
#data_connection_timeout=120
#nopriv_user=test
#async_abor_enable=YES
#ascii_upload_enable=YES
#ascii_download_enable=YES
ftpd_banner=welcome
#deny_email_enable=YES
#banned_email_file=/etc/vsftpd.banned_emails
#chroot_local_user=YES
#chroot_list_enable=YES
#chroot_list_file=/etc/vsftpd.chroot_list
#ls_recurse_enable=YES
listen=YES
#listen_ipv6=YES
#ssl_enable=NO
pasv_enable=YES
pasv_max_port=12500
pasv_min_port=12000
port_enable=YES
pasv_address=192.0.0.20
pasv_promiscuous=YES
port_promiscuous=YES
file_open_mode=0666