It appears that when a config change commit is initiated, but is unsuccessful in completion (for one of a few reasons), a hung thread for 'sudo write' to return a message to the pty of the user committing the change occurs.
The configuration subsystem then becomes inoperable until hung threads are cleaned up.
bbabich@pauseq4rbdr1# commit ^C^C^C ^Z [1]+ Stopped /opt/vyatta/sbin/my_commit "${args[@]}" 2>&1 [edit] bbabich@pauseq4rbdr1# ps -ef | grep -i commit bbabich 35765 35503 0 00:29 pts/0 00:00:00 /opt/vyatta/sbin/my_commit bbabich 35923 35503 0 00:30 pts/0 00:00:00 grep -i commit [edit] bbabich@pauseq4rbdr1# kill -9 35765 [edit] bbabich@pauseq4rbdr1# compare [1]+ Killed /opt/vyatta/sbin/my_commit "${args[@]}" 2>&1 ... bbabich@pauseq4rbdr1:~$ ps -ef | grep -i bbabich root 10974 2753 0 Jan04 ? 00:00:00 sshd: bbabich [priv] bbabich 10982 10974 0 Jan04 ? 00:00:00 sshd: bbabich@pts/2 bbabich 10983 10982 0 Jan04 pts/2 00:00:00 -vbash bbabich 11102 11101 0 Jan04 pts/2 00:00:00 vbash root 22485 1 0 Jan04 ? 00:00:00 sudo write bbabich pts/2 root 22486 22485 0 Jan04 ? 00:00:00 write bbabich pts/2 root 22922 2753 0 Jan04 ? 00:00:00 sshd: bbabich [priv] bbabich 22928 22922 0 Jan04 ? 00:00:00 sshd: bbabich@pts/1 bbabich 22929 22928 0 Jan04 pts/1 00:00:00 -vbash root 25712 1 0 Jan04 ? 00:00:00 sudo write bbabich pts/2 root 25713 25712 0 Jan04 ? 00:00:00 write bbabich pts/2 root 26430 1 0 Jan04 ? 00:00:00 sudo write bbabich pts/2 root 26431 26430 0 Jan04 ? 00:00:00 write bbabich pts/2 root 27135 1 0 Jan04 ? 00:00:00 sudo write bbabich pts/2 root 27136 27135 0 Jan04 ? 00:00:00 write bbabich pts/2 root 28109 1 0 Jan04 ? 00:00:00 sudo write bbabich pts/2 root 28110 28109 0 Jan04 ? 00:00:00 write bbabich pts/2 root 28663 1 0 Jan04 ? 00:00:00 sudo write bbabich pts/2 root 28664 28663 0 Jan04 ? 00:00:00 write bbabich pts/2 root 29526 1 0 Jan04 ? 00:00:00 sudo write bbabich pts/2 root 29527 29526 0 Jan04 ? 00:00:00 write bbabich pts/2 root 30490 1 0 Jan04 ? 00:00:00 sudo write bbabich pts/2 root 30491 30490 0 Jan04 ? 00:00:00 write bbabich pts/2 root 30819 1 0 Jan04 ? 00:00:00 sudo write bbabich pts/2 root 30820 30819 0 Jan04 ? 00:00:00 write bbabich pts/2 root 33242 1 0 00:09 ? 00:00:00 sudo write bbabich pts/2 root 33243 33242 0 00:09 ? 00:00:00 write bbabich pts/2 root 34145 1 0 00:15 ? 00:00:00 sudo write bbabich pts/2 root 34146 34145 0 00:15 ? 00:00:00 write bbabich pts/2 root 34648 1 0 00:20 ? 00:00:00 sudo write bbabich pts/2 root 34649 34648 0 00:20 ? 00:00:00 write bbabich pts/2 root 35377 2753 0 00:28 ? 00:00:00 sshd: bbabich [priv] bbabich 35381 35377 0 00:28 ? 00:00:00 sshd: bbabich@pts/0 bbabich 35382 35381 0 00:28 pts/0 00:00:00 -vbash root 35812 1 0 00:29 pts/0 00:00:00 sudo write bbabich pts/2 root 35813 35812 0 00:29 pts/0 00:00:00 write bbabich pts/2 root 49999 1 0 03:30 pts/0 00:00:00 sudo write bbabich pts/2 root 50000 49999 0 03:30 pts/0 00:00:00 write bbabich pts/2 root 53824 53811 0 04:22 pts/1 00:00:00 sudo write bbabich pts/2 root 53825 53824 0 04:22 pts/1 00:00:00 write bbabich pts/2 bbabich 54033 35382 0 04:25 pts/0 00:00:00 ps -ef bbabich 54034 35382 0 04:25 pts/0 00:00:00 grep -i bbabich bbabich@pauseq4rbdr1:~$ ps -ef | grep -i bbabich | awk '{print $2}' | xargs kill Connection to 10.0.222.141 closed by remote host. Connection to 10.0.222.141 closed. ...