Lingering SSHD processes after logout, FreeNAS-11-STABLE

[GoranTheGreat]

I'm running a FreeNAS 11 VM under ESXi for some testing before I hopefully can deploy this for production. I have SSH enabled with PubkeyAuthentication and there's no problem logging in as a regular user, but after I log out, there are sshd processes left behind running, and they consume a lot of CPU as well.

Typically, after a single login-logout as "myuser" (real username masked), I see this in top:

Code:

77 processes:  2 running, 74 sleeping, 1 zombie
CPU:  4.3% user,  0.0% nice, 20.2% system,  0.0% interrupt, 75.5% idle
Mem: 132M Active, 2581M Inact, 5659M Wired, 3743M Free
ARC: 4582M Total, 2312M MFU, 2011M MRU, 324K Anon, 35M Header, 224M Other
Swap: 4096M Total, 4096M Free

  PID USERNAME	THR PRI NICE   SIZE	RES STATE   C   TIME	WCPU COMMAND
91133 myuser		1  83	0 82852K  7332K CPU1	1   0:12  58.47% sshd
91126 myuser		1  20	0 24276K  3740K CPU0	0   0:00   0.07% top
 2140 root		  2  20	0 65128K 11548K select  1   3:47   0.05% vmtoolsd
73078 root		  2  20	0   127M 33588K select  1   2:12   0.02% python3.6
 1268 root		  1  20	0  9564K  5244K select  1   0:47   0.01% devd
...

Any tips as to how to investigate this is much appreciated; log files to look at, sshd settings, whatever.

The FreeNAS installation is updated and verified. I can produce this behavior from multiple ssh clients. My primary ssh client is OpenSSH_7.3p1, LibreSSL 2.4.1 on Mac OS X 10.12, but also an older Windows/Cygwin client causes left-behind sshd processes.

 

[GoranTheGreat]

My /usr/local/etc/sshd_config is:

Code:

Subsystem	   sftp	/usr/libexec/sftp-server -l ERROR -f AUTH
Protocol 2
UseDNS no
ChallengeResponseAuthentication no
ClientAliveCountMax 3
ClientAliveInterval 15
NoneEnabled yes
VersionAddendum none
Port 22
ListenAddress 127.0.0.1
ListenAddress 192.168.1.5
ListenAddress 192.168.1.2
PermitRootLogin without-password
AllowTcpForwarding no
Compression no
PasswordAuthentication yes
PubkeyAuthentication yes

192.168.1.5 is the main FreeNAS IP that the GUI responds on, and where I want sshd to listen. The other one is for a jail where OwnCloud is running.

 

[GoranTheGreat]

Hm.. interestingly enough, a reboot made this issue go away... let's hope it stays that way.