desktop version of MATLAB doesn't exit

The desktop (GUI) version of MATLAB doesn't terminate when type the "exit" command (at the MATLAB command window). It just hangs "Busy" until I forcefully kill the process.

If I close the window, I get a popup window: "MATLAB is BUSY", pick "Stop now", get another popup, confirm that I want a stop, and finally the desktop closes and the process is gone.

The non-desktop version, terminates normally.

Release 2018b on Debian 10

Thanks,

Razvan

[Rik]

Before you type exit, does it already say 'busy'?

[Razvan Popescu]

No, it's "ready".

Also, several other "gui" related operations hung: e.g. clicking the "prefereces" button, brings up an empty pane, gets matlab into "busy" and stays like that indefinitely. "documentation" button, the same....

I'm running a Debian 10 server, X tunneled to Mac Sierra running Xquartz 2.7.11

Thanks,

(and thanks for the comment correction, Rik)

[OCDER]

https://www.mathworks.com/help/matlab/ref/finish.html

Do you have any custom function, or have modified, the following functions?

quit.m
exit.m
finishsav.m

[Razvan Popescu]

No. This is a fresh vanilla installation on a newly installed machine.

But my understanding of the problem changed -- the issue is not related to exiting the application but rather with the startup:

• start MATLAB with "/apps/bin/matlab -c 27000@<ip address of the license server> -desktop" to eliminate(?) suspicions over license server location delays.
• The GUI comes up and after a few seconds of "Initializing" turn to "Ready"
• The whole startup takes a very reasonable 10-20sec.
• The prompt on the command window returns as expected when pressing the Enter key.

Now the interesting part:

• ANY command, be it "ver" (at the command prompt), or pressing the "Preferences" button on the top strip, TAKES ~25MINUTES to complete! Status is "Busy" all this time.
• Once this painful wait for the FIRST command is passed, the behaviour is normal: any command completes in a few sec. max.

?????

I attached an strace to the process -- it's waiting on a futex:

(live)root@gridtest1:~# strace -p 12936

strace: Process 12936 attached

futex(0x23e11d8, FUTEX_WAIT_PRIVATE, 0, NULL

Any ideas?

Thanks!!

[OCDER]

Try contacting MathWorks directly, via the Contact Us link above this website. They'll know a lot more about the internal workings of the Matlab startup-license-checking routine, which seems to be the slow step here.

[Razvan Popescu]

It turned out the problem had to do with the startup not the exit... The application took 22min to execute the first command (then it proceeded normaly) ... After engaging the help of Mathworks support, we discovered that it all had to do with the Connector's internal web service not being able to connect via the Ipv6 loopback interface... (my IPv6 firewall rules were excessively restrictive). Quite tricky...

Answer 1

[Razvan Popescu]

Turns out the problem had to do with a delayed startup -- more than 20min to execute the first command. License server access was fine.

The cause turned out to be the host firewall (iptables) blocking IPv6 loopback interface access! Deactivate IPv6 or make sure your firewall allows access to the IPv6 loopback interface (as well as to the IPv4 one).

Internally, MATLAB starts the Connector service, and attempts to connect via the loopback interfaces (both v4 and v6). As my v6 loopback was blocked by the host firewall, the code had to reach a timeout, repeatedly, for a total of more than 20min, before proceeding.