Description of problem:
Starting Dec 12, 2015, on my personal system I had a custom systemd service I've created (in a .service file in /etc/systemd/system/multi-user.target.wants/) suddenly stop working.  I thought it was very odd.  It just happened again 1 day later on a second, similar, machine I administer.  Now I'm worried it's a bug.

The symptom is the service stops, and systemd won't let me restart it.  Status shows an error.  I can run the executable the service file is supposed to run and it works fine.  But the service won't run.  *** HERE's the buggy part, if I rename the .service file a few times, and systemctl daemon-reload a few times, and keep trying to restart the service, it will eventually start under the new name!  Then after that if I rename it back to the original name and try again, it then, sometimes, works!  Non-deterministic!

COMPUTER #2:
#systemctl restart tec-dynamic-ip-update.service
Failed to restart tec-dynamic-ip-update.service: Unit tec-dynamic-ip-update.service failed to load: No such file or directory.
Exit 6

#systemctl -n30 status tec-dynamic-ip-update.service
* tec-dynamic-ip-update.service
   Loaded: not-found (Reason: No such file or directory)
   Active: failed (Result: exit-code) since Sun 2015-12-13 03:46:20 CST; 16min ago
 Main PID: 4639 (code=exited, status=143)

Dec 12 16:46:00 zzz.ca systemd[1]: Started tec dynamic-ip-update.
Dec 12 16:46:00 zzz.ca systemd[1]: Starting tec dynamic-ip-update...
Dec 13 03:46:20 zzz.ca systemd[1]: tec-dynamic-ip-update.service: main process exited, code=exited, status=143/n/a
Dec 13 03:46:20 zzz.ca systemd[1]: Unit tec-dynamic-ip-update.service entered failed state.
Dec 13 03:46:20 zzz.ca systemd[1]: tec-dynamic-ip-update.service failed.
Exit 3

#cd /etc/systemd/system/multi-user.target.wants/
#ll
...
tec-dynamic-ip-update.service

#mv tec-dynamic-ip-update.service tec-dynamic-ip.service
#systemctl daemon-reload
#systemctl restart tec-dynamic-ip.service
[no error!!!!!!]
[service is running ok now!]


Sometimes when I try to rename it back to the old file name, it keeps failing.  And then it fails in the new name and I have to come up with yet another name, and then it works again!  Huh??!?!?

Again, this happened on two different machines, for two differently-named and different-function services, at two different times about 12 hours apart.  I have never seen this before on any machine.

I just tested it on the service that failed on COMPUTER #1 earlier and just a simple restart of the service caused the bug to hit.  To fix I had to rename file 3 times until it finally worked again.  So it looks like I can reproduce this fairly easily.

The error message "No such file or directory" is key, I'm sure... exactly which file is "No such file or directory"?  The .service file, or the exec it calls, or???  Ambiguous, the error message should be more precise.


Version-Release number of selected component (if applicable):
systemd-219-26.fc22.i686 (COMPUTER #2)
systemd-219-25.fc22.x86_64 (COMPUTER #1)


How reproducible:
Once it "hits" then I can get the error forever until I start renaming .service files.  It seems that service is left a bit wonky as I can reproduce the bug more easily on that service from that point on, especially if I can get the thing to work after I rename it back to the original (desired) name.


Steps to Reproduce:
1. Make a custom .service file for some service you have created yourself
2. Wait for a service to randomly die for no reason (or reboot so all services have to come up)
3. Hopefully get lucky and this bug hits
4. systemctl restart x.service

Actual results:
* x.service
   Loaded: not-found (Reason: No such file or directory)
   Active: failed (Result: exit-code) since Sun 2015-12-13 03:46:20 CST; 16min ago
 Main PID: 4639 (code=exited, status=143)

Expected results:
- no output; service starts properly and keeps running


Additional info:
#cat   tec-dynamic.service
[Unit]
Description=tec dynamic-ip-update
Before=network.target
After=other-custom.service
After=syslog.target

[Service]
Type=simple
ExecStart=/usr/local/sbin/tec-systemd-wrapper /usr/local/sbin/dynamic-ip-update /var/log/dynamic-ip-update.log
StandardOutput=null
TimeoutSec=5
Restart=always

[Install]
WantedBy=multi-user.target


#cat /usr/local/sbin/tec-systemd-wrapper
# ya cheesy but systemd (at least at first) didn't give me a log option like inittab gave with a simple > redirect
# so I had to improvise in the meantime just to keep my custom daemons running
#!/usr/bin/perl -w

$|=1;

$ENV{'SHELL'}='/bin/bash';

$flog=pop();
if (!-f $flog) {
  open  F,">$flog" or die;
  close F;
}

chmod 0640,$flog or die;
exec join(' ',@ARGV)." >>$flog 2>&1";