xubuntu 13.04 mdm no logout about mdm HOT 8 CLOSED

Same here with both MATE and Cinnamon. We're investigating.

from mdm.

if i do a pkill -KILL -u user
i get a login screen again from mdm

from mdm.

Here's a technical description of what the dev. team knows:

clem> well...
clem> where shall I start :))
clem> ok, up until 13.04, everything was fine
clem> in 13.04, initially we found out you couldn't log in with mdm...
clem> so we did this: 0b059f0
clem> what happens is that the slave forks into launching the greeter and waits on it to die..
clem> but the slave does other stuff... for instance it reads stuff that needs to go into .xsession-errors
clem> anyway, if you look at that commit...
clem> the select() call used to hang in 13.04
clem> when the greeter exited, it became a zombie process...
clem> normally, the select() call would pick it up and read its FD and it would die as a process..
clem> but in 13.04, it would remain as a zombie
clem> so instead of select() we called waitpid(), and w00t, problem solved
clem> .. until one day...
clem> ... glebihan found out why we were getting random session freezes on the desktop :)
clem> ... whenever an app needed to log something in .xsession-errors, the whole thing would collapse...
clem> because that select() call we removed also handled that
clem> you're with me? :)
glebihan> I knew I was going to be blamed for that one too :)
clem> lol
clem> so we reverted it.. ef21da9
clem> and we fixed it "better": 8833830
clem> in that "better" fix, we call waitpid() but only on the greeter... the rest is still handled with select()
clem> with that, Bob's our uncle, the greeter dies a peaceful death, and .xsession-errors works fine with no more freezes
clem> ... until one day...
clem> ... I just found out we couldn't logout anymore :)
clem> and guess what... if we go back to that horrible random desktop freezer of 0b059f0, w00t you can login/logout again :)
clem> so, or options are:
clem> - login and logout with occasional desktop freezes
clem> - login with no freeze but can't logout
clem> - understand more stuff
glebihan> lol
glebihan> I vote for the 3rd option :)
clem> the weird thing is... select() has been working fine until 13.04, so there's something changed somewhere we don't get...
clem> probably in the kernel, I'm not really sure
clem> oh cool..
mtwebster> this is only reproduceably in 13.04?
mtwebster> reproduceable
clem> well, I don't know..
clem> it doesn't happen in Maya/Nadia
clem> I'm not sure whether it's ubuntu 13.04 specific or whether it's introduced upstream of ubuntu (for instance in newer kernels)

from mdm.

Here is syslog of xubuntu 13.04 with mdm debug enabled.
Root login and logout hang
http://www.multiseatcomputer.be/syslog.txt

from mdm.

Fixed by 60c464a

from mdm.

Can you confirm whether this solves the issues for you? I didn't test root login.

from mdm.

Dear,
Root can logout ok and gets a login again.
This is in xfce4.
But a user that logs in kde4, and logs out is getting no login screen.

Maybe it's a kde problem.
here are the logs of root login and logout.

And login of ubu1 and hanging logout:
http://www.multiseatcomputer.be/syslogmdm.txt

guy

Can you confirm whether this solves the issues for you? I didn't test root
login.

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Reply to this email directly or view it on GitHub:
#38 (comment)

from mdm.

Is ok for kde4 also.
I had a specific logout script.
Just changed the kde logout to:
qdbus org.kde.ksmserver /KSMServer logout 0 0 0

now getting mdm login screen again

Fixed by
60c464a
6ef4a7

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Reply to this email directly or view it on GitHub:
#38 (comment)

from mdm.