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#1 2013-10-06 23:46:47

hugelgupf
Member
Registered: 2013-10-06
Posts: 4

lightdm/dbus issues

Hi all,

I am fairly new to systems administration and Arch, and I have been having quite the weird problem with lightdm/dbus. To set the stage: Small university department network. I left in May for the usual summer break, our computer labs were pretty much unused. The first update after summer break happened around the beginning of August, and that's when this problem starts showing up.

lightdm starts up, but opens and closes greeter (lightdm-gtk-greeter) sessions repeatedly - _sometimes_. Sometimes, it'll start up and work perfectly.

So, let's look at logs for lightdm when it fails:

-- Reboot --
Sep 15 23:25:04 <hostname> lightdm[340]: ** (process:456): WARNING **: Could not get accounts proxy: Error calling StartServiceByName for org.freedesktop.Accounts: Timeout was reached
Sep 15 23:25:29 <hostname> lightdm[340]: ** (lightdm:340): WARNING **: Could not get accounts proxy: Error calling StartServiceByName for org.freedesktop.Accounts: Timeout was reached
Sep 15 23:25:29 <hostname> lightdm[456]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0)
Sep 15 23:25:42 <hostname> lightdm[456]: pam_unix(lightdm-greeter:session): session closed for user lightdm
Sep 15 23:26:11 <hostname> lightdm[511]: ** (process:521): WARNING **: Could not get accounts proxy: Error calling StartServiceByName for org.freedesktop.Accounts: GDBus.Error:org.freede
Sep 15 23:26:36 <hostname> lightdm[511]: ** (lightdm:511): WARNING **: Could not get accounts proxy: Error calling StartServiceByName for org.freedesktop.Accounts: GDBus.Error:org.freede
Sep 15 23:26:36 <hostname> lightdm[521]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0)

Okay. What about dbus-daemon?

-- Reboot --
Sep 15 23:24:38 <hostname> dbus-daemon[335]: nss_ldap: could not search LDAP server - Server is unavailable
(a whole lot of these repeated)
and then,
Sep 15 23:24:39 <hostname> dbus-daemon[335]: dbus[335]: [system] Activating systemd to hand-off: service name='org.freedesktop.Accounts' unit='accounts-daemon.service'
Sep 15 23:24:39 <hostname> dbus[335]: [system] Activating systemd to hand-off: service name='org.freedesktop.Accounts' unit='accounts-daemon.service'
Sep 15 23:25:04 <hostname> dbus-daemon[335]: dbus[335]: [system] Failed to activate service 'org.freedesktop.Accounts': timed out
Sep 15 23:25:04 <hostname> dbus[335]: [system] Failed to activate service 'org.freedesktop.Accounts': timed out
Sep 15 23:25:04 <hostname> dbus[335]: [system] Failed to activate service 'org.freedesktop.systemd1': timed out
Sep 15 23:25:04 <hostname> dbus-daemon[335]: dbus[335]: [system] Failed to activate service 'org.freedesktop.systemd1': timed out
(this also keeps repeating)

I am fairly helpless. After the machines are started up, I can ssh to them and pkill dbus-daemon to fix the problem. But... I don't want to do that all the time. Isn't it true that /usr/lib/systemd/system/lightdm.service says that for Type=dbus, systemd waits until the bus named in BusName becomes available by dbus? I.e., it names BusName=org.freedesktop.Accounts in lightdm.service. Then why is lightdm started when that bus isn't available yet? (I actually don't quite know how dbus works, but I'm assuming if the bus isn't activated, then it isn't "available".?)

Why does dbus activation time out for those services? It just repeats and repeats timing out until I kill dbus-daemon and somehow it starts back up. Is there a way to raise the activation timeout time?

I'd be happy to provide more details / paste more logs somewhere if needed. I've been scratching my head over this for a while.

Thanks,
Chris

Last edited by hugelgupf (2013-10-07 17:25:37)

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#2 2013-10-07 13:32:01

jrussell
Member
From: Cape Town, South Africa
Registered: 2012-08-16
Posts: 510

Re: lightdm/dbus issues

You should use code tags

like this

for your output in the forums smile
https://bbs.archlinux.org/help.php#bbcode

What do you mean by lightdm opening and closing greeter sessions repeatedly? Does the screen flicker and repeatedly flash the greeter?

Which greeters do you have installed?

I know I had wierd flashing problems with lightdm when I had no greeter and when I had the two (gtk and gtk3) greeters insatlled at the same time (If I remember corrcectly). I think they conflict now.

Edit: Have you checked here https://www.archlinux.org/news/ when updating? Need to make sure you've handled all those manual interventions correctly.

Last edited by jrussell (2013-10-07 13:36:00)


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#3 2013-10-07 17:08:45

hugelgupf
Member
Registered: 2013-10-06
Posts: 4

Re: lightdm/dbus issues

Only the gtk3 greeter is installed. And yes - screen goes to the defined background in the greeter, stays there for a few seconds, then goes back to black and repeats. Yes, I've checked the news and I have checked any and all .pacnew and .pacsave files I can find. I've also checked the pacman.log for warnings etc and fixed those.

Funny thing is: on a fresh installed system, this problem doesn't happen. I've been diffing all kinds of configuration files and systemd unit files... It's quite a mess.

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#4 2013-10-10 18:30:28

jrussell
Member
From: Cape Town, South Africa
Registered: 2012-08-16
Posts: 510

Re: lightdm/dbus issues

Have you perhaps changed your graphics card? You sure you have all the correct graphics drivers installed? intel, ati, nouveau etc?


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#5 2013-10-11 05:30:00

hugelgupf
Member
Registered: 2013-10-06
Posts: 4

Re: lightdm/dbus issues

No change in graphics card. This issue happens across multiple different machines with different hardware (but some of them the same). Graphics driver installed and working.

Mods: is there any way you could move this topic to a more appropriate subforum, perhaps the System Administration or the Desktop Env forum? It seems this issue is more complex and shouldn't be here.

Last edited by hugelgupf (2013-10-11 05:32:27)

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#6 2013-10-11 06:32:29

jrussell
Member
From: Cape Town, South Africa
Registered: 2012-08-16
Posts: 510

Re: lightdm/dbus issues

I think it has to be a mistake by you I'm afraid, try installing arch on a USB drive now with a new live cd and see if lightdm works on any of those machines. I presume you've missed smithing during an upgrade.

You could try reinstalling all packages, and search your / for any pac files, look in the pacman tips and pacman wiki. When you reinstall, make sure you go though all of pacmans output.


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#7 2013-10-11 06:45:12

hugelgupf
Member
Registered: 2013-10-06
Posts: 4

Re: lightdm/dbus issues

jrussell wrote:

I think it has to be a mistake by you I'm afraid

No shit, that's why I'm posting here.

jrussell wrote:

, try installing arch on a USB drive now with a new live cd and see if lightdm works on any of those machines. I presume you've missed smithing during an upgrade.

Read above. I've already said that on a fresh install on one of my lab computers, there don't seem to be any problems. I've been going through and diffing /etc-files and various other things, I've cleaned up any and all .pacnew or .pacsave or .pac* files, but the problem persists.

Do you have any answers for my questions above - the time out of dbus activations?

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#8 2013-10-11 12:05:14

jrussell
Member
From: Cape Town, South Africa
Registered: 2012-08-16
Posts: 510

Re: lightdm/dbus issues

No need to be rude, you said this:

hugelgupf wrote:

No change in graphics card. This issue happens across multiple different machines with different hardware (but some of them the same). Graphics driver installed and working.

Which could point to a problem with specific hardware and a change in some update causing problems, but I don't think it is.

Have you used pacman -Qkk with some grepping to look for file differences? and have you tried reinstalling all packages? What happens with other display manages?

I don't know about the exact problem with dbus time outs, but Ill help you try rule things out and narrow down the problem.


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#9 2013-10-11 15:17:12

ewaller
Administrator
From: Pasadena, CA
Registered: 2009-07-13
Posts: 19,994

Re: lightdm/dbus issues

hugelgupf wrote:

Mods: is there any way you could move this topic to a more appropriate subforum, perhaps the System Administration or the Desktop Env forum? It seems this issue is more complex and shouldn't be here.

Done.  In the future, go ahead and use the report link and leave a note for the moderators with your request.  We are sure to see it that way.

Also, this thread was going pretty well and then something happened and it started to derail. 
Be good to each other smile

Last edited by ewaller (2013-10-11 15:21:14)


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