Comment 3 for bug 1599775

Revision history for this message
Michael Thayer (michael-thayer) wrote :

Just checked, I do not have that message in the current log file, attached the file from yesterday containing the message.

I asked about this on #ubuntu-devel, here are the relevant logs:

(17:09:06) michael-vb: Afternoon. Not sure if this is the right place to ask, but someone will probably know what is.
(17:09:06) michael-vb: I have the following problem with my VirtualBox Ubuntu 16.04 guest with development Guest Additions installed: when I start the guest I get the message "The system is running in low-graphics mode" (on VT 2) even though the X server is running fine (on VT 7).
(17:09:06) michael-vb: I would very much like to know exactly what logic triggers that message so I can work out why I am triggering it and change whatever is responsible (I am the developer of the VirtualBox guest driver and Additions installer).

(18:04:34) michael-vb: Interesting - I just booted the guest system twice with a loaded host (rebuilding VirtualBox) and did not get the "low-graphics mode" message.

(18:27:01) michael-vb: CRITICAL: session_get_login1_session_id: assertion 'session != NULL' failed in the lightdm log file.

(18:31:13) michael-vb: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=814760

(09:57:21) sladen: michael-vb: http://askubuntu.com/questions/141606/how-to-fix-the-system-is-running-in-low-graphics-mode-error
(09:57:35) michael-vb: Found that already.

(09:57:50) michael-vb: I am wanting to understand this as a developer, not as a user.

(09:59:07) michael-vb: sladen: it was following from that askubuntu question that I found the system log entry.
(09:59:34) michael-vb: The session clearly gets started just after lightdm checks whether it is running.
(10:01:04) michael-vb: As I said, this does not happen under high load. I suppose the question is, who would understand this stuff well enough to tell me how I can avoid triggering it.
(10:01:15) michael-vb: Or what causes the session to start too late, or lightdm too early.
(10:03:00) michael-vb: I assume that some dependency is not specified well enough somewhere.
(10:03:31) sladen: michael-vb: apt-get source lightdm && grep -r "Error message" is probably the most effective way of identifing the logic causing the error (if it is coming from lightdm)
(10:03:31) michael-vb: But it is annoying, because if it hits users they will blame us first, not you!

(10:04:15) sladen: michael-vb: I'm not too familiar with the inner workings of lightdm; the developer was Robert Ancell in the DX team
(10:04:57) sladen: michael-vb: if it's happening so of the time (seemingly randomly), then there's probably a race condition
(10:06:33) michael-vb: I'm sort of suspecting that it is related to the change to systemd which upset some expectation in lightdm.
(10:08:13) sladen: willcooke: if you're around later, could you get in contact with michael-vb (upstream developer of VirtualBox guest driver), about debugging and resolving the "The system is running in low-graphics mode" message. https://irclogs.ubuntu.com/2016/07/07/%23ubuntu-devel.html#t07:52 onwards
(10:08:50) michael-vb: willcooke: and michael dot thayer at oracle if I am not on IRC at that time.
(10:08:56) michael-vb: sladen, willcooke: thanks.
(10:10:59) willcooke: Trevinho, is this something you can help with? ^
(10:11:09) willcooke: It looks like it's a problem with X rather than Unity though
(10:11:13) willcooke: "problem"
(10:11:22) willcooke: maybe tjaalton knows what triggers it? ^
(10:13:46) talatb [~talatb@137.158.22.10] entered the room.
(10:14:23) tjaalton: I don't, if lightdm is randomly not starting on debian (which doesn't have "failsafe-x")
(10:15:20) tjaalton: sounds like a lightdm bug to me
(10:16:59) willcooke: oki
(10:17:04) willcooke: thanks tjaalton
(10:30:07) willcooke: michael-vb, Hmm, I can't see anything obvious here. Please log a bug in Ubuntu against lightdm if there isn't already one, and we take take a look.
(10:30:54) michael-vb: willcooke: to me it sounds like an init dependency problem.
(10:31:18) sladen: michael-vb: can we get as much of the (known good) information into a Launchpad bug report
(10:31:34) michael-vb: If I understood all this GNOME-systemd-login stuff better...
(10:31:41) michael-vb: sladen: sounds reasonable.
(10:31:44) sladen: michael-vb: and then get that linked to/from the debbugs and Askubuntu pages
(10:33:25) michael-vb: Oh how nice, for reasons unknown I can no longer trigger it.
(10:33:34) willcooke: \o/
(10:33:47) willcooke: fixed!
(10:34:00) willcooke: certainly smells like a race then
(10:34:23) michael-vb: I think that is clear enough from the Debian bug.
(10:34:47) michael-vb: I think that someone from the systemd camp would be best placed to solve it.
(10:36:07) michael-vb: But before I open a bug report I will at least try to track down the error in the lightdm sources.
(10:39:45) sladen: yes, it would be good to point in the bug report exactly where the origin of the assert is coming from, but if it can't be found, please file the bug report (and link to this IRC log and anytthing/everything that you've already found, so that we've got a trackable braindump in one place)
(10:40:27) michael-vb: The assertion is easy to find, I am trying to logically work out the callers.
(10:42:02) michael-vb: Ah, (about to show my lack of understanding of these things) is Ubuntu still using console-kit instead of systemd-logind?
(10:42:23) michael-vb: I see "console-kit-daemon" in that Debian bug logging.
(10:44:16) pitti: hell no
(10:44:37) pitti: michael-vb: we switched to logind in saucy, I believe
(10:45:12) pitti: oh, LXDE is still using it
(10:45:13) michael-vb: Ah right, logging from systemd-logind there too.
(10:45:23) pitti: (at least apparently)
(10:45:36) michael-vb: This is an absolute plain Ubuntu installation.
(10:45:47) pitti: then it shouldn't even be installed
(10:45:52) michael-vb: No "L", "K" or anything else.
(10:47:06) michael-vb: Got the error again. Booting from power off did not produce it, clean rebooting did.
(10:48:16) michael-vb: Will open a bug.
(10:49:05) michael-vb: It would be good if I could find some way to at least avoid triggering the race, otherwise both we and you will have lots of annoyed users.