Comment 100 for bug 1766137

Revision history for this message
Heikki Moisander (moisander) wrote : Re: [Bug 1766137] Re: [regression] Password accepted but login fails (blank purple screen and mouse pointer only)

Fresh install 18.04 gdm3 did succeed occasionally, but mostly froze
completely so that power button was only way out.
There was a fix that was available in proposed repository (or something)
that made things a bit different. Failure became a rule, but it was
possible to get back with ctrl+alt+F1/F2 (randomly pressing both)
Now this latest version is the first one that seems to work everytime. My
personal wish would be that please stop complicating the thing and put it
in production.

to 31. toukok. 2018 klo 6.55 Jehandan Jeyaseelan (<email address hidden>)
kirjoitti:

> Hi,
>
> In addition to my post #96 above, I downgraded gdm3 back to the release
> version - 3.28.0-0ubuntu1 and am able to confirm that switching users
> works perfectly between two users for me.
>
> Therefore sounds like the fix for gdm3 - 3.28.2-0ubuntu1.1 - has
> introduced further issues.
>
> --
> You received this bug notification because you are subscribed to a
> duplicate bug report (1768619).
> https://bugs.launchpad.net/bugs/1766137
>
> Title:
> [regression] Password accepted but login fails (blank purple screen
> and mouse pointer only)
>
> Status in gdm:
> Fix Released
> Status in Release Notes for Ubuntu:
> Fix Released
> Status in gdm3 package in Ubuntu:
> Fix Released
> Status in gnome-shell package in Ubuntu:
> Invalid
> Status in gdm3 source package in Bionic:
> Fix Committed
> Status in gnome-shell source package in Bionic:
> Invalid
>
> Bug description:
> [ Description ]
>
> Due to a refcounting bug, a GDBusConnection was getting disposed when
> it was still required. The symptom of this was that you couldn't log
> in on the second attempt if you'd got your password wrong on the first
> attempt. All you'd see is a blank purple screen and mouse pointer
> only.
>
> [ Test case ]
>
> 1. Boot to GDM
> 2. Click your username
> 3. Type the wrong password a couple of times, pressing enter after each
> time
> 4. Type the right password
>
> If the bug is happening, after 4. the system hangs at a blank screen
> with the mouse cursor. If you then switch to a VT or otherwise connect
> to the machine, you can examine the journal and you'll see a
> G_IS_DBUS_CONNECTION failure.
>
> [ Fix ]
>
> Marco and I worked upstream on this fix. We found out that there was a
> problem like this-
>
> The GdmClient has a shared GDBusConnection for its operations. The
> first time someone calls for it, it is created and stored in the
> object's private structure. Subsequent calls return *a new reference*
> to this same object. It turned out that the asynchronous method to get
> the connection was accidentally unreferencing its object before giving
> it to the caller if it was returning an already-existing connection.
>
> For this to work properly, we need to nullify the pointer we stored
> when the connection goes away, so we know when to make a new one.
> There were some cases where we didn't add the weak references required
> to do that. Those are also fixed.
>
> [ Regression potential ]
>
> Now we share connections more than we did before. We also more
> carefully track when to clear our object. If we got this wrong, we
> might end up leaking the connection or dropping it in even more cases.
>
> [ Original report ]
>
> WORKAROUND: After typing an incorrect password, click Cancel, then
> click your name, then enter your password again.
>
> ---
>
> Trying to log into my session (Gnome, Xorg), if I enter the wrong
> password before entering it correctly, the session doesn't load and I
> get a purple screen, a mouse cursor, and an invisible but clickable
> menu in the top right. If I enter it correctly the first time, there
> is no problem.
>
> I've replicated this from a fresh boot, after logging out and after
> 'sudo service gdm restart' from the Ctrl-Alt-F4 console.
>
> This is a fresh install, and didn't occur when I was using a previous
> install of 18.04 (until Friday).
>
> ProblemType: Bug
> DistroRelease: Ubuntu 18.04
> Package: gdm3 3.28.0-0ubuntu1
> ProcVersionSignature: Ubuntu 4.15.0-15.16-generic 4.15.15
> Uname: Linux 4.15.0-15-generic x86_64
> ApportVersion: 2.20.9-0ubuntu6
> Architecture: amd64
> CurrentDesktop: ubuntu:GNOME
> Date: Sun Apr 22 20:31:13 2018
> InstallationDate: Installed on 2018-04-22 (0 days ago)
> InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64
> (20180421.1)
> SourcePackage: gdm3
> UpgradeStatus: No upgrade log present (probably fresh install)
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/gdm/+bug/1766137/+subscriptions
>