Problem logging in using GDM

Problem logging in using GDM

[Tanguy Le Carrour]

Hi Guix!

As previously discussed [1], I sometimes have problems logging in using GDM.
And today is one of those days! :-(

[1]: https://lists.gnu.org/archive/html/guix-devel/2019-10/msg00434.html

Thanks to Joshua and Diego, I now have a SLiM alternative that works.
But as Alex pointed out, that might not be such a great idea!

So, symptoms are: when I try to log in using GDM, it goes black and…
*bang* goes back to the login screen!
When I reconfigure my system back to using SLiM, I can log in again. So, to
me, it does not seem like a problem with my WM or user conf.

Unfortunately, removing the gdm/gnome temp files [2] didn't solve the
problem!

[2]: sudo rm -rf /var/lib/gdm
     rm -rf .cache/gnome-*
     rm -rf .local/share/gnome-shell/application_state

Any help welcome!

-- 
Tanguy

Re: Problem logging in using GDM

[Joshua Branson]

Tanguy Le Carrour <tanguy@bioneland.org> writes:

> Hi Guix!
>
> As previously discussed [1], I sometimes have problems logging in using GDM.
> And today is one of those days! :-(
>
> [1]: https://lists.gnu.org/archive/html/guix-devel/2019-10/msg00434.html
>
> Thanks to Joshua and Diego, I now have a SLiM alternative that works.
> But as Alex pointed out, that might not be such a great idea!

Hey hey!  That's me!  :)

>
> So, symptoms are: when I try to log in using GDM, it goes black and…
> *bang* goes back to the login screen!
> When I reconfigure my system back to using SLiM, I can log in again. So, to
> me, it does not seem like a problem with my WM or user conf.

So, I've actually had problems using GDM to log into GNOME too.  I've
also had weird GNOME issues too.  For now, I use sway wm.  I do not have
a login manager.  I just run sway at login.  That is something that you
could try.  :)

>
> Unfortunately, removing the gdm/gnome temp files [2] didn't solve the
> problem!
>
> [2]: sudo rm -rf /var/lib/gdm
>      rm -rf .cache/gnome-*
>      rm -rf .local/share/gnome-shell/application_state
>
> Any help welcome!

--
Joshua Branson
Sent from Emacs and Gnus

Re: Problem logging in using GDM

[Tanguy Le Carrour]

Hi Joshua


Le 10/19, Joshua Branson a écrit :
> For now, I use sway wm.  I do not have a login manager.  I just run sway
> at login.  That is something that you could try.  :)

Sounds like a good solution! I use bspwm anyway. But then I would have
to find a way to make the TTY screen more… mmm… sexy! :-)

Is there other services that I can get rid of from the %desktop-services?
Like NetworkManager?

Regards,

-- 
Tanguy

Re: Problem logging in using GDM

[pelzflorian (Florian Pelz)]

On Fri, Oct 18, 2019 at 06:31:32PM +0200, Tanguy Le Carrour wrote:
> So, symptoms are: when I try to log in using GDM, it goes black and…
> *bang* goes back to the login screen!

Does /var/log/gdm/greeter.log tell anything?

Regards,
Florian

Re: Problem logging in using GDM

[Ricardo Wurmus]

Hi Tanguy

> So, symptoms are: when I try to log in using GDM, it goes black and…
> *bang* goes back to the login screen!
[…]
> Unfortunately, removing the gdm/gnome temp files [2] didn't solve the
> problem!
>
> [2]: sudo rm -rf /var/lib/gdm
>      rm -rf .cache/gnome-*
>      rm -rf .local/share/gnome-shell/application_state
>
> Any help welcome!

Pity, that would have been my suggestion, as this usually fixes any
problems with GDM and gnome-shell for me after upgrades.

The question here is: is it a failure of GDM or gnome-shell?  The exact
point where GDM starts gnome-shell is hard to pin-point, of course, but
the logs (even those on TTY1, Ctrl-Alt-F1) might tell you something
about whether it is gnome-shell that is crashing or if it doesn’t even
get that far.

Other problems may include a failure to start some user services via
dbus.

This is tricky and frustrating.  I hope someone here will come up with
an idea to make this more robust.

--
Ricardo

Re: Problem logging in using GDM

[pelzflorian (Florian Pelz)]

[-- Attachment #1: Type: text/plain, Size: 707 bytes --]

On Sat, Oct 19, 2019 at 10:58:56PM +0200, Ricardo Wurmus wrote:
> Other problems may include a failure to start some user services via
> dbus.
> 
> This is tricky and frustrating.  I hope someone here will come up with
> an idea to make this more robust.
> 

When I was trying to debug a different GDM error
<https://issues.guix.info/issue/36221>, I patched gdm for debugging
(see attachment): I had to add more g_debug calls to many places in
the code so I could see where it went wrong.  It was really ugly, but
I do not know of a better way to debug GDM.  Let’s hope it won’t be
necessary here and TTY1 output and /var/log/gdm/greeter.log and the
like are enough.

Regards,
Florian

[-- Attachment #2: 0001-testing-only-gdmtest.patch --]
[-- Type: text/plain, Size: 5219 bytes --]

From 310c31c7a8a31159985bc5ffb696286c3d9c15db Mon Sep 17 00:00:00 2001
From: Florian Pelz <pelzflorian@pelzflorian.de>
Date: Sat, 19 Oct 2019 23:23:48 +0200
Subject: [PATCH] [testing only] gdmtest

---
 gnu/packages/gnome.scm             |  1 +
 gnu/packages/patches/gdmtest.patch | 72 ++++++++++++++++++++++++++++++
 gnu/services/xorg.scm              |  5 ++-
 3 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 gnu/packages/patches/gdmtest.patch

diff --git a/gnu/packages/gnome.scm b/gnu/packages/gnome.scm
index f17bd941cd..4ec668b3cf 100644
--- a/gnu/packages/gnome.scm
+++ b/gnu/packages/gnome.scm
@@ -5754,6 +5754,7 @@ libxml2.")
               (uri (string-append "mirror://gnome/sources/" name "/"
                                   (version-major+minor version) "/"
                                   name "-" version ".tar.xz"))
+              (patches (search-patches "gdmtest.patch" "gdm-CVE-2018-14424.patch"))
               (sha256
                (base32
                 "15f7lz7z75krgbq8vb800afj96h8mw2fpy1s28za2911x5vgq0ak"))))
diff --git a/gnu/packages/patches/gdmtest.patch b/gnu/packages/patches/gdmtest.patch
new file mode 100644
index 0000000000..041a3b311d
--- /dev/null
+++ b/gnu/packages/patches/gdmtest.patch
@@ -0,0 +1,72 @@
+--- old/daemon/gdm-local-display-factory.c	2019-06-17 19:12:51.080000000 +0200
++++ daemon/gdm-local-display-factory.c	2019-06-20 20:30:10.677217240 +0200
+@@ -280,6 +280,7 @@
+                 }
+                 gdm_display_store_remove (store, display);
+ 
++                g_debug ("DDDDDDDDDISPLAY FinishED");
+                 /* if this is a local display, do a full resync.  Only
+                  * seats without displays will get created anyway.  This
+                  * ensures we get a new login screen when the user logs out,
+@@ -297,6 +298,8 @@
+                    so that it doesn't get reused */
+                 gdm_display_store_remove (store, display);
+ 
++                g_debug ("DDDDDDDDDISPLAY FAILED");
++
+                 /* Create a new equivalent display if it was static */
+                 if (is_local) {
+ 
+@@ -573,6 +576,41 @@
+ 
+         g_return_val_if_fail (GDM_IS_LOCAL_DISPLAY_FACTORY (factory), FALSE);
+ 
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++        g_debug ("x/x/x/x/x/x/x/x/x/x");
++
++
++        
+         store = gdm_display_factory_get_display_store (GDM_DISPLAY_FACTORY (factory));
+ 
+         g_signal_connect_object (G_OBJECT (store),
+--- old/common/gdm-log.c	2019-06-17 19:12:50.916000000 +0200
++++ common/gdm-log.c	2019-06-20 16:47:52.852000000 +0200
+@@ -130,7 +130,7 @@
+ 
+         initialized = TRUE;
+ 
+-        g_log_set_default_handler (gdm_log_default_handler, NULL);
++        //        g_log_set_default_handler (gdm_log_default_handler, NULL);
+ }
+ 
+ void
diff --git a/gnu/services/xorg.scm b/gnu/services/xorg.scm
index 1d55e388a1..3932e7a47c 100644
--- a/gnu/services/xorg.scm
+++ b/gnu/services/xorg.scm
@@ -866,7 +866,7 @@ the GNOME desktop environment.")
                    "WaylandEnable=false\n"
                    "\n"
                    "[debug]\n"
-                   "#Enable=true\n"
+                   "Enable=true\n"
                    "\n"
                    "[security]\n"
                    "#DisallowTCP=true\n"
@@ -904,8 +904,11 @@ the GNOME desktop environment.")
                     (fork+exec-command
                      (list #$(file-append (gdm-configuration-gdm config)
                                           "/bin/gdm"))
+                     #:log-file "/var/log/gdm-debug"
                      #:environment-variables
                      (list (string-append
+                            "G_MESSAGES_DEBUG=all")
+                           (string-append
                             "GDM_CUSTOM_CONF="
                             #$(gdm-configuration-file config))
                            (string-append
-- 
2.23.0

Re: Problem logging in using GDM

[Tanguy Le Carrour]

Hi Ricardo!


Le 10/19, Ricardo Wurmus a écrit :
> The question here is: is it a failure of GDM or gnome-shell?  The exact
> point where GDM starts gnome-shell is hard to pin-point, of course, but
> the logs (even those on TTY1, Ctrl-Alt-F1) might tell you something
> about whether it is gnome-shell that is crashing or if it doesn’t even
> get that far.

I don't use gnome-shell, but bspwm, so I guess it is a pure gdm problem.
The fact that it works with slim seems to confirm this.

"Funny" thing, I have 2 different problems!

At home, GDM does not even start. I just see the mouse pointer on the
TTY. Nothing really informative in the logs. Just an endless succession
of "New session c1 of user gdm […] closing session […] New session c2 of
user gdm […]".

At work, I can see the GDM screen, but when I provide my
username/password nothing happens.

I'll try to update my laptop at the WE. Hope I won't end up with yet
another variation of the problem! ^_^'

If I have some meaningful logs, I'll post them here.

-- 
Tanguy