GDM with multiple displays (on Xorg) stops working when uutils replaces gnu coreutils

[korewaChino]

It seems like GNOME does not work properly on uutils.

I think this might be related to a bug somewhere?

System Details Report

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Report details

• Date generated: 2023-11-08 19:55:43

Hardware Information:

• Hardware Model: HP OMEN by HP Laptop 15-ce0xx
• Memory: 16.0 GiB
• Processor: Intel® Core™ i7-7700HQ × 8
• Graphics: NVIDIA GeForce GTX 1050
• Graphics 1: NVIDIA GeForce GTX 1050
• Disk Capacity: 1.1 TB

Software Information:

• Firmware Version: F.24
• OS Name: Ultramarine Linux 39 (GNOME Edition)
• OS Build: (null)
• OS Type: 64-bit
• GNOME Version: 45.1
• Windowing System: X11
• Kernel Version: Linux 6.5.9-300.fc39.x86_64

[sylvestre]

not sure how this bug is actionable, sorry :(
please provide more information
(I have been using gnome & rust/coreutils for a year without any issue)

[korewaChino]

I'm using NVIDIA with Xorg, linked to an external display though HDMI.

I might try testing on other window managers just to be safe.

[korewaChino]

I just tested this on KDE Plasma. Displays also broken.

I may have pinpointed the issue to Xorg.

Does anyone know if Xorg use any weird coreutils features?

[sylvestre]

i don't think xorg relies much on the coreutils, less on weird features

do you see anything in the logs?

[jokeyrhyme]

I recently found a place where gnome-session calls your $SHELL in "login" mode, probably so that it can initialise your environment variables as expected: https://gitlab.gnome.org/GNOME/gnome-session/-/blob/998ed1d8ee2ff5396583c284230648625b4103e5/gnome-session/gnome-session.in#L10

I discovered this, because I had some bugs in my shell configuration that did not handle this well, and prevented the GNOME session from starting successfully

This particular example is probably unrelated, but I wonder if there are other places where KDE/GNOME call out to utilities or our $SHELLs, or if some people have similarly-sensitive shell configurations?

[sylvestre]

ok, it would be nice if you could comment some of the content in gnome-session to see which lines cause the problem

[jokeyrhyme]

@korewaChino ^ ?

[korewaChino]

I changed my $SHELL from fish to bash and the issue is still there.

Honestly, I don't know what part to comment to still have my session work.

Weirdly enough, using Wayland works fine.

I ran bpftrace execsnoop to see if this is somehow runs any executables owned by uutils, and it seems like GDM uses touch. So, I have pinpointed the issue to maybe the fact that touch may have some inconsistencies with GNU's version

TIME(ms)   PID   ARGS
1929       4467  /usr/bin/touch /run/udev/gdm-machine-has-hardware-gpu
1944       4468  /usr/bin/touch /run/udev/gdm-machine-has-hardware-gpu

Also just tried using LightDM, now X works fine. So it's GDM abusing GNU coreutils behaviour. Could anyone check the code whether if GDM does something with calling systems coreutils?

[sylvestre]

could you please replace your screenshot by text ? it is terrible for accessibility and search :)
Thanks

[korewaChino]

could you please replace your screenshot by text ? it is terrible for accessibility and search :) Thanks

Sorry :p
replaced with logs

[korewaChino]

I'll consider forwarding this issue to upstream GDM, since it seems like a weird quirk of GDM itself... But since inconsistencies between uutils and gnu are considered bugs, maybe we should keep it open since seems like GDM is relying on a GNU quirk