Bug 512441 - Printer Settings Freeze/Crash
Summary: Printer Settings Freeze/Crash
Status: REPORTED
Alias: None
Product: systemsettings
Classification: Applications
Component: kcm_printer_manager (other bugs)
Version First Reported In: 6.5.3
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-11-21 16:12 UTC by Tom Strausbaugh
Modified: 2025-12-05 19:37 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


Attachments
Video of the Crash (1.70 MB, video/webm)
2025-11-21 16:12 UTC, Tom Strausbaugh
Details

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Description Tom Strausbaugh 2025-11-21 16:12:11 UTC
Created attachment 187036 [details]
Video of the Crash

SUMMARY

I am getting a freeze when going into the printer settings. I am using a remote cups server to do the printing. My cups client config located in ~/.cups/client.conf reads as follows:

ServerName 10.1.10.107:631

When I open the printer I get a message about not having access but that message eventually disappears and I have setup my cups server to allow my local subnet access (10.1.10.0/24). I can print to the printer but anytime I enter the settings it causes the entire settings app to crash. I will attach a video showing the crash.

STEPS TO REPRODUCE
1. Setup local CUPs to use remote CUPs server
2. Go to System Settings Printer Configuration
3. Select a printer
4. Attempt to go anywhere else within System Settings

OBSERVED RESULT

Freezing / Crash of System Settings

EXPECTED RESULT


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux KDE 6.5.3
KDE Plasma Version: 6.5.3
KDE Frameworks Version: 6.20.0
Qt Version: 6.10.0

ADDITIONAL INFORMATION
N/A
Comment 1 Mike 2025-11-21 16:25:02 UTC
Interesting, looks like an authentication issue, still shouldn't freeze/crash however.  There should be a dialog that pops up to prompt for elevated user/password.  By chance do you see a dialog behind the settings window or somewhere else on screen, maybe hidden behind other windows? 

Also, could you paste the results of `lpinfo -v` (you'll have to elevate privileges)
Comment 2 Tom Strausbaugh 2025-11-22 02:17:45 UTC
(In reply to Mike from comment #1)
> Interesting, looks like an authentication issue, still shouldn't
> freeze/crash however.  There should be a dialog that pops up to prompt for
> elevated user/password.  By chance do you see a dialog behind the settings
> window or somewhere else on screen, maybe hidden behind other windows? 
> 
> Also, could you paste the results of `lpinfo -v` (you'll have to elevate
> privileges)

There is no dialog window when that authorize message appears.

Here is the the output of lpinfo -v

Password for tom on 10.1.10.107?  *********
network beh
network ipp
file cups-brf:/
network http
network ipps
network socket
network https
network lpd
network dnssd://Canon%20MF420%20Series._pdl-datastream._tcp.local/?uuid=6d4ff0ce-6b11-11d8-8020-00bbc171d8b9
network socket://10.1.10.5

And here is the output of "sudo lpinfo -v"

lpinfo: Bad file descriptor
Comment 3 Mike 2025-11-25 15:31:42 UTC
A quick try and I can't reproduce this, my gut is that's related to CUPS auth somehow.  IIRC, there's a dialog (with event loop) involved which can cause issues with QML.

Do you have any special setup involving sudoers at all?
If you go to system settings/printers and choose "Add Printer", do you see the authorization dialog (user/password)?
Comment 4 Tom Strausbaugh 2025-11-26 02:14:28 UTC
(In reply to Mike from comment #3)
> A quick try and I can't reproduce this, my gut is that's related to CUPS
> auth somehow.  IIRC, there's a dialog (with event loop) involved which can
> cause issues with QML.
> 
> Do you have any special setup involving sudoers at all?
> If you go to system settings/printers and choose "Add Printer", do you see
> the authorization dialog (user/password)?

I do not have any special sudoers file to my knowledge. Here is the only configuration I have:

tom ALL=(ALL) ALL

tom is my user. I do get an authentication dialog when I attempt to add a printer. It asks for login credentials for my remote cups server. I can enter credentials and it works as normal. I can print to that remote cups server without any issues as well. I can understand needing to enter credentials for adding a printer but why does it need any credentials to view an existing printer? I do not have to enter any credentials on the cups web UI when viewing the printer information. Either way I think you are on to something with the cups authorization being part of the issue. Seems like the printer view is running into issues with cups authorization and causing the freezing/crash.
Comment 5 Mike 2025-11-26 12:49:19 UTC
> I can understand needing to enter
> credentials for adding a printer but why does it need any credentials to
> view an existing printer? 

Technically, it doesn't, but the assumption is that you're going to the printer details to make a change, and there are a couple of attributes that require elevated privileges to change, so we ask for auth when going to printer details.  I'll also take a look at this, there may be an easy way to ask for auth just when the specific attributes change.
Comment 6 Bug Janitor Service 2025-12-05 19:37:31 UTC
A possibly relevant merge request was started @ https://invent.kde.org/plasma/print-manager/-/merge_requests/293