Bug 432314

Summary: Cca 20 seconds delay after "su" in Konsole (due to systemd startup?)
Product: [Plasma] plasmashell Reporter: Petr Bartos <bartos.petr>
Component: generalAssignee: David Edmundson <kde>
Status: RESOLVED NOT A BUG    
Severity: major CC: plasma-bugs-null
Priority: NOR    
Version First Reported In: 5.20.90   
Target Milestone: 1.0   
Platform: Fedora RPMs   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Petr Bartos 2021-01-30 15:48:06 UTC 
SUMMARY

When switching to root in Konsole (or Yakuake), there is cca 20 seconds delay after submitting valid password before root prompt is shown.

STEPS TO REPRODUCE
1. Open Konsole
2. Enter "su"
3. Login

OBSERVED RESULT

There is cca 20 seconds delay after login before showing root prompt

EXPECTED RESULT

Root prompt should be available immediately after login

SOFTWARE/OS VERSIONS

Linux/KDE Plasma: Fedora 33
KDE Plasma Version: 5.20.90
KDE Frameworks Version: 5.78.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION

I suspect problem is with systemd startup as it did not happen for me in 5.20.5. 

When printing services as regular user via "systemd-analyze blame --user", following is shown:

756ms plasma-powerdevil.service                                       
565ms plasma-plasmashell.service                                      
491ms plasma-kwin_x11.service                                         
479ms plasma-ksmserver.service                                        
331ms pulseaudio.service                                              
283ms plasma-kcminit.service                                          
267ms plasma-krunner.service                                          
179ms plasma-polkit-agent.service                                     
166ms plasma-kglobalaccel.service                                     
163ms plasma-kded.service                                             
 53ms app-baloo_file-autostart.service                                
 49ms app-klipper-autostart.service                                   
 45ms plasma-kcminit-phase1.service                                   
 45ms plasma-kactivitymanagerd.service                                
 29ms app-dropboxd-autostart.service                                  
 29ms app-geoclue\x2ddemo\x2dagent-autostart.service                  
 27ms app-org.kde.dolphin-autostart.service                           
 21ms app-org.kde.yakuake-autostart.service                           
 20ms plasma-restoresession.service                                   
 20ms app-org.gnome.SettingsDaemon.DiskUtilityNotify-autostart.service
 18ms plasma-ksplash-ready.service                                    
 15ms gvfs-daemon.service                                             
 15ms app-vmware\x2duser-autostart.service                            
 14ms dbus.socket                                                     
 14ms app-pam_kwallet_init-autostart.service                          
 13ms at-spi-dbus-bus.service                                         
 13ms systemd-tmpfiles-clean.service                                  
 13ms app-vboxclient-autostart.service                                
 11ms obex.service                                                    
 11ms grub-boot-success.service                                       
  9ms systemd-tmpfiles-setup.service                                  
  3ms dbus-broker.service

however as root (after the login delay) I end up either with:

Failed to connect to bus: Permission denied

when using "su" or with:

Failed to connect to bus: $DBUS_SESSION_BUS_ADDRESS and $XDG_RUNTIME_DIR not defined

when using "su -". In first case, both variables points to directories of original user. So i guess plasma is trying to start also for root user, fails due to dbus connection problems, but there is some timeout in some of started services causing that 20 seconds delay.

Problem happens only in plasmashell environment, there is no delay when logging in separate terminal.

Might be also caused by some packaging/configuration problem as I am using this unofficial COPR repository https://copr.fedorainfracloud.org/coprs/mkyral/plasma-unstable
Comment 1 David Edmundson 2021-02-01 14:08:33 UTC 
>I suspect problem is with systemd startup as it did not happen for me in 5.20.5. 

Not reproducible here also with the systemd startup. I also struggle to see how it could be related. su is a very low level command.

Can you run "su root -c /bin/sh" and confirm if that is slow.
Comment 2 Petr Bartos 2021-02-01 14:48:39 UTC 
Unfortunately same result. However there is probably some other problem. Previously i have reverted whole dnf update transaction and problem was gone, now i've tried downgrade only plasma and problem is still present. So there was probably another updated package not related to plasma causing this problem.
Comment 3 Petr Bartos 2021-02-01 15:16:51 UTC 
So i found the problem is in sddm. Upgrade transaction contained upgrade from sddm-0.19.0-3 to sddm-0.19.0-5. Reverting to sddm-0.18.1-8 (as i am able to revert only to release version, not previous update version) fixes it.