Bug 2368463 - In its default configuration, `avahi-daemon.service` slows all Qt (but not GTK) print modals by ⪆ 9s. [NEEDINFO]
Summary: In its default configuration, `avahi-daemon.service` slows all Qt (but not GT...
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: avahi
Version: 44
Hardware: x86_64
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Michal Sekletar
QA Contact: Fedora Extras Quality Assurance
URL: https://github.com/avahi/avahi/issues...
Whiteboard:
: 2367102 2383997 (view as bug list)
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-05-25 16:22 UTC by Mr Beedell, Roke Julian Lockhart
Modified: 2026-05-07 22:01 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:
8ru2u4gz: needinfo? (msekleta)


Attachments (Terms of Use)
A Screencast Demonstrating That This Affects All Qt 6 Applications (2.81 MB, video/webm)
2025-05-25 16:26 UTC, Mr Beedell, Roke Julian Lockhart
no flags Details


Links
System ID Private Priority Status Summary Last Updated
Github avahi avahi issues 701#issue-3087466051 0 None open In its default configuration (on `fedora:42`), `avahi-daemon.service` slows all Qt (but not GTK) print modals by ⪆ 9s. 2025-07-28 11:17:21 UTC
KDE Software Compilation 504678 0 NOR RESOLVED KWalletManager freezes if (first?) wallet creation is aborted 2025-07-28 11:16:39 UTC
KDE Software Compilation 507587 0 NOR UNCONFIRMED [ANR] I left Dolphin open, and it hung 2025-07-28 11:15:36 UTC
Red Hat Bugzilla 2367102 0 unspecified CLOSED [abrt] khelpcenter: __syscall_cancel_arch(): khelpcenter killed by SIGABRT 2025-07-28 11:17:21 UTC

Internal Links: 2383997

Description Mr Beedell, Roke Julian Lockhart 2025-05-25 16:22:42 UTC
When I invoke the `QPrintDialog` with `avahi-daemon.service` enabled, the time elapsed until the modal print window appears is ⪆ 8s. When disabled, invocation is instantaneous.

Reproducibility:

:	Always.

Steps to Reproduce:

:	1.	`sudo systemctl start avahi-daemon.service`:

		> ~~~YAML
		> ● avahi-daemon.service - Avahi mDNS/DNS-SD Stack
		>     Loaded: loaded (/usr/lib/systemd/system/avahi-daemon.service; disabled; preset: enabled)
		>    Drop-In: /usr/lib/systemd/system/service.d
		>             └─10-timeout-abort.conf
		>     Active: active (running) since Fri 2025-05-23 20:31:06 BST; 18min ago
		> Invocation: 9c282b6215cc4106bf249678c1b8488b
		> TriggeredBy: ● avahi-daemon.socket
		>   Main PID: 147627 (avahi-daemon)
		>     Status: "avahi-daemon 0.8 starting up."
		>      Tasks: 2 (limit: 37207)
		>     Memory: 888K (peak: 1.1M)
		>        CPU: 68ms
		>     CGroup: /system.slice/avahi-daemon.service
		>             ├─147627 "avahi-daemon: running [Beedell.local]"
		>             └─147629 "avahi-daemon: chroot helper"
		> 
		> May 23 20:31:06 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Joining mDNS multicast group on interface lo.IPv6 with address ::1.
		> May 23 20:31:06 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: New relevant interface lo.IPv6 for mDNS.
		> May 23 20:31:06 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Joining mDNS multicast group on interface lo.IPv4 with address 127.0.0.1.
		> May 23 20:31:06 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: New relevant interface lo.IPv4 for mDNS.
		> May 23 20:31:06 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Network interface enumeration completed.
		> May 23 20:31:06 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Registering new address record for fdce:b268:c9db:0:3ff3:b235:c981:2418 on enp74s0.*.
		> May 23 20:31:06 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Registering new address record for 192.168.1.178 on enp74s0.IPv4.
		> May 23 20:31:06 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Registering new address record for ::1 on lo.*.
		> May 23 20:31:06 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Registering new address record for 127.0.0.1 on lo.IPv4.
		> May 23 20:31:07 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Server startup complete. Host name is Beedell.local. Local service cookie is 1282367389.
		> ~~~

	2.	Invoke the undermentioned script:

		~~~py
		import sys
		from PySide6.QtWidgets import QApplication, QWidget, QVBoxLayout, QPushButton
		from PySide6.QtPrintSupport import QPrinter, QPrintDialog

		class PrintDialogApp(QWidget):
		   def __init__(self):
		       super().__init__()
		       self.setWindowTitle("Print Dialog (PySide6)")

		       layout = QVBoxLayout()
		       self.print_button = QPushButton("Open Print Dialog")
		       self.print_button.clicked.connect(self.open_print_dialog)
		       layout.addWidget(self.print_button)

		       self.setLayout(layout)

		   def open_print_dialog(self):
		       printer = QPrinter()
		       dialog = QPrintDialog(printer, self)
		       if dialog.exec():
		           print("Print dialog accepted")
		       else:
		           print("Print dialog canceled")

		if __name__ == "__main__":
		   app = QApplication(sys.argv)
		   window = PrintDialogApp()
		   window.show()
		   sys.exit(app.exec())
		~~~

	3.	Click the button.

	4.	~~~sh
		#!/usr/bin/env sh
		sudo systemctl disable avahi-daemon.service && \
		sudo systemctl stop avahi-daemon.service
		~~~

		To confirm, `systemctl status avahi-daemon` shall return:

		> ~~~YAML
		> ○ avahi-daemon.service - Avahi mDNS/DNS-SD Stack
		>     Loaded: loaded (/usr/lib/systemd/system/avahi-daemon.service; disabled; preset: enabled)
		>    Drop-In: /usr/lib/systemd/system/service.d
		>             └─10-timeout-abort.conf
		>     Active: inactive (dead) since Fri 2025-05-23 21:03:38 BST; 3s ago
		>   Duration: 32min 31.926s
		> Invocation: 9c282b6215cc4106bf249678c1b8488b
		> TriggeredBy: ● avahi-daemon.socket
		>    Process: 147627 ExecStart=/usr/bin/avahi-daemon -s (code=exited, status=0/SUCCESS)
		>   Main PID: 147627 (code=exited, status=0/SUCCESS)
		>     Status: "avahi-daemon 0.8 starting up."
		>   Mem peak: 1.3M
		>        CPU: 136ms
		> 
		> May 23 20:31:07 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Server startup complete. Host name is Beedell.local. Local service cookie is 1282367389.
		> May 23 21:03:38 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Got SIGTERM, quitting.
		> May 23 21:03:38 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Leaving mDNS multicast group on interface enp74s0.IPv6 with address fdce:b268:c9db:0:3ff3:b235:c981:2418.
		> May 23 21:03:38 Beedell.RokeJulianLockhart.desktop.SSV2AY systemd[1]: Stopping avahi-daemon.service - Avahi mDNS/DNS-SD Stack...
		> May 23 21:03:38 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Leaving mDNS multicast group on interface enp74s0.IPv4 with address 192.168.1.178.
		> May 23 21:03:38 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Leaving mDNS multicast group on interface lo.IPv6 with address ::1.
		> May 23 21:03:38 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: Leaving mDNS multicast group on interface lo.IPv4 with address 127.0.0.1.
		> May 23 21:03:38 Beedell.RokeJulianLockhart.desktop.SSV2AY avahi-daemon[147627]: avahi-daemon 0.8 exiting.
		> May 23 21:03:38 Beedell.RokeJulianLockhart.desktop.SSV2AY systemd[1]: avahi-daemon.service: Deactivated successfully.
		> May 23 21:03:38 Beedell.RokeJulianLockhart.desktop.SSV2AY systemd[1]: Stopped avahi-daemon.service - Avahi mDNS/DNS-SD Stack.
		> ~~~

	5.	Invoke the script.

	6.	Click the button. This is instantaneous.

Actual Results:

:	With the service enabled, loading Qt print modals takes ⪆ 9s. Without it enabled, doing so is instantaneous.

Expected Results:

:	It should be instantaneous.

Additional Information:

:	Already reported upstream at https://github.com/avahi/avahi/issues/701#issue-3087466051, but I've yet to hear a response. This replaces https://bugzilla.redhat.com/show_bug.cgi?id=2367102.

Comment 1 Mr Beedell, Roke Julian Lockhart 2025-05-25 16:23:55 UTC
*** Bug 2367102 has been marked as a duplicate of this bug. ***

Comment 2 Mr Beedell, Roke Julian Lockhart 2025-05-25 16:26:45 UTC
Created attachment 2091543 [details]
A Screencast Demonstrating That This Affects All Qt 6 Applications

Comment 3 Mr Beedell, Roke Julian Lockhart 2025-05-31 10:03:56 UTC
https://bugs.kde.org/show_bug.cgi?id=504678#c0


reporter:       libreport-2.17.15
type:           CCpp
reason:         kwalletmanager5 killed by SIGABRT
journald_cursor: s=c1f108f1ef4e48808a377c0a73f168fc;i=5bbd53;b=e7b17d2b53834bf5a00a818d3a14f8eb;m=56f58795;t=6366b97b1faf2;x=e09d2dab3b1c30a6
executable:     /usr/bin/kwalletmanager5
cmdline:        /usr/bin/kwalletmanager5
cgroup:         0::/user.slice/user-1000.slice/user/app.slice/dbus-:1.2-org.kde.kwalletmanager
rootdir:        /
uid:            1000
kernel:         6.14.8-300.fc42.x86_64
package:        kwalletmanager5-25.04.1-1.fc42
runlevel:       N 5
backtrace_rating: 4
crash_function: KCrash::defaultCrashHandler
comment:        https://bugs.kde.org/show_bug.cgi?id=504678#c0

Comment 4 Mr Beedell, Roke Julian Lockhart 2025-05-31 10:05:23 UTC
(In reply to Mr. Beedell, Roke Julian Lockhart (RJLB) from comment #3)

Comment 3 is a completely different issue to Comment 0. How did it manage to be registered as a duplicate? Is that a problem with GNOME Abrt?

Comment 5 Mr Beedell, Roke Julian Lockhart 2025-07-28 11:14:34 UTC
As https://bugs.kde.org/show_bug.cgi?id=507587 explains, "I left Dolphin open, and it hung."


reporter:       libreport-2.17.15
type:           CCpp
reason:         dolphin killed by SIGABRT
journald_cursor: s=a2d6d580caa24cf3a9483be7f85033e4;i=1b54d1;b=ab6c70bb71be401fbbd67899b56456a9;m=15511dd53;t=63afb4892dfab;x=282f93b8c0708859
executable:     /usr/bin/dolphin
cmdline:        /usr/bin/dolphin
cgroup:         0::/user.slice/user-1000.slice/user/app.slice/app-org.kde.konsole-48970.scope
rootdir:        /
uid:            1000
kernel:         6.15.7-200.fc42.x86_64
package:        dolphin-25.04.3-1.fc42
runlevel:       N 5
backtrace_rating: 4
crash_function: KCrash::defaultCrashHandler
comment:        As https://bugs.kde.org/show_bug.cgi?id=507587 explains, "I left Dolphin open, and it hung."

Comment 6 Mr Beedell, Roke Julian Lockhart 2025-07-28 17:25:35 UTC
*** Bug 2383997 has been marked as a duplicate of this bug. ***

Comment 7 Mr Beedell, Roke Julian Lockhart 2025-07-29 12:44:59 UTC
I reproduced https://bugzilla.redhat.com/show_bug.cgi?id=2368463#c6.


reporter:       libreport-2.17.15
type:           CCpp
reason:         assistant-qt6 killed by SIGABRT
journald_cursor: s=c1f108f1ef4e48808a377c0a73f168fc;i=9d1651;b=7c73c9025bfd4b3ea14c302bfe5a7228;m=1ec65cfd3;t=63b10b9abd6ac;x=d810fd50c149748a
executable:     /usr/bin/assistant-qt6
cmdline:        /usr/bin/assistant-qt6
cgroup:         0::/user.slice/user-1000.slice/user/app.slice/app-qt6\x2dassistant
rootdir:        /
uid:            1000
kernel:         6.15.7-200.fc42.x86_64
package:        qt6-assistant-6.9.1-1.fc42
runlevel:       N 5
backtrace_rating: 4
crash_function: __syscall_cancel_arch
comment:        I reproduced https://bugzilla.redhat.com/show_bug.cgi?id=2368463#c6.

Comment 8 Mr Beedell, Roke Julian Lockhart 2025-07-29 12:45:15 UTC
I reproduced https://bugzilla.redhat.com/show_bug.cgi?id=2368463#c6.


reporter:       libreport-2.17.15
type:           CCpp
reason:         linguist-qt6 killed by SIGABRT
journald_cursor: s=c1f108f1ef4e48808a377c0a73f168fc;i=9d17da;b=7c73c9025bfd4b3ea14c302bfe5a7228;m=1ef91a8e8;t=63b10bcd7afc1;x=36978b0de38098a9
executable:     /usr/bin/linguist-qt6
cmdline:        /usr/bin/linguist-qt6
cgroup:         0::/user.slice/user-1000.slice/user/app.slice/app-qt6\x2dlinguist
rootdir:        /
uid:            1000
kernel:         6.15.7-200.fc42.x86_64
package:        qt6-linguist-6.9.1-1.fc42
runlevel:       N 5
backtrace_rating: 4
crash_function: __syscall_cancel_arch
comment:        I reproduced https://bugzilla.redhat.com/show_bug.cgi?id=2368463#c6.

Comment 9 _audax 2025-08-25 12:28:32 UTC
I choose expert mode then i created pair of keys and after appearing terminal window i closed it and error happen.


reporter:       libreport-2.17.15
type:           CCpp
reason:         kgpg killed by SIGABRT
journald_cursor: s=db37208aba5f4113bc8d60ffdf923701;i=10ddab;b=6bf6a6caadb54b4f864ad097ed9ec8b5;m=34a35adf4;t=63d2ed311449c;x=4788c9ebee82f56d
executable:     /usr/bin/kgpg
cmdline:        /usr/bin/kgpg
cgroup:         0::/user.slice/user-1002.slice/user/app.slice/app-org.kde.kgpg
rootdir:        /
uid:            1002
kernel:         6.15.10-200.fc42.x86_64
package:        kgpg-25.08.0-1.fc42
runlevel:       N 5
backtrace_rating: 4
crash_function: KCrash::defaultCrashHandler
comment:        I choose expert mode then i created pair of keys and after appearing terminal window i closed it and error happen.

Comment 10 Fedora Release Engineering 2026-05-06 13:02:51 UTC
This message is a reminder that Fedora Linux 42 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 42 on 2026-05-13.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
'version' of '42'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, change the 'version' 
to a later Fedora Linux version. Note that the version field may be hidden.
Click the "Show advanced fields" button if you do not see it.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora Linux 42 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora Linux, you are encouraged to change the 'version' to a later version
prior to this bug being closed.

Comment 11 Mr Beedell, Roke Julian Lockhart 2026-05-07 22:01:45 UTC
This persists with `release-identity-kde-desktop-44`, so I've increased the version to prevent EOL closure.


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