Created attachment 166890 [details]
image captcher of problem

I can reproduce this.  I have the UFW firewall installed and the issue is present whether it's enabled or disabled: while the KCM is selected my CPU usage is about 50% on my two-core processor and when I switch to a different KCM the CPU drops to less than 10%.

Setting to confirmed

Operating System: Arch Linux 
KDE Plasma Version: 6.0.1
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2
Kernel Version: 6.7.9-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 2 × AMD A6-6400K APU with Radeon(tm) HD Graphics
Graphics Processor: AMD CEDAR

Also changing importance to "major" as per the guidelines https://community.kde.org/index.php?title=Guidelines_and_HOWTOs/Bug_triaging

Created attachment 166900 [details]
attachment-1830528-0.html

Could you inform which backend are you using?

On Sun, 10 Mar 2024, 16:38 Erfan, <bugzilla_noreply@kde.org> wrote:

> https://bugs.kde.org/show_bug.cgi?id=483132
>
>             Bug ID: 483132
>            Summary: system settings high CPU usage opening firewall tab
>     Classification: Applications
>            Product: systemsettings
>            Version: 6.0.1
>           Platform: Arch Linux
>                 OS: Linux
>             Status: REPORTED
>           Severity: critical
>           Priority: NOR
>          Component: kcm_firewall
>           Assignee: plasma-bugs@kde.org
>           Reporter: erfan.qeui@gmail.com
>                 CC: lucas.biaggi@kde.org, tcanabrava@kde.org
>   Target Milestone: ---
>
> SUMMARY
> ***
> ***
> when i open firewall setting in kde settings cpu usage going high and my
> laptop
> fan speed also last time systemsetting even can't show status of firewall
> but
> now its fixed with new update i get from arch but i have still cpu problem
>
> SOFTWARE/OS VERSIONS
> Linux/KDE Plasma:  Arch linux 6.0.1
> (available in About System)
> KDE Plasma Version: 6.0.1
> KDE Frameworks Version: 6.0.0
> Qt Version: 6.6.2
>
> ADDITIONAL INFORMATION
>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.

Created attachment 166901 [details]
attachment-1830753-0.html

Could you test with firewalld?

On Sun, 10 Mar 2024, 17:24 Paul Worrall, <bugzilla_noreply@kde.org> wrote:

> https://bugs.kde.org/show_bug.cgi?id=483132
>
> Paul Worrall <p.r.worrall@gmail.com> changed:
>
>            What    |Removed                     |Added
>
> ----------------------------------------------------------------------------
>              Status|REPORTED                    |CONFIRMED
>      Ever confirmed|0                           |1
>                  CC|                            |p.r.worrall@gmail.com
>
> --- Comment #2 from Paul Worrall <p.r.worrall@gmail.com> ---
> I can reproduce this.  I have the UFW firewall installed and the issue is
> present whether it's enabled or disabled: while the KCM is selected my CPU
> usage is about 50% on my two-core processor and when I switch to a
> different
> KCM the CPU drops to less than 10%.
>
> Setting to confirmed
>
> Operating System: Arch Linux
> KDE Plasma Version: 6.0.1
> KDE Frameworks Version: 6.0.0
> Qt Version: 6.6.2
> Kernel Version: 6.7.9-arch1-1 (64-bit)
> Graphics Platform: Wayland
> Processors: 2 × AMD A6-6400K APU with Radeon(tm) HD Graphics
> Graphics Processor: AMD CEDAR
>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.

Uninstalled ufw and installed firewalld, the issue seems to be unchanged

I have still this problem even removed ufw and install firewalld i checked journal when I open kcm firewall there loop created and make this problem

qrc:/kcm/kcm_firewall/main.qml:29:5: QML OverlaySheet: Binding loop detected for property "implicitHeight"

after update to latest version of plasma-firewall 6.0.2-3 in arch still this problem exist

after update to plasma 6.0.3 and plasma-firewall 6.0.3-1 problem still there is there any hope this is get fix?

Please don't spam bug reports. When it's fixed you'll know because the bug report gets moved into RESOLVED FIXED state. Until that happens, pinging people with comments like this is just annoying and reduces people's motivation to actually fix it.

(In reply to Nate Graham from comment #10)
> Please don't spam bug reports. When it's fixed you'll know because the bug
> report gets moved into RESOLVED FIXED state. Until that happens, pinging
> people with comments like this is just annoying and reduces people's
> motivation to actually fix it.

sorry i sent that because status wasn't change from reported and chat was finish incompletely
so now i change status to resolved upstream as you said

Now I'm confused because I didn't ask you to change the status to RESOLVED UPSTREAM. Are you saying you found an upstream issue that's causing the bug?