After the latest system update, Fedora 43 completely freezes when trying to change the input language using the Caps Lock key (which I have configured in gnome via the additional input options in Gnome Tweaks).
The system freezes completely, so you can’t switch to another tty or even reboot using Alt+SysRq. You just need to turn off the power to restart the system.
Rolling back to btrfs snapshot before updating packages returns everything to normal. What could be the problem here?
I don’t use GNOME but could it be this bug?
Your -b -1 logs show what looks like an endless loop of key remappings. This user found that downgrading mutter to 49.0 fixed the issue, which would explain why rolling back your last update transaction fixes it for you.
Separately…
From the -b -1 log, it looks like the SysRq sequence is recognised but rejected:
окт 26 14:07:19 homepc kernel: sysrq: This sysrq operation is disabled.
So possibly this is down to your kernel args rather than being a consequence of the mutter issue?
the same just happened to me: Fedora Workstation freeze after upgrade 42 → 43. Caps Lock is not working as a layout changing key.
❯ gsettings get org.gnome.desktop.input-sources xkb-options
[‘lv3:rwin_switch’, ‘misc:typo’, ‘grp:caps_toggle’]
~
❯ gsettings get org.gnome.desktop.input-sources sources
[(‘xkb’, ‘us+symbolic’), (‘xkb’, ‘ru’)]
I’ve sent an update which should fix this. Sorry for the trouble.
How could this be forced to enter at least ‘updates-testing’ repo? It’s insane, that such a dramatic problem still unresolved during TWO days since the RELEASE. 
It should already be in the updates-testing repo.
Have you tried this command (as shown on the page that @adamwill linked to)?
sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2025-70e9a20c7b
Oh. Looks like I didn’t add --refresh last time I checked. Now I’ve received this. Thank you.