What were you trying to do that didn't work?

In RHEL 10 with systemd 257, systemd-journald continuously outputs log messages directly to the serial console (ttyS2), interrupting interactive user sessions. This behavior was not present in RHEL 9.6 and makes serial console usage difficult.

Messages appear as: [timestamp] systemd-journald[PID]: Sent WATCHDOG=1 notification. [timestamp] systemd-journald[PID]: Successfully sent stream file descriptor to service manager. The issue persists despite: - Setting StandardError=null in systemd-journald service - Adjusting kernel printk levels (console_loglevel) - Modifying journald.conf settings This appears to be a regression from RHEL 9.6 behavior where serial console remained clean during interactive use.

What is the impact of this issue to you?

making interactive sessions difficult to use effectively.

Please provide the package NVR for which the bug is seen:

How reproducible is this bug?: 10/10

Steps to reproduce

1. 1. Install RHEL 10 with serial console configured (console=ttyS2)
2. Log into serial console for interactive session
3. Observe continuous systemd-journald messages interrupting command line 
4. Compare with RHEL 9.6 where this behavior does not occur

Expected results

Serial console should remain clean for interactive use, similar to RHEL 9.6 behavior

Actual results

systemd-journald messages continuously appear on serial console, disrupting user interaction