[systemd-devel] What causes "systemd-journald[3256]: Missed 127 kernel messages"

[Lennart Poettering]

On Di, 01.06.21 12:42, Ulrich Windl (Ulrich.Windl at rz.uni-regensburg.de) wrote:

> Jun 01 12:33:10 h18 systemd-journald[3256]: Missed 195 kernel messages
>
> A few questions:
> 1) What causes this?

Dunno. Something is massively flooding the kernel log buffer. Probably
some borked driver or so. "dmesg" might tell you what.

> 2) How can systemd know how many messasges were missed?

Kernel messages delivered to userspace come with a sequence number. If
there are some missing we know the kernel dropped them from the kmsg
log buffer before we could read them.

> 3) Can I avoid that problem?

Figure out which kernel driver/subsystem is responsible.

You could also enlarge the kernel log buffer, see log_buf_mem= kernel
cmdline switch.

Lennart

--
Lennart Poettering, Berlin