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

[Ulrich Windl]

>>> Lennart Poettering <lennart at poettering.net> schrieb am 01.06.2021 um 13:39
in
Nachricht <YLYcdMZ+MgmcPdmG at gardel-login>:
> 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.

I had meant the dropping of messages, not the creation of such. It seems it's
intentional.

> 
>> 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.

OK!

> 
>> 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.

Confused: So is it the kjernel dropping/loosing messages, or is it journald?

> 
> Lennart
> 
> ‑‑
> Lennart Poettering, Berlin