Comment # 5 on bug 1028027 from Gerald Hofer

I have now found what is actually sending the messages into every single shell.
The reason is that the kernel is using "Emergency" for these messages and
rsyslog has following rule in /etc/rsyslog.conf:

# Emergency messages to everyone logged on (wall)
*.emerg                                         :omusrmsg:*

After commenting out the rule, the messages are still logged, but will not spam
every single shell any more.

I think that should limit the problem down a bit:
Some change in or around kernel 4.4.49-16 is now sending emergency messages
when we trigger thermal events. The messages directly out of the kernel are
misleading and have the level emergency:

2017-03-09T17:12:09.755648+10:00 gerald6 kernel: [123760.500209] mce: [Hardware
Error]: Machine check events logged
2017-03-09T17:12:09.755649+10:00 gerald6 kernel: [123760.500224] mce: [Hardware
Error]: CPU 3: Machine Check: 0 Bank 128: 0000000088030003
2017-03-09T17:12:09.755655+10:00 gerald6 kernel: [123760.500238] mce: [Hardware
Error]: TSC 12d27289fb91e 
2017-03-09T17:12:09.755656+10:00 gerald6 kernel: [123760.500249] mce: [Hardware
Error]: PROCESSOR 0:306a9 TIME 1489043529 SOCKET 0 APIC 3 microcode 1c

The messages are then interpreted by mcelog (this is the latest git) and again
logged into syslog and look sensible:

2017-03-09T17:12:09.773831+10:00 gerald6 mcelog[17636]: Hardware event. This is
not a software error.
2017-03-09T17:12:09.774797+10:00 gerald6 mcelog[17636]: MCE 0
2017-03-09T17:12:09.774977+10:00 gerald6 mcelog[17636]: CPU 3 THERMAL EVENT TSC
12d27289fb91e
2017-03-09T17:12:09.775133+10:00 gerald6 mcelog[17636]: TIME 1489043529 Thu Mar
 9 17:12:09 2017
2017-03-09T17:12:09.775288+10:00 gerald6 mcelog[17636]: Processor 3 heated
above trip temperature. Throttling enabled.
2017-03-09T17:12:09.775438+10:00 gerald6 mcelog[17636]: Please check your
system cooling. Performance will be impacted
2017-03-09T17:12:09.775582+10:00 gerald6 mcelog[17636]: Running trigger
`unknown-error-trigger'
2017-03-09T17:12:09.775726+10:00 gerald6 mcelog[17636]: STATUS 88030003
MCGSTATUS 0
2017-03-09T17:12:09.775868+10:00 gerald6 mcelog[17636]: MCGCAP c09 APICID 3
SOCKETID 0
2017-03-09T17:12:09.776004+10:00 gerald6 mcelog[17636]: CPUID Vendor Intel
Family 6 Model 58