NMI watchdog on Debian Stretch after kernel update

AdbekunkusMX · 06-05-2016, 10:14 PM

Hi.

I've been getting this error a few seconds after the GRUB screen on Debian Stretch, kernel 4.5.0-2

Code:

NMI Watchdog: watchdog detected hard LOCKUP on cpu0

Browsing through the logs I noticed that the last upgrade included some linux headers packages, specifically:

Code:

2016-06-05 15:55:03 upgrade linux-compiler-gcc-5-x86:amd64 4.5.4-1 4.5.5-1
2016-06-05 15:55:04 upgrade linux-headers-4.5.0-2-all:amd64 4.5.4-1 4.5.5-1
2016-06-05 15:55:04 upgrade linux-headers-4.5.0-2-all-amd64:amd64 4.5.4-1 4.5.5-1
2016-06-05 15:55:06 upgrade linux-headers-4.5.0-2-amd64:amd64 4.5.4-1 4.5.5-1
2016-06-05 15:55:12 upgrade linux-headers-4.5.0-2-common:amd64 4.5.4-1 4.5.5-1
2016-06-05 15:55:23 upgrade linux-kbuild-4.5:amd64 4.5.4-1 4.5.5-1
2016-06-05 15:55:25 upgrade linux-image-4.5.0-2-amd64:amd64 4.5.4-1 4.5.5-1
2016-06-05 15:55:40 upgrade linux-libc-dev:amd64 4.5.4-1 4.5.5-1

I can acces my system by booting into recovery mode and then resume booting with Ctrl+D when prompted for root password. Any ideas of why this happens? Any suggestions? Thanks in advance

serafean · 06-06-2016, 04:02 PM

Hi,

the NMI watchdog is a hardware watchdog for (hard)lockups. Meaning that if you get a hard lockup, it fires, and might trigger a hard reboot. ( I use it this way on my home server)

As for why it happens, getting a log from a locked up boot would be the greatest solution.
My first guess would be a bug in hw initialization. If it started happening after a kernel update, try downgrading (or upgrading more

)

NMI kernel doc

Serafean.

AdbekunkusMX · 06-06-2016, 04:06 PM

Quote:

Originally Posted by serafean

Hi,

the NMI watchdog is a hardware watchdog for (hard)lockups. Meaning that if you get a hard lockup, it fires, and might trigger a hard reboot. ( I use it this way on my home server)

As for why it happens, getting a log from a locked up boot would be the greatest solution.
My first guess would be a bug in hw initialization. If it started happening after a kernel update, try downgrading (or upgrading more

)

NMI kernel doc

Serafean.

Hi Serafean, thanks.

How do I get a log from a locked up boot?

How can I safely downgrade the kernel?

Thanks! Cheers!

serafean · 06-09-2016, 09:49 AM

Quote:

Originally Posted by AdbekunkusMX

Hi Serafean, thanks.

How do I get a log from a locked up boot?

I've never done it, but IMO netconsole is the way to do it.
https://wiki.archlinux.org/index.php/Netconsole

Quote:

How can I safely downgrade the kernel?

AFAIK Debian leaves old kernels installed, just use the older one.
I don't use debian, so can't help you much there.