Haines Brown <haines@???> writes:
> I installed 64bit jessie on a new HDD, and initially used the 3.16.0
> kernel. Then I installed the 4.50 kernel and ran into trouble.
>
> kernel:[25090.816205] NMI watchdog: BUG: soft lockup - CPU #7
> stuck for 22!s
> [colord-sane:20969]
>
> This message is displayed every few seconds in whatever happens to have
> the focus and is accompanied with a beep. The keyboard and mouse
> hang so that I must do a hot reboot.
>
> Is this in fact a kernel bug?
The message comes from the NMI watchdog in the kernel and indicates a
possibly bug in some application. The comment above the statement
printing this message may be helpful here:
/* check for a softlockup
* This is done by making sure a high priority task is
* being scheduled. The task touches the watchdog to
* indicate it is getting cpu time. If it hasn't then
* this is a good indication some task is hogging the cpu
*/
If this feature is enabled, there's a dedicated kernel thread running on
each CPU (named watchdog/<number>) which will reset the watchdog timeout
whenever it gets CPU time to do so. The message is printed of this
thread didn't have a chance to run during the checking interval because
another task ate all available CPU time. The stack backtrace & other
information printed together with this message should provide more
information about this other task.
NB: I've been running 4.5.0 ever since it was released (the upstream
kernel).