How can I investigate the cause of total hang? Is there some information that I should pay attention to in order to get some hint?

[Peter Flynn]

On Thu, 2 Jul 2020 at 07:11, 孙世龙 sunshilong <sunshilong369 at gmail.com> 
wrote:
> Hi,
>
> My x86 machine sometimes hangs, suddenly not responding in
> any way to the mouse or the keyboard.
>
> How can I investigate the cause of total hang? Is there some
> information that I should pay attention to in order to get some hint?

IMNSHO on old machines this is often a timing problem: some 
[background?] processes may be assuming that things will occur in a 
certain timescale, and when they don't, there are several classes of 
error that can occur.

If you can ssh into the machine either over a wireless or (better) wired 
connection from another machine, log into your account and see what is 
running (the ps axu command). The top command will show you if there is 
a single process or group of processes that are consuming all the 
resources. You can start killing off suspect processes with the kill 
command, and you may find that one of them suddenly frees up the system.

If you can't log in with ssh, it's dead. Reboot, log in, and run a 
single typical user application and see how long it lasts before 
hanging. If it doesn't hang, run another application, and wait. Exercise 
the processes gently (open an email, or browse to a web site), and keep 
a record of what happens.

Or reinstall using one of the very lightweight Linux distributions and 
see if that helps.

Peter