how do I find out what's hanging me up?

Tony Baechler tony at
Sat Jul 2 14:12:50 UTC 2016

On 7/2/2016 1:54 AM, Mark Peveto wrote:
> The short version of a long story.  I've just installed sonar on a dell pc.  I've also got it installed on a compaq/hp machine, where the followig
> problem doesn't exist.  On the dell, sudo reboot seems to hang.  Sudo shutdown works fine.  I've tried sudo shutdown -r now, sudo systemctl reboot, and
> other options.  How, without sighted help, can I find out what's causing this machine to hang when I reboot.  What's strange is this...why does it shut
> down just fine, but not reboot?

I'm not familiar with Sonar, so consider these random guesses. First, have 
you looked in /var/log/syslog and kern.log? There might be a process not 
shutting down properly. If you halt the system, all processes are killed and 
all filesystems are unmounted. A reboot only resets the system, so I suppose 
it's possible that a process is behaving badly or the kernel can't unmount a 
filesystem. I see this sometimes with slow USB devices, like if I copy a ton 
of files to my SD card. A more likely explanation is an ACPI or power 
management issue. You didn't say how old the machines are, but it could be a 
BIOS bug. Recent kernels should work around this. Without knowing the age of 
the machine and the kernel version, I can only guess.

Also, the machine isn't a laptop, right? Laptops usually have power 
management issues. On Debian, there is a package called acpi-tools. Try 
installing it if it isn't there or purging it if it's there. I have better 
luck without it installed. I would bet syslog and kern.log would have clues 
to your problem. I would check those first. Make note of the time you reboot 
the machine and look at those files with less. You could try booting a live 
CD to avoid adding all of the boot messages to the logs. You didn't say if 
that happens on a live CD, booting from the hard drive, other distros, etc. 
I''ve noticed most live CDs have strange shutdown problems. You might have 
to pass a parameter on the kernel command line. Both HP and Dell have issues 
with Linux.

Tony Baechler, founder, Baechler Access Technology Services
Putting accessibility at the forefront of technology
mailto:bats at
Phone: 1-619-746-8310  SMS text: 1-619-375-2545

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