Re: [PLUG] kernel panic from unknown cause

[Eric <eric@lucii.org>]

Wow, that's interesting.  This appears to be a rare and random problem but I
like the idea of letting the log stream on the console.  The server is in my
basement so access is not a problem.

What is the Alt-SysRq key on a "PC" type keyboard?

I did find this:

>From SSH terminal etc., you can use the Alt-SysRq feature by writing to the
"/proc/sysrq-trigger". For example, "echo s > /proc/sysrq-trigger; echo u >
/proc/sysrq-trigger" from the root shell prompt syncs and umounts all mounted
filesystems.

I presume that I could then "echo 9 > /proc/sysrq-trigger" and get the same
effect as Alt-SysRq-9?

The value of /proc/sys/kernel/sysrq was 0 which supposedly turns the trigger off
so I set it to 1.

From:
http://www.debian.org/doc/manuals/debian-reference/ch09.en.html#_alt_sysrq_key

Here's hoping it works the same way in CentOS :-)


Thanks,
Eric


Randall A Sindlinger wrote:
> Eric,
> 
> If it's a system that you'd like to have up right away, and can afford to
> have another unpredictable kernel panic happen on, then this is what I've
> found to be useful -
> 
> After booting the system normally, manually set the loglevel to 9 and 
> switch over to tty10.  You'll need to have some kind of kvm hooked up
> to it, of course, too, and not just work remotely.
> 
> Alt-SysRq-9 will set loglevel 9.  Ctrl-Alt-F10 will put you into tty10,
> where loglevel 9 will spit *everything* out.  (actually all log levels
> spit out there)  Make sure you _leave_ the machine at tty10 on the
> monitor.  (Once the system hangs, you can't switch ttys)
> 
> The last few errors you see there will provide the best clues to what
> caused the kernel panic.
> 
> Hope that helps,
> -Randall Sindlinger
>  Systems Programmer
>  CETS, School of Engineering
>  University of Pennsyvania
> 
> On Fri, Sep 11, 2009 at 12:53:06PM -0400, Eric wrote:
>> Downloading SystemRescueCD right now.
>>
>> Thanks
>>
>> brent timothy saner wrote:
>>> Burn a sysresccd[2] and do a memtest (memtest at the boot prompt) and also do a badblocks test to check for bad sectors in your /boot.
>>>
>>> [1] http://www.google.com/linux?hl=en&ie=ISO-8859-1&q=debugging+kernel+panics&btnG=Search
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-- 
#  Eric Lucas
#
#                "Oh, I have slipped the surly bond of earth
#                 And danced the skies on laughter-silvered wings...
#                                        -- John Gillespie Magee Jr
___________________________________________________________________________
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