[aclug-L] Re: kernel panic question

[Tom Hull <thull@xxxxxxxxxxx>]

John Reinke wrote:
> 
> I was just downloading a rather large file (117 MB), and this suddenly
> appeared:
> 
> Message from syslogd@jupiter at Fri Jul 21 11:06:45 2000 ...
> jupiter kernel: Kernel panic: VFS: LRU block list corrupted

This call/message is from fs/buffer.c. The LRU list is double-linked,
and one or more links have invalid data, so memory corruption is
indicated.

> 1) How serious is a kernel panic? I stopped the download after about 20 MB,
> but didn't know if it is just a little warning, or if things are at DEFCON
> 1 and the system is about to crash.

Kernel panics occurs when the kernel detects something insane, and decides
that death is preferable to madness. See kernel/panic.c. So the answer to
"how serious?" is extremely.

However, it sounds like you were still running, so maybe the kernel panic
message came from some other machine? The message normally goes to system
console (usually /dev/console).

> 2) Where can I go to learn about kernel panics and fixing whatever caused it?

Not sure. I'd expect something about this in a Kernel-Hackers-HOWTO or some
such similar documents. Source code, of course. My understanding is that
Linux kernel debugging tools are primitive (relative to other Unix; i.e.,
no standard kdb or crash). In any case, debugging kernel is difficult,
debugging memory corruption is difficult, debugging both is worse. But
I'd like to know more, myself.

> Thanks,
> John
> 
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