[Haifux] Kernel oops, so what?
eli at billauer.co.il
Sat Jan 16 13:04:51 MSK 2010
Kohn Emil Dan wrote:
> No, it isn't. Crashing is one of the best of the options in some
> situations. Imagine a bug in the filesystem that writes a zero byte at
> random places on the filesystem or even funnier, on the neighboring
> partitions where you have installed another operating system. (yes I
> made one such bug once but I did not have another OS installed on
> other partitions;-). This won't crash the kernel too fast. But the
> consequences are not funny at all.
If I had my own homecooked filesystem driver in the kernel I would be
more alert about oopses, yes. Actually, if I had anything untested in my
And I happen to share this paranoia, that if something went wrong with
the kernel surely my computer will explode here and now. But having been
through some nasty crashes, I've learned that the damage is usually no
more than the reboot.
I suppose it's a tradeoff between crashing here and now, leaving files
in an inconsistent state, or just going on. Forcing a reboot or warmly
suggesting one would be an elegant solution, though. It's interesting,
that Red Hat, which takes the Enterprise Approach, choose to leave
things as is (I'm on Fedora 12).
And here's a little twist: We seem to agree that the kernel can mess up
the filesystem, but it just so happens that I've just restored much of
my /usr directory from backup (I'm so lucky I had one handy) after
inventing my own variant on the rm -rf / stunt. If case you wonder, I
mounted my (still used) root directory over NFS on the new computer just
to check something. The mount point was inside the home directory of a
temporary user, which I chose to remove, including the home directory
without first unmounting. And I didn't understand why removing the user
took so much time.
So there I am again: The kernel can mess things up, my computer can be
attacked, and aliens can invade my CPU. But in the end, it's my own
stupid mistake that almost wiped a lot of dear files. I was merely lucky
/home wasn't reached.
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