Subject: Re: Userland crashing the system
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-kern
Date: 11/25/2001 16:01:20
(I've changed the Subject, which used to be "kern/14721: It's possible
to crash the system by opening a large number of files", because this
is really veering off in a new direction.)

> On the grounds that you shouldn't be able to crash the system from
> user space if nothing else.....

As a nonprivileged user, I'd agree.  But as root, there are lots of
foot-pointed pistols available.

Now, there are lots of things only root can do that _should't_ be able
to crash the system, like binding low-numbered TCP ports or using bpf
listeners, and if any of those crashed the system it would be
reasonable to call it a bug.

But where is the line between those and stuff like "dd if=/dev/zero
of=/dev/mem"?  How do you draw that line between "if this crashes the
kernel it's a bug that needs fixing" and "this is pilot error"?

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