Re: Strange OOPS in 2.0.25 kernel

Ion Badulescu (ionut@moisil.wal.rhno.columbia.edu)
Tue, 3 Dec 1996 23:16:39 -0500 (EST)


On Tue, 3 Dec 1996, Tyson D Sawyer wrote:

> Well, I tried. :-{

That's OK, nobody is born with knowledge of linux kernel programming (and
debugging). :)

> I think that in only one case the pointer was NULL. What about the others?
> I had forgotten about the 0 page in Linux and so didn't catch the NULL.

The others are even more intriguing, as they are basically bogus
user-space pointers (the kind of stuff that the new exceptions in
2.1.x handle so graciously). As I said, I didn't have much time to spend
on this, so I only looked at the first oops.

The NULL pointer oops might be the result of a race condition in the
memory management code (which I can't find, it's protected by cli()/sti(),
so it should be fine) but it could also be caused by bad hardware
(anything could be caused by bad hardware, right?). The other two oopses
would make some sense on a pentium with stepping 5 using 4MB pages, except
that this is a 486DX/33...

And because it's a 486DX/33, it shouldn't even have/need a CPU fan. :)

Ionut

--
  It is better to keep your mouth shut and be thought a fool,
            than to open it and remove all doubt.