Re: innd mmap bug in 2.4.0-test12

Dan Aloni
2000-12-25T03:00:52Z

On 25 Dec 2000, Zlatko Calusic wrote:

> Linus Torvalds <torvalds@transmeta.com> writes:
>
> > On Sun, 24 Dec 2000, Linus Torvalds wrote:
> > >
> > > Marco, would you mind changing the test in reclaim_page(), somewheer
> > > around line mm/vmscan.c:487 that says:
> >
>
> Speaking of page_launder() I just stumbled upon two oopsen today on
> the UP build. Maybe it could give a hint to someone, I'm not that good
> at Oops decoding.
>
> Unable to handle kernel NULL pointer dereference at virtual address 0000000c
> printing eip:
> c012872e
> *pde = 00000000
> Oops: 0000
> CPU: 0
> EIP: 0010:[page_launder+510/2156]

I suspected I'm not the only one who is getting these exact same Oopses
(and the lockups that follow them) so earlier today, I've decoded the Oops
I got, and found that the problem is in vmscan.c:line-605, where
page->mapping is NULL and a_ops gets resolved and dereferenced at
0x0000000c.

I leave the fix for the mm experts, I've notified Linus, I guess he's
looking into it.

--
Dan Aloni
dax@karrde.org