Re: 2.6.25-git2: BUG: unable to handle kernel paging request atffffffffffffffff

From: Linus Torvalds
Date: Thu Apr 24 2008 - 19:47:22 EST




On Fri, 25 Apr 2008, Jiri Slaby wrote:
>
> Blah, sorry, I lived in a theory, that Rafael got one from 2.6.25 and no,
> really, he had -git2 applied. Mea culpa, anyway I'll test 2.6.25 too, just for
> sure.

No problem. I do think this is a post-2.6.25 thing, because I don't think
we've ever seen it before that.

There is a 2.6.25-rc8-mm2 report, but that was a -mm tree that had a lot
of the stuff that was merged after 2.6.25, so I'm pretty sure that counts
as "post" too. If it wasn't, we'd be seeing a lot more of this.

> Not really. I have no idea what triggers it. Seems like suspend is some kind
> of catalyzer not working every time.

I don't think suspend/resume is sufficient, because I've tried to
reproduce it here (and I tried your test program too) on my macmini, and
it's not happening. So there almost certainly something else too required
to trigger it.

Btw, how do you suspend/resume? That matters, because I've been testing
just the normal

echo mem > /sys/power/state

and with a kernel where everything is compiled-in. But if you use the GUI
suspend, on a common distro, I think that one ends up doing a whole lot
more, including doing things like unloading and reloading modules, and for
all we know the problem is not about suspend itself, but about the things
going on around it.

And it might be a module unload issue, rather than the suspend itself (the
same way I theorized that it might be a ifconfig down/up rather than the
suspend code itself). Who knows..

It might also very well be hardware-specific. You guys seem to have
different wireless setups (ath5k vs b43) but it migth be generic 80211
code, but it might also be something *totally* unrelated, and the only
reason wireless has shown up might be that networking is just in use when
the problem happens.

Jiri, Zdenek, Rafael, could you try to compare hardware with each other
and see if there is some pattern there?

(And btw, the program you used that allocates a hundred meg and tries to
find it - I'm assuming you're not paging or anythign like that, ie you're
not even close to out-of-memory. If that isn't correct, holler. I'm trying
to reproduce this thing).

Linus
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