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

[Linus Torvalds]

On Mon, 21 Apr 2008, Jiri Slaby wrote:
> 
> BTW. I haven't see this without suspend/resume cycle, do you, Rafael? It
> doesn't mean anything, since it needs longer time to trigger, but anyway, it
> might be a clue.

There's a separate (and very different-looking) bug-report about the atl1 
driver having problems when doing an "ifconfig down" on it. In fact, the 
problem report says:

> With this commit in tree, I can reproduce either
> a) kmalloc-2048 corruption after initscripts shutdown eth0
>         http://marc.info/?l=linux-kernel&m=120820360221261&w=2
> 
> b) or oopses at filp_close() first reported long ago
>         (sorry, can't find that email)

where that "or oopses at filp_close()" thing is somewhat interesting, 
since your original bug was about something that looked like file pointer 
corruption.

Now, I doubt you have an ATL chip, and I doubt the two are _really_ 
related in any way (the ATL bug was actually triggered by enabling 64-bit 
DMA), but the filp_close thing makes me go "hmm".

The two affected corrupted SLUB areas were the 2kB allocation (1560-byte 
ethernet packets plus skb_shared_info overhead, anyone?) and apparently 
the one that filp's are in (perhaps a 20-byte TCP ACK packet or other 
"small" packet + the skb_shared_info overhead would be a common case that 
might be in that 200-byte range?)

Maybe the ATL bug isn't ATL-specific at all, but somehow connected to 
NETIF_F_HIGHDMA. Do you have 4GB+ of RAM?

And one thing that suspend/resume does, which is not necessarily commonly 
done during normal operation, is that ifconfig down/up pattern. Maybe 
there is something broken in general there?

			Linus
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