Re: nfsd oops with 2.6.5-rc2-mm4

[Andrew Morton <akpm@osdl.org>]

Linus Torvalds <torvalds@osdl.org> wrote:
>
> 
> This oops is on a 
> 
> 	lock incl 0x4(%edx)
> 
> and as far as I can tell, it's from do_tcp_sendpages():
> 
> 		....
> 
>                 i = skb_shinfo(skb)->nr_frags;
>                 if (can_coalesce(skb, i, page, offset)) {
>                         skb_shinfo(skb)->frags[i - 1].size += copy;
>                 } else if (i < MAX_SKB_FRAGS) {
> *********		get_page(page);			***************
>                         fill_page_desc(skb, i, page, offset, copy);
>                 } else {
>                         tcp_mark_push(tp, skb);
>                         goto new_segment;
>                 }
> 		...
> 
> where "page" is NULL.
> 
> The caller seems to be svc_sendto()->tcp_sendpage()->do_tcp_sendpages()  
> (the other addresses seem to be stale crud on the stack), which doesn't
> look like it has changed lately. Unless there are changes in this area in
> -mm..

There are some knfsd patches in -mm.

This one might be the cuplrit:

ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.5-rc2/2.6.5-rc2-mm4/broken-out/knfsd-03-auth_error-formatting-fix.patch

Frank, if you have time it would be interesting to try reverting that (and
the other knfsd-* patches), see if the crash goes away.