Re: 2.6.16-rc6-mm2

[Christoph Lameter <clameter@sgi.com>]

I guess this is correct. nfs_clear_page_writeback also ignores the page 
if req->wb_page == NULL. Trond?

On Mon, 12 Jun 2006, Christoph Lameter wrote:

> On Mon, 12 Jun 2006, Cedric Le Goater wrote:
> 
> > Unable to handle kernel NULL pointer dereference at 0000000000000007 RIP:
> >  [<ffffffff8025b017>] dec_zone_page_state+0x1/0x5b
> 
> Seems that req->wb_page may be NULL.
> 
> This patch may fix it but we may miss an unstable page then. We may 
> have to move the decrement of NR_UNSTABLE to a different location when
> wb_page is still valid.
> 
> Index: linux-2.6.17-rc6-cl/fs/nfs/write.c
> ===================================================================
> --- linux-2.6.17-rc6-cl.orig/fs/nfs/write.c	2006-06-12 13:37:47.321243148 -0700
> +++ linux-2.6.17-rc6-cl/fs/nfs/write.c	2006-06-12 15:13:48.020908204 -0700
> @@ -1419,7 +1419,8 @@ static void nfs_commit_done(struct rpc_t
>  		nfs_mark_request_dirty(req);
>  	next:
>  		nfs_clear_page_writeback(req);
> -		dec_zone_page_state(req->wb_page, NR_UNSTABLE);
> +		if (req->wb_page)
> +			dec_zone_page_state(req->wb_page, NR_UNSTABLE);
>  	}
>  }
>  
> 
> 
-
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