Re: linux-next NFSD: NULL pointer dereference at nfsd_svc()

["J. Bruce Fields" <bfields@fieldses.org>]

On Thu, Aug 05, 2010 at 10:10:16AM +0900, Tetsuo Handa wrote:
> J. Bruce Fields wrote:
> > Maybe figuring out exactly hwere that is would help work out what's
> > going on.  Doing
> > 
> > 	make net/sunrpc/svc.lst
> > 
> > then looking for c1356dd4 (or just mailing me svc.lst) could help.
> 
> "make net/sunrpc/svc.lst" failed due to following error.
> 
>   BFD: Dwarf Error: Abbrev offset (3238007024) greater than or equal to .debug_abbrev size (1607).
> 
> Manual printk() debug reported that
> rqstp->rq_argp == rqstp->rq_resp == ZERO_SIZE_PTR and

Huh.  As far as I can tell that will only happen if you've not no nfsd
versions defined; how is that happening?

--b.

> procp->pc_argsize == procp->pc_ressize == 4.
> 
> --- linux-2.6.35-next.orig/net/sunrpc/svc.c
> +++ linux-2.6.35-next/net/sunrpc/svc.c
> @@ -1084,6 +1084,11 @@ svc_process_common(struct svc_rqst *rqst
>  	procp->pc_count++;
> 
>  	/* Initialize storage for argp and resp */
> +	printk(KERN_INFO "rqstp=%p procp=%p\n", rqstp, procp);
> +	printk(KERN_INFO "rqstp->rq_argp=%p procp->pc_argsize=%u\n",
> +	       rqstp->rq_argp, procp->pc_argsize);
> +	printk(KERN_INFO "rqstp->rq_resp=%p procp->pc_ressize=%u\n",
> +	       rqstp->rq_resp, procp->pc_ressize);
>  	memset(rqstp->rq_argp, 0, procp->pc_argsize);
>  	memset(rqstp->rq_resp, 0, procp->pc_ressize);
>  
> 
> [   37.669174] NET: Registered protocol family 10
> [   38.080725] svc: failed to register lockdv1 RPC service (errno 97).
> [  122.895707] rqstp=dcb91000 procp=c154ca20
> [  122.896533] rqstp->rq_argp=00000010 procp->pc_argsize=4
> [  122.897484] rqstp->rq_resp=00000010 procp->pc_ressize=4
> [  122.898609] BUG: unable to handle kernel NULL pointer dereference at 00000010
> [  122.899964] IP: [<c1356e80>] svc_process_common+0x370/0x640
> [  122.900493] *pde = 00000000 
> [  122.900493] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
> [  122.923308] last sysfs file: /sys/devices/pci0000:00/0000:00:10.0/host0/target0:0:1/0:0:1:0/type
> [  122.923308] Modules linked in: nfs ipv6 pcnet32
> 
> > OK, I wonder if Sarge didn't yet mount the nfsd filesystem on
> > /proc/fs/nfsd.
> 
> According to /proc/mounts , the nfsd filesystem is not mounted on
> /proc/fs/nfsd . But mounting it manually before starting nfsd did not help.
> 
> Regards.