Re: [CHECKER] 84 bugs in 2.4.4/2.4.4-ac8 where NULL pointers are deref'd

[Steve Whitehouse <steve@gw.chygwyn.com>]

Hi,

> 
> 
> [ Steve: Just skim down to the decnet bug, you should have a look
>          at it.
> 
[various bits deleted]

Thanks for pointing this out. At first glance the problem is not where the
error says that it is since it should be impossible to get here with a NULL
neighbour cache entry (well we shouldn't be creating an output route without
a next hop :-)

I've got some other little DECnet fixes to forward shortly, but I'm probably
not going to get a chance to do so before the end of the week now so I'll
look at this properly and send fixes then,

Steve.

[DECnet bug report reproduced here for context]
>  > ---------------------------------------------------------
>  > [BUG] contradicts
>  > /u2/engler/mc/oses/linux/2.4.4/net/decnet/dn_route.c:808:dn_route_output_slow: ERROR:INTERNAL_NULL:798:808: [type=set] (set at line 798) Dereferencing NULL ptr "neigh" illegally! [val=1000]
>  > 	
>  > 	rt->key.saddr  = src;
>  > 	rt->rt_saddr   = src;
>  > 	rt->key.daddr  = dst;
>  > 	rt->rt_daddr   = dst;
>  > Start --->
>  > 	rt->key.oif    = neigh ? neigh->dev->ifindex : -1;
>  > 	rt->key.iif    = 0;
>  > 	rt->key.fwmark = 0;
>  > 
>  > 	rt->u.dst.neighbour = neigh;
>  > 	rt->u.dst.dev = neigh ? neigh->dev : NULL;
>  > 	rt->u.dst.lastuse = jiffies;
>  > 	rt->u.dst.output = dn_output;
>  > 	rt->u.dst.input  = dn_rt_bug;
>  > 
>  > Error --->
>  > 	if (dn_dev_islocal(neigh->dev, rt->rt_daddr))
>  > 		rt->u.dst.input = dn_nsp_rx;
>  > 
>  > 	hash = dn_hash(rt->key.saddr, rt->key.daddr);
> 
> Yeah, this one is wrong, I'll leave this to Steve Whitehouse though,
> the DecNET maintainer.
>