> De : Evgeniy Polyakov <johnpol@2ka.mipt.ru>
> À : Nj A <nj_a83@yahoo.fr>
> Cc :
netdev@vger.kernel.org
> Envoyé le : Mercredi, 14 Novembre 2007, 12h13mn 05s
> Objet : Re: Bug in using inet_lookup ()
>
> On Wed, Nov 14, 2007 at 09:26:18AM +0000, Nj A (
nj_a83@yahoo.fr) wrote:
> > /* The kernel TCP hashtable */
> > struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
> > .lhash_lock = __RW_LOCK_UNLOCKED (tcp_hashinfo.lhash_lock),
> > .lhash_users = ATOMIC_INIT (0),
> > .lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER (tcp_hashinfo.lhash_wait),
> > };
> > ...
> > struct sock *sk;
> > struct sk_buff *skb;
> > skb = alloc_skb (MAX_TCP_HEADER + 15, GFP_KERNEL);
> > if (skb == NULL)
> > printk ("%s: Unable to allocate memory \n", __FUNCTION__);
> > sk = inet_lookup (&tcp_hashinfo, ip_src, src_port, ip_dst, dst_port, inet_iif
> (skb));
> > if (!sk)
> > ...
> > This portion of code seems to cause the kernel to panic due to dereferencing a
> NULL pointer.
> > Can anyone please tell me what is the error above?
> > Best Regards,
>
> Where exactly? Likely in inet_iif(), since it dereferences dst (routing
> info), which is not presented after simple alloc_skb().
> You have to setup skb correctly, check how ip_rcv() does it.
>
> --
> Evgeniy
> Polyakov
>