[e1000 debug] KERNEL: assertion (!sk_forward_alloc) failed...

["Brandeburg, Jesse" <jesse.brandeburg@intel.com>]

Hi all, I've identified you as people who have at some point in the past
emailed one of the Linux lists with problems with e1000 and
sk_forward_alloc.  It seems to be fairly widespread, but only seems to
have appeared with recent kernel changes (after 2.6.12...)

What I need from you is a reproducible test, and some information.  I
have never been able to reproduce this, and I'm trying to isolate the
problem a bit.  What motherboards are you using?  What seems to cause
this problem?  Are you all using iptables?  Are you all routing? From
the reports I assume none of you are using an 82571/2/3 (pci express)

As far as I know e1000 has the same requirement as tg3 and some others
where we have to modify the header of the skb in the case of transmits
using TSO.  I don't see anywhere else that the driver modifies the skb.
Tomorrow I'll generate a patch to try a more paranoid copying of the
skb, I hope some of you can test.

To do this we have code like so in e1000_tso:
2529         if (skb_shinfo(skb)->tso_size) {
2530                 if (skb_header_cloned(skb)) {
2531                         err = pskb_expand_head(skb, 0, 0,
GFP_ATOMIC);
2532                         if (err)
2533                                 return err;
2534                 }
2535 
2536                 hdr_len = ((skb->h.raw - skb->data) +
(skb->h.th->doff << 2));
2537                 mss = skb_shinfo(skb)->tso_size;
2538                 if (skb->protocol == ntohs(ETH_P_IP)) {
2539                         skb->nh.iph->tot_len = 0;
2540                         skb->nh.iph->check = 0;

Thanks for your assistance

Jesse


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