Messages in this thread | | | Date | Fri, 10 Dec 2010 12:18:45 -0800 (PST) | Subject | Re: unable to handle kernel NULL pointer dereference in skb_dequeue | From | David Miller <> |
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From: Denys Fedoryshchenko <nuclearcat@nuclearcat.com> Date: Fri, 10 Dec 2010 21:51:04 +0200
> On Friday 03 December 2010 16:46:35 Eric Dumazet wrote: >> Le vendredi 03 décembre 2010 à 15:37 +0100, Andrej Ota a écrit : >> > >> Patch that works for me is below. Now I only hope I haven't >> > >> (re)introduced a memory leak... >> > > >> > > Problem comes from commit 55c95e738da85 (fix return value of >> > > __pppoe_xmit() method) >> > > >> > > I am not sure patch is OK >> > >> > Me neither. That's why I wrote "works for me". All I dare say is that it >> > works better than current code and is probably no worse than it was >> > before above mentioned commit. Apart from that, there is no point in >> > having return value for __pppoe_xmit if return value isn't needed. >> > >> > Easiest way of triggering this BUG is by terminating PPPoE on the server >> > side, which then hits "if (!dev) { goto abort; }". This in turn calls >> > "kfree_skb(skb); return 0;" which returns to pppoe_rcv_core which then >> > goto-s to "abort_put" which again calls "kfree_skb(skb)". Voila the bug. >> > >> > I don't know how to trigger "if (skb_cow_head(skb, ..." to see if I have >> > just caused another BUG. However, if I read file comments at the top, I >> > see a comment from 19/07/01 stating that I have to delete original skb >> > if code succeeds and never delete it on failure. About the skb copy >> > mentioned in the same comment, I don't know. 2001 was many commits ago. >> >> Well, all I wanted to say was that _I_ was not sure, but probably other >> network guys have a better diagnostic. >> >> Rami, could you re-explain the rationale of your patch ? >> >> Thanks >> >> >> -- >> To unsubscribe from this list: send the line "unsubscribe netdev" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > Is there any plans to queue any patch to stable? > pppoe is almost dead in 2.6.36.*
I'll deal with it for -stable once I evaluate this patch for upstream, which I haven't even gotten to yet.
When people bark about -stable this and -stable that, it just takes more time away from me actually getting through all the patches. If it causes a crash, I know it should go to stable and I'll take care of it. So there is no need to make an explicit note or query about it.
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