On Sun, 2009-01-04 at 17:28 +0100, Andi Kleen wrote: > > Thanks, but I'll need to look at this in more detail, we need to make > > sure that we orphan the skb before > > What do you mean with orphaning the skb? Well, touching truesize is absolutely not allowed while the skb is charged to a socket. This is what causes the truesize warning. The thing we need to do is figure out is why the skb has a wrong truesize. > etc. And then, we need to check > > whether it makes sense to do this in pskb_expand_head(). > > Well whatever you do this short term patch is needed, there's no > reason to delay it. Given that we've had this problem for a very long time now I think there's no reason to rush a workaround now. I realise that we already have a workaround like this in the tx path which we added because I thought the tx path was the problem, but it still doesn't make much sense to work around it at all spots until we know why it is required. I think this patch similarly just papers over the problem with pskb_expand_head(). I haven't looked through all the code yet, but if anything then I think pskb_expand_head() should fix up truesize afterwards, and we should audit all other callers too. Similar problems exist in net/core/pktgen.c, drivers/net/wireless/libertas/rx.c, net/ipv4/netfilter.c and many more, though those seem to not run into trouble. Only a few users adjust truesize. Any proper fix should also verify that the skb isn't charged to a socket while it's being reallocated. johannes
Attachment:
signature.asc
Description: This is a digitally signed message part
