Hi Alex,
On ti, 2014-12-09 at 19:42 +0100, Alexander Aring wrote:
> Hi Jukka,
>
> On Tue, Dec 09, 2014 at 04:05:49PM +0200, Jukka Rissanen wrote:
> > Hi Alex,
> >
> > On ti, 2014-12-09 at 12:52 +0100, Alexander Aring wrote:
> > > Hi Jukka,
> > >
> > > On Tue, Dec 09, 2014 at 01:28:16PM +0200, Jukka Rissanen wrote:
> > > > Hi Alex,
> > > >
> > > > the module unloading caused some issues in the receiving end.
> > > >
> > > > I tried this:
> > > > * setup bluetooth 6lowpan connection
> > > > * transfer some UDP data
> > > > * unload the nhc_rfc6282_udp module (in one peer only, the other still
> > > > had udp nhc module loaded)
> > > > * try to send more data
> > > >
> > > > This caused kernel crash in peer that had udp module unloaded:
> > > >
> > > >
> > >
> > > mhh, okay. I don't know why this happens also the log gave me not much
> > > information, but thanks anyway.
> > >
> > > Maybe this is a global issue with bluetooth 6LoWPAN error handling.
> > >
> > > Can you simple do something like this:
> > >
> > > diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
> > > index 32ffec6..2228dce 100644
> > > --- a/net/6lowpan/iphc.c
> > > +++ b/net/6lowpan/iphc.c
> > > @@ -425,6 +425,8 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
> > > return -EINVAL;
> > > }
> > >
> > > + return -EINVAL;
> > > +
> > > /* UDP data uncompression */
> > > if (iphc0 & LOWPAN_IPHC_NH_C) {
> > > struct udphdr uh;
> > >
> > >
> > > based on current bluetooth-next/master without the NHC framework.
> > >
> > > This should be working, maybe you never hit any error while calling
> > > lowpan_header_decompress function. It's simple testing the error
> > > handling not more.
> >
> > Hmm, I get the same crash here also without this patchset. So something
> > goes wrong if <0 code is returned.
> >
>
> Okay, do you already working on it?
Yes, I will investigate this.
>
> > >
> > > Do this please on one node, the other node should send some 6LoWPAN IPHC
> > > packets to check if the error handling working there.
> > >
> > >
> > >
> > >
> > >
> > > Another issue is that I see that skb->dev isn't set before calling
> > > lowpan_header_decompress. Because inside your log is a "NULL":
> > >
> > > (NULL net_device): received unknown nhc id which was not found.
> > >
> > > Can you change that? That skb->dev is set to before calling
> > > lowpan_header_decompress.
> >
> > I am setting the skb->dev after the call to lowpan_header_decompress().
> > And anyway the skb->dev is only used when printing the err.
> > Actually should we replace the skb->dev in lowpan_header_decompress()
> > with plain dev as that is given to the function as a parameter.
> >
>
> Ok, how we introduce this now? You wanna add this do the patch series for
> fixing the above issue, or should I add it to my patch series for
> introduce nhc framework?
I am fine with either. If you have time, please go ahead and send a
patch or I can do it also after figuring what is causing the crash.
Cheers,
Jukka
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