Re: [Linux-ATM-General] Fwd: Re: [PATCH] pppoatm carrier status

[Karl H. <ka...@hi...>]

On 09/22/10 16:21, chas williams - CONTRACTOR wrote:
> On Tue, 21 Sep 2010 21:19:45 -0700
> Philip Prindeville <phi...@re...> wrote:
> 
> 
>> BUG: unable to handle kernel NULL pointer dereference at 00000090
> 
> like it said, null pointer dereference.  i.e. (null)->something
> 
>> IP: [<e0133050>] :ppp_generic:ppp_channel_carrier_on+0x16/0x31
> 
> very early in ppp_channel_carrier_on() which means it is likely
> 'struct channel *pch = chan->ppp;' where chan is null for some reason.
> there could be an ordering issue here.  pvcc->chan might not be
> assigned by the time the event is ready to fire.  it is reasonable to
> expect that the carrier status of the hardware device will change
> before the vcc is even assigned to the ppp layer.
> 
> 

Yeah, thats exactly what it is. The last version of the patch i sent
checks "if (pch->ppp)"

in pppoatm when ppp_register_channel() is called the PPP channel is not
yet connected so pch->ppp is null.