Subject: Re: [PATCH 1/9] net classifier: dont allow filters on semi-classful qdisc

From: Jarek Poplawski <[email-masked]>
Date: Sat, 07 Aug 2010 00:26:17 +0200

Stephen Hemminger wrote, On 06.08.2010 23:58:

> On Fri, 06 Aug 2010 23:24:47 +0200
> Jarek Poplawski <[email-masked]> wrote:
> 
>> Stephen Hemminger wrote, On -10.01.-28163 20:59:
>>
>>> There are several qdisc which only support a single class (sfq, mq, tbf)
>>> and the kernel would dereference a null pointer (bind_tcf), if a user
>>> attempted to apply a filter one of these classes.
>>
>>
>> mq and tbf can't have this issue because they don't have
>> .tcf_chain class method. sfq should support it on purpose
>> after this patch:
>>
>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=7d2681a6ff4f9ab5e48d02550b4c6338f1638998
>> and needs tiny fix only.
> 
> Probably best to fix both ways.  Fix sfq to allow filters to
> be chained, and fix API to prevent refuse to allow qdisc to
> register with tcf_chain && !bind_tcf
> 

Yes, but your patch needs a different changelog and I'm not sure
it's necessary for stable (there should be no other such cases
for now).

Jarek P.