From mboxrd@z Thu Jan  1 00:00:00 1970
From: jamal <hadi@cyberus.ca>
Subject: Re: [BUG] net_cls: Panic occured when net_cls subsystem use
Date: Sat, 30 May 2009 07:56:34 -0400
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Cc: Minoru Usui <mi.usui@gmail.com>,
	Minoru Usui <usui@mxm.nes.nec.co.jp>, netdev@vger.kernel.org,
	containers@lists.linux-foundation.org
To: Jarek Poplawski <jarkao2@gmail.com>
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On Sat, 2009-05-30 at 13:45 +0200, Jarek Poplawski wrote:

> > > >       }
> > > >
> > > >       err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
> > > > -     if (err == 0)
> > > > +     if (err == 0) {
> > > > +             if (n->nlmsg_type == RTM_NEWTFILTER &&
> > > > +                 (n->nlmsg_flags&NLM_F_CREATE)) {
> 
> Since "tc filter replace" uses this type and flag too without creating
> tp, this check is not enough. I guess we could simply use a variable
> like tp_created etc. 

It will be superfluos. 
tp_created is the check
n->nlmsg_type == RTM_NEWTFILTER && n->nlmsg_flags&NLM_F_CREATE
replace will be
n->nlmsg_type == RTM_NEWTFILTER && n->nlmsg_flags & NLM_F_EXCL

> Anyway, changing this place looks tricky to me,
> so maybe it would be safer to do a separate cls_cgroup fix just for
> -stable, and this one patch for -next only?

I think they are two separate issues.
The fact that we dont destroy an allocated tp on failure is an issue
regardless of what cls_group does. In the case of Minoru's issue
it is because he is misconfiguring cls_group.

cheers,
jamal