netdev - Re: [PATCH] p54: Prevent from dereferencing null pointer when releasing SKB

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Date:   Thu, 20 Apr 2017 16:25:35 -0700
From:   Greg Rose <gvrose8192@...il.com>
To:     Myungho Jung <mhjungk@...il.com>
Cc:     edumazet@...gle.com, netdev@...r.kernel.org
Subject: Re: [PATCH] p54: Prevent from dereferencing null pointer when
 releasing SKB

On Thu, 2017-04-20 at 16:23 -0700, Myungho Jung wrote:
> On Thu, Apr 20, 2017 at 04:03:43PM -0700, Greg Rose wrote:
> > On Thu, 2017-04-20 at 11:25 -0700, Myungho Jung wrote:
> > > Added NULL check to make __dev_kfree_skb_irq consistent with kfree
> > > family of functions.
> > > 
> > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=195289
> > > 
> > > Signed-off-by: Myungho Jung <mhjungk@...il.com>
> > 
> > Hi,
> > 
> > I think the patch is fine but I'm confused by the subject.  You mention
> > p54 driver but the change is in dev.c.  I know the bugzilla references
> > the p54 but that's not where the change is.
> > 
> > Seems odd to me.
> > 
> > - Greg
> > 
> > > ---
> > >  net/core/dev.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > > 
> > > diff --git a/net/core/dev.c b/net/core/dev.c
> > > index 7869ae3..22be2a6 100644
> > > --- a/net/core/dev.c
> > > +++ b/net/core/dev.c
> > > @@ -2450,6 +2450,9 @@ void __dev_kfree_skb_irq(struct sk_buff *skb, enum skb_free_reason reason)
> > >  {
> > >  	unsigned long flags;
> > >  
> > > +	if (unlikely(!skb))
> > > +		return;
> > > +
> > >  	if (likely(atomic_read(&skb->users) == 1)) {
> > >  		smp_rmb();
> > >  		atomic_set(&skb->users, 0);
> > 
> > 
> > 
> 
> Hi Greg,
> 
> Thank you for checking my patch. I missed that I moved change from p54
> to net/dev. Do I need to resubmit patch v2 to modify subject?
> 
> Thanks,
> Myungho

Yes, I think that's the best idea.

Thanks,

- Greg