From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Rose Subject: Re: [PATCH] p54: Prevent from dereferencing null pointer when releasing SKB Date: Thu, 20 Apr 2017 16:03:43 -0700 Message-ID: <1492729423.17866.6.camel@gmail.com> References: <1492712723-9350-1-git-send-email-mhjungk@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: edumazet@google.com, netdev@vger.kernel.org To: Myungho Jung Return-path: Received: from mail-io0-f195.google.com ([209.85.223.195]:35823 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755185AbdDTXDr (ORCPT ); Thu, 20 Apr 2017 19:03:47 -0400 Received: by mail-io0-f195.google.com with SMTP id d203so22072762iof.2 for ; Thu, 20 Apr 2017 16:03:47 -0700 (PDT) In-Reply-To: <1492712723-9350-1-git-send-email-mhjungk@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: 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 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);