From: Jeff Garzik <jgarzik@pobox.com>
To: Tobias DiPasquale <toby@cbcg.net>
Cc: netdev@oss.sgi.com, linux-net@vger.kernel.org,
linux-kernel@vger.kernel.org, coreteam@netfilter.org,
netfilter@lists.netfilter.org, akpm@zip.com.au, davem@redhat.com,
kuznet@ms2.inr.ac.ru, pekkas@netcore.fi,
jmorris@intercode.com.au, yoshfuji@linux-ipv6.org
Subject: Re: [PATCH] kfree_skb() bug in 2.4.22
Date: Wed, 08 Oct 2003 09:09:48 -0400 [thread overview]
Message-ID: <3F840C9C.9050704@pobox.com> (raw)
In-Reply-To: <1065617075.1514.29.camel@localhost>
Tobias DiPasquale wrote:
> Hi all,
>
> I was debugging one of my iptables/netfilter modules yesterday and I
> came across this bug in kfree_skb(). One of my functions returns a
> struct skbuff * on success and NULL on failure. When it failed, the code
> calling said function attempted to free the struct skbuff *, which at
> that point was NULL. This produced a kernel panic. I investigated the
> problem and found that, not only should I be checking for a NULL pointer
> when freeing the struct skbuff *, but the actual cause of the panic was
> because kfree_skb() and kfree_skb_fast() do not check for skb==NULL,
> either. They immediately attempt to dereference the users field of the
> struct skbuff * in order to decrement that reference counter.
I would prefer that you fix your code instead, to not pass NULL to
kfree_skb()...
next prev parent reply other threads:[~2003-10-08 13:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-08 12:44 [PATCH] kfree_skb() bug in 2.4.22 Tobias DiPasquale
2003-10-08 13:09 ` Jeff Garzik [this message]
2003-10-08 13:47 ` David S. Miller
2003-10-10 12:53 ` Ingo Oeser
2003-10-10 13:00 ` David S. Miller
2003-10-10 15:43 ` Ingo Oeser
2003-10-10 16:57 ` Dan Kegel
2003-10-08 14:11 ` Tobias DiPasquale
2003-10-08 14:11 ` David S. Miller
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