From: David Miller <davem@davemloft.net>
To: ast@plumgrid.com
Cc: jhs@mojatatu.com, daniel@iogearbox.net, jiri@resnulli.us,
netdev@vger.kernel.org
Subject: Re: [PATCH net-next] tc: fix tc actions in case of shared skb
Date: Sat, 11 Jul 2015 21:29:17 -0700 (PDT) [thread overview]
Message-ID: <20150711.212917.1463596559900301434.davem@davemloft.net> (raw)
In-Reply-To: <1436573411-5021-1-git-send-email-ast@plumgrid.com>
From: Alexei Starovoitov <ast@plumgrid.com>
Date: Fri, 10 Jul 2015 17:10:11 -0700
> TC actions need to check for very unlikely event skb->users != 1,
> otherwise subsequent pskb_may_pull/pskb_expand_head will crash.
> When skb_shared() just drop the packet, since in the middle of actions
> it's too late to call skb_share_check(), since classifiers/actions assume
> the same skb pointer.
>
> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
I think whatever creates this skb->users != 1 situation should be fixed,
they should clone the packet.
In fact, it would really help enormously if you could explain in detail
how this situation can actually arise. Especially since I do not consider
it acceptable to drop the packet in this situation.
Thanks.
next prev parent reply other threads:[~2015-07-12 4:29 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-11 0:10 [PATCH net-next] tc: fix tc actions in case of shared skb Alexei Starovoitov
2015-07-12 4:29 ` David Miller [this message]
2015-07-13 19:47 ` Alexei Starovoitov
2015-07-13 20:04 ` David Miller
2015-07-13 20:17 ` Alexei Starovoitov
2015-07-13 20:55 ` Daniel Borkmann
2015-07-13 22:26 ` Alexei Starovoitov
2015-07-14 10:29 ` Daniel Borkmann
2015-07-14 11:57 ` Jamal Hadi Salim
2015-07-14 12:19 ` Daniel Borkmann
2015-07-14 15:46 ` Alexei Starovoitov
2015-07-14 22:34 ` David Miller
2015-07-14 23:08 ` Alexei Starovoitov
2015-07-15 0:58 ` John Fastabend
2015-07-15 1:01 ` Alexei Starovoitov
2015-07-13 13:13 ` Jamal Hadi Salim
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