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From: Johannes Berg <johannes@sipsolutions.net>
To: David Miller <davem@davemloft.net>
Cc: eric@regit.org, netdev@vger.kernel.org,
	linux-wireless@vger.kernel.org, linville@tuxdriver.com
Subject: Re: [RFC PATCH] af_packet: don't to defrag shared skb
Date: Fri, 07 Dec 2012 22:41:42 +0100	[thread overview]
Message-ID: <1354916502.9124.18.camel@jlt4.sipsolutions.net> (raw)
In-Reply-To: <1354915824.9124.11.camel@jlt4.sipsolutions.net> (sfid-20121207_223020_561049_DB965D43)

On Fri, 2012-12-07 at 22:30 +0100, Johannes Berg wrote:

> The only other theory I can come up with right now is that the skb_get()
> happens in deliver_skb via __netif_receive_skb. Keeping in mind that
> wpa_supplicant might have another packet socket open for authentication
> packets, that seems like a possibility. I'll test it once I figure out
> how to do this "defrag" option you speak of :)

Hmm now I'm venturing into the unknown (for me) and realm of
speculation...

wpa_supplicant opens a packet socket for ETH_P_EAPOL, which indirectly
eventually calls dev_add_pack(). But if you do the same for another
socket, you'll get the same again, and then deliver_skb() will deliver
only a refcounted packet to the prot_hook->func().

This seems like it could very well cause the problem?

johannes

  reply	other threads:[~2012-12-07 21:41 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-07 18:56 [RFC PATCH] af_packet: don't to defrag shared skb Eric Leblond
2012-12-07 19:10 ` David Miller
2012-12-07 20:31 ` David Miller
2012-12-07 20:42   ` Johannes Berg
2012-12-07 20:54   ` Eric Leblond
2012-12-07 21:30   ` Johannes Berg
2012-12-07 21:41     ` Johannes Berg [this message]
     [not found]       ` <1354916502.9124.18.camel-8Nb76shvtaUJvtFkdXX2HixXY32XiHfO@public.gmane.org>
2012-12-07 22:12         ` Johannes Berg
2012-12-07 22:23           ` Johannes Berg
     [not found]             ` <1354919017.9124.33.camel-8Nb76shvtaUJvtFkdXX2HixXY32XiHfO@public.gmane.org>
2012-12-10  9:29               ` Johannes Berg
2012-12-10  9:41                 ` [PATCH] ipv4: ip_check_defrag must not modify skb before unsharing Johannes Berg
2012-12-10 11:02                   ` Eric Leblond
2012-12-10 18:41                   ` David Miller
2012-12-10 18:45                     ` Johannes Berg
     [not found]                       ` <1355165152.8083.4.camel-8Nb76shvtaUJvtFkdXX2HixXY32XiHfO@public.gmane.org>
2012-12-10 18:50                         ` David Miller
2012-12-07 21:46     ` [RFC PATCH] af_packet: don't to defrag shared skb Eric Leblond
2012-12-07 21:56       ` Johannes Berg

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