From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: herbert@gondor.hengli.com.au, evonlanthen@gmail.com,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
timo.teras@iki.fi
Subject: Re: PROBLEM: System call 'sendmsg' of process ospfd (quagga) causes kernel oops
Date: Wed, 19 Oct 2011 09:18:33 +0200 [thread overview]
Message-ID: <1319008713.17914.8.camel@edumazet-laptop> (raw)
In-Reply-To: <20111019.030914.218521668377472155.davem@davemloft.net>
Le mercredi 19 octobre 2011 à 03:09 -0400, David Miller a écrit :
> From: Herbert Xu <herbert@gondor.hengli.com.au>
> Date: Tue, 18 Oct 2011 15:45:37 +0200
>
> > On Tue, Oct 18, 2011 at 02:56:00PM +0200, Eric Dumazet wrote:
> >>
> >> I am ok by this way, but we might hit another similar problem elsewhere.
> >>
> >> (igmp.c ip6_output, ...)
> >>
> >> We effectively want to remove LL_ALLOCATED_SPACE() usage and obfuscate
> >> code...
> >
> > Here's another idea, provide a helper to do the skb allocation
> > and the skb_reserve in one go. That way this ugliness would only
> > need to be done once.
>
> Someone please test this:
>
> --------------------
> net: Fix crashes on devices which dynamically change needed headroom.
>
> One such device is IP_GRE.
>
> The problem is that we evaluate the device characteristics twice, once
> to determine the allocation size, and once to do the skb_reserve().
>
> Combine these into one operation using a helper function.
>
> With help from Eric Dumazet and Herbert Xu.
>
> Reported-by: Reported-by: Elmar Vonlanthen <evonlanthen@gmail.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
>
Seems fine (Maybe do the +15 in caller site ?), but we also have other
problematic cases, using alloc_skb() only...
next prev parent reply other threads:[~2011-10-19 7:18 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CA+0Zf5Be5JUSvssH9CrDQq=jtETZr=veAPC7jriM8B-FZKbbpg@mail.gmail.com>
2011-10-14 14:57 ` PROBLEM: System call 'sendmsg' of process ospfd (quagga) causes kernel oops Eric Dumazet
2011-10-17 7:16 ` Elmar Vonlanthen
2011-10-18 2:30 ` Eric Dumazet
2011-10-18 9:34 ` Herbert Xu
2011-10-18 10:01 ` Eric Dumazet
2011-10-18 10:05 ` Herbert Xu
2011-10-18 10:23 ` Eric Dumazet
2011-10-18 10:45 ` Herbert Xu
2011-10-18 11:37 ` Eric Dumazet
2011-10-18 11:49 ` Herbert Xu
2011-10-18 12:56 ` Eric Dumazet
2011-10-18 13:45 ` Herbert Xu
2011-10-19 7:09 ` David Miller
2011-10-19 7:18 ` Eric Dumazet [this message]
2011-10-19 7:30 ` David Miller
2011-10-19 7:52 ` Eric Dumazet
2011-10-19 8:02 ` David Miller
2011-10-19 8:08 ` Herbert Xu
2011-10-20 9:30 ` David Miller
2011-10-20 9:35 ` Herbert Xu
2011-10-20 20:21 ` David Miller
2011-10-25 11:54 ` Herbert Xu
2011-10-26 3:12 ` David Miller
2011-11-18 12:18 ` [0/6] Replace LL_ALLOCATED_SPACE to allow needed_headroom adjustment Herbert Xu
2011-11-18 12:20 ` [PATCH 3/6] net: Remove all uses of LL_ALLOCATED_SPACE Herbert Xu
2011-11-18 12:20 ` [PATCH 2/6] ipv6: " Herbert Xu
2011-11-18 12:20 ` [PATCH 1/6] ipv4: " Herbert Xu
2011-11-18 12:20 ` [PATCH 4/6] net: Remove LL_ALLOCATED_SPACE Herbert Xu
2011-11-18 12:20 ` [PATCH 5/6] packet: Add needed_tailroom to packet_sendmsg_spkt Herbert Xu
2011-11-18 12:20 ` [PATCH 6/6] ip_gre: Set needed_headroom dynamically again Herbert Xu
2011-11-18 20:01 ` [0/6] Replace LL_ALLOCATED_SPACE to allow needed_headroom adjustment David Miller
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