From: Eric Dumazet <eric.dumazet@gmail.com>
To: Aaron Williams <awilliams@atheros.com>
Cc: netdev@vger.kernel.org
Subject: Re: skb allocation size question
Date: Wed, 01 Sep 2010 21:04:45 +0200 [thread overview]
Message-ID: <1283367885.2484.16.camel@edumazet-laptop> (raw)
In-Reply-To: <201009011151.02639.awilliams@atheros.com>
Le mercredi 01 septembre 2010 à 11:51 -0700, Aaron Williams a écrit :
> Hi,
>
> I have been trying to track down an issue in one of our drivers with SKB
> allocation and in my research I came across something that seems a bit
> strange. In __alloc_skb, a block for the data allocates size + sizeof(struct
> skb_shared_info) bytes, yet skb->truesize is set to size + sizeof(struct
> sk_buff). Is there a reason for this discrepancy?
Hi Aaron
Not really. We also could add in truesize the sizeof(struct
skb_shared_info).
Including sizeof(struct sk_buff) is enough to prevent a malicious user
filling kernel memory with skb of one byte of payload.
Problem is, adding this extra overhead could slowdown some applications,
using too small RCVBUF / SNDBUF settings.
prev parent reply other threads:[~2010-09-01 19:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-01 18:51 skb allocation size question Aaron Williams
2010-09-01 19:04 ` Eric Dumazet [this message]
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