From: Daniel Borkmann <dborkman@redhat•com>
To: David Laight <David.Laight@ACULAB•COM>
Cc: Atzm Watanabe <atzm@stratosphere•co.jp>,
netdev@vger•kernel.org,
Stephen Hemminger <stephen@networkplumber•org>,
Ben Hutchings <bhutchings@solarflare•com>,
David Miller <davem@davemloft•net>
Subject: Re: [PATCH v3 2/3] packet: fill the gap of TPACKET_ALIGNMENT with zeros
Date: Mon, 16 Dec 2013 11:22:35 +0100 [thread overview]
Message-ID: <52AED46B.3090601@redhat.com> (raw)
In-Reply-To: <AE90C24D6B3A694183C094C60CF0A2F6026B7491@saturn3.aculab.com>
On 12/16/2013 11:16 AM, David Laight wrote:
>>> + memset(h.h2->tp_padding, 0,
>>> + hdrlen - offsetof(struct tpacket2_hdr, tp_padding));
>
> What is wrong with 'sizeof h.h2->tp_padding' ?
> The compiler will probably inline the memset into a couple of word
> sized writes of zero - probably not measurable.
> Not zeroing them might be leaking kernel memory contents (depends
> where the memory came from - might just be stale packet data).
The ring buffer memory we're operating on comes from mmap(2) btw.
> David
>
>
>
next prev parent reply other threads:[~2013-12-16 10:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-16 8:12 [PATCH v3 2/3] packet: fill the gap of TPACKET_ALIGNMENT with zeros Atzm Watanabe
2013-12-16 10:09 ` Daniel Borkmann
2013-12-16 10:16 ` David Laight
2013-12-16 10:22 ` Daniel Borkmann [this message]
2013-12-16 12:41 ` Atzm Watanabe
2013-12-16 12:55 ` Daniel Borkmann
2013-12-16 16:48 ` Atzm Watanabe
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