netdev - Re: [PATCH net-next] myri10ge: fix truesize underestimation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4EA08CCB.8030207@myri.com>
Date:	Thu, 20 Oct 2011 17:04:11 -0400
From:	Andrew Gallatin <gallatin@...i.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	Jon Mason <mason@...i.com>, David Miller <davem@...emloft.net>,
	netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next] myri10ge: fix truesize underestimation

On 10/20/11 16:59, Eric Dumazet wrote:
> Le jeudi 20 octobre 2011 à 16:45 -0400, Andrew Gallatin a écrit :
>> On 10/20/11 16:44, Eric Dumazet wrote:
>>> Le jeudi 20 octobre 2011 à 15:33 -0500, Jon Mason a écrit :
>>>> On Thu, Oct 20, 2011 at 3:10 PM, Eric Dumazet<eric.dumazet@...il.com>   wrote:
>>>>> skb->truesize must account for allocated memory, not the used part of
>>>>> it. Doing this work is important to avoid unexpected OOM situations.
>>>>>
>>>>> Signed-off-by: Eric Dumazet<eric.dumazet@...il.com>
>>>>
>>>> Acked-by: Jon Mason<mason@...i.com>
>>>
>>> Thanks for reviewing Jon !
>>>
>>>
>>
>> Please wait a second..  I think the patch is incorrect.
>>
>> There is already code in myri10ge_rx_skb_build() which
>> attempts to set the truesize.  However, it sets it to
>> the used, rather than the allocated size so it is apparently
>> incorrect.
>>
>> I'd prefer we fix that code.
>
> Well, I believe I did exactly that :)
>
> truesize of initial skb is fine.
>
> Then for everay frag added, you must add to skb-truesize the allocated
> memory for this frag.
>
> You add frags of a given size (small or big)
>
> In the end, its truesize += bytes * number_of_frags
>
> (bytes being small_size or big_size)
>
>

OK, I'm feeling foolish.  I somehow missed the first hunk
of your patch (some local change made it not apply cleanly, and
I did not notice that).

Yes, your patch is correct.  Sorry for the hassle!


Acked-by: Andrew Gallatin <gallatin@...i.com>
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html