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From: John <jw@nuclearfallout.net>
To: David Miller <davem@davemloft.net>, eric.dumazet@gmail.com
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net] xps: must clear sender_cpu before forwarding
Date: Thu, 12 Mar 2015 19:36:38 -0700	[thread overview]
Message-ID: <55024D36.7040108@nuclearfallout.net> (raw)
In-Reply-To: <20150311.235134.2179029122534232611.davem@davemloft.net>

On 3/11/2015 8:51 PM, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Wed, 11 Mar 2015 18:42:02 -0700
>
>> From: Eric Dumazet <edumazet@google.com>
>>
>> John reported that my previous commit added a regression
>> on his router.
>>
>> This is because sender_cpu & napi_id share a common location,
>> so get_xps_queue() can see garbage and perform an out of bound access.
>>
>> We need to make sure sender_cpu is cleared before doing the transmit,
>> otherwise any NIC busy poll enabled (skb_mark_napi_id()) can trigger
>> this bug.
>>
>> Signed-off-by: Eric Dumazet <edumazet@google.com>
>> Reported-by: John <jw@nuclearfallout.net>
>> Bisected-by: John <jw@nuclearfallout.net>
>> Fixes: 2bd82484bb4c ("xps: fix xps for stacked devices")
> Applied, thanks Eric.

Running this patch, I have confirmed that I no longer see panics under 
the conditions that I saw them previously.

-John

  reply	other threads:[~2015-03-13  2:36 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <5500E52C.7080603@nuclearfallout.net>
     [not found] ` <CANn89iLHkYc2Kay7z+v=tHMW5aYSqUf8V4f70Z-d5fUuuUXnpw@mail.gmail.com>
2015-03-12  1:42   ` [PATCH net] xps: must clear sender_cpu before forwarding Eric Dumazet
2015-03-12  3:51     ` David Miller
2015-03-13  2:36       ` John [this message]
2015-03-13  2:53         ` David Miller
2015-03-13  2:57         ` Eric Dumazet
2015-03-12  5:21     ` John

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