From: John Fastabend <john.fastabend@gmail.com>
To: eric.dumazet@gmail.com
Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: [PATCH net] net: sched: fix panic in rate estimators
Date: Sat, 31 Jan 2015 20:45:02 -0800 [thread overview]
Message-ID: <54CDAF4E.7040402@gmail.com> (raw)
In-Reply-To: <20150131.175520.1521332119325954392.davem@davemloft.net>
On 01/31/2015 05:55 PM, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Thu, 29 Jan 2015 17:30:12 -0800
>
>> From: Eric Dumazet <edumazet@google.com>
>>
>> Doing the following commands on a non idle network device
>> panics the box instantly, because cpu_bstats gets overwritten
>> by stats.
>>
>> tc qdisc add dev eth0 root <your_favorite_qdisc>
>> ... some traffic (one packet is enough) ...
>> tc qdisc replace dev eth0 root est 1sec 4sec <your_favorite_qdisc>
> ...
>> Lets play safe and not use an union : percpu 'pointers' are mostly read
>> anyway, and we have typically few qdiscs per host.
>>
>> Signed-off-by: Eric Dumazet <edumazet@google.com>
>> Cc: John Fastabend <john.fastabend@gmail.com>
>> Fixes: 22e0f8b9322c ("net: sched: make bstats per cpu and estimator RCU safe")
>
> Applied and queued up for -stable, thanks Eric.
>
Thanks Eric, looks like my "replace" test scripts never sent traffic
before the replace call.
Also I haven't seen any RCU splats in awhile so I'll send out a patch
to drop the qdisc_lock on ing_filter shortly.
--
John Fastabend Intel Corporation
prev parent reply other threads:[~2015-02-01 4:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-30 1:30 [PATCH net] net: sched: fix panic in rate estimators Eric Dumazet
2015-02-01 1:55 ` David Miller
2015-02-01 4:45 ` John Fastabend [this message]
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