From: Stephen Hemminger <shemminger@linux-foundation.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>, Jeff Dike <jdike@addtoit.com>,
David Miller <davem@davemloft.net>
Subject: Re: [PATCH] net: fix race in process_backlog
Date: Wed, 3 Oct 2007 09:15:26 -0700 [thread overview]
Message-ID: <20071003091526.2c1c6c1d@freepuppy.rosehill> (raw)
In-Reply-To: <1191426293.5599.27.camel@lappy>
On Wed, 03 Oct 2007 17:44:53 +0200
Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> Subject: net: fix race in process_backlog
>
> The recent NAPI rework (4fa57c9ea9f36f9ca852f3a88ca5d2f1aebbc960)
> introduced a race between netif_rx() and process_backlog() which
> resulted in softirq processing to drop dead.
>
> netif_rx() process_backlog()
>
> irq_disable();
> skb = __skb_dequeue();
> irq_enable();
>
> irq_disable();
> __skb_queue_tail();
> napi_schedule();
> irq_enable();
>
> if (!skb)
> napi_complete(); <-- oops!
>
> we cleared the napi bit, even though there is data to process.
>
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Stephen Hemminger <shemminger@linux-foundation.org>
--
Stephen Hemminger <shemminger@linux-foundation.org>
next prev parent reply other threads:[~2007-10-03 16:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-03 15:44 [PATCH] net: fix race in process_backlog Peter Zijlstra
2007-10-03 16:15 ` Stephen Hemminger [this message]
2007-10-03 21:58 ` David Miller
2007-10-03 22:05 ` Stephen Hemminger
2007-10-03 23:39 ` David Miller
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