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From: Ingo Molnar <mingo@elte.hu>
To: David Miller <davem@davemloft.net>
Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
	shemminger@linux-foundation.org, Jeff Garzik <jgarzik@pobox.com>
Subject: Re: WARNING: at net/core/dev.c:2161 net_rx_action()
Date: Tue, 16 Oct 2007 00:07:20 +0200	[thread overview]
Message-ID: <20071015220720.GA16101@elte.hu> (raw)
In-Reply-To: <20071015220357.GA7174@elte.hu>


* Ingo Molnar <mingo@elte.hu> wrote:

> > This is a driver bug, the work "budget" passed into a driver's 
> > ->poll() handler should never be exceeded.  That's what this warning 
> > assertion is checking.
> > 
> > What ethernet card is in your system and what driver is being used 
> > to drive it?
> 
> it's forcedeth.
> 
> i've checked nv_napi_poll(), and i dont see how it could return larger 
> than 'limit' number of packets.
> 
> it could return packets == limit though:
> 
>                 pkts = nv_rx_process_optimized(dev, budget);
> ...
> 
>         if (pkts < budget) {
>                 /* re-enable receive interrupts */
>                 spin_lock_irqsave(&np->lock, flags);
> 
>                 __netif_rx_complete(dev, napi);
> 
> ...
>         return pkts;
> 
> shouldnt that be "pkts <= budget"? But even that shouldnt cause a larger 
> than limit return. Weird.
> 
> there are two networking cards in the system, the other one is a:
> 
>   eth1: RealTek RTL8139 at 0xf080e000, 00:c0:df:03:68:5d, IRQ 11
>   eth1:  Identified 8139 chip type 'RTL-8139B'
> 
> but this one should be inactive (not plugged into the network). Should 
> i try to get a debug print out of the actual 'weight' and 'work' 
> integers, and of the n->poll function address?

ok, i've added such a patch.

looking at the dev.c code - can napi_struct->weight be zero 
legitimately? If yes then the 0 gets passed to the driver and the driver 
would return 1 - violating the assertion.

	Ingo

  reply	other threads:[~2007-10-15 22:07 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-15 11:24 WARNING: at net/core/dev.c:2161 net_rx_action() Ingo Molnar
2007-10-15 11:27 ` Ingo Molnar
2007-10-15 16:18   ` Ingo Molnar
2007-10-15 19:57 ` David Miller
2007-10-15 22:03   ` Ingo Molnar
2007-10-15 22:07     ` Ingo Molnar [this message]
2007-10-15 22:21       ` David Miller
2007-10-15 22:30       ` [patch] forcedeth: fix the NAPI poll function Ingo Molnar
2007-10-15 22:39         ` David Miller
2007-10-15 22:40         ` Jeff Garzik
2007-10-15 22:41           ` Jeff Garzik
2007-10-16  5:42           ` Ingo Molnar
2007-10-16  5:47             ` Jeff Garzik
2007-10-16  6:40               ` Ingo Molnar
2007-10-16  7:17                 ` Jeff Garzik
2007-10-16  7:49                   ` Ingo Molnar
2007-10-16 16:52                     ` Jeff Garzik
2007-10-16 21:20         ` Jeff Garzik
2007-10-17  7:25           ` Ingo Molnar
2007-10-17 10:18             ` [patch] forcedeth: fix the NAPI poll function, take #2 Ingo Molnar
2007-10-18  0:21               ` Jeff Garzik
2007-10-15 22:18     ` WARNING: at net/core/dev.c:2161 net_rx_action() David Miller
2007-10-15 22:20     ` Jeff Garzik

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