From: Stephen Hemminger <shemminger@linux-foundation.org>
To: David Miller <davem@davemloft.net>
Cc: takano@axe-inc.co.jp, netdev@vger.kernel.org,
ilpo.jarvinen@helsinki.fi, mchan@broadcom.com
Subject: Re: Regression in net-2.6.24?
Date: Thu, 11 Oct 2007 16:55:48 -0700 [thread overview]
Message-ID: <20071011165548.6545b207@freepuppy.rosehill> (raw)
In-Reply-To: <20071011.164827.64988925.davem@davemloft.net>
On Thu, 11 Oct 2007 16:48:27 -0700 (PDT)
David Miller <davem@davemloft.net> wrote:
> From: TAKANO Ryousei <takano@axe-inc.co.jp>
> Date: Thu, 11 Oct 2007 22:51:46 +0900 (JST)
>
> > Modules linked in: 8021q tcp_bic netconsole evdev joydev sg st sr_mod ohci_hcd i2c_amd756 i2c_amd8111 i2c_core ipv6 tg3 usbhid usbcore ff_memless dm_mod ext3 jbd sata_sil libata sd_mod scsi_mod
> ...
> > RIP points at __list_del (net_rx_action -> list_move_tail -> __list_del).
>
> There is a contract between the driver's ->poll() method and
> net_rx_action() in that it is assumed that if the entire quota has
> been used up, the driver will not perform a netif_rx_complete().
>
> It seems that in a corner case the tg3 driver, which you appear to be
> using, will not abide by this rule. That corner case is when the card
> has exactly "budget" receive packets pending. In such a case
> tg3_has_work() will be false, and we will RX complete when work_done
> >= budget, which violates the above mentioned rule.
>
> Can you see if the following test patch makes the crash go away?
>
> Michael, I know you're not pleased with this patch and neither am
> I. It might be better to just strictly RX complete when
> (work < budget) and if tg3_has_work(), trigger a HW interrupt.
>
> Alternatively we could loop in tg3_poll() until either budget
> is exhausted or tg3_has_work() returns false. Actually, this sounds
> like a cleaner scheme the more I think about it.
>
> BNX2 likely has a similar issue.
sky2 as well.
--
Stephen Hemminger <shemminger@linux-foundation.org>
next prev parent reply other threads:[~2007-10-11 23:56 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-09 12:19 [RFC PATCH net-2.6.24 0/3]: Attempt to fix lost_retrans brokeness Ilpo Järvinen
2007-10-09 12:20 ` [PATCH] [TCP]: Separate lost_retrans loop into own function Ilpo Järvinen
2007-10-09 12:20 ` [RFC PATCH] [TCP]: Fix lost_retrans loop vs fastpath problems Ilpo Järvinen
2007-10-09 12:20 ` [RFC PATCH] [TCP]: Limit processing lost_retrans loop to work-to-do cases Ilpo Järvinen
2007-10-10 9:44 ` David Miller
2007-10-10 9:44 ` David Miller
2007-10-11 1:55 ` [RFC PATCH] [TCP]: Fix lost_retrans loop vs fastpath problems TAKANO Ryousei
2007-10-11 10:12 ` Ilpo Järvinen
2007-10-11 13:51 ` Regression in net-2.6.24? TAKANO Ryousei
2007-10-11 23:48 ` David Miller
2007-10-11 23:55 ` Stephen Hemminger [this message]
2007-10-12 0:17 ` David Miller
2007-10-12 0:31 ` Stephen Hemminger
2007-10-12 0:40 ` David Miller
2007-10-12 0:50 ` Stephen Hemminger
2007-10-12 1:00 ` David Miller
2007-10-12 1:03 ` David Miller
2007-10-12 1:14 ` David Miller
2007-10-12 1:22 ` Stephen Hemminger
2007-10-12 1:25 ` David Miller
2007-10-12 3:17 ` Michael Chan
2007-10-12 2:40 ` David Miller
2007-10-12 8:54 ` Michael Chan
2007-10-12 8:39 ` David Miller
2007-10-12 10:22 ` TAKANO Ryousei
2007-10-12 10:56 ` David Miller
2007-10-10 9:45 ` [PATCH] [TCP]: Separate lost_retrans loop into own function David Miller
2007-10-09 13:03 ` [RFC PATCH net-2.6.24 0/3]: Attempt to fix lost_retrans brokeness Ilpo Järvinen
2007-10-10 9:48 ` David Miller
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