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From: Anton Vorontsov <avorontsov@ru.mvista.com>
To: David Miller <davem@davemloft.net>
Cc: linuxppc-dev@ozlabs.org, netdev@vger.kernel.org,
	Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Subject: [PATCH 1/3] ucc_geth: Fix empty TX queue processing
Date: Thu, 24 Dec 2009 18:31:03 +0300	[thread overview]
Message-ID: <20091224153103.GA1206@oksana.dev.rtsoft.ru> (raw)
In-Reply-To: <20091224153034.GA32535@oksana.dev.rtsoft.ru>

Following oops was seen with the ucc_geth driver:

 Unable to handle kernel paging request for data at address 0x00000058
 Faulting instruction address: 0xc024f2fc
 Oops: Kernel access of bad area, sig: 11 [#1]
 [...]
 NIP [c024f2fc] skb_recycle_check+0x14/0x100
 LR [e30aa0a4] ucc_geth_poll+0xd8/0x4e0 [ucc_geth_driver]
 Call Trace:
 [df857d50] [c000b03c] __ipipe_grab_irq+0x3c/0xa4 (unreliable)
 [df857d60] [e30aa0a4] ucc_geth_poll+0xd8/0x4e0 [ucc_geth_driver]
 [df857dd0] [c0258cf8] net_rx_action+0xf8/0x1b8
 [df857e10] [c0032a38] __do_softirq+0xb8/0x13c
 [df857e60] [c00065cc] do_softirq+0xa0/0xac
 [...]

This is because ucc_geth_tx() tries to process an empty queue when
queues are logically stopped. Stopping the queues doesn't disable
polling, and since nowadays ucc_geth_tx() is actually called from
the polling routine, the oops above might pop up.

Fix this by removing 'netif_queue_stopped() == 0' check.

Reported-by: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Tested-by: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Cc: Stable <stable@vger.kernel.org> [2.6.32]
---
 drivers/net/ucc_geth.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index afaf088..0f8c99e 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -3273,7 +3273,7 @@ static int ucc_geth_tx(struct net_device *dev, u8 txQ)
 		/* Handle the transmitted buffer and release */
 		/* the BD to be used with the current frame  */
 
-		if ((bd == ugeth->txBd[txQ]) && (netif_queue_stopped(dev) == 0))
+		if (bd == ugeth->txBd[txQ]) /* queue empty? */
 			break;
 
 		dev->stats.tx_packets++;
-- 
1.6.3.3

WARNING: multiple messages have this Message-ID (diff)
From: Anton Vorontsov <avorontsov@ru.mvista.com>
To: David Miller <davem@davemloft.net>
Cc: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>,
	Li Yang <leoli@freescale.com>,
	netdev@vger.kernel.org, linuxppc-dev@ozlabs.org
Subject: [PATCH 1/3] ucc_geth: Fix empty TX queue processing
Date: Thu, 24 Dec 2009 18:31:03 +0300	[thread overview]
Message-ID: <20091224153103.GA1206@oksana.dev.rtsoft.ru> (raw)
In-Reply-To: <20091224153034.GA32535@oksana.dev.rtsoft.ru>

Following oops was seen with the ucc_geth driver:

 Unable to handle kernel paging request for data at address 0x00000058
 Faulting instruction address: 0xc024f2fc
 Oops: Kernel access of bad area, sig: 11 [#1]
 [...]
 NIP [c024f2fc] skb_recycle_check+0x14/0x100
 LR [e30aa0a4] ucc_geth_poll+0xd8/0x4e0 [ucc_geth_driver]
 Call Trace:
 [df857d50] [c000b03c] __ipipe_grab_irq+0x3c/0xa4 (unreliable)
 [df857d60] [e30aa0a4] ucc_geth_poll+0xd8/0x4e0 [ucc_geth_driver]
 [df857dd0] [c0258cf8] net_rx_action+0xf8/0x1b8
 [df857e10] [c0032a38] __do_softirq+0xb8/0x13c
 [df857e60] [c00065cc] do_softirq+0xa0/0xac
 [...]

This is because ucc_geth_tx() tries to process an empty queue when
queues are logically stopped. Stopping the queues doesn't disable
polling, and since nowadays ucc_geth_tx() is actually called from
the polling routine, the oops above might pop up.

Fix this by removing 'netif_queue_stopped() == 0' check.

Reported-by: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Tested-by: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Cc: Stable <stable@vger.kernel.org> [2.6.32]
---
 drivers/net/ucc_geth.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index afaf088..0f8c99e 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -3273,7 +3273,7 @@ static int ucc_geth_tx(struct net_device *dev, u8 txQ)
 		/* Handle the transmitted buffer and release */
 		/* the BD to be used with the current frame  */
 
-		if ((bd == ugeth->txBd[txQ]) && (netif_queue_stopped(dev) == 0))
+		if (bd == ugeth->txBd[txQ]) /* queue empty? */
 			break;
 
 		dev->stats.tx_packets++;
-- 
1.6.3.3


  reply	other threads:[~2009-12-24 15:31 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-24 15:30 [PATCH 0/3] ucc_geth: Some more fixes Anton Vorontsov
2009-12-24 15:31 ` Anton Vorontsov [this message]
2009-12-24 15:31   ` [PATCH 1/3] ucc_geth: Fix empty TX queue processing Anton Vorontsov
2009-12-24 15:31 ` [PATCH 2/3] ucc_geth: Fix netdev watchdog triggering on link changes Anton Vorontsov
2009-12-24 15:31   ` Anton Vorontsov
2009-12-24 15:31 ` [PATCH 3/3] ucc_geth: Don't needlessly change MAC settings in adjust_link() Anton Vorontsov
2009-12-24 15:31   ` Anton Vorontsov
2009-12-27  4:25 ` [PATCH 0/3] ucc_geth: Some more fixes David Miller
2009-12-27  4:25   ` David Miller
     [not found] <0A1FE637C2C7E148B9573BB60CC630E56C3E90@zch01exm26.fsl.freescale.net>
2010-01-11  3:47 ` [PATCH 1/3] ucc_geth: Fix empty TX queue processing Wu Jiajun-B06378
2010-01-11  3:47   ` Wu Jiajun-B06378
2010-01-11 10:52   ` Anton Vorontsov
2010-01-11 10:52     ` Anton Vorontsov
2010-01-11 11:52     ` Wu Jiajun-B06378
2010-01-11 11:52       ` Wu Jiajun-B06378
  -- strict thread matches above, loose matches on Subject: below --
2010-06-22 13:02 [stable] Please apply ucc_geth driver fixes to 2.6.32-stable Petri Lehtinen
2010-06-22 13:02 ` [PATCH 1/3] ucc_geth: Fix empty TX queue processing Petri Lehtinen

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