From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jia-Ju Bai" <baijiaju1990@163.com>
Subject: [PATCH] e1000 in linux-3.18.0: a potential bug
Date: Sat, 20 Dec 2014 15:50:43 +0800
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Cc: <linux.nics@intel.com>, <e1000-devel@lists.sourceforge.net>
To: <todd.fujinaka@intel.com>, <netdev@vger.kernel.org>
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I have actually tested e1000 driver on the real hardware(Intel 82540EM PCI
Gigabit Ethernet Controller), and find a potential bug:
The target file is drivers/net/ethernet/intel/e1000/e1000_main.c, which is
used to build e1000.ko.

(1) In the normal process, netif_napi_add is called in e1000_probe, but
netif_napi_del is not called in e1000_remove. However, many other ethernet
card drivers call them in pairs, even in the error handling paths, such as
r8169 and igb.

Meanwhile, I also write the patch to fix the bug. I have run the patch on
the hardware, it can work normally and fix the above bug.

diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c
b/drivers/net/ethernet/intel/e1000/e1000_main.c
index 24f3986..f6def7b 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -1004,7 +1004,7 @@ static int e1000_probe(struct pci_dev *pdev, const
struct pci_device_id *ent)
 	/* make ready for any if (hw->...) below */
 	err = e1000_init_hw_struct(adapter, hw);
 	if (err)
-		goto err_sw_init;
+		goto err_dma;
 
 	/* there is a workaround being applied below that limits
 	 * 64-bit DMA addresses to 64-bit hardware.  There are some
@@ -1239,8 +1239,9 @@ err_eeprom:
 		iounmap(hw->flash_address);
 	kfree(adapter->tx_ring);
 	kfree(adapter->rx_ring);
-err_dma:
 err_sw_init:
+	netif_napi_del(&adapter->napi);
+err_dma:
 err_mdio_ioremap:
 	iounmap(hw->ce4100_gbe_mdio_base_virt);
 	iounmap(hw->hw_addr);
@@ -1271,6 +1272,7 @@ static void e1000_remove(struct pci_dev *pdev)
 	e1000_down_and_stop(adapter);
 	e1000_release_manageability(adapter);
 
+	netif_napi_del(&adapter->napi);
 	unregister_netdev(netdev);
 
 	e1000_phy_hw_reset(hw);

Thanks!