[PATCH net 1/3] net: fealnx: fix teardown order in remove

["Жамбакиев Радий Рикардинович" <r.zhambakiev@prosoftsystems.ru>]

From: Radiy Zhambakiev <r.zhambakiev@prosoftsystems.ru>

fealnx_remove_one() frees the DMA rings before unregistering the
netdev, while the interface may still be up, which leaves a
window where freed memory can be accessed.

Call unregister_netdev() first so dev_close() stops the Tx/Rx
engines, deletes the timers, and frees the IRQ before the rings are
freed. While at it use dev_err() instead of printk() for the 
unknown-device case.

Found by Linux Verification Center (linuxtesting.org)

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Radiy Zhambakiev <r.zhambakiev@prosoftsystems.ru>
---
 drivers/net/ethernet/fealnx.c | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/fealnx.c b/drivers/net/ethernet/fealnx.c
index bdc38aac5850..d7cd1644a375 100644
--- a/drivers/net/ethernet/fealnx.c
+++ b/drivers/net/ethernet/fealnx.c
@@ -678,20 +678,23 @@ static int fealnx_init_one(struct pci_dev *pdev,
 static void fealnx_remove_one(struct pci_dev *pdev)
 {
 	struct net_device *dev = pci_get_drvdata(pdev);
+	struct netdev_private *np;
+
+	if (!dev) {
+		dev_err(&pdev->dev, "remove for unknown device\n");
+		return;
+	}
+
+	np = netdev_priv(dev);
 
-	if (dev) {
-		struct netdev_private *np = netdev_priv(dev);
-
-		dma_free_coherent(&pdev->dev, TX_TOTAL_SIZE, np->tx_ring,
-				  np->tx_ring_dma);
-		dma_free_coherent(&pdev->dev, RX_TOTAL_SIZE, np->rx_ring,
-				  np->rx_ring_dma);
-		unregister_netdev(dev);
-		pci_iounmap(pdev, np->mem);
-		free_netdev(dev);
-		pci_release_regions(pdev);
-	} else
-		printk(KERN_ERR "fealnx: remove for unknown device\n");
+	unregister_netdev(dev);
+	dma_free_coherent(&pdev->dev, TX_TOTAL_SIZE, np->tx_ring,
+			  np->tx_ring_dma);
+	dma_free_coherent(&pdev->dev, RX_TOTAL_SIZE, np->rx_ring,
+			  np->rx_ring_dma);
+	pci_iounmap(pdev, np->mem);
+	pci_release_regions(pdev);
+	free_netdev(dev);
 }
 
 
-- 
2.53.0