From 0845d45e900cad5f7f855a7a6a21c33477800b1f Mon Sep 17 00:00:00 2001 From: Jia-Ju Bai Date: Wed, 5 Aug 2015 18:16:10 +0800 Subject: [PATCH] e1000e: Modify Tx/Rx configurations to avoid null pointer dereferences in e1000_open When e1000e_setup_rx_resources is failed in e1000_open, e1000e_free_tx_resources in "err_setup_rx" segment is executed. "writel(0, tx_ring->head)" statement in e1000_clean_tx_ring in e1000e_free_tx_resources will cause a null poonter dereference(crash), because "tx_ring->head" is only assigned in e1000_configure_tx in e1000_configure, but it is after e1000e_setup_rx_resources. This patch moves head/tail register writing to e1000_configure_tx/rx, which can fix this problem. It is inspired by igb_configure_tx_ring in the igb driver. Specially, thank Alexander Duyck for his valuable suggestion. Signed-off-by: Jia-Ju Bai Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/e1000e/netdev.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c index 546b5da168dc..faf4b3f3d0b5 100644 --- a/drivers/net/ethernet/intel/e1000e/netdev.c +++ b/drivers/net/ethernet/intel/e1000e/netdev.c @@ -1737,12 +1737,6 @@ static void e1000_clean_rx_ring(struct e1000_ring *rx_ring) rx_ring->next_to_clean = 0; rx_ring->next_to_use = 0; adapter->flags2 &= ~FLAG2_IS_DISCARDING; - - writel(0, rx_ring->head); - if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA) - e1000e_update_rdt_wa(rx_ring, 0); - else - writel(0, rx_ring->tail); } static void e1000e_downshift_workaround(struct work_struct *work) @@ -2447,12 +2441,6 @@ static void e1000_clean_tx_ring(struct e1000_ring *tx_ring) tx_ring->next_to_use = 0; tx_ring->next_to_clean = 0; - - writel(0, tx_ring->head); - if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA) - e1000e_update_tdt_wa(tx_ring, 0); - else - writel(0, tx_ring->tail); } /** @@ -2954,6 +2942,12 @@ static void e1000_configure_tx(struct e1000_adapter *adapter) tx_ring->head = adapter->hw.hw_addr + E1000_TDH(0); tx_ring->tail = adapter->hw.hw_addr + E1000_TDT(0); + writel(0, tx_ring->head); + if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA) + e1000e_update_tdt_wa(tx_ring, 0); + else + writel(0, tx_ring->tail); + /* Set the Tx Interrupt Delay register */ ew32(TIDV, adapter->tx_int_delay); /* Tx irq moderation */ @@ -3275,6 +3269,12 @@ static void e1000_configure_rx(struct e1000_adapter *adapter) rx_ring->head = adapter->hw.hw_addr + E1000_RDH(0); rx_ring->tail = adapter->hw.hw_addr + E1000_RDT(0); + writel(0, rx_ring->head); + if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA) + e1000e_update_rdt_wa(rx_ring, 0); + else + writel(0, rx_ring->tail); + /* Enable Receive Checksum Offload for TCP and UDP */ rxcsum = er32(RXCSUM); if (adapter->netdev->features & NETIF_F_RXCSUM) -- 2.11.0