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 <baijiaju1990@163.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 546b5da..faf4b3f 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -1737,12 +1737,6 @@
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 @@
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 @@
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 @@
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)