2015-08-03 01:36:58

by Jia-Ju Bai

[permalink] [raw]
Subject: [PATCH]Fix a null dereference 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 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 adds a check to fix it.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/net/ethernet/intel/e1000e/netdev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 89d788d..838ec8e 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -2448,7 +2448,8 @@ 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 (tx_ring->head)
+ writel(0, tx_ring->head);
if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA)
e1000e_update_tdt_wa(tx_ring, 0);
else
--
1.7.9.5