[PATCH] e1000: zero-out pointers in e1000_free_desc_rings

In e1000_free_desc_rings, zero-out pointers after the memory they
point to is freed.  The test rings are static and get re-used, and
failures during subsequent test setups can cause e1000_free_desc_rings
to get called with dirty pointers.  Dirty pointers can cause oopses
or crashes...

Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/net/e1000/e1000_ethtool.c b/drivers/net/e1000/e1000_ethtool.c
index 8584e9382c2c..8646914964e7 100644
--- a/drivers/net/e1000/e1000_ethtool.c
+++ b/drivers/net/e1000/e1000_ethtool.c
@@ -960,13 +960,21 @@ e1000_free_desc_rings(struct e1000_adapter *adapter)
                 }
         }
 
-        if(txdr->desc)
+        if(txdr->desc) {
                 pci_free_consistent(pdev, txdr->size, txdr->desc, txdr->dma);
-        if(rxdr->desc)
+                txdr->desc = NULL;
+        }
+        if(rxdr->desc) {
                 pci_free_consistent(pdev, rxdr->size, rxdr->desc, rxdr->dma);
+                rxdr->desc = NULL;
+        }
 
         kfree(txdr->buffer_info);
+        txdr->buffer_info = NULL;
+
         kfree(rxdr->buffer_info);
+        rxdr->buffer_info = NULL;
+
         return;
 }