ehea: fix invalid pointer access

This patch fixes an invalid pointer access in case the receive queue
holds no pointer to the next skb when the queue is empty.

Signed-off-by: Hannes Hering <hering2@de.ibm.com>
Signed-off-by: Jan-Bernd Themann <themann@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 19 insertions, 14 deletions

diff --git a/drivers/net/ehea/ehea.h b/drivers/net/ehea/ehea.h
index 6e317caf429..16a41389575 100644
--- a/drivers/net/ehea/ehea.h
+++ b/drivers/net/ehea/ehea.h
@@ -40,7 +40,7 @@
 #include <asm/io.h>
 
 #define DRV_NAME        "ehea"
-#define DRV_VERSION     "EHEA_0100"
+#define DRV_VERSION     "EHEA_0101"
 
 /* eHEA capability flags */
 #define DLPAR_PORT_ADD_REM 1
diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
index 604c844d076..b22dab9153f 100644
--- a/drivers/net/ehea/ehea_main.c
+++ b/drivers/net/ehea/ehea_main.c
@@ -545,14 +545,17 @@ static inline struct sk_buff *get_skb_by_index(struct sk_buff **skb_array,
         x &= (arr_len - 1);
 
         pref = skb_array[x];
-        prefetchw(pref);
-        prefetchw(pref + EHEA_CACHE_LINE);
-
-        pref = (skb_array[x]->data);
-        prefetch(pref);
-        prefetch(pref + EHEA_CACHE_LINE);
-        prefetch(pref + EHEA_CACHE_LINE * 2);
-        prefetch(pref + EHEA_CACHE_LINE * 3);
+        if (pref) {
+                prefetchw(pref);
+                prefetchw(pref + EHEA_CACHE_LINE);
+
+                pref = (skb_array[x]->data);
+                prefetch(pref);
+                prefetch(pref + EHEA_CACHE_LINE);
+                prefetch(pref + EHEA_CACHE_LINE * 2);
+                prefetch(pref + EHEA_CACHE_LINE * 3);
+        }
+
         skb = skb_array[skb_index];
         skb_array[skb_index] = NULL;
         return skb;
@@ -569,12 +572,14 @@ static inline struct sk_buff *get_skb_by_index_ll(struct sk_buff **skb_array,
         x &= (arr_len - 1);
 
         pref = skb_array[x];
-        prefetchw(pref);
-        prefetchw(pref + EHEA_CACHE_LINE);
+        if (pref) {
+                prefetchw(pref);
+                prefetchw(pref + EHEA_CACHE_LINE);
 
-        pref = (skb_array[x]->data);
-        prefetchw(pref);
-        prefetchw(pref + EHEA_CACHE_LINE);
+                pref = (skb_array[x]->data);
+                prefetchw(pref);
+                prefetchw(pref + EHEA_CACHE_LINE);
+        }
 
         skb = skb_array[wqe_index];
         skb_array[wqe_index] = NULL;