[IPV4]: fib_trie initialzation fix

In some kernel configs /proc functions seems to be accessed before the
trie is initialized. The patch below checks for this.

Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 2 deletions

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index e320b32373e5..8aa31fe514ee 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -50,7 +50,7 @@
  *              Patrick McHardy <kaber@trash.net>
  */
 
-#define VERSION "0.404"
+#define VERSION "0.405"
 
 #include <linux/config.h>
 #include <asm/uaccess.h>
@@ -2040,7 +2040,15 @@ rescan:
 static struct node *fib_trie_get_first(struct fib_trie_iter *iter,
                                        struct trie *t)
 {
-        struct node *n = rcu_dereference(t->trie);
+        struct node *n ;
+
+        if(!t)
+                return NULL;
+
+        n = rcu_dereference(t->trie);
+
+        if(!iter)
+                return NULL;
 
         if (n && IS_TNODE(n)) {
                 iter->tnode = (struct tnode *) n;