fib_trie: remove potential out of bound access
[ Upstream commit aab515d7c32a34300312416c50314e755ea6f765 ]
AddressSanitizer [1] dynamic checker pointed a potential
out of bound access in leaf_walk_rcu()
We could allocate one more slot in tnode_new() to leave the prefetch()
in-place but it looks not worth the pain.
Bug added in commit 82cfbb008572b ("[IPV4] fib_trie: iterator recode")
[1] :
https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 49616fe..6e8a13d 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -71,7 +71,6 @@
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
-#include <linux/prefetch.h>
#include <linux/export.h>
#include <net/net_namespace.h>
#include <net/ip.h>
@@ -1761,10 +1760,8 @@
if (!c)
continue;
- if (IS_LEAF(c)) {
- prefetch(rcu_dereference_rtnl(p->child[idx]));
+ if (IS_LEAF(c))
return (struct leaf *) c;
- }
/* Rescan start scanning in new node */
p = (struct tnode *) c;