ipv4: Add a missing rcu_assign_pointer() in routing cache.
rt_intern_hash() is doing an update of a RCU guarded hash chain
without using rcu_assign_pointer() or equivalent barrier.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index a6d7c58..8d23cc7 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1109,7 +1109,12 @@
printk("\n");
}
#endif
- rt_hash_table[hash].chain = rt;
+ /*
+ * Since lookup is lockfree, we must make sure
+ * previous writes to rt are comitted to memory
+ * before making rt visible to other CPUS.
+ */
+ rcu_assign_pointer(rt_hash_table[hash].chain, rt);
spin_unlock_bh(rt_hash_lock_addr(hash));
*rp = rt;
return 0;