ipv4: fix a race in update_or_create_fnhe()

nh_exceptions is effectively used under rcu, but lacks proper
barriers. Between kzalloc() and setting of nh->nh_exceptions(),
we need a proper memory barrier.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 4895c771c7f00 ("ipv4: Add FIB nexthop exceptions.")
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 9922093..f30fd55 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -87,7 +87,7 @@ struct fib_nh {
        int                     nh_saddr_genid;
        struct rtable __rcu * __percpu *nh_pcpu_rth_output;
        struct rtable __rcu     *nh_rth_input;
-       struct fnhe_hash_bucket *nh_exceptions;
+       struct fnhe_hash_bucket __rcu *nh_exceptions;
 };
 
 /*

diff --cc net/ipv4/fib_semantics.c
Simple merge

diff --cc net/ipv4/route.c
Simple merge