net: set fib rule refcount after malloc

The configure callback of fib_rules_ops can change the refcnt of a
fib rule. For instance, mlxsw takes a refcnt when adding the processing
of the rule to a work queue. Thus the rule refcnt can not be reset to
to 1 afterwards. Move the refcnt setting to after the allocation.

Fixes: 5361e209 ("net: avoid one splat in fib_nl_delrule()")
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/fib_rules.c

@@ -400,6 +400,7 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 		err = -ENOMEM;
 		goto errout;
 	}
+	refcount_set(&rule->refcnt, 1);
 	rule->fr_net = net;
 
 	rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
@@ -517,8 +518,6 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 		last = r;
 	}
 
-	refcount_set(&rule->refcnt, 1);
-
 	if (last)
 		list_add_rcu(&rule->list, &last->list);
 	else