fib:fix BUG_ON in fib_nl_newrule when add new fib rule

[ Upstream commit 561dac2d410ffac0b57a23b85ae0a623c1a076ca ]

add new fib rule can cause BUG_ON happen
the reproduce shell is
ip rule add pref 38
ip rule add pref 38
ip rule add to 192.168.3.0/24 goto 38
ip rule del pref 38
ip rule add to 192.168.3.0/24 goto 38
ip rule add pref 38

then the BUG_ON will happen
del BUG_ON and use (ctarget == NULL) identify whether this rule is unresolved

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 008dc70b064b3043cbf17fd4a63605db51d0fa94..f39ef5c6084b943c7cd69fd82b05072fb65b7ba5 100644 (file)
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -384,8 +384,8 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
                 */
                list_for_each_entry(r, &ops->rules_list, list) {
                        if (r->action == FR_ACT_GOTO &&
-                           r->target == rule->pref) {
-                               BUG_ON(rtnl_dereference(r->ctarget) != NULL);
+                           r->target == rule->pref &&
+                           rtnl_dereference(r->ctarget) == NULL) {
                                rcu_assign_pointer(r->ctarget, rule);
                                if (--ops->unresolved_rules == 0)
                                        break;