mpls: Use rcu_dereference_rtnl() in mpls_route_input_rcu().
In the Linux kernel, the following vulnerability has been resolved: mpls: Use rcu_dereference_rtnl() in mpls_route_input_rcu(). As syzbot reported [0], mpls_route_input_rcu() can be called from mpls_getroute(), where is under RTNL. net->mpls.platform_label is only updated under RTNL. Let's use rcu_dereference_rtnl() in mpls_route_input_rcu() to silence the splat. [0]: WARNING: suspicious RCU usage 6.15.0-rc7-syzkaller-00082-g5cdb2c77c4c3 #0 Not tainted ---------------------------- net/mpls/af_mpls.c:84 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock h