mctp: perform route destruction under RCU read lock
authorJeremy Kerr <jk@codeconstruct.com.au>
Wed, 8 Sep 2021 04:13:10 +0000 (12:13 +0800)
committerDavid S. Miller <davem@davemloft.net>
Wed, 8 Sep 2021 10:29:16 +0000 (11:29 +0100)
The kernel test robot reports:

  [  843.509974][  T345] =============================
  [  843.524220][  T345] WARNING: suspicious RCU usage
  [  843.538791][  T345] 5.14.0-rc2-00606-g889b7da23abf #1 Not tainted
  [  843.553617][  T345] -----------------------------
  [  843.567412][  T345] net/mctp/route.c:310 RCU-list traversed in non-reader section!!

- we're missing the rcu read lock acquire around the destruction path.

This change adds the acquire/release - the path is already atomic, and
we're using the _rcu list iterators.

Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/mctp/route.c

index 5265525..5ca186d 100644 (file)
@@ -1083,8 +1083,10 @@ static void __net_exit mctp_routes_net_exit(struct net *net)
 {
        struct mctp_route *rt;
 
+       rcu_read_lock();
        list_for_each_entry_rcu(rt, &net->mctp.routes, list)
                mctp_route_release(rt);
+       rcu_read_unlock();
 }
 
 static struct pernet_operations mctp_net_ops = {