datapath: ovs_ct_exit to be done under ovs_lock

Upstream commit:
    commit 27de77cec985233bdf6546437b9761853265c505
    Author: Tonghao Zhang <xiangxia.m.yue@gmail.com>
    Date:   Fri Apr 17 02:57:31 2020 +0800

    net: openvswitch: ovs_ct_exit to be done under ovs_lock

    syzbot wrote:
    | =============================
    | WARNING: suspicious RCU usage
    | 5.7.0-rc1+ #45 Not tainted
    | -----------------------------
    | net/openvswitch/conntrack.c:1898 RCU-list traversed in non-reader section!!
    |
    | other info that might help us debug this:
    | rcu_scheduler_active = 2, debug_locks = 1
    | ...
    |
    | stack backtrace:
    | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
    | Workqueue: netns cleanup_net
    | Call Trace:
    | ...
    | ovs_ct_exit
    | ovs_exit_net
    | ops_exit_list.isra.7
    | cleanup_net
    | process_one_work
    | worker_thread

    To avoid that warning, invoke the ovs_ct_exit under ovs_lock and add
    lockdep_ovsl_is_held as optional lockdep expression.

Link: https://lore.kernel.org/lkml/000000000000e642a905a0cbee6e@google.com
    Fixes: 11efd5cb04a1 ("openvswitch: Support conntrack zone limit")
    Cc: Pravin B Shelar <pshelar@ovn.org>
    Cc: Yi-Hung Wei <yihung.wei@gmail.com>
    Reported-by: syzbot+7ef50afd3a211f879112@syzkaller.appspotmail.com
    Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
    Acked-by: Pravin B Shelar <pshelar@ovn.org>
    Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Fixes: cb2a5486a3a3 ("datapath: conntrack: Support conntrack zone limit")
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Acked-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

diff --git a/datapath/conntrack.c b/datapath/conntrack.c
index c7a318baf282cc48547671fd891f80c4522eb7ea..50b4d7bd6aa0aa1c630c6438495068c56c5fb0b6 100644 (file)
--- a/datapath/conntrack.c
+++ b/datapath/conntrack.c
@@ -1984,7 +1984,8 @@ static void ovs_ct_limit_exit(struct net *net, struct ovs_net *ovs_net)
                struct hlist_head *head = &info->limits[i];
                struct ovs_ct_limit *ct_limit;
 
-               hlist_for_each_entry_rcu(ct_limit, head, hlist_node)
+               hlist_for_each_entry_rcu(ct_limit, head, hlist_node,
+                                        lockdep_ovsl_is_held())
                        kfree_rcu(ct_limit, rcu);
        }
        kfree(ovs_net->ct_limit_info->limits);

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 8e9b9a706194ac3a7112f47d35dc90c41d53ab03..b88d16107cbfc74ec8f931285278f9fcbcd9028c 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -2572,8 +2572,10 @@ static void __net_exit ovs_exit_net(struct net *dnet)
 
        ovs_netns_frags6_exit(dnet);
        ovs_netns_frags_exit(dnet);
-       ovs_ct_exit(dnet);
        ovs_lock();
+
+       ovs_ct_exit(dnet);
+
        list_for_each_entry_safe(dp, dp_next, &ovs_net->dps, list_node)
                __dp_destroy(dp);