netdev - [PATCH net-next v3 04/32] net: Move mutex_unlock() in cleanup

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Message-ID: <151851399379.5034.2323658592354088065.stgit@localhost.localdomain>
Date:   Tue, 13 Feb 2018 12:26:33 +0300
From:   Kirill Tkhai <ktkhai@...tuozzo.com>
To:     davem@...emloft.net, vyasevic@...hat.com,
        kstewart@...uxfoundation.org, pombredanne@...b.com,
        vyasevich@...il.com, mark.rutland@....com,
        gregkh@...uxfoundation.org, adobriyan@...il.com, fw@...len.de,
        nicolas.dichtel@...nd.com, xiyou.wangcong@...il.com,
        roman.kapl@...go.com, paul@...l-moore.com, dsahern@...il.com,
        daniel@...earbox.net, lucien.xin@...il.com,
        mschiffer@...verse-factory.net, rshearma@...cade.com,
        netdev@...r.kernel.org, ktkhai@...tuozzo.com,
        ebiederm@...ssion.com, avagin@...tuozzo.com,
        gorcunov@...tuozzo.com, eric.dumazet@...il.com,
        stephen@...workplumber.org, ktkhai@...tuozzo.com
Subject: [PATCH net-next v3 04/32] net: Move mutex_unlock() in cleanup_net()
 up

net_sem protects from pernet_list changing, while
ops_free_list() makes simple kfree(), and it can't
race with other pernet_operations callbacks.

So we may release net_mutex earlier then it was.

Signed-off-by: Kirill Tkhai <ktkhai@...tuozzo.com>
Acked-by: Andrei Vagin <avagin@...tuozzo.com>
---
 net/core/net_namespace.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index e89b2b7abd36..f8453c438798 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -522,11 +522,12 @@ static void cleanup_net(struct work_struct *work)
 	list_for_each_entry_reverse(ops, &pernet_list, list)
 		ops_exit_list(ops, &net_exit_list);
 
+	mutex_unlock(&net_mutex);
+
 	/* Free the net generic variables */
 	list_for_each_entry_reverse(ops, &pernet_list, list)
 		ops_free_list(ops, &net_exit_list);
 
-	mutex_unlock(&net_mutex);
 	up_read(&net_sem);
 
 	/* Ensure there are no outstanding rcu callbacks using this