This reverts commit fdeba99b1e58ecd18c2940c453e19e4ef20ff591.

The commit caused to another deadlock as syzbot reported:
======================================================
WARNING: possible circular locking dependency detected
5.9.0-rc2-next-20200828-syzkaller #0 Not tainted
------------------------------------------------------
kworker/u4:6/349 is trying to acquire lock:
ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: 
flush_workqueue+0xe1/0x13e0 kernel/workqueue.c:2777

but task is already holding lock:
ffffffff8a879430 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xb10 
net/core/net_namespace.c:565

[...]
 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(pernet_ops_rwsem);
                               lock(&sb->s_type->i_mutex_key#13);
                               lock(pernet_ops_rwsem);
  lock((wq_completion)events);

 *** DEADLOCK ***
[...]

We need to find out another solution to fix the original issue.

Reported-by: syzbot+d5aa7e0385f6a5d0f...@syzkaller.appspotmail.com
Fixes: fdeba99b1e58 ("tipc: fix use-after-free in tipc_bcast_get_mode")
Signed-off-by: Hoang Huu Le <hoang.h...@dektech.com.au>
---
 net/tipc/core.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/net/tipc/core.c b/net/tipc/core.c
index 37d8695548cf..4f6dc74adf45 100644
--- a/net/tipc/core.c
+++ b/net/tipc/core.c
@@ -109,11 +109,6 @@ static void __net_exit tipc_exit_net(struct net *net)
 {
        tipc_detach_loopback(net);
        tipc_net_stop(net);
-
-       /* Make sure the tipc_net_finalize_work stopped
-        * before releasing the resources.
-        */
-       flush_scheduled_work();
        tipc_bcast_stop(net);
        tipc_nametbl_stop(net);
        tipc_sk_rht_destroy(net);
-- 
2.25.1



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