FYI, we noticed the below changes on

https://github.com/lunn/linux.git v4.4-rc8-batman-netns
commit dd0fd6c66a2432322ebd996d6356db382028c7a0 ("batman-adv: debugfs: Add netns support")


+------------------------------------------------------+------------+------------+
|                                                      | 22994309f6 | dd0fd6c66a |
+------------------------------------------------------+------------+------------+
| boot_successes                                       | 120        | 126        |
| boot_failures                                        | 5          | 18         |
| WARNING:at_kernel/trace/ftrace.c:#ftrace_bug()       | 5          | 6          |
| backtrace:perf_ftrace_event_register                 | 5          | 6          |
| backtrace:perf_trace_init                            | 5          | 6          |
| backtrace:perf_tp_event_init                         | 5          | 6          |
| backtrace:perf_try_init_event                        | 5          | 6          |
| backtrace:SYSC_perf_event_open                       | 5          | 6          |
| backtrace:SyS_perf_event_open                        | 5          | 6          |
| is_trying_to_release_lock(batadv_debugfs_ns_mutex)at | 0          | 12         |
| backtrace:batadv_hardif_remove_interface_finish      | 0          | 12         |
+------------------------------------------------------+------------+------------+



[   45.722187] [ BUG: bad unlock balance detected! ]
[   45.723356] 4.4.0-rc8-00061-gdd0fd6c #195 Not tainted
[   45.724587] -------------------------------------
[   45.725766] kworker/u2:2/150 is trying to release lock (batadv_debugfs_ns_mutex) at:
[   45.728048] [<ffffffff82e2f085>] mutex_unlock+0xe/0x10
[   45.729328] but there are no more locks to release!
[   45.730573] 
[   45.730573] other info that might help us debug this:
[   45.732570] 2 locks held by kworker/u2:2/150:
[   45.733732]  #0:  ("%s""bat_events"){.+.+..}, at: [<ffffffff810ee1dd>] process_one_work+0x156/0x484
[   45.749452]  #1:  ((&hard_iface->cleanup_work)){+.+...}, at: [<ffffffff810ee1dd>] process_one_work+0x156/0x484
[   45.752254] 
[   45.752254] stack backtrace:
[   45.753922] CPU: 0 PID: 150 Comm: kworker/u2:2 Not tainted 4.4.0-rc8-00061-gdd0fd6c #195
[   45.756223] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[   45.758601] Workqueue: bat_events batadv_hardif_remove_interface_finish
[   45.760549]  0000000000000000 ffff880023d9bc68 ffffffff8173d814 ffff880023d946c0
[   45.762882]  ffff880023d9bc90 ffffffff81113453 00000000ffffffff ffff880023d946c0
[   45.765243]  ffffffff843d6990 ffff880023d9bd08 ffffffff81116433 ffff880023d946c0
[   45.767631] Call Trace:
[   45.768594]  [<ffffffff8173d814>] dump_stack+0x4b/0x63
[   45.769979]  [<ffffffff81113453>] print_unlock_imbalance_bug+0xc7/0xd0
[   45.771576]  [<ffffffff81116433>] lock_release+0x23f/0x41a
[   45.788280]  [<ffffffff811ee306>] ? kfree+0x101/0x15c
[   45.789710]  [<ffffffff82e2f085>] ? mutex_unlock+0xe/0x10
[   45.791123]  [<ffffffff82e2f01e>] __mutex_unlock_slowpath+0xd3/0x12c
[   45.792662]  [<ffffffff82e2f085>] mutex_unlock+0xe/0x10
[   45.794030]  [<ffffffff82e07cc9>] batadv_debugfs_ns_put+0x3d/0x4d
[   45.795530]  [<ffffffff82e0801d>] batadv_debugfs_del_hardif+0x4c/0x51
[   45.797080]  [<ffffffff82e09f09>] batadv_hardif_remove_interface_finish+0x19/0x2d
[   45.799315]  [<ffffffff810ee2d2>] process_one_work+0x24b/0x484
[   45.815632]  [<ffffffff810ee9b8>] worker_thread+0x1f5/0x2a7
[   45.817078]  [<ffffffff810ee7c3>] ? rescuer_thread+0x289/0x289
[   45.818516]  [<ffffffff810ee7c3>] ? rescuer_thread+0x289/0x289
[   45.830189]  [<ffffffff810f38a8>] kthread+0xc5/0xcd
[   45.831491]  [<ffffffff810f37e3>] ? kthread_parkme+0x24/0x24
[   45.832896]  [<ffffffff82e3145f>] ret_from_fork+0x3f/0x70
[   45.834250]  [<ffffffff810f37e3>] ? kthread_parkme+0x24/0x24
[   99.320313] Unregister pv shared memory for cpu 0
[   99.804560] reboot: Restarting system
[   99.805673] reboot: machine restart





Thanks,
Ying Huang