FYI, we noticed the below changes on git://git.kernel.org/pub/scm/linux/kernel/git/horms/ipvs-next.git master commit 085db2c04557d31db61541f361bd8b4de92c9939 ("netfilter: Per network namespace netfilter hooks.") +--------------------------------------------------+------------+------------+ | | 0edcf282b0 | 085db2c045 | +--------------------------------------------------+------------+------------+ | boot_successes | 909 | 215 | | boot_failures | 1 | 15 | | BUG:kernel_test_hang | 1 | | | INFO:task_blocked_for_more_than#seconds | 0 | 15 | | EIP_is_at_default_send_IPI_mask_logical | 0 | 15 | | Kernel_panic-not_syncing:hung_task:blocked_tasks | 0 | 15 | | backtrace:reg_timeout_work | 0 | 11 | | backtrace:watchdog | 0 | 15 | | backtrace:cleanup_net | 0 | 4 | +--------------------------------------------------+------------+------------+ [ 240.093107] INFO: task kworker/u2:1:17 blocked for more than 120 seconds. [ 240.094412] Not tainted 4.2.0-rc2-00147-g085db2c #3 [ 240.095169] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 240.096140] kworker/u2:1 D b1b1d440 6844 17 2 0x00000000 [ 240.097163] Workqueue: netns cleanup_net [ 240.097907] c2987dd4 00000086 bf8ae680 b1b1d440 c296b000 00000000 c2988000 c296b000 [ 240.099855] c2987de4 b1718a1c 00000000 b1b72080 c2987dec b1718ce0 c2987e18 b171ad73 [ 240.102143] b1b720a4 00000246 c34b1e64 b1b720a4 c296b000 c2987dfc bede8b40 bede8b40 [ 240.103952] Call Trace: [ 240.104603] [<b1718a1c>] schedule+0x53/0x7b [ 240.105799] [<b1718ce0>] schedule_preempt_disabled+0x13/0x1b [ 240.107069] [<b171ad73>] mutex_lock_nested+0x22b/0x3dd [ 240.108871] [<b147d2da>] rtnl_lock+0x14/0x16 [ 240.115405] [<b14bfda9>] nf_queue_nf_hook_drop+0x12/0x9b [ 240.121794] [<b14be545>] nf_unregister_net_hook+0x125/0x134 [ 240.128473] [<b14bea09>] netfilter_net_exit+0x28/0x45 [ 240.131980] [<b1460d07>] ops_exit_list+0x61/0x6e [ 240.138438] [<b146228d>] cleanup_net+0x17a/0x1e9 [ 240.141807] [<b106eabb>] ? process_one_work+0x311/0x730 [ 240.149483] [<b106eba6>] process_one_work+0x3fc/0x730 [ 240.152593] [<b106f51d>] ? worker_thread+0x35/0x77d [ 240.161270] [<b106fa99>] worker_thread+0x5b1/0x77d [ 240.165669] [<b106f4e8>] ? max_active_store+0x5a/0x5a [ 240.169037] [<b1074c11>] kthread+0xe3/0xe8 [ 240.175216] [<b171e460>] ret_from_kernel_thread+0x20/0x30 [ 240.181989] [<b1074b2e>] ? kthread_create_on_node+0x1b6/0x1b6 [ 240.187791] 5 locks held by kworker/u2:1/17: [ 240.191200] #0: ("%s""netns"){......}, at: [<b106eabb>] process_one_work+0x311/0x730 [ 240.202113] #1: (net_cleanup_work){......}, at: [<b106eabb>] process_one_work+0x311/0x730 [ 240.211897] #2: (net_mutex){......}, at: [<b1462176>] cleanup_net+0x63/0x1e9 [ 240.221486] #3: (rtnl_mutex){......}, at: [<b147d2da>] rtnl_lock+0x14/0x16 [ 240.231105] #4: (rtnl_mutex){......}, at: [<b147d2da>] rtnl_lock+0x14/0x16 [ 240.237208] INFO: task kworker/u2:2:788 blocked for more than 120 seconds. [ 240.245612] Not tainted 4.2.0-rc2-00147-g085db2c #3 [ 240.251163] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 240.261207] kworker/u2:2 D b1b1d440 7124 788 2 0x00000000 [ 240.267688] Workqueue: events_power_efficient reg_check_chans_work [ 240.274290] bff75e24 00000086 bfe99b60 b1b1d440 bfe9e000 00000000 bff76000 bfe9e000 [ 240.284554] bff75e34 b1718a1c 00000000 b1b72080 bff75e3c b1718ce0 bff75e68 b171ad73 [ 240.292243] b1b720a4 00000246 b0331e88 c34b1e64 bfe9e000 bff75e4c b1b7f800 bfd7fa10 [ 240.302183] Call Trace: [ 240.305765] [<b1718a1c>] schedule+0x53/0x7b [ 240.308953] [<b1718ce0>] schedule_preempt_disabled+0x13/0x1b [ 240.317708] [<b171ad73>] mutex_lock_nested+0x22b/0x3dd [ 240.322027] [<b147d2da>] rtnl_lock+0x14/0x16 [ 240.325525] [<b167695e>] reg_check_chans_work+0x1d/0x44a [ 240.328688] [<b106eabb>] ? process_one_work+0x311/0x730 [ 240.334785] [<b106eba6>] process_one_work+0x3fc/0x730 [ 240.338101] [<b106f51d>] ? worker_thread+0x35/0x77d [ 240.342105] [<b106fa99>] worker_thread+0x5b1/0x77d [ 240.347328] [<b106f4e8>] ? max_active_store+0x5a/0x5a [ 240.351090] [<b1074c11>] kthread+0xe3/0xe8 [ 240.354570] [<b171e460>] ret_from_kernel_thread+0x20/0x30 [ 240.358949] [<b1074b2e>] ? kthread_create_on_node+0x1b6/0x1b6 [ 240.364724] 3 locks held by kworker/u2:2/788: [ 240.368484] #0: ("events_power_efficient"){......}, at: [<b106eabb>] process_one_work+0x311/0x730 [ 240.377346] #1: ((reg_check_chans).work){......}, at: [<b106eabb>] process_one_work+0x311/0x730 [ 240.385463] #2: (rtnl_mutex){......}, at: [<b147d2da>] rtnl_lock+0x14/0x16 ... Thanks, Ying Huang