unregister_netdevice: waiting for lo to become free. Usage count = 2 unregister_netdevice: waiting for lo to become free. Usage count = 2 unregister_netdevice: waiting for lo to become free. Usage count = 2 unregister_netdevice: waiting for lo to become free. Usage count = 2 unregister_netdevice: waiting for lo to become free. Usage count = 2 INFO: task syz-executor5:27032 blocked for more than 120 seconds. Not tainted 4.16.0-rc7+ #367 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D21408 27032 4236 0x00000004 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 io_schedule+0x1c/0x70 kernel/sched/core.c:5115 wait_on_page_bit_common+0x4b3/0x770 mm/filemap.c:1099 wait_on_page_bit mm/filemap.c:1132 [inline] wait_on_page_writeback include/linux/pagemap.h:546 [inline] __filemap_fdatawait_range+0x282/0x430 mm/filemap.c:533 filemap_fdatawait_keep_errors+0x2a/0xb0 mm/filemap.c:600 fdatawait_one_bdev+0x50/0x70 fs/sync.c:95 iterate_bdevs+0x109/0x260 fs/block_dev.c:2162 sys_sync+0x120/0x1c0 fs/sync.c:117 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x454879 RSP: 002b:00007fcf3c070c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007fcf3c0716d4 RCX: 0000000000454879 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000626 R14: 00000000006fa430 R15: 0000000000000000 Showing all locks held in the system: 4 locks held by kworker/1:1/23: #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000cf3e46ba>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000cf3e46ba>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000cf3e46ba>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000cf3e46ba>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: ((work_completion)(&cw->work)){+.+.}, at: [<00000000f50f8e16>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<000000006ac450d3>] get_online_cpus include/linux/cpu.h:124 [inline] #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<000000006ac450d3>] memcg_create_kmem_cache+0x16/0x170 mm/slab_common.c:619 #3: (slab_mutex){+.+.}, at: [<000000000d6f8825>] memcg_create_kmem_cache+0x24/0x170 mm/slab_common.c:622 2 locks held by khungtaskd/800: #0: (rcu_read_lock){....}, at: [<000000006b88855d>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000006b88855d>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000133cbfc8>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 2 locks held by getty/4157: #0: (&tty->ldisc_sem){++++}, at: [<00000000c7219e42>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000047c4e215>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4158: #0: (&tty->ldisc_sem){++++}, at: [<00000000c7219e42>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000047c4e215>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4159: #0: (&tty->ldisc_sem){++++}, at: [<00000000c7219e42>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000047c4e215>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4160: #0: (&tty->ldisc_sem){++++}, at: [<00000000c7219e42>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000047c4e215>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4161: #0: (&tty->ldisc_sem){++++}, at: [<00000000c7219e42>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000047c4e215>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4162: #0: (&tty->ldisc_sem){++++}, at: [<00000000c7219e42>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000047c4e215>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4163: #0: (&tty->ldisc_sem){++++}, at: [<00000000c7219e42>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000047c4e215>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 4 locks held by kworker/1:4/6711: #0: ((wq_completion)"cgroup_destroy"){+.+.}, at: [<00000000cf3e46ba>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"cgroup_destroy"){+.+.}, at: [<00000000cf3e46ba>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"cgroup_destroy"){+.+.}, at: [<00000000cf3e46ba>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"cgroup_destroy"){+.+.}, at: [<00000000cf3e46ba>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: ((work_completion)(&css->destroy_work)#3){+.+.}, at: [<00000000f50f8e16>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<00000000b58f55af>] get_online_cpus include/linux/cpu.h:124 [inline] #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<00000000b58f55af>] memcg_destroy_kmem_caches+0xf/0x80 mm/slab_common.c:771 #3: (slab_mutex){+.+.}, at: [<00000000523c5c7d>] memcg_destroy_kmem_caches+0x24/0x80 mm/slab_common.c:774 4 locks held by kworker/0:5/7149: #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000cf3e46ba>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000cf3e46ba>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000cf3e46ba>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000cf3e46ba>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: ((work_completion)(&cw->work)){+.+.}, at: [<00000000f50f8e16>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<000000006ac450d3>] get_online_cpus include/linux/cpu.h:124 [inline] #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<000000006ac450d3>] memcg_create_kmem_cache+0x16/0x170 mm/slab_common.c:619 #3: (slab_mutex){+.+.}, at: [<000000000d6f8825>] memcg_create_kmem_cache+0x24/0x170 mm/slab_common.c:622 4 locks held by kworker/u4:15/21907: #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000cf3e46ba>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000cf3e46ba>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000cf3e46ba>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000cf3e46ba>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: (net_cleanup_work){+.+.}, at: [<00000000f50f8e16>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (net_mutex){+.+.}, at: [<000000007787165c>] cleanup_net+0x242/0xcb0 net/core/net_namespace.c:484 #3: (rcu_sched_state.barrier_mutex){+.+.}, at: [<000000002eef97ae>] _rcu_barrier+0x142/0x750 kernel/rcu/tree.c:3517 3 locks held by kworker/u4:20/21938: #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000cf3e46ba>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000cf3e46ba>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000cf3e46ba>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000cf3e46ba>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: [<00000000f50f8e16>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (&type->s_umount_key#33){++++}, at: [<000000003719505c>] trylock_super+0x20/0x100 fs/super.c:395 1 lock held by blkid/26338: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000e850a77f>] blkdev_put+0x2a/0x4f0 fs/block_dev.c:1808 1 lock held by syz-executor5/27032: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000592da4a5>] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2160 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 800 Comm: khungtaskd Not tainted 4.16.0-rc7+ #367 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x123/0x180 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10402 Comm: kworker/0:6 Not tainted 4.16.0-rc7+ #367 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: cgroup_destroy css_free_work_fn RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline] RIP: 0010:compound_head include/linux/page-flags.h:142 [inline] RIP: 0010:virt_to_head_page include/linux/mm.h:617 [inline] RIP: 0010:qlink_to_cache mm/kasan/quarantine.c:127 [inline] RIP: 0010:qlist_move_cache+0x8d/0xf0 mm/kasan/quarantine.c:276 RSP: 0018:ffff880197a570c8 EFLAGS: 00000086 RAX: ffffea0006d6c500 RBX: 000077ff80000000 RCX: ffff8801b5b143c0 RDX: ffff8801b0d77c40 RSI: ffff880197a570e8 RDI: ffffffff885ed218 RBP: ffff880197a570d8 R08: ffffea0007329260 R09: 0000000080000000 R10: ffff8801aecdf1e0 R11: ffffea0000000000 R12: ffffea0006da23df R13: ffffffff86fd55a0 R14: ffffffff885ef2a0 R15: ffff8801b0d77c40 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 0000000006e22004 CR4: 00000000001606f0 DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: quarantine_remove_cache+0x79/0xf0 mm/kasan/quarantine.c:317 kasan_cache_shutdown+0x9/0x10 mm/kasan/kasan.c:381 shutdown_cache+0x15/0x1b0 mm/slab_common.c:577 memcg_destroy_kmem_caches+0x62/0x80 mm/slab_common.c:781 memcg_free_kmem mm/memcontrol.c:2856 [inline] mem_cgroup_css_free+0x2a4/0x3f0 mm/memcontrol.c:4298 css_free_work_fn+0x1c8/0x1420 kernel/cgroup/cgroup.c:4541 process_one_work+0xc47/0x1bb0 kernel/workqueue.c:2113 worker_thread+0x223/0x1990 kernel/workqueue.c:2247 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406 Code: 89 d1 48 01 47 10 4d 85 d2 74 5c 48 89 c8 4c 8b 11 4c 01 c8 72 62 49 89 d8 4c 01 c0 48 c1 e8 0c 48 c1 e0 06 4c 01 d8 4c 8b 40 20 <4d> 8d 60 ff 41 83 e0 01 49 0f 45 c4 48 8b 40 30 48 39 c2 75 a4