INFO: task kworker/u4:12:9340 blocked for more than 143 seconds. Not tainted 5.4.0-rc7-next-20191115 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:12 D28136 9340 2 0x80004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x8e1/0x1f30 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136 __flush_work+0x4fe/0xa50 kernel/workqueue.c:3041 flush_work+0x18/0x20 kernel/workqueue.c:3062 flush_all_backlogs net/core/dev.c:5489 [inline] rollback_registered_many+0x60e/0x10d0 net/core/dev.c:8729 unregister_netdevice_many.part.0+0x1b/0x1f0 net/core/dev.c:9907 unregister_netdevice_many+0x3b/0x50 net/core/dev.c:9906 ip6gre_exit_batch_net+0x53c/0x760 net/ipv6/ip6_gre.c:1604 ops_exit_list.isra.0+0x10c/0x160 net/core/net_namespace.c:175 cleanup_net+0x538/0xaf0 net/core/net_namespace.c:597 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 1 lock held by khungtaskd/1048: #0: ffffffff88faccc0 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/8749: #0: ffff88809899a420 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/8839: #0: ffff8880a0a96090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f312e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8840: #0: ffff8880a38ab090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f252e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8841: #0: ffff8880975fa090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f1d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8842: #0: ffff88809a117090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f152e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8843: #0: ffff8880a280c090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f392e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8844: #0: ffff8880a049a090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f352e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8845: #0: ffff888091d3b090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f092e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 5 locks held by kworker/u4:12/9340: #0: ffff8880a994ad28 ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880a994ad28 ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a994ad28 ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880a994ad28 ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880a994ad28 ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880a994ad28 ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880a994ad28 ((wq_completion)netns){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 #1: ffff888054bdfdc0 (net_cleanup_work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 #2: ffffffff899ae608 (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0xaf0 net/core/net_namespace.c:559 #3: ffffffff899ba940 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 #4: ffffffff88f62f50 (cpu_hotplug_lock.rw_sem){++++}, at: get_online_cpus include/linux/cpu.h:137 [inline] #4: ffffffff88f62f50 (cpu_hotplug_lock.rw_sem){++++}, at: flush_all_backlogs net/core/dev.c:5482 [inline] #4: ffffffff88f62f50 (cpu_hotplug_lock.rw_sem){++++}, at: rollback_registered_many+0x4e3/0x10d0 net/core/dev.c:8729 1 lock held by syz-executor.2/10842: #0: ffffffff899ba940 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1048 Comm: khungtaskd Not tainted 5.4.0-rc7-next-20191115 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:269 [inline] watchdog+0xc8f/0x1350 kernel/hung_task.c:353 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 11351 Comm: syz-executor.2 Not tainted 5.4.0-rc7-next-20191115 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:write_comp_data+0x1e/0x70 kernel/kcov.c:208 Code: 48 89 34 d1 48 89 11 5d c3 0f 1f 00 65 4c 8b 04 25 c0 1e 02 00 65 8b 05 e8 44 8e 7e a9 00 01 1f 00 75 51 41 8b 80 00 13 00 00 <83> f8 03 75 45 49 8b 80 08 13 00 00 45 8b 80 04 13 00 00 4c 8b 08 RSP: 0018:ffff888054a27840 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffff817e51f6 RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffff888054a27848 R08: ffff88805cc4e0c0 R09: ffffed10148fb282 R10: ffffed10148fb281 R11: ffff8880a47d940b R12: ffff8880a47d9408 R13: 0000000000000003 R14: ffffed10148fb281 R15: ffff888054a27918 FS: 00007f8c8edf0700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8c8ed68f88 CR3: 0000000008e6d000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: irq_work_sync+0x106/0x1d0 kernel/irq_work.c:193 _free_event+0x89/0x13b0 kernel/events/core.c:4584 put_event+0x47/0x60 kernel/events/core.c:4709 perf_event_release_kernel+0x6d5/0xd70 kernel/events/core.c:4824 perf_release+0x37/0x50 kernel/events/core.c:4834 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x904/0x2e60 kernel/exit.c:817 do_group_exit+0x135/0x360 kernel/exit.c:921 get_signal+0x47c/0x24f0 kernel/signal.c:2734 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a639 Code: Bad RIP value. RSP: 002b:00007f8c8edefc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: 0000000000010000 RBX: 0000000000000003 RCX: 000000000045a639 RDX: 0000000041395527 RSI: 0000000020000340 RDI: 0000000000000005 RBP: 000000000075c118 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8c8edf06d4 R13: 00000000004c7120 R14: 00000000004e2678 R15: 00000000ffffffff