IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_team: link becomes ready INFO: task kworker/u4:4:4034 blocked for more than 120 seconds. Not tainted 4.9.101-gaef17a5 #29 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:4 D28280 4034 2 0x00000000 Workqueue: events_unbound flush_to_ldisc ffff8801d706e000 ffff8801c5e49a40 ffff88018b6b4fc0 ffff8801c4bb3000 ffff8801db221b98 ffff8801d5507908 ffffffff839e39bd ffff8801d706e8c8 ffffed003ae0dd18 ffff8801d706e000 00fffc0000000000 ffff8801db222468 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3557 [] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3590 [] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621 [] flush_echoes drivers/tty/n_tty.c:799 [inline] [] __receive_buf drivers/tty/n_tty.c:1617 [inline] [] n_tty_receive_buf_common+0xcfd/0x2300 drivers/tty/n_tty.c:1711 [] n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1746 [] tty_ldisc_receive_buf+0xaf/0x190 drivers/tty/tty_buffer.c:455 [] receive_buf drivers/tty/tty_buffer.c:474 [inline] [] flush_to_ldisc+0x253/0x370 drivers/tty/tty_buffer.c:533 [] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092 [] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Showing all locks held in the system: 2 locks held by khungtaskd/519: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 2 locks held by getty/3651: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133 6 locks held by kworker/u4:4/4034: #0: ("events_unbound"){.+.+.+}, at: [] work_static include/linux/workqueue.h:186 [inline] #0: ("events_unbound"){.+.+.+}, at: [] set_work_data kernel/workqueue.c:617 [inline] #0: ("events_unbound"){.+.+.+}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: ("events_unbound"){.+.+.+}, at: [] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085 #1: ((&buf->work)){+.+...}, at: [] process_one_work+0x728/0x1500 kernel/workqueue.c:2089 #2: (&tty->ldisc_sem){++++++}, at: [] tty_ldisc_ref+0x20/0x80 drivers/tty/tty_ldisc.c:296 #3: (&port->buf.lock/1){+.+...}, at: [] flush_to_ldisc+0x86/0x370 drivers/tty/tty_buffer.c:505 #4: (&o_tty->termios_rwsem/1){++++..}, at: [] n_tty_receive_buf_common+0x8b/0x2300 drivers/tty/n_tty.c:1674 #5: (&ldata->output_lock){+.+...}, at: [] flush_echoes drivers/tty/n_tty.c:799 [inline] #5: (&ldata->output_lock){+.+...}, at: [] __receive_buf drivers/tty/n_tty.c:1617 [inline] #5: (&ldata->output_lock){+.+...}, at: [] n_tty_receive_buf_common+0xcfd/0x2300 drivers/tty/n_tty.c:1711 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.101-gaef17a5 #29 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d889fd08 ffffffff81eb1009 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffffffff810b7da0 ffff8801d889fd40 ffffffff81ebc307 0000000000000000 0000000000000000 0000000000000003 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6b4/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6906 Comm: syz-executor7 Not tainted 4.9.101-gaef17a5 #29 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801c9b68000 task.stack: ffff8801c1198000 RIP: 0010:[] c [] __write_once_size include/linux/compiler.h:272 [inline] RIP: 0010:[] c [] __sanitizer_cov_trace_pc+0x4b/0x50 kernel/kcov.c:108 RSP: 0018:ffff8801c119f898 EFLAGS: 00000246 RAX: 0000000000040000 RBX: ffffc90010dd9000 RCX: ffffc90003d40000 RDX: 0000000000040000 RSI: ffffffff82118c21 RDI: ffffc90010ddb20a RBP: ffff8801c119f898 R08: ffff8801c9b68938 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000849cb7faa R13: 0000000000006656 R14: dffffc0000000000 R15: 0000000849cb7fab FS: 00007ffa3b25f700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1bf3499000 CR3: 00000001c76a6000 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8801c119f910c ffffffff82118c21c 0000000000000000c ffff8801c9b688b4c ffffc90010ddb278c ffffed0038372295c ffff8801c1b914acc ffffc90010dd9020c 0000000000000000c ffff8801c1b91100c ffffc90010dd9000c ffff8801c1b91100c Call Trace: [] echo_buf drivers/tty/n_tty.c:146 [inline] [] __process_echoes+0x611/0x780 drivers/tty/n_tty.c:735 [] commit_echoes+0x147/0x1b0 drivers/tty/n_tty.c:766 [] n_tty_receive_char_special+0xd64/0x2860 drivers/tty/n_tty.c:1286 [] n_tty_receive_buf_fast drivers/tty/n_tty.c:1579 [inline] [] __receive_buf drivers/tty/n_tty.c:1613 [inline] [] n_tty_receive_buf_common+0x18ea/0x2300 drivers/tty/n_tty.c:1711 [] n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1740 [] tiocsti drivers/tty/tty_io.c:2314 [inline] [] tty_ioctl+0xc8f/0x2270 drivers/tty/tty_io.c:2905 [] vfs_ioctl fs/ioctl.c:43 [inline] [] file_ioctl fs/ioctl.c:493 [inline] [] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677 [] SYSC_ioctl fs/ioctl.c:694 [inline] [] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685 [] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Code: c8b c90 c80 c12 c00 c00 c83 cfa c02 c75 c20 c48 c8b c88 c88 c12 c00 c00 c8b c80 c84 c12 c00 c00 c48 c8b c11 c48 c83 cc2 c01 c48 c39 cd0 c76 c07 c48 c89 c34 cd1 c48 c89 c11 c<5d> cc3 c0f c1f c00 c55 c48 c89 ce5 c41 c57 c41 c56 c41 c55 c41 c54 c53 c48 c89 cf3 c