INFO: task kworker/u4:3:1200 blocked for more than 120 seconds. Not tainted 4.13.0-rc6+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:3 D14000 1200 2 0x00000000 Workqueue: kkcmd kcm_tx_work Call Trace: context_switch kernel/sched/core.c:2771 [inline] __schedule+0x8e8/0x2070 kernel/sched/core.c:3332 schedule+0x108/0x440 kernel/sched/core.c:3391 __lock_sock+0x1dc/0x2f0 net/core/sock.c:2245 lock_sock_nested+0xf3/0x110 net/core/sock.c:2766 lock_sock include/net/sock.h:1459 [inline] kcm_sendpage+0x16e/0x1880 net/kcm/kcmsock.c:774 kernel_sendpage+0x8d/0xe0 net/socket.c:3387 kcm_write_msgs+0x404/0x1b80 net/kcm/kcmsock.c:646 kcm_tx_work+0x2e/0x190 net/kcm/kcmsock.c:731 process_one_work+0xbf3/0x1bc0 kernel/workqueue.c:2097 worker_thread+0x223/0x1860 kernel/workqueue.c:2231 kthread+0x35e/0x430 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:425 Showing all locks held in the system: 2 locks held by khungtaskd/635: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0xd2/0x410 kernel/locking/lockdep.c:4417 3 locks held by kworker/u4:3/1200: #0: ("%s""kkcmd"){.+.+..}, at: [] __write_once_size include/linux/compiler.h:279 [inline] #0: ("%s""kkcmd"){.+.+..}, at: [] atomic64_set arch/x86/include/asm/atomic64_64.h:33 [inline] #0: ("%s""kkcmd"){.+.+..}, at: [] atomic_long_set include/asm-generic/atomic-long.h:56 [inline] #0: ("%s""kkcmd"){.+.+..}, at: [] set_work_data kernel/workqueue.c:617 [inline] #0: ("%s""kkcmd"){.+.+..}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: ("%s""kkcmd"){.+.+..}, at: [] process_one_work+0xadf/0x1bc0 kernel/workqueue.c:2090 #1: ((&kcm->tx_work)){+.+...}, at: [] process_one_work+0xb32/0x1bc0 kernel/workqueue.c:2094 #2: (sk_lock-AF_KCM){+.+.+.}, at: [] lock_sock include/net/sock.h:1459 [inline] #2: (sk_lock-AF_KCM){+.+.+.}, at: [] kcm_tx_work+0x26/0x190 net/kcm/kcmsock.c:726 1 lock held by rsyslogd/2841: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0x12b/0x190 fs/file.c:767 2 locks held by getty/2924: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2925: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2926: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2927: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2928: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2929: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2930: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 635 Comm: khungtaskd Not tainted 4.13.0-rc6+ #28 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 nmi_cpu_backtrace+0x20e/0x240 lib/nmi_backtrace.c:102 nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:61 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 trigger_all_cpu_backtrace include/linux/nmi.h:105 [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+0x35e/0x430 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:425 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2952 Comm: syzkaller817404 Not tainted 4.13.0-rc6+ #28 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d1e8c140 task.stack: ffff8801d2050000 RIP: 0010:arch_local_irq_disable arch/x86/include/asm/paravirt.h:819 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:832 [inline] RIP: 0010:lock_is_held_type+0xc3/0x210 kernel/locking/lockdep.c:3889 RSP: 0000:ffff8801d20577a8 EFLAGS: 00000082 RAX: dffffc0000000000 RBX: 0000000000000286 RCX: 0000000000000000 RDX: 1ffffffff0b59432 RSI: 00000000ffffffff RDI: ffffffff85aca190 RBP: ffff8801d20577c8 R08: 0000000000028c40 R09: 0000000000000000 R10: ffffffffffffffe8 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff85b38240 R14: 0000000000001102 R15: 0000000006fbd5c0 FS: 00000000007ec880(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000206d4fed CR3: 00000001d9abf000 CR4: 00000000001406f0 Call Trace: lock_is_held include/linux/lockdep.h:348 [inline] ___might_sleep+0x3d8/0x470 kernel/sched/core.c:5959 clear_huge_page+0xb5/0x3a0 mm/memory.c:4354 __do_huge_pmd_anonymous_page mm/huge_memory.c:570 [inline] do_huge_pmd_anonymous_page+0x584/0x1b90 mm/huge_memory.c:728 create_huge_pmd mm/memory.c:3643 [inline] __handle_mm_fault+0x172f/0x3860 mm/memory.c:3846 handle_mm_fault+0x3bb/0x860 mm/memory.c:3906 __do_page_fault+0x4f6/0xb60 arch/x86/mm/fault.c:1445 do_page_fault+0x54/0x70 arch/x86/mm/fault.c:1508 page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1007 RIP: 0033:0x400bb6 RSP: 002b:00007ffcd7094530 EFLAGS: 00010246 RAX: ffffffffffffffff RBX: 00000000006ccd60 RCX: 000000000043fe49