INFO: task syz-executor.0:11011 blocked for more than 143 seconds. Not tainted 5.2.0-next-20190710 #35 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28160 11011 8675 0x00004004 Call Trace: context_switch kernel/sched/core.c:3252 [inline] __schedule+0x755/0x1580 kernel/sched/core.c:3878 schedule+0xa8/0x270 kernel/sched/core.c:3942 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1783 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 kthread_stop+0x131/0x720 kernel/kthread.c:559 io_sq_thread_stop fs/io_uring.c:2464 [inline] io_finish_async+0x73/0x140 fs/io_uring.c:2471 io_ring_ctx_free fs/io_uring.c:2982 [inline] io_ring_ctx_wait_and_kill+0x133/0x600 fs/io_uring.c:3046 io_uring_release+0x42/0x50 fs/io_uring.c:3054 __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 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4134b1 Code: af fe ff ff 31 c9 31 f6 41 b9 b0 20 41 00 41 b8 fc 97 65 00 ba 04 00 00 00 bf 02 38 44 00 ff 15 cd a1 24 00 85 c0 0f 85 87 fe ff 31 c9 31 f6 41 b9 b0 20 41 00 41 b8 00 98 65 00 ba 07 00 00 RSP: 002b:00007ffe45df2fd0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 00000000004134b1 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000001 R08: 000000005a5a438a R09: 000000005a5a438e R10: 00007ffe45df30b0 R11: 0000000000000293 R12: 000000000075bf20 R13: 000000000002c1d2 R14: 00000000007605a0 R15: ffffffffffffffff Showing all locks held in the system: 3 locks held by kworker/u4:3/820: #0: 000000009b9970f6 (&rq->lock){-.-.}, at: idle_balance kernel/sched/fair.c:9815 [inline] #0: 000000009b9970f6 (&rq->lock){-.-.}, at: pick_next_task_fair+0xc42/0x1a50 kernel/sched/fair.c:6852 #1: 00000000e8e644fd (rcu_read_lock){....}, at: __update_idle_core+0x45/0x3f0 kernel/sched/fair.c:5820 #2: 000000000a78e544 (&base->lock){-.-.}, at: lock_timer_base+0x56/0x1b0 kernel/time/timer.c:932 1 lock held by khungtaskd/1051: #0: 00000000e8e644fd (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5257 2 locks held by getty/8631: #0: 00000000b5ffda13 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000089760bbc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8632: #0: 000000001ff41f0a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000d2898d55 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8633: #0: 00000000d69b57d7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000f05acae6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8634: #0: 000000000f693186 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000003a8da74d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8635: #0: 00000000029e19c8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000004e3af79a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8636: #0: 000000008271f3c6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000051ca8c7f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8637: #0: 00000000608a1de3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000044c0db15 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1051 Comm: khungtaskd Not tainted 5.2.0-next-20190710 #35 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+0x172/0x1f0 lib/dump_stack.c:113 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:249 [inline] watchdog+0xc54/0x1320 kernel/hung_task.c:333 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60