INFO: task kworker/u4:5:216 blocked for more than 143 seconds. Not tainted 5.10.0-rc4-next-20201119-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:5 state:D stack:24088 pid: 216 ppid: 2 flags:0x00004000 Workqueue: events_unbound io_ring_exit_work Call Trace: context_switch kernel/sched/core.c:4269 [inline] __schedule+0x890/0x2030 kernel/sched/core.c:5019 schedule+0xcf/0x270 kernel/sched/core.c:5098 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1847 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x163/0x260 kernel/sched/completion.c:138 kthread_stop+0x17a/0x720 kernel/kthread.c:596 io_put_sq_data fs/io_uring.c:7242 [inline] io_sq_thread_stop+0x452/0x570 fs/io_uring.c:7339 io_finish_async fs/io_uring.c:7346 [inline] io_ring_ctx_free fs/io_uring.c:8501 [inline] io_ring_exit_work+0x102/0x7a0 fs/io_uring.c:8595 process_one_work+0x933/0x15a0 kernel/workqueue.c:2272 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Showing all locks held in the system: 2 locks held by kworker/1:0/17: #0: ffff8880b9f34f98 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1318 [inline] #0: ffff8880b9f34f98 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x217/0x2030 kernel/sched/core.c:4936 #1: ffff8880b9f20088 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x305/0x440 kernel/sched/psi.c:833 2 locks held by kworker/u4:5/216: #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2243 #1: ffffc9000109fda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 1 lock held by khungtaskd/1649: #0: ffffffff8b339ca0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6252 4 locks held by kworker/0:2/3000: #0: ffff8880b9e34f98 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1318 [inline] #0: ffff8880b9e34f98 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x217/0x2030 kernel/sched/core.c:4936 #1: ffff8880b9e20088 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x305/0x440 kernel/sched/psi.c:833 #2: ffff88801c0d32b0 (&dev->power.lock){-...}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:379 [inline] #2: ffff88801c0d32b0 (&dev->power.lock){-...}-{2:2}, at: __rpm_callback+0x2d1/0x4d0 drivers/base/power/runtime.c:377 #3: ffff8880b9e24918 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x5a/0x1f0 kernel/time/timer.c:944 1 lock held by systemd-journal/4875: #0: ffffffff8ba00af8 (tomoyo_ss){....}-{0:0}, at: tomoyo_path_perm+0x1c1/0x400 security/tomoyo/file.c:847 3 locks held by kworker/1:3/4882: #0: ffff888141693d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888141693d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888141693d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888141693d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888141693d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888141693d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2243 #1: ffffc90000e9fda8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 #2: ffff88801c14b218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:731 [inline] #2: ffff88801c14b218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x42d0 drivers/usb/core/hub.c:5537 1 lock held by systemd-udevd/4898: 1 lock held by in:imklog/8175: #0: ffff888011e9eaf0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:932 5 locks held by kworker/0:0/15697: 2 locks held by kworker/u4:12/16350: 3 locks held by kworker/1:2/25602: #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2243 #1: ffffc90002127da8 ((work_completion)(&hcd->wakeup_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 #2: ffff88801c0d3218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:731 [inline] #2: ffff88801c0d3218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x42d0 drivers/usb/core/hub.c:5537 3 locks held by kworker/0:5/25775: #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888010e07138 ((wq_completion)pm){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2243 #1: ffffc900028e7da8 ((work_completion)(&hcd->wakeup_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 #2: ffff88801c193218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:731 [inline] #2: ffff88801c193218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x42d0 drivers/usb/core/hub.c:5537 2 locks held by kworker/1:6/26516: #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888010066538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2243 #1: ffffc9000bb87da8 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 3 locks held by syz-executor.4/28050: #0: ffff888052800210 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:774 [inline] #0: ffff888052800210 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:594 #1: ffff888050d9e120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1583 [inline] #1: ffff888050d9e120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pptp_release+0x4f/0x280 drivers/net/ppp/pptp.c:501 #2: ffffffff8b3423e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #2: ffffffff8b3423e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x4f2/0x610 kernel/rcu/tree_exp.h:836 3 locks held by syz-executor.3/28052: #0: ffff888032518c90 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:774 [inline] #0: ffff888032518c90 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:594 #1: ffff888050526120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1583 [inline] #1: ffff888050526120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pptp_release+0x4f/0x280 drivers/net/ppp/pptp.c:501 #2: ffffffff8b3423e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline] #2: ffffffff8b3423e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x27e/0x610 kernel/rcu/tree_exp.h:836 2 locks held by syz-executor.1/28061: #0: ffff88802eb6b150 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:774 [inline] #0: ffff88802eb6b150 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:594 #1: ffff88804d911120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1583 [inline] #1: ffff88804d911120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pptp_release+0x4f/0x280 drivers/net/ppp/pptp.c:501 2 locks held by syz-executor.0/28066: #0: ffff8880325151d0 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:774 [inline] #0: ffff8880325151d0 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:594 #1: ffff888025ecd120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1583 [inline] #1: ffff888025ecd120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pptp_release+0x4f/0x280 drivers/net/ppp/pptp.c:501 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1649 Comm: khungtaskd Not tainted 5.10.0-rc4-next-20201119-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] watchdog+0xd89/0xf30 kernel/hung_task.c:338 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:110 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x1c9/0x250 drivers/acpi/processor_idle.c:516