INFO: task kworker/u4:17:10647 blocked for more than 143 seconds. Not tainted 5.11.0-rc1-next-20210104-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:17 state:D stack:24456 pid:10647 ppid: 2 flags:0x00004000 Workqueue: events_unbound io_ring_exit_work Call Trace: context_switch kernel/sched/core.c:4313 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5064 schedule+0xcf/0x270 kernel/sched/core.c:5143 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1854 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_park+0x122/0x1b0 kernel/kthread.c:557 io_sq_thread_park fs/io_uring.c:7375 [inline] io_sq_thread_park fs/io_uring.c:7369 [inline] io_sq_thread_stop+0xfe/0x570 fs/io_uring.c:7393 io_finish_async fs/io_uring.c:7411 [inline] io_ring_ctx_free fs/io_uring.c:8576 [inline] io_ring_exit_work+0xac/0x730 fs/io_uring.c:8668 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Showing all locks held in the system: 1 lock held by khungtaskd/1644: #0: ffffffff8b363c60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6254 1 lock held by in:imklog/8320: #0: ffff88801d2c6ff0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:947 2 locks held by agetty/8411: #0: ffff888147648098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:266 #1: ffffc900010082e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x21d/0x1aa0 drivers/tty/n_tty.c:2158 2 locks held by kworker/u4:3/9279: #0: ffff8880b9e34c58 (&rq->lock){-.-.}-{2:2}, at: newidle_balance+0x789/0xe50 kernel/sched/fair.c:10642 #1: ffffc900031c7da8 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2250 3 locks held by kworker/u4:17/10647: #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+0x871/0x15f0 kernel/workqueue.c:2246 #1: ffffc900025b7da8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2250 #2: ffff88802d7ecc70 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_park fs/io_uring.c:7374 [inline] #2: ffff88802d7ecc70 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_park fs/io_uring.c:7369 [inline] #2: ffff88802d7ecc70 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_stop+0xd6/0x570 fs/io_uring.c:7393 2 locks held by syz-executor.0/14577: #0: ffff888144a04458 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x41/0x540 net/netfilter/x_tables.c:1206 #1: ffffffff8b36c368 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #1: ffffffff8b36c368 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x4f2/0x610 kernel/rcu/tree_exp.h:836 2 locks held by kworker/1:0/27726: #0: ffff88801007c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88801007c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff88801007c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff88801007c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff88801007c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff88801007c538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x871/0x15f0 kernel/workqueue.c:2246 #1: ffffc90009edfda8 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2250 1 lock held by systemd-udevd/1964: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1644 Comm: khungtaskd Not tainted 5.11.0-rc1-next-20210104-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+0x3b1/0x4a0 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