INFO: task kworker/u4:2:77 blocked for more than 143 seconds. Not tainted 5.11.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:2 state:D stack:23808 pid: 77 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:7345 [inline] io_sq_thread_park fs/io_uring.c:7339 [inline] io_sq_thread_stop+0xfe/0x570 fs/io_uring.c:7363 io_finish_async fs/io_uring.c:7381 [inline] io_ring_ctx_free fs/io_uring.c:8554 [inline] io_ring_exit_work+0xac/0x730 fs/io_uring.c:8646 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: 3 locks held by kworker/u4:2/77: #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: ffffc9000104fda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2250 #2: ffff888013635c70 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_park fs/io_uring.c:7344 [inline] #2: ffff888013635c70 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_park fs/io_uring.c:7339 [inline] #2: ffff888013635c70 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_stop+0xd6/0x570 fs/io_uring.c:7363 1 lock held by khungtaskd/1650: #0: ffffffff8b363860 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6254 1 lock held by in:imklog/8210: 2 locks held by agetty/8401: #0: ffff88801b505098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:266 #1: ffffc90000f3c2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x21d/0x1aa0 drivers/tty/n_tty.c:2158 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1650 Comm: khungtaskd Not tainted 5.11.0-rc1-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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd43/0xfa0 kernel/hung_task.c:294 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4887 Comm: systemd-journal Not tainted 5.11.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:task_on_rq_queued kernel/sched/sched.h:1736 [inline] RIP: 0010:__schedule+0x9d0/0x21a0 kernel/sched/core.c:5059 Code: 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 0e 11 00 00 41 83 86 cc 0c 00 00 01 e9 2c f8 ff ff 49 8d 7d 68 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84 RSP: 0018:ffffc9000163fbc0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000004 RCX: ffffffff88ecefbe RDX: 1ffff11002380769 RSI: 0000000000000008 RDI: ffff888011c037e8 RBP: ffffc9000163fc88 R08: 0000000000000001 R09: ffff888011c03787 R10: ffffed10023806f0 R11: 0000000000000001 R12: ffff8880b9e34c40 R13: ffff888011c03780 R14: ffffffff8ae45ec8 R15: ffff888014938000 FS: 00007f8bfa08f8c0(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa0ad199000 CR3: 000000002598d000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:5326 irqentry_exit_cond_resched kernel/entry/common.c:393 [inline] irqentry_exit_cond_resched kernel/entry/common.c:385 [inline] irqentry_exit+0x7a/0xa0 kernel/entry/common.c:423 asm_sysvec_reschedule_ipi+0x12/0x20 arch/x86/include/asm/idtentry.h:633 RIP: 0010:devkmsg_read+0x3da/0x740 kernel/printk/printk.c:754 Code: 01 80 3c 02 00 0f 85 19 03 00 00 48 c7 c7 20 47 35 8b 4c 89 6d 00 e8 d5 17 93 07 e8 d0 48 00 00 e8 8b 63 1d 00 fb 48 8b 2c 24 <4c> 89 ff 48 c7 c3 ea ff ff ff 48 89 ee e8 b4 99 17 00 49 39 ef 77 RSP: 0018:ffffc9000163fd68 EFLAGS: 00000206 RAX: 0000000000430e35 RBX: ffff88801237a0f8 RCX: ffffffff81580937 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000002000 R08: 0000000000000001 R09: ffffffff8ebda84f R10: fffffbfff1d7b509 R11: 000000000000005c R12: 1ffff920002c7fb2 R13: 0000000000003cd8 R14: ffff888012378068 R15: 000000000000002e vfs_read+0x1b5/0x570 fs/read_write.c:494 ksys_read+0x12d/0x250 fs/read_write.c:634 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f8bf961f210 Code: 73 01 c3 48 8b 0d 98 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d b9 c1 20 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 4e fc ff ff 48 89 04 24 RSP: 002b:00007ffe647dcde8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007ffe647df860 RCX: 00007f8bf961f210 RDX: 0000000000002000 RSI: 00007ffe647dd660 RDI: 0000000000000009 RBP: 0000000000000000 R08: 0000000000000008 R09: 00007ffe647e90f0 R10: 000000000003bd58 R11: 0000000000000246 R12: 00007ffe647dd660 R13: 00007ffe647df7b8 R14: 000055f397d7f958 R15: 0005b7d2a2f6783e