INFO: task kworker/u4:8:18084 blocked for more than 143 seconds. Not tainted 5.11.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:8 state:D stack:24240 pid:18084 ppid: 2 flags:0x00004000 Workqueue: events_unbound io_ring_exit_work Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5078 schedule+0xcf/0x270 kernel/sched/core.c:5157 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:582 io_sq_thread_park fs/io_uring.c:7469 [inline] io_sq_thread_park fs/io_uring.c:7463 [inline] io_sq_thread_stop+0xfe/0x570 fs/io_uring.c:7487 io_finish_async fs/io_uring.c:7505 [inline] io_ring_ctx_free fs/io_uring.c:8670 [inline] io_ring_exit_work+0x62/0x6d0 fs/io_uring.c:8763 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/u4:1/24: 1 lock held by khungtaskd/1647: #0: ffffffff8b373da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6259 no locks held by systemd-journal/4877. 1 lock held by systemd-udevd/4886: #0: ffff88814380f120 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev fs/block_dev.c:1444 [inline] #0: ffff88814380f120 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x255/0x5e0 fs/block_dev.c:1413 1 lock held by in:imklog/8358: #0: ffff888018a79d70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:947 1 lock held by syz-executor.0/8452: #0: ffff8881438010e0 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev fs/block_dev.c:1444 [inline] #0: ffff8881438010e0 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x255/0x5e0 fs/block_dev.c:1413 2 locks held by syz-executor.2/8455: #0: ffff8881479f4d88 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x41/0x540 net/netfilter/x_tables.c:1206 #1: ffffffff8b37c668 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #1: ffffffff8b37c668 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x4f2/0x610 kernel/rcu/tree_exp.h:836 1 lock held by syz-executor.1/8456: #0: ffff8881479f4d88 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x41/0x540 net/netfilter/x_tables.c:1206 1 lock held by syz-executor.3/8458: #0: ffff8881479f4d88 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x41/0x540 net/netfilter/x_tables.c:1206 1 lock held by syz-executor.4/8578: #0: ffff8881479f4d88 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x41/0x540 net/netfilter/x_tables.c:1206 3 locks held by kworker/u4:8/18084: #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x871/0x15f0 kernel/workqueue.c:2246 #1: ffffc90002a57da8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2250 #2: ffff888027228470 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_park fs/io_uring.c:7468 [inline] #2: ffff888027228470 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_park fs/io_uring.c:7463 [inline] #2: ffff888027228470 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_stop+0xd6/0x570 fs/io_uring.c:7487 2 locks held by kworker/0:1/1480: #0: ffff888010073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888010073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888010073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888010073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888010073538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x871/0x15f0 kernel/workqueue.c:2246 #1: ffffc90008797da8 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2250 2 locks held by systemd-udevd/6279: #0: ffff888016dde360 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev fs/block_dev.c:1444 [inline] #0: ffff888016dde360 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x255/0x5e0 fs/block_dev.c:1413 #1: ffffffff8be1a868 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1882 2 locks held by systemd-udevd/6289: #0: ffff88814381e160 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xf0/0x800 fs/block_dev.c:1565 #1: ffffffff8be1a868 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1901 2 locks held by systemd-udevd/6291: #0: ffff8881438010e0 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xf0/0x800 fs/block_dev.c:1565 #1: ffffffff8be1a868 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1901 2 locks held by systemd-udevd/6293: #0: ffff888016dd0320 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xf0/0x800 fs/block_dev.c:1565 #1: ffffffff8be1a868 (loop_ctl_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x88/0xee0 drivers/block/loop.c:1203 2 locks held by systemd-udevd/6295: #0: ffff888016dc32e0 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev fs/block_dev.c:1444 [inline] #0: ffff888016dc32e0 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x255/0x5e0 fs/block_dev.c:1413 #1: ffffffff8be1a868 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1882 2 locks held by systemd-udevd/7773: #0: ffff88814380f120 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev fs/block_dev.c:1444 [inline] #0: ffff88814380f120 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x255/0x5e0 fs/block_dev.c:1413 #1: ffffffff8be1a868 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_open+0x19/0xd0 drivers/block/loop.c:1882 1 lock held by syz-executor.5/17280: #0: ffff888016dde360 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_put+0x59/0x570 fs/block_dev.c:1591 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1647 Comm: khungtaskd Not tainted 5.11.0-rc5-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4877 Comm: systemd-journal Not tainted 5.11.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_acquire+0xc18/0x54f0 kernel/locking/lockdep.c:4829 Code: 48 c1 e3 06 48 81 c3 c0 1b d4 8e 48 8d 7b 40 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 5f 45 00 00 <48> 83 7b 40 00 0f 84 59 0d 00 00 0f b7 44 24 38 8b 4c 24 50 8b 5c RSP: 0018:ffffc90001077b28 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffffff8ed41f80 RCX: ffffffff8158678c RDX: 1ffffffff1da83f8 RSI: 0000000000000008 RDI: ffffffff8ed41fc0 RBP: ffff88801459e280 R08: 0000000000000000 R09: ffffffff8ed417a7 R10: fffffbfff1da82f4 R11: 0000000000000001 R12: ffff88801459ec30 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f779cf998c0(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f779a4bf010 CR3: 0000000012738000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire kernel/locking/lockdep.c:5442 [inline] lock_acquire+0x1a8/0x720 kernel/locking/lockdep.c:5407 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 devkmsg_read+0x111/0x740 kernel/printk/printk.c:722 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: 0033:0x7f779c529210 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:00007ffee9aa6cd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007ffee9aa9750 RCX: 00007f779c529210 RDX: 0000000000002000 RSI: 00007ffee9aa7550 RDI: 0000000000000009 RBP: 0000000000000000 R08: 0000000000000008 R09: 00005618621567d8 R10: 00005618621567a0 R11: 0000000000000246 R12: 00007ffee9aa7550 R13: 00007ffee9aa96a8 R14: 00005618613ac958 R15: 0005ba1f79c5d69b