INFO: task kworker/u4:1:706 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/u4:1 state:D stack:24856 pid: 706 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 INFO: task kworker/u4:5:14430 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:25992 pid:14430 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/u4:0/8: #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: ffffc90000cd7da8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 2 locks held by kworker/u4:6/319: #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: ffffc90001eefda8 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 1 lock held by khungtaskd/1658: #0: ffffffff8b339ca0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6252 1 lock held by systemd-udevd/4900: #0: ffff888015ed2100 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1472 1 lock held by in:imklog/8198: #0: ffff8880188cad70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:932 1 lock held by syz-executor.0/8516: #0: ffff888010410700 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1472 1 lock held by syz-executor.5/8653: #0: ffff888015ed3480 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1472 2 locks held by systemd-udevd/9953: #0: ffff888015ed3480 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1762 #1: ffffffff8bd23528 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1909 2 locks held by systemd-udevd/9954: #0: ffff888010412100 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1762 #1: ffffffff8bd23528 (loop_ctl_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x88/0xe50 drivers/block/loop.c:1210 2 locks held by systemd-udevd/9991: #0: ffff888015ed1a80 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1762 #1: ffffffff8bd23528 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1909 2 locks held by systemd-udevd/10042: #0: ffff888015ed2100 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1762 #1: ffffffff8bd23528 (loop_ctl_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x770/0xe50 drivers/block/loop.c:1295 2 locks held by systemd-udevd/10297: #0: ffff888010410700 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1762 #1: ffffffff8bd23528 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1909 2 locks held by kworker/u4:1/706: #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: ffffc90016f8fda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 2 locks held by kworker/u4:5/14430: #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: ffffc9001776fda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247 2 locks held by syz-executor.4/29949: #0: ffff888015ed2780 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_put+0xfc/0x890 fs/block_dev.c:1762 #1: ffffffff8bd23528 (loop_ctl_mutex){+.+.}-{3:3}, at: lo_release+0x1a/0x1f0 drivers/block/loop.c:1909 1 lock held by syz-executor.2/29954: #0: ffff888015ed1a80 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1472 1 lock held by syz-executor.3/29953: #0: ffff888015ed2100 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1472 1 lock held by syz-executor.1/29956: #0: ffff888010412100 (&bdev->bd_mutex){+.+.}-{3:3}, at: __blkdev_get+0x457/0x1870 fs/block_dev.c:1472 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1658 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4885 Comm: systemd-journal Not tainted 5.10.0-rc4-next-20201119-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0033:0x7efd4679e300 Code: 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f2 66 0f ef c0 eb 28 0f 1f 40 00 48 39 d1 0f 82 67 32 07 00 0f 1f 80 00 00 00 00 <66> 0f 6e c6 48 89 f8 66 0f 60 c0 66 0f 61 c0 66 0f 70 c0 00 48 83 RSP: 002b:00007ffe789a2c48 EFLAGS: 00000246 RAX: 000000000000003b RBX: 00007efd46ab3b00 RCX: 0000000000000000 RDX: 00000000000001d8 RSI: 0000000000000000 RDI: 000055fdcef60b40 RBP: 000055fdcef60b40 R08: 00007efd46ab4088 R09: 00000000000001e0 R10: 0000000000000069 R11: 00007efd46884060 R12: 00000000000001d8 R13: 0000000000012e10 R14: 000055fdcef631f0 R15: 00007ffe789a3640 FS: 00007efd475398c0 GS: 0000000000000000