INFO: task syz-executor.2:2321 blocked for more than 143 seconds.
      Not tainted 6.0.0-rc4-syzkaller-17255-ga6b443748715 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:    0 pid: 2321 ppid:  3065 flags:0x00000009
Call trace:
 __switch_to+0x180/0x28c arch/arm64/kernel/process.c:557
 context_switch kernel/sched/core.c:5182 [inline]
 __schedule+0x414/0x5a0 kernel/sched/core.c:6494
 schedule+0x64/0xa4 kernel/sched/core.c:6570
 schedule_timeout+0x64/0x1b4 kernel/time/timer.c:1911
 do_wait_for_common+0xf4/0x184 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 __flush_workqueue+0x2b0/0x6dc kernel/workqueue.c:2861
 nbd_start_device_ioctl+0x188/0x25c drivers/block/nbd.c:1418
 __nbd_ioctl+0x16c/0x334 drivers/block/nbd.c:1481
 nbd_ioctl+0xec/0x13c drivers/block/nbd.c:1521
 blkdev_ioctl+0x250/0x764 block/ioctl.c:614
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0xd0/0x140 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
 el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:624
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:642
 el0t_64_sync+0x18c/0x190

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/10:
 #0: ffff80000d4634e8 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x3c/0x450 kernel/rcu/tasks.h:507
1 lock held by rcu_tasks_trace/11:
 #0: ffff80000d463b38 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x3c/0x450 kernel/rcu/tasks.h:507
1 lock held by khungtaskd/26:
 #0: ffff80000d4633c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x4/0x48 include/linux/rcupdate.h:279
1 lock held by udevd/2559:
2 locks held by getty/2716:
 #0: ffff0000c6215098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x28/0x58 drivers/tty/tty_ldisc.c:244
 #1: ffff80000f63e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x19c/0x89c drivers/tty/n_tty.c:2177
1 lock held by syz-executor.4/3067:
 #0: ffff80000d464978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
 #0: ffff80000d464978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x210/0x47c kernel/rcu/tree_exp.h:940
2 locks held by kworker/u5:8/3086:
 #0: ffff0000c37a1138 ((wq_completion)nbd2-recv){+.+.}-{0:0}, at: process_one_work+0x270/0x504 kernel/workqueue.c:2262
 #1: ffff8000128b3d80 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x29c/0x504 kernel/workqueue.c:2264
2 locks held by kworker/0:3/3121:
 #0: ffff0000c0010f38 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x270/0x504 kernel/workqueue.c:2262
 #1: ffff8000129cbd80 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x29c/0x504 kernel/workqueue.c:2264
1 lock held by udevd/2410:
 #0: ffff0000c545c7d0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:811 [inline]
 #0: ffff0000c545c7d0 (mapping.invalidate_lock#2){++++}-{3:3}, at: page_cache_ra_unbounded+0x5c/0x338 mm/readahead.c:220
1 lock held by udevd/2411:
1 lock held by syz-executor.2/2414:
 #0: ffff80000d464978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
 #0: ffff80000d464978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x1e0/0x47c kernel/rcu/tree_exp.h:940
1 lock held by udevd/3073:
3 locks held by kworker/u4:17/4724:
1 lock held by syz-executor.3/13743:
 #0: ffff0000cada9350 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
 #0: ffff0000cada9350 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release net/socket.c:649 [inline]
 #0: ffff0000cada9350 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: sock_close+0x40/0xf0 net/socket.c:1365

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