INFO: task syz-executor.0:5429 blocked for more than 143 seconds.
      Not tainted 6.4.0-syzkaller-00847-g88afbb21d4b3 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:26488 pid:5429  ppid:5357   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5343 [inline]
 __schedule+0x18c5/0x4910 kernel/sched/core.c:6669
 schedule+0xbf/0x180 kernel/sched/core.c:6745
 schedule_timeout+0xac/0x300 kernel/time/timer.c:2143
 do_wait_for_common+0x441/0x5e0 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+0x46/0x60 kernel/sched/completion.c:138
 __flush_workqueue+0x737/0x1610 kernel/workqueue.c:2980
 nbd_start_device_ioctl drivers/block/nbd.c:1426 [inline]
 __nbd_ioctl drivers/block/nbd.c:1488 [inline]
 nbd_ioctl+0xaf4/0xe70 drivers/block/nbd.c:1528
 blkdev_ioctl+0x369/0x6f0 block/ioctl.c:621
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xf8/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f684048c389
RSP: 002b:00007f6841255168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f68405abf80 RCX: 00007f684048c389
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007f68404d7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc0d54db8f R14: 00007f6841255300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/13:
 #0: ffffffff8d126330 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:518
1 lock held by rcu_tasks_trace/14:
 #0: ffffffff8d1266f0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:518
1 lock held by khungtaskd/28:
 #0: ffffffff8d126160 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by kworker/u5:1/4407:
 #0: ffff88801ff2b138 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x77a/0x10c0 kernel/workqueue.c:2381
 #1: ffffc9000565fd20 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7c0/0x10c0 kernel/workqueue.c:2383
2 locks held by getty/4753:
 #0: ffff888028b20098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900015902f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6ad/0x1db0 drivers/tty/n_tty.c:2176
1 lock held by syz-executor.0/9088:
 #0: ffff88801fe17198 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x146/0xe70 drivers/block/nbd.c:1521
1 lock held by syz-executor.0/9089:
 #0: ffff88801fe17198 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x146/0xe70 drivers/block/nbd.c:1521

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.4.0-syzkaller-00847-g88afbb21d4b3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x494/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x183/0x2d0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xeba/0xf00 kernel/hung_task.c:379
 kthread+0x2b0/0x340 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 12 Comm: kworker/u4:1 Not tainted 6.4.0-syzkaller-00847-g88afbb21d4b3 #0