INFO: task syz-executor.2:10704 blocked for more than 143 seconds.
      Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:26064 pid:10704 tgid:10703 ppid:5102   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5409 [inline]
 __schedule+0xf15/0x5c70 kernel/sched/core.c:6736
 __schedule_loop kernel/sched/core.c:6813 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6828
 schedule_timeout+0x258/0x2a0 kernel/time/timer.c:2548
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common+0x3de/0x5f0 kernel/sched/completion.c:116
 __flush_workqueue+0x39e/0x1200 kernel/workqueue.c:3994
 nbd_start_device_ioctl drivers/block/nbd.c:1463 [inline]
 __nbd_ioctl drivers/block/nbd.c:1524 [inline]
 nbd_ioctl+0x308/0xfd0 drivers/block/nbd.c:1564
 blkdev_ioctl+0x2f7/0x770 block/ioctl.c:640
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:904 [inline]
 __se_sys_ioctl fs/ioctl.c:890 [inline]
 __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:890
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f0e0867dda9
RSP: 002b:00007f0e0934c0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f0e087abf80 RCX: 00007f0e0867dda9
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005
RBP: 00007f0e086ca47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f0e087abf80 R15: 00007ffe442248a8
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u8:1/11:
 #0: ffff888015081148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1296/0x1a60 kernel/workqueue.c:3229
 #1: ffffc90000107d80 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_one_work+0x906/0x1a60 kernel/workqueue.c:3230
1 lock held by khungtaskd/29:
 #0: ffffffff8d7b08e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
 #0: ffffffff8d7b08e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
 #0: ffffffff8d7b08e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6614
2 locks held by kworker/u8:5/134:
2 locks held by kworker/u9:1/4455:
 #0: ffff88802038c948 ((wq_completion)nbd2-recv){+.+.}-{0:0}, at: process_one_work+0x1296/0x1a60 kernel/workqueue.c:3229
 #1: ffffc9000d45fd80 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x906/0x1a60 kernel/workqueue.c:3230
2 locks held by getty/4812:
 #0: ffff88802a16e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900015f02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc8/0x1490 drivers/tty/n_tty.c:2201
1 lock held by syz-executor.1/12922:
3 locks held by syz-executor.3/12975:
1 lock held by syz-executor.2/12976:
4 locks held by syz-executor.4/12982:
3 locks held by syz-executor.0/12981:

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

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf86/0x1210 kernel/hung_task.c:379
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 23 Comm: ksoftirqd/1 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
RIP: 0010:smpboot_thread_fn+0x1f1/0xa10 kernel/smpboot.c:137
Code: 24 08 83 f8 01 0f 84 08 01 00 00 e8 19 59 31 00 e8 44 56 fe ff e9 87 fe ff ff e8 0a 59 31 00 4c 89 e0 48 c1 e8 03 0f b6 04 28 <84> c0 74 08 3c 03 0f 8e bf 06 00 00 45 8b 34 24 e8 aa be 76 09 41
RSP: 0018:ffffc900001d7e98 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff888017e8da00 RCX: ffffffff815b9e98
RDX: ffff888017e8da00 RSI: ffffffff815b9fa6 RDI: 0000000000000001
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888015ee93e0
R13: ffffffff8d65b9c0 R14: 0000000000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc2e6dad988 CR3: 000000006169a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
 </TASK>