INFO: task syz-executor.0:6164 blocked for more than 143 seconds.
      Not tainted 6.13.0-next-20250131-syzkaller-10663-gdf4b2bbff898-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:25432 pid:6164  tgid:6163  ppid:6142   task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6764
 __schedule_loop kernel/sched/core.c:6841 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6856
 schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 __flush_workqueue+0x575/0x1280 kernel/workqueue.c:3998
 nbd_start_device_ioctl drivers/block/nbd.c:1540 [inline]
 __nbd_ioctl drivers/block/nbd.c:1601 [inline]
 nbd_ioctl+0xbd1/0xf40 drivers/block/nbd.c:1641
 blkdev_ioctl+0x57d/0x6a0 block/ioctl.c:693
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x456e69
RSP: 002b:00007f9081a330d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000055bf80 RCX: 0000000000456e69
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00000000004b0cab R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004b02b7
R13: 000000000000000b R14: 000000000055bf80 R15: 00007ffdaf1cd5a8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e938960 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e938960 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e938960 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6746
2 locks held by getty/5587:
 #0: ffff8880359120a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
2 locks held by kworker/u9:2/5841:
 #0: ffff888025742948 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
 #0: ffff888025742948 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3317
 #1: ffffc90003effc60 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
 #1: ffffc90003effc60 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3317

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-next-20250131-syzkaller-10663-gdf4b2bbff898-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline]
 watchdog+0x1058/0x10a0 kernel/hung_task.c:399
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-next-20250131-syzkaller-10663-gdf4b2bbff898-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:__lock_acquire+0xcbf/0x2100 kernel/locking/lockdep.c:5201
Code: bf 00 00 00 00 00 fc ff df 48 0f a3 1d 1a fb 95 12 0f 83 66 09 00 00 49 8d 9d e0 0a 00 00 48 89 d8 48 c1 e8 03 48 89 44 24 58 <80> 3c 38 00 74 12 48 89 df e8 13 2d 8b 00 48 bf 00 00 00 00 00 fc
RSP: 0018:ffffc90000007810 EFLAGS: 00000806
RAX: 1ffffffff1cd2e0c RBX: ffffffff8e697060 RCX: ffffffff819abd14
RDX: 0000000000000000 RSI: 0000000000000008 RDI: dffffc0000000000
RBP: ffffffff8e6970e8 R08: ffffffff9430b847 R09: 1ffffffff2861708
R10: dffffc0000000000 R11: fffffbfff2861709 R12: ffffffff8e697054
R13: ffffffff8e696580 R14: 0000000000000000 R15: ffffffff8e697108
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc0ad0ec5c CR3: 000000000e738000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock_sched include/linux/rcupdate.h:941 [inline]
 pfn_valid include/linux/mmzone.h:2067 [inline]
 __virt_addr_valid+0x1a0/0x530 arch/x86/mm/physaddr.c:65
 kasan_addr_to_slab+0xd/0x80 mm/kasan/common.c:37
 kasan_record_aux_stack+0xf/0xc0 mm/kasan/generic.c:533
 insert_work+0x3e/0x330 kernel/workqueue.c:2183
 __queue_work+0xc8b/0xf50 kernel/workqueue.c:2339
 call_timer_fn+0x187/0x650 kernel/time/timer.c:1789
 expire_timers kernel/time/timer.c:1835 [inline]
 __run_timers kernel/time/timer.c:2414 [inline]
 __run_timer_base+0x695/0x8e0 kernel/time/timer.c:2426
 run_timer_base kernel/time/timer.c:2435 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2445
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline]
RIP: 0010:acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112
Code: 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 80 d6 03 00 48 f7 00 08 00 00 00 75 10 66 90 0f 00 2d 25 d9 70 00 f3 0f 1e fa fb f4 <fa> c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90
RSP: 0018:ffffffff8e607ca8 EFLAGS: 00000246
RAX: ffffffff8e696580 RBX: ffff8881416da064 RCX: 0000000000066d51
RDX: 0000000000000001 RSI: ffff8881416da000 RDI: ffff8881416da064
RBP: 000000000003aab8 R08: ffff8880b863799b R09: 1ffff110170c6f33
R10: dffffc0000000000 R11: ffffffff8bf97bd0 R12: ffff8881472ff000
R13: 0000000000000001 R14: 0000000000000001 R15: ffffffff8f1348a0
 acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:699
 cpuidle_enter_state+0x109/0x470 drivers/cpuidle/cpuidle.c:268
 cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:389
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:230 [inline]
 do_idle+0x372/0x5c0 kernel/sched/idle.c:325
 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423
 rest_init+0x2dc/0x300 init/main.c:743
 start_kernel+0x484/0x510 init/main.c:1099
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:515
 x86_64_start_kernel+0x9f/0xa0 arch/x86/kernel/head64.c:496
 common_startup_64+0x13e/0x147
 </TASK>