INFO: task syz-executor.0:6051 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:28584 pid:6051  tgid:6049  ppid:6020   task_flags:0x480140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5264 [inline]
 __schedule+0x1848/0x4ec0 kernel/sched/core.c:6872
 __schedule_loop kernel/sched/core.c:6954 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6969
 blk_mq_freeze_queue_wait+0xf4/0x170 block/blk-mq.c:190
 blk_mq_freeze_queue include/linux/blk-mq.h:938 [inline]
 queue_limits_commit_update_frozen+0x5d/0x3e0 block/blk-settings.c:597
 nbd_set_size+0x47e/0x6a0 drivers/block/nbd.c:374
 nbd_start_device_ioctl drivers/block/nbd.c:1548 [inline]
 __nbd_ioctl drivers/block/nbd.c:1623 [inline]
 nbd_ioctl+0x56e/0xe10 drivers/block/nbd.c:1663
 blkdev_ioctl+0x60e/0x710 block/ioctl.c:707
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0369879829
RSP: 002b:00007f036a9810c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f036998c030 RCX: 00007f0369879829
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000004
RBP: 00007f03698d5074 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f036998c030 R15: 00007ffd700509b8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3b720 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3b720 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8df3b720 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by klogd/5182:
 #0: ffff8880b863a3d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
2 locks held by getty/5584:
 #0: ffff888034cda0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
4 locks held by syz-executor.0/6051:
 #0: ffff888025d15278 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_start_device+0x189/0xb10 drivers/block/nbd.c:1490
 #1: ffff888025d19aa8 (&q->limits_lock){+.+.}-{4:4}, at: queue_limits_start_update include/linux/blkdev.h:1088 [inline]
 #1: ffff888025d19aa8 (&q->limits_lock){+.+.}-{4:4}, at: nbd_set_size+0x292/0x6a0 drivers/block/nbd.c:354
 #2: ffff888025d19448 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:938 [inline]
 #2: ffff888025d19448 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: queue_limits_commit_update_frozen+0x5d/0x3e0 block/blk-settings.c:597
 #3: ffff888025d19480 (&q->q_usage_counter(queue)#33){+.+.}-{0:0}, at: blk_mq_freeze_queue include/linux/blk-mq.h:938 [inline]
 #3: ffff888025d19480 (&q->q_usage_counter(queue)#33){+.+.}-{0:0}, at: queue_limits_commit_update_frozen+0x5d/0x3e0 block/blk-settings.c:597

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:336 [inline]
 watchdog+0xfa9/0xff0 kernel/hung_task.c:499
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </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 syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 13 f1 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d f3 0a 0c 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c2
RAX: 665cacdcbb501300 RBX: ffffffff81976627 RCX: 665cacdcbb501300
RDX: 0000000000000001 RSI: ffffffff8d786e5e RDI: ffffffff8bbf41e0
RBP: ffffffff8dc07ea8 R08: ffff8880b863339b R09: 1ffff110170c6673
R10: dffffc0000000000 R11: ffffed10170c6674 R12: ffffffff8f7da970
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92660
FS:  0000000000000000(0000) GS:ffff888125ec2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558bf6917660 CR3: 000000000dd36000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x1e7/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
 rest_init+0x2de/0x300 init/main.c:758
 start_kernel+0x3ac/0x410 init/main.c:1208
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x147
 </TASK>