INFO: task kworker/1:2H:32061 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:2H    state:D stack:27328 pid:32061 tgid:32061 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: kblockd blk_mq_requeue_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7026
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 wait_for_reconnect drivers/block/nbd.c:1110 [inline]
 nbd_handle_cmd drivers/block/nbd.c:1152 [inline]
 nbd_queue_rq+0xd12/0x12d0 drivers/block/nbd.c:1210
 blk_mq_dispatch_rq_list+0x416/0x1e20 block/blk-mq.c:2129
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
 blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
 __blk_mq_sched_dispatch_requests+0xcb7/0x15f0 block/blk-mq-sched.c:307
 blk_mq_sched_dispatch_requests+0xd8/0x1b0 block/blk-mq-sched.c:329
 blk_mq_run_hw_queue+0x239/0x670 block/blk-mq.c:2367
 blk_mq_run_hw_queues+0x117/0x450 block/blk-mq.c:2416
 blk_mq_requeue_work+0x59f/0x7d0 block/blk-mq.c:1583
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
2 locks held by rcu_tasks_trace/29:
 #0: ffffffff8e3c3bd0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{4:4}, at: rcu_tasks_one_gp+0x72d/0xe20 kernel/rcu/tasks.h:614
 #1: ffffffff8e3cfcf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311
1 lock held by khungtaskd/31:
 #0: ffffffff8e3c4760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e3c4760 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8e3c4760 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/5576:
 #0: ffff88814cf5b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000331e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
4 locks held by kworker/1:2H/32061:
 #0: ffff888141283548 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
 #1: ffffc90002fc7d00 ((work_completion)(&(&q->requeue_work)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
 #2: ffff888026007c10 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline]
 #2: ffff888026007c10 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline]
 #2: ffff888026007c10 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x22b/0x670 block/blk-mq.c:2367
 #3: ffff8880267f51f8 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xbd/0x12d0 drivers/block/nbd.c:1202
1 lock held by udevd/2074:
 #0: ffff8881433fd358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:945
no locks held by syz.2.9238/4517.

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 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:332 [inline]
 watchdog+0xf3f/0x1170 kernel/hung_task.c:495
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 4518 Comm: syz.2.9238 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:58 [inline]
RIP: 0010:stack_access_ok+0x60/0x200 arch/x86/kernel/unwind_orc.c:393
Code: 4c 8d 6b 10 4c 8b 7b 08 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 52 01 00 00 48 89 da 48 8b 4b 10 <48> b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 04 02 84 c0 74 08
RSP: 0018:ffffc90003546f30 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffc90003546fe0 RCX: ffffc90003548000
RDX: ffffc90003546fe0 RSI: ffffc90003547ca0 RDI: ffffc90003546fe0
RBP: ffffc90003547ca0 R08: ffffffff9116a196 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000007c92 R12: 0000000000000008
R13: ffffc90003546ff0 R14: ffffc90003546fe8 R15: ffffc90003540000
FS:  0000000000000000(0000) GS:ffff888124b05000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0ee82d2d58 CR3: 000000002a5fe000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline]
 unwind_next_frame+0xcfe/0x20a0 arch/x86/kernel/unwind_orc.c:585
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x160/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:311
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 free_unref_folios+0xa31/0x1610 mm/page_alloc.c:2958
 folios_put_refs+0x4be/0x750 mm/swap.c:1002
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x58f/0x1150 mm/shmem.c:1119
 shmem_truncate_range mm/shmem.c:1231 [inline]
 shmem_evict_inode+0x3a1/0xbe0 mm/shmem.c:1359
 evict+0x3e6/0x920 fs/inode.c:810
 iput_final fs/inode.c:1914 [inline]
 iput.part.0+0x6a9/0xb00 fs/inode.c:1966
 iput+0x35/0x40 fs/inode.c:1929
 dentry_unlink_inode+0x29c/0x480 fs/dcache.c:466
 __dentry_kill+0x1d0/0x600 fs/dcache.c:669
 dput.part.0+0x4b1/0x9b0 fs/dcache.c:911
 dput+0x1f/0x30 fs/dcache.c:901
 __fput+0x51c/0xb70 fs/file_table.c:476
 task_work_run+0x150/0x240 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x86f/0x2bf0 kernel/exit.c:966
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
 get_signal+0x2671/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7c0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0ee738f749
Code: Unable to access opcode bytes at 0x7f0ee738f71f.
RSP: 002b:00007f0ee82d20e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f0ee75e6188 RCX: 00007f0ee738f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f0ee75e6188
RBP: 00007f0ee75e6180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0ee75e6218 R14: 00007ffccc976310 R15: 00007ffccc9763f8
 </TASK>
vkms_vblank_simulate: vblank timer overrun