INFO: task syz.6.3553:19889 blocked for more than 144 seconds.
      Not tainted 6.15.0-next-20250527-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.3553      state:D stack:28112 pid:19889 tgid:19881 ppid:18969  task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5392 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6781
 __schedule_loop kernel/sched/core.c:6859 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6874
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6931
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:747
 bdev_release+0x1a9/0x650 block/bdev.c:1128
 blkdev_release+0x15/0x20 block/fops.c:684
 __fput+0x449/0xa70 fs/file_table.c:467
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:114
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd58778e969
RSP: 002b:00007fd58854e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007fd5879b6160 RCX: 00007fd58778e969
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 000000000000000a
RBP: 00007fd587810ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fd5879b6160 R15: 00007ffe67a99f18
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13f080 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13f080 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13f080 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
5 locks held by kworker/u8:5/69:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc9000211fbc0 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000211fbc0 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffff8880b863b918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:606
 #3: ffff8880b8623f08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39a/0x6d0 kernel/sched/psi.c:987
 #4: ffff8880b8623f08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_change+0xe5/0x250 kernel/sched/psi.c:912
2 locks held by getty/5594:
 #0: ffff88814db300a0 (&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
3 locks held by kworker/1:5/5893:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc90004e7fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90004e7fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffff8880568e3240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180 drivers/net/netdevsim/fib.c:1490
1 lock held by udevd/10392:
 #0: ffff88802534f358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945
1 lock held by syz.6.3553/19889:
 #0: ffff88802534f358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1a9/0x650 block/bdev.c:1128
1 lock held by syz.2.3860/21384:
2 locks held by modprobe/21406:
3 locks held by dhcpcd-run-hook/21408:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-next-20250527-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 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: 69 Comm: kworker/u8:5 Not tainted 6.15.0-next-20250527-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue:  0x0 (events_unbound)
RIP: 0010:__list_del_entry_valid_or_report+0xbe/0x190 lib/list_debug.c:71
Code: 1f 0f 85 92 00 00 00 4d 8d 7e 08 4d 89 fc 49 c1 ec 03 43 80 3c 2c 00 74 08 4c 89 ff e8 8b 27 5d fd 49 39 1f 0f 85 9e 00 00 00 <b0> 01 5b 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc cc 48 c7 c7 20 99
RSP: 0018:ffffc9000211fbf8 EFLAGS: 00000046
RAX: 1ffff1100b5af381 RBX: ffff88805ad79c08 RCX: ffff88801af5da00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff88805ad79c10
RBP: ffff88805ad79c08 R08: ffff888140403087 R09: 1ffff11028080610
R10: dffffc0000000000 R11: ffffed1028080611 R12: 1ffffffff1ea2ab6
R13: dffffc0000000000 R14: ffffffff8f5155a8 R15: ffffffff8f5155b0
FS:  0000000000000000(0000) GS:ffff888125d55000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ba5fba6b0 CR3: 000000000df38000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:124 [inline]
 __list_del_entry include/linux/list.h:215 [inline]
 list_move_tail include/linux/list.h:310 [inline]
 move_linked_works kernel/workqueue.c:1147 [inline]
 assign_work+0x1fb/0x410 kernel/workqueue.c:1199
 worker_thread+0x88f/0xda0 kernel/workqueue.c:3401
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>