INFO: task syz.0.2156:15587 blocked for more than 143 seconds.
      Not tainted 6.16.0-syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2156      state:D
 stack:24696 pid:15587 tgid:15586 ppid:5842   task_flags:0x40054c flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5397 [inline]
 __schedule+0x16fd/0x4cf0 kernel/sched/core.c:6786
 __schedule_loop kernel/sched/core.c:6864 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6879
 wb_wait_for_completion+0x15f/0x260 fs/fs-writeback.c:216
 sync_inodes_sb+0x1bb/0xa10 fs/fs-writeback.c:2833
 sync_filesystem+0x17a/0x230 fs/sync.c:64
 generic_shutdown_super+0x6f/0x2c0 fs/super.c:622
 kill_block_super+0x44/0x90 fs/super.c:1755
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1417
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6b5/0x22e0 kernel/exit.c:964
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1105
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:111
 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: 0033:0x7fdfddb8e9a9
RSP: 002b:00007fdfdeabe038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: 000000000000005c RBX: 00007fdfdddb5fa0 RCX: 00007fdfddb8e9a9
RDX: 0000000000004014 RSI: 00002000000000c0 RDI: 0000000000000007
RBP: 00007fdfddc10d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fdfdddb5fa0 R15: 00007ffd4fb966e8
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u8:0/12:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13f0e0
 (
rcu_read_lock
){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
2 locks held by kworker/u8:7/1093:
 #0: ffff88801ba85948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801ba85948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc9000400fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000400fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
3 locks held by kworker/u8:9/2980:
 #0: 
ffff88814bf3a148
 (
(wq_completion)ipv6_addrconf
){+.+.}-{0:0}
, at: process_one_work kernel/workqueue.c:3213 [inline]
, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: 
ffffc9000bc37bc0
 (
(work_completion)(&(&ifa->dad_work)->work)
){+.+.}-{0:0}
, at: process_one_work kernel/workqueue.c:3214 [inline]
, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: 
ffffffff8f51c1c8
 (
rtnl_mutex
){+.+.}-{4:4}
, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4193
2 locks held by getty/5602:
 #0: 
ffff8880312260a0
 (