INFO: task syz-executor:4707 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:4707  ppid:1      flags:0x00000009
Call trace:
 __switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0xdd0/0x1b0c kernel/sched/core.c:6562
 schedule+0xc4/0x170 kernel/sched/core.c:6638
 wb_wait_for_completion+0x150/0x29c fs/fs-writeback.c:191
 sync_inodes_sb+0x190/0x844 fs/fs-writeback.c:2756
 sync_filesystem+0x160/0x218 fs/sync.c:64
 generic_shutdown_super+0x70/0x324 fs/super.c:474
 kill_block_super+0x70/0xdc fs/super.c:1470
 deactivate_locked_super+0xac/0x120 fs/super.c:332
 deactivate_super+0xe4/0x104 fs/super.c:363
 cleanup_mnt+0x390/0x418 fs/namespace.c:1191
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1198
 task_work_run+0x1ec/0x278 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0x1fa0/0x2aa4 arch/arm64/kernel/signal.c:1151
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x98/0x128 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
5 locks held by kworker/0:0/7:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff8000153e7c30 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff8000153e8450 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
3 locks held by kworker/1:0/22:
 #0: ffff0000d6115938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265
 #1: ffff80001ca97c20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267
 #2: ffff80001787f188 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
3 locks held by kworker/1:1/24:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265
 #1: ffff80001cab7c20 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267
 #2: ffff0000d5b47240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x1d0/0x27cc drivers/net/netdevsim/fib.c:1491
1 lock held by khungtaskd/28:
 #0: ffff8000153e72c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
2 locks held by getty/4080:
 #0: 
ffff0000d682e098 (&tty->ldisc_sem
){++++}-{0:0}
, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: 
ffff80001cfe62f0
 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2ec/0xfa0 drivers/tty/n_tty.c:2198
4 locks held by kworker/u4:15/4546:
 #0: ffff0000c2c10938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265
 #1: ffff800020d87c20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267
 #2: ffff0000f81e2650 (sb_internal#3){.+.+}-{0:0}, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4571 [inline]
 #2: ffff0000f81e2650 (sb_internal#3){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x27c/0x12c0 fs/xfs/libxfs/xfs_bmap.c:4698
 #3: ffff0000d7a83758 (&xfs_nondir_ilock_class){++++}-{3:3}, at: mrupdate_nested fs/xfs/mrlock.h:36 [inline]
 #3: ffff0000d7a83758 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_ilock+0x210/0x480 fs/xfs/xfs_inode.c:211
2 locks held by syz-executor/4707:
 #0: ffff0000f81e20e0 (&type->s_umount_key#52){+.+.}-{3:3}, at: deactivate_super+0xdc/0x104 fs/super.c:362
 #1: ffff0000ce7aa7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff0000ce7aa7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x178/0x844 fs/fs-writeback.c:2754
5 locks held by kworker/0:7/4764:
3 locks held by kworker/0:11/5387:
 #0: ffff0000d6115938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265
 #1: ffff800020ef7c20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267
 #2: 
ffff80001787f188 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
4 locks held by kworker/u4:38/7168:
 #0: ffff0000c0845138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x6b8/0x13a4 kernel/workqueue.c:2265
 #1: ffff800023167c20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x6fc/0x13a4 kernel/workqueue.c:2267
 #2: ffff8000178728d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x134/0xa84 net/core/net_namespace.c:594
 #3: ffff80001787f188 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz-executor/7905:
 #0: ffff80001787f188 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff80001787f188 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x650/0xcdc net/core/rtnetlink.c:6147

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