INFO: task syz-executor:4327 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    state:D stack:0     pid:4327  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+0xdb4/0x1a6c kernel/sched/core.c:6562
 schedule+0xc4/0x170 kernel/sched/core.c:6638
 wb_wait_for_completion+0x158/0x29c fs/fs-writeback.c:191
 sync_inodes_sb+0x188/0x81c fs/fs-writeback.c:2756
 sync_filesystem+0x160/0x218 fs/sync.c:64
 generic_shutdown_super+0x74/0x32c fs/super.c:474
 kill_block_super+0x78/0xe0 fs/super.c:1470
 deactivate_locked_super+0xb4/0x128 fs/super.c:332
 deactivate_super+0xe4/0x104 fs/super.c:363
 cleanup_mnt+0x3a8/0x430 fs/namespace.c:1191
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1198
 task_work_run+0x1f4/0x280 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0x20f8/0x2c84 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:
4 locks held by kworker/u4:1/11:
 #0: 
ffff0000c2c2c138
 (
(wq_completion)writeback
){+.+.}-{0:0}, at: process_one_work+0x69c/0x13bc kernel/workqueue.c:-1
 #1: ffff80001caf7c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x6e8/0x13bc kernel/workqueue.c:2267
 #2: ffff0000cbfce650 (sb_internal#2){.+.+}-{0:0}, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4571 [inline]
 #2: ffff0000cbfce650 (sb_internal#2){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x25c/0x129c fs/xfs/libxfs/xfs_bmap.c:4698
 #3: ffff0000f6513758
 (
&xfs_nondir_ilock_class
){++++}-{3:3}, at: mrupdate_nested fs/xfs/mrlock.h:36 [inline]
){++++}-{3:3}, at: xfs_ilock+0x210/0x480 fs/xfs/xfs_inode.c:211
1 lock held by rcu_tasks_kthre/12:
 #0: ffff800015507db0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xc48 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff8000155085d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xc48 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffff800015507440 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
1 lock held by dhcpcd/3993:
 #0: 
ffff8000179a32c8 (
rtnl_mutex
){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
2 locks held by getty/4081:
 #0: ffff0000d688a098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff800020a8b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2e8/0xfa8 drivers/tty/n_tty.c:2198
2 locks held by syz-executor/4327:
 #0: ffff0000d9fd40e0 (&type->s_umount_key#54){++++}-{3:3}, at: deactivate_super+0xdc/0x104 fs/super.c:362
 #1: 
ffff0000ceee07d0
 (&bdi->wb_switch_rwsem){+.+.}-{3:3}
, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
, at: sync_inodes_sb+0x170/0x81c fs/fs-writeback.c:2754
2 locks held by syz-executor/4328:
 #0: 
ffff000101c260e0
 (
&type->s_umount_key
#54){++++}-{3:3}, at: deactivate_super+0xdc/0x104 fs/super.c:362
 #1: ffff0000ceefc7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff0000ceefc7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x170/0x81c fs/fs-writeback.c:2754
2 locks held by syz-executor/4332:
 #0: 
ffff0000cbfce0e0 (&type->s_umount_key#54){++++}-{3:3}, at: deactivate_super+0xdc/0x104 fs/super.c:362
 #1: ffff0000cee4a7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff0000cee4a7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x170/0x81c fs/fs-writeback.c:2754
4 locks held by kworker/u4:9/4525:
 #0: 
ffff0000c2c2c138
 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x69c/0x13bc kernel/workqueue.c:-1
 #1: ffff8000214b7c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x6e8/0x13bc kernel/workqueue.c:2267
 #2: 
ffff000101c26650
 (sb_internal#2){.+.+}-{0:0}, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4571 [inline]
 (sb_internal#2){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x25c/0x129c fs/xfs/libxfs/xfs_bmap.c:4698
 #3: 
ffff0000f653af98
 (
&xfs_nondir_ilock_class
){++++}-{3:3}
, at: mrupdate_nested fs/xfs/mrlock.h:36 [inline]
, at: xfs_ilock+0x210/0x480 fs/xfs/xfs_inode.c:211
2 locks held by kworker/0:9/4528:
4 locks held by kworker/u4:15/4689:
 #0: ffff0000c2c2c138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x69c/0x13bc kernel/workqueue.c:-1
 #1: 
ffff8000216f7c40
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}
, at: process_one_work+0x6e8/0x13bc kernel/workqueue.c:2267
 #2: 
ffff0000d9fd4650
 (
sb_internal
#2
){.+.+}-{0:0}
, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4571 [inline]
, at: xfs_bmapi_convert_delalloc+0x25c/0x129c fs/xfs/libxfs/xfs_bmap.c:4698
 #3: ffff0000e1e53f18 (&xfs_nondir_ilock_class){++++}-{3:3}, at: mrupdate_nested fs/xfs/mrlock.h:36 [inline]
 #3: ffff0000e1e53f18 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_ilock+0x210/0x480 fs/xfs/xfs_inode.c:211
4 locks held by kworker/u4:17/4850:
 #0: ffff0000c0845138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x69c/0x13bc kernel/workqueue.c:-1
 #1: 
ffff800021717c40
 (
net_cleanup_work
){+.+.}-{0:0}
, at: process_one_work+0x6e8/0x13bc kernel/workqueue.c:2267
 #2: ffff800017996a50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x144/0xa90 net/core/net_namespace.c:594
 #3: ffff8000179a32c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz.7.289/5916:
 #0: ffff0000d9fd40e0 (&type->s_umount_key#54){++++}-{3:3}, at: iterate_supers+0xa8/0x1d4 fs/super.c:755
3 locks held by kworker/u4:25/6002:
 #0: 
ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x69c/0x13bc kernel/workqueue.c:-1
 #1: 
ffff800021b57c40
 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x6e8/0x13bc kernel/workqueue.c:2267
 #2: 
ffff8000179a32c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
3 locks held by kworker/0:13/6582:
 #0: 
ffff0000d6416538
 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x69c/0x13bc kernel/workqueue.c:-1
 #1: ffff8000216e7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6e8/0x13bc kernel/workqueue.c:2267
 #2: 
ffff8000179a32c8
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz.9.747/7938:
 #0: 
ffff8000179a32c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz.1.753/7955:
 #0: ffff8000179a32c8 (rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
, at: rtnetlink_rcv_msg+0x64c/0xcc4 net/core/rtnetlink.c:6155
1 lock held by syz.2.755/7965:
 #0: 
ffff8000179a32c8
 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x64c/0xcc4 net/core/rtnetlink.c:6155
1 lock held by syz.4.762/7991:
 #0: ffff8000179a32c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffff8000179a32c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x64c/0xcc4 net/core/rtnetlink.c:6155
1 lock held by syz.4.762/7992:
 #0: 
ffff8000179a32c8
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz.4.762/7993:
 #0: ffff8000179a32c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz.4.762/7994:
 #0: 
ffff8000179a32c8
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
, at: rtnetlink_rcv_msg+0x64c/0xcc4 net/core/rtnetlink.c:6155
1 lock held by syz.8.765/8003:
 #0: 
ffff8000179a32c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz.8.765/8004:
 #0: ffff8000179a32c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz.8.765/8005:
 #0: ffff8000179a32c8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:74
1 lock held by syz.8.765/8006:
 #0: 
ffff8000179a32c8
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
, at: rtnetlink_rcv_msg+0x64c/0xcc4 net/core/rtnetlink.c:6155

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