INFO: task syz.3.350:8453 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.350       state:D stack:23136 pid:8453  tgid:8452  ppid:7823   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x149b/0x4fd0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x99/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 __se_sys_quotactl+0x353/0x950
 do_syscall_64+0xec/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc06158f7c9
RSP: 002b:00007fc062440038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007fc0617e5fa0 RCX: 00007fc06158f7c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000102
RBP: 00007fc0615f297f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc0617e6038 R14: 00007fc0617e5fa0 R15: 00007ffd520c2e28
 </TASK>
INFO: task syz.3.350:8459 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.350       state:D stack:26904 pid:8459  tgid:8452  ppid:7823   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x149b/0x4fd0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x99/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 __se_sys_quotactl+0x353/0x950
 do_syscall_64+0xec/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc06158f7c9
RSP: 002b:00007fc06241f038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007fc0617e6090 RCX: 00007fc06158f7c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000102
RBP: 00007fc0615f297f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc0617e6128 R14: 00007fc0617e6090 R15: 00007ffd520c2e28
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8df41a20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/u10:12/3613:
 #0: ffff888100089948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770
 #1: ffffc90023237bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770
 #2: ffffffff8f311c48 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
1 lock held by dhcpcd/5578:
 #0: ffffffff8f311c48 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_deladdr+0x20f/0x330
2 locks held by getty/5660:
 #0: ffff888175a120a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460
3 locks held by syz-executor/5834:
5 locks held by kworker/u8:4/5867:
 #0: ffff888100ef7948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770
 #1: ffffc90005b47bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770
 #2: ffffffff8f304bb0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x7a0
 #3: ffffffff8f311c48 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xdc/0x9e0
 #4: ffffffff8df47578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x36e/0x6e0
4 locks held by syz-executor/7199:
1 lock held by syz.3.350/8453:
 #0: ffff8881bb0040e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.3.350/8459:
 #0: ffff8881bb0040e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.6.520/9715:
 #0: ffff8881bcdca0e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x25c/0x3b0
1 lock held by syz.0.521/9719:
 #0: ffff8881bb0040e0 (&type->s_umount_key#62){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz-executor/11361:
 #0: ffffffff8df47578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x36e/0x6e0
1 lock held by syz-executor/11597:
 #0: ffffffff8f311c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8ec/0x1c90

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xf95/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x510/0xa50
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 11361 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:debug_object_activate+0x2f4/0x540
Code: 03 42 80 3c 30 00 74 08 4c 89 ff e8 d6 4f 8f fd 4d 8b 1f 4d 85 db 74 3b 48 8b 7c 24 10 2e e8 03 9e c4 06 48 89 44 24 08 eb 32 <43> 0f b6 04 37 84 c0 0f 85 21 02 00 00 41 c7 04 24 03 00 00 00 48
RSP: 0018:ffffc90008e0f778 EFLAGS: 00000093
RAX: 0000000000000000 RBX: ffffc90007360000 RCX: ffffc90008e10001
RDX: ffffc90008e08000 RSI: ffffffff8bc082c0 RDI: ffff888114efd940
RBP: ffff888114efd930 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff81a5d770 R12: ffff888114efd940
R13: 0000000000000001 R14: dffffc0000000000 R15: 1ffff110229dfb28
FS:  000055556fdd7500(0000) GS:ffff88818e821000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d312ff8 CR3: 00000001b9694000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 call_rcu+0x43/0x890
 put_task_stack+0x133/0x1c0
 finish_task_switch+0x4b9/0x940
 __schedule+0x14a3/0x4fd0
 preempt_schedule_common+0x83/0xd0
 preempt_schedule_thunk+0x16/0x30
 try_to_wake_up+0x82b/0x12b0
 kthread_stop+0x177/0x590
 xfs_trans_ail_destroy+0x59/0x70
 xfs_log_unmount+0x13c/0x1c0
 xfs_unmountfs+0x25d/0x320
 xfs_fs_put_super+0x65/0x160
 generic_shutdown_super+0x135/0x2c0
 kill_block_super+0x44/0x90
 xfs_kill_sb+0x15/0x50
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x425/0x4c0
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xef/0x4e0
 do_syscall_64+0x2b7/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb352d90af7
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffd4ed8dd28 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fb352dee72f RCX: 00007fb352d90af7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd4ed8dde0
RBP: 00007ffd4ed8dde0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd4ed8ee70
R13: 00007fb352dee72f R14: 000000000004d69f R15: 00007ffd4ed8eeb0
 </TASK>
