INFO: task syz.9.1033:16225 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.1033      state:D stack:24568 pid:16225 tgid:16224 ppid:14478  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x6d9/0x940
 down_read+0x99/0x2e0
 super_lock+0x2d6/0x3d0
 __iterate_supers+0x126/0x250
 __ia32_sys_sync+0xa0/0x120
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f014579cdd9
RSP: 002b:00007f01466aa028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f0145a15fa0 RCX: 00007f014579cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f0145a15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0145a16038 R14: 00007f0145a15fa0 R15: 00007fff0c52cc98
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e95d020 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
5 locks held by kworker/u10:4/3525:
1 lock held by udevd/5258:
2 locks held by getty/5636:
 #0: ffff88810b7400a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000346b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
1 lock held by udevd/7636:
2 locks held by syz-executor/7655:
2 locks held by syz-executor/11294:
1 lock held by syz.9.1033/16225:
 #0: ffff8881138ae0d8 (&type->s_umount_key#50){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
1 lock held by syz.2.1079/16691:
 #0: ffff8881138ae0d8 (&type->s_umount_key#50){++++}-{4:4}, at: super_lock+0x289/0x3d0
1 lock held by syz.0.1125/17173:
 #0: ffff8881138ae0d8 (&type->s_umount_key#50){++++}-{4:4}, at: super_lock+0x2d6/0x3d0
2 locks held by syz.3.1263/18551:
1 lock held by syz.8.1264/18565:
 #0: ffff888114cba0d8 (&type->s_umount_key#62/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0
2 locks held by udevadm/18570:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 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+0xfaa/0x1000
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 3525 Comm: kworker/u10:4 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
Workqueue: btrfs-endio-meta simple_end_io_work
RIP: 0010:__lock_acquire+0x197b/0x2cf0
Code: 14 25 ff 0f 00 00 39 05 8f f6 a3 12 73 06 89 05 87 f6 a3 12 48 8b 02 48 89 df 4c 39 e8 0f 84 2c fe ff ff 4c 89 60 30 48 8b 00 <4c> 39 e8 75 f4 48 89 df e9 18 fe ff ff 48 89 fb 48 c7 c7 b0 b1 82
RSP: 0018:ffffc900222f73c0 EFLAGS: 00000002
RAX: ffffffff96f2ed98 RBX: 00000000000003fd RCX: 00000000000001d0
RDX: ffffffff96dd9fb8 RSI: ffff888175cd0c08 RDI: 00000000000003fd
RBP: 6d3933e953f95e7b R08: ffffc900222f7388 R09: 0000000000000020
R10: 0000000000000003 R11: ffffffff81a1e3d0 R12: ffffffff96df9ba8
R13: ffffffff93edf978 R14: ffff888175cd0000 R15: 00000000000001cf
FS:  0000000000000000(0000) GS:ffff8882a9245000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff4e14ea028 CR3: 000000010e2d6000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x350
 seqcount_lockdep_reader_access+0x55/0x100
 ktime_get+0x45/0x220
 clockevents_program_event+0x290/0x5f0
 __hrtimer_rearm_deferred+0x270/0x450
 irqentry_exit+0x6a0/0x730
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80
Code: f7 e8 0d 5c ec f5 f7 c3 00 02 00 00 74 05 e8 10 78 17 f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> a4 ed dd f5 65 8b 05 9d f0 87 07 85 c0 74 18 5b 41 5e e9 41 48
RSP: 0018:ffffc900222f7808 EFLAGS: 00000206
RAX: 0000000000000002 RBX: 0000000000000246 RCX: 0000000000000001
RDX: 0000000000000006 RSI: ffffffff8dfb655a RDI: 0000000000000001
RBP: 1ffffffff1d2c500 R08: ffffffff903215b7 R09: 1ffffffff20642b6
R10: dffffc0000000000 R11: fffffbfff20642b7 R12: ffffffff8e962ca0
R13: ffffffff8e962bc0 R14: ffffffff8e963118 R15: 0000000000000000
 rcu_preempt_deferred_qs_irqrestore+0x906/0xbc0
 __rcu_read_unlock+0x83/0xe0
 btrfs_validate_extent_buffer+0x758/0x1c90
 end_bbio_meta_read+0x10f/0x1e0
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
