INFO: task syz.3.1957:11000 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1957      state:D stack:28272 pid:11000 tgid:10998 ppid:6773   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 super_lock+0x2a9/0x3b0
 __iterate_supers+0x126/0x290
 ksys_sync+0x94/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe9fa98eba9
RSP: 002b:00007fe9fb75b038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fe9fabd5fa0 RCX: 00007fe9fa98eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fe9fabd5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe9fabd6038 R14: 00007fe9fabd5fa0 R15: 00007ffe3901c558
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/u11:0/55:
 #0: ffff888109767948 ((wq_completion)hci6){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900007dfbc0 ((work_completion)(&hdev->power_on)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888122de4dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_power_on+0x1ac/0x680
3 locks held by kworker/1:2/792:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900045bfbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888035086240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180
2 locks held by getty/5682:
 #0: ffff88802935c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029032f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
2 locks held by syz-executor/5857:
1 lock held by syz.3.1957/11000:
 #0: ffff88802b6220e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.0.2710/13015:
 #0: ffff88802b6220e0 (&type->s_umount_key#81){++++}-{4:4}, at: super_lock+0x2a9/0x3b0
1 lock held by syz.7.2749/13139:
 #0: ffffffff8e13f9b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
2 locks held by syz.8.3102/14104:
1 lock held by syz.9.3116/14146:
 #0: ffffffff8e13f9b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730

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

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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 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: 13139 Comm: syz.7.2749 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_lockdep_rcu_enabled+0x21/0x40
Code: 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 31 c0 83 3d 57 72 29 04 00 74 1e 83 3d 6a a2 29 04 00 74 15 65 48 8b 0c 25 08 b0 a0 92 <31> c0 83 b9 ec 0a 00 00 00 0f 94 c0 e9 ce dc 02 00 cc cc cc cc cc
RSP: 0018:ffffc900071c7530 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff903f6501 RCX: ffff88811cbfd640
RDX: ffffc900071c7601 RSI: dffffc0000000000 RDI: ffffc900071c7610
RBP: dffffc0000000000 R08: ffffc900071c7970 R09: 0000000000000000
R10: ffffc900071c7658 R11: fffff52000e38ecd R12: ffffc900071c7980
R13: ffffc900071c0000 R14: ffffc900071c7608 R15: ffffffff8172c195
FS:  00007f48b6f536c0(0000) GS:ffff8881a3c15000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f48b6f07d60 CR3: 00000000293c4000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 unwind_next_frame+0x195c/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 save_stack+0xf5/0x1f0
 __reset_page_owner+0x71/0x1f0
 __free_frozen_pages+0xbc4/0xd30
 vfree+0x25a/0x400
 kcov_close+0x28/0x50
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f48b61c1465
Code: Unable to access opcode bytes at 0x7f48b61c143b.
RSP: 002b:00007f48b6f52f80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f48b63d5fa0 RCX: 00007f48b61c1465
RDX: 00007f48b6f52fc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f48b6211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007f48b63d6038 R14: 00007f48b63d5fa0 R15: 00007fff68f197b8
 </TASK>
