INFO: task syz.2.1490:9860 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1490      state:D stack:26024 pid:9860  tgid:9859  ppid:5847   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 sync_bdevs+0x1ac/0x340
 ksys_sync+0xb9/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8f9a58ec29
RSP: 002b:00007f8f9b3ee038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f8f9a7d5fa0 RCX: 00007f8f9a58ec29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f8f9a7d5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8f9a7d6038 R14: 00007f8f9a7d5fa0 R15: 00007ffe6dfa9c38
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5675:
 #0: ffff88810a25f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by udevd/6052:
 #0: ffff8881078ac358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
3 locks held by kworker/1:5/6887:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900044ffbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888045f7b240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180
1 lock held by syz.2.1490/9860:
 #0: ffff8881078ac358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340

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

NMI backtrace for cpu 1
CPU: 1 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+0x439/0x7d0
 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: 0 Comm: swapper/0 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:native_apic_msr_write+0x39/0x50
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 cc cc cc cc cc f3 0f 1e fa 89 f6 31 d2 e9 12 17 8f 03 66
RSP: 0018:ffffc90000007e50 EFLAGS: 00000046
RAX: 0000000000001a7f RBX: ffff88804b023900 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 0000000000001a7f RDI: 0000000000000838
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81ae036e
R10: 0000000000000003 R11: ffffffff81703490 R12: 0000000010003fc0
R13: dffffc0000000000 R14: 0000000000001a7f R15: 0000000000000020
FS:  0000000000000000(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2ade9a3368 CR3: 0000000112c42000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 lapic_next_event+0x11/0x20
 clockevents_program_event+0x1cf/0x360
 hrtimer_interrupt+0x620/0xaa0
 __sysvec_apic_timer_interrupt+0x10b/0x410
 sysvec_apic_timer_interrupt+0xa1/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:pv_native_safe_halt+0x13/0x20
Code: 53 e8 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d b3 d9 0d 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8de07d80 EFLAGS: 00000282
RAX: a307077caa310d00 RBX: ffffffff819683f8 RCX: a307077caa310d00
RDX: 0000000000000001 RSI: ffffffff8d9ba2fc RDI: ffffffff8be33f80
RBP: ffffffff8de07eb8 R08: ffff88804b032f9b R09: 1ffff110096065f3
R10: dffffc0000000000 R11: ffffed10096065f4 R12: ffffffff8fa3a730
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a20
 default_idle+0x13/0x20
 default_idle_call+0x74/0xb0
 do_idle+0x1e8/0x510
 cpu_startup_entry+0x44/0x60
 rest_init+0x2de/0x300
 start_kernel+0x3a9/0x410
 x86_64_start_reservations+0x24/0x30
 x86_64_start_kernel+0x143/0x1c0
 common_startup_64+0x13e/0x147
 </TASK>
