INFO: task syz.6.670:10128 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.670       state:D stack:26024 pid:10128 tgid:10126 ppid:9430   task_flags:0x400140 flags:0x00080002
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/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f97d518f749
RSP: 002b:00007f97d5f76038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f97d53e6090 RCX: 00007f97d518f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f97d53e6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f97d53e6128 R14: 00007f97d53e6090 R15: 00007ffd1ef57918
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/0:0/9:
 #0: ffff888100075948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900000e7ba0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88816e854240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1f7/0x3b0
1 lock held by khungtaskd/35:
 #0: 
ffffffff8df3d6a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
6 locks held by kworker/0:2/2215:
 #0: ffff888168121948 ((wq_completion)usb_hub_wq
){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: 
ffffc9000bc6fba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88810b0f4198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
 #3: ffff88810b0f7518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21b8/0x4a20
 #4: ffff88810b084768 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21e5/0x4a20
 #5: ffffffff8eb94950 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x163/0x1750
2 locks held by getty/5639:
 #0: ffff88817661e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by udevd/5823:
 #0: ffff88816c36d358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
5 locks held by kworker/1:8/6343:
 #0: ffff888168121948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: 
ffffc900036e7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88810b05c198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
 #3: ffff88816f857198 (
&dev->mutex
){....}-{4:4}
, at: __device_attach+0x88/0x400
 #4: ffff88816f854160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400
1 lock held by syz.6.670/10128:
 #0: ffff88816c36d358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.7.866/11080:
 #0: ffff88816c36d358 (
&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.3.1174/12430:
 #0: ffff88816c36d358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
8 locks held by syz.0.1263/12829:
1 lock held by syz.0.1263/12851:
 #0: ffff888028c44e30 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: process_measurement+0x3d8/0x1a40

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

NMI backtrace for cpu 0
CPU: 0 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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf60/0xfa0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 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: 12829 Comm: syz.0.1263 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:asm_sysvec_apic_timer_interrupt+0x0/0x20
Code: 36 56 47 0a e9 61 06 00 00 90 f3 0f 1e fa 0f 1f 00 fc 6a ff e8 11 05 00 00 48 89 c4 48 89 e7 e8 46 55 47 0a e9 41 06 00 00 90 <f3> 0f 1e fa 0f 1f 00 fc 6a ff e8 f1 04 00 00 48 89 c4 48 89 e7 e8
RSP: 0018:ffffc90005f86a78 EFLAGS: 00000046
RAX: ffffffff81a02ae5 RBX: ffffffff81a0293e RCX: 0000000000080000
RDX: ffffc90009ff5000 RSI: 000000000007ffff RDI: ffffffff8df31680
RBP: ffffc90005f86bb0 R08: ffffffff8f7cf777 R09: 1ffffffff1ef9eee
R10: dffffc0000000000 R11: fffffbfff1ef9eef R12: 0000000000000000
R13: 0000000000000060 R14: 0000000000000200 R15: 1ffff92000bf0d58
FS:  00007f44d5d7c6c0(0000) GS:ffff8882a9f36000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f44d5d5bd58 CR3: 00000001205e0000 CR4: 00000000000006f0
Call Trace:
 <TASK>
RIP: 0010:vprintk_emit+0x49d/0x590
Code: 0f 84 34 ff ff ff e8 82 ee 1f 00 fb eb 44 e8 7a ee 1f 00 e8 35 47 a7 09 4d 85 f6 74 94 e8 6b ee 1f 00 fb 48 c7 c7 80 16 f3 8d <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 0b 39
RSP: 0018:ffffc90005f86aa0 EFLAGS: 00000246
 _printk+0xcf/0x120
 xfs_buf_alert_ratelimited+0x224/0x230
 xfs_buf_read_map+0x584/0xa50
 xfs_trans_read_buf_map+0x1d7/0x8e0
 xfs_alloc_read_agfl+0x202/0x410
 xfs_alloc_fix_freelist+0xb93/0x1300
 xfs_alloc_vextent_prepare_ag+0xdb/0x610
 xfs_alloc_vextent_iterate_ags+0x140/0x940
 xfs_alloc_vextent_start_ag+0x388/0x850
 xfs_bmapi_allocate+0x188e/0x2e00
 xfs_bmapi_write+0x7df/0x1260
 xfs_alloc_file_space+0x522/0x9d0
 __xfs_file_fallocate+0x983/0x1610
 xfs_file_fallocate+0x27b/0x340
 vfs_fallocate+0x669/0x7e0
 __x64_sys_fallocate+0xc0/0x110
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f44d4f8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f44d5d7c038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f44d51e5fa0 RCX: 00007f44d4f8f749
RDX: 0000000000000003 RSI: 0000000000000010 RDI: 0000000000000005
RBP: 00007f44d5013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000007c27 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f44d51e6038 R14: 00007f44d51e5fa0 R15: 00007ffc31dffee8
 </TASK>
