INFO: task syz.8.1591:12751 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.1591      state:D stack:24424 pid:12751 tgid:12750 ppid:12065  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: 0033:0x7f1070b8ec29
RSP: 002b:00007f107199c038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f1070dd5fa0 RCX: 00007f1070b8ec29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f1070dd5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1070dd6038 R14: 00007f1070dd5fa0 R15: 00007fff31b418a8
 </TASK>

Showing all locks held in the system:
5 locks held by kworker/0:0/9:
 #0: ffff888104b27948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900000c7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff8881094c8198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
 #3: ffff888032356198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400
 #4: ffff8880200f6d68 (hcd->bandwidth_mutex){+.+.}-{4:4}, at: usb_set_configuration+0x53e/0x20e0
5 locks held by kworker/1:0/24:
 #0: ffff888104b27948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900001c7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888024798198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
 #3: ffff88802479b518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21b8/0x4a20
 #4: ffff88802012e368 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21e5/0x4a20
1 lock held by khungtaskd/34:
 #0: ffffffff8e33d320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5672:
 #0: ffff8880208d10a0 (&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/5856:
 #0: ffff8880234a7358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
4 locks held by udevd/9590:
 #0: ffff88802881d2f0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe20
 #1: ffff88812a3ecc88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420
 #2: ffff888023a8a4b8 (kn->active#31){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420
 #3: ffff888032356198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0
1 lock held by syz.8.1591/12751:
 #0: ffff8880234a7358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340
1 lock held by syz.2.2292/15888:
 #0: ffffffff8e342db8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
1 lock held by syz.1.2293/15890:

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

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+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: 15888 Comm: syz.2.2292 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:__sanitizer_cov_trace_pc+0x2f/0x70
Code: 8b 04 24 65 48 8b 0c 25 08 40 c2 92 65 8b 15 18 e4 01 11 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 7c 16 00 00 00 <74> 2c 8b 91 58 16 00 00 83 fa 02 75 21 48 8b 91 60 16 00 00 48 8b
RSP: 0018:ffffc900001e0da0 EFLAGS: 00000046
RAX: ffffffff81ae3b95 RBX: 0000000000000040 RCX: ffff888020f15700
RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200003c170 R12: ffff888136627b38
R13: 00000078ee775a64 R14: 0000000000000000 R15: ffff888024296418
FS:  00007f5b75c176c0(0000) GS:ffff8881a39fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000020000 CR3: 0000000033ed2000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 __hrtimer_next_event_base+0x235/0x2d0
 hrtimer_run_softirq+0x1ff/0x2b0
 handle_softirqs+0x286/0x870
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:lock_release+0x2b5/0x3e0
Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 1b 30 24 11 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90004dc7470 EFLAGS: 00000206
RAX: 3f809b5da5e41a00 RBX: 0000000000000206 RCX: 3f809b5da5e41a00
RDX: 0000000000000000 RSI: ffffffff8dd8de2b RDI: ffffffff8c03da60
RBP: ffff888020f16230 R08: ffffc90004dc75f8 R09: 0000000000000000
R10: ffffc90004dc7658 R11: fffff520009b8ecd R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff8e33d320 R15: ffff888020f15700
 unwind_next_frame+0x19a9/0x2390
 __unwind_start+0x5b9/0x760
 arch_stack_walk+0xe4/0x150
 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+0x1285/0x1340
 arch_do_signal_or_restart+0xa0/0x790
 exit_to_user_mode_loop+0x72/0x130
 do_syscall_64+0x2bd/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5b74d8e82b
Code: Unable to access opcode bytes at 0x7f5b74d8e801.
RSP: 002b:00007f5b75c14eb0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffea RBX: 00007f5b75100320 RCX: 00007f5b74d8e82b
RDX: 00007f5b7510034c RSI: 0000000040095505 RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000011 R11: 0000000000000246 R12: 00007f5b7510034e
R13: 00007f5b7510034c R14: 0000000000000000 R15: 0000000000000000
 </TASK>
