INFO: task syz.0.85:6246 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.85        state:D stack:26120 pid:6246  tgid:6245  ppid:5817   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 bdev_open+0xe0/0xd30
 blkdev_open+0x457/0x600
 do_dentry_open+0x953/0x13f0
 vfs_open+0x3b/0x340
 path_openat+0x2ee5/0x3830
 do_filp_open+0x1fa/0x410
 do_sys_openat2+0x121/0x1c0
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa55478d810
RSP: 002b:00007fa5556aeb70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000082 RCX: 00007fa55478d810
RDX: 0000000000000082 RSI: 00007fa5556aec10 RDI: 00000000ffffff9c
RBP: 00007fa5556aec10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd
R13: 00007fa5549e6038 R14: 00007fa5549e5fa0 R15: 00007ffdda99a318
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8df3d2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/1:2/973:
 #0: ffff888168133548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900075b7ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88816e538198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
6 locks held by kworker/u9:3/1090:
2 locks held by getty/5638:
 #0: ffff8881144cc0a0 (&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/5816:
 #0: ffff888105be7358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
3 locks held by kworker/0:4/6114:
 #0: ffff888168133548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90005f7fba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88810b030198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20
1 lock held by syz.0.85/6246:
 #0: ffff888105be7358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
1 lock held by syz.0.85/6247:
 #0: ffff888116c4c0e0 (&type->s_umount_key#75/1){+.+.}-{4:4}, at: alloc_super+0x1bb/0x930

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

NMI backtrace for cpu 1
CPU: 1 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 8287 Comm: syz.2.598 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:deref_stack_reg+0x1cf/0x230
Code: 24 18 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 83 24 b2 00 4c 89 33 b0 01 eb 02 31 c0 48 83 c4 20 5b 41 5c 41 5d <41> 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 80 c1 03 38 c1
RSP: 0018:ffffc90001787518 EFLAGS: 00000286
RAX: 1ffff920002f0e01 RBX: ffffffff9019c13a RCX: 0000000000000001
RDX: ffffc90001787648 RSI: dffffc0000000000 RDI: ffffc90001787a10
RBP: 1ffff920002f0ec1 R08: ffffc90001787a10 R09: 0000000000000000
R10: ffffc90001787658 R11: fffff520002f0ecd R12: ffffc90001787a10
R13: ffffc90001787658 R14: ffffc90001787ad0 R15: dffffc0000000000
FS:  00007fae2a5df6c0(0000) GS:ffff88818eb35000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc6b9ccbc8 CR3: 000000000dd38000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 unwind_next_frame+0x17c4/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 save_stack+0xf5/0x1f0
 __reset_page_owner+0x71/0x1f0
 __free_frozen_pages+0xbc8/0xd30
 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: 0033:0x7fae297c1885
Code: Unable to access opcode bytes at 0x7fae297c185b.
RSP: 002b:00007fae2a5def80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007fae299e5fa0 RCX: 00007fae297c1885
RDX: 00007fae2a5defc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fae29811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007fae299e6038 R14: 00007fae299e5fa0 R15: 00007ffcb665d738
 </TASK>
hpet: Lost 8 RTC interrupts
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
