INFO: task syz-executor:5821 blocked for more than 143 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21672 pid:5821  tgid:5821  ppid:1      task_flags:0x40014c flags:0x00080001
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 wb_wait_for_completion+0x15f/0x260
 sync_inodes_sb+0x1bb/0xa10
 sync_filesystem+0x17a/0x230
 generic_shutdown_super+0x6f/0x2c0
 kill_block_super+0x44/0x90
 ext4_kill_sb+0x68/0xb0
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x425/0x4c0
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x2300
 do_group_exit+0x21c/0x2d0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x21f7/0x2200
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb39918f749
RSP: 002b:00007ffc89c17028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fb399213def RCX: 00007fb39918f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000010 R08: 00007ffc89c14dc6 R09: 00007ffc89c182e0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc89c182e0
R13: 00007fb399213d7d R14: 0000555578b7e4a8 R15: 00007ffc89c193b0
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u10:0/27:
1 lock held by khungtaskd/35:
 #0: ffffffff8df3d6a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5637:
 #0: ffff8881744780a0 (&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
2 locks held by syz-executor/5821:
 #0: ffff888113c6e0e0 (&type->s_umount_key#31){++++}-{4:4}, at: deactivate_super+0xa9/0xe0
 #1: ffff888108e60820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10
3 locks held by kworker/0:5/6469:
1 lock held by syz-executor/9268:
1 lock held by syz.6.1176/9440:
2 locks held by syz.9.1178/9448:
 #0: ffffffff8f2cc808 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
 #1: ffffffff8df43138 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730

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

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: 9268 Comm: syz-executor 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:validate_chain+0x3/0x2140
Code: 4c 89 ff 29 f5 0f 82 91 fe ff ff eb b3 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 <41> 56 41 55 41 54 53 48 81 ec e0 00 00 00 49 89 cf 65 48 8b 05 24
RSP: 0018:ffffc900047673f0 EFLAGS: 00000086
RAX: ffffffff931758a8 RBX: 0000000000000000 RCX: 0ac0d5affe09d4ff
RDX: 0000000000000001 RSI: ffff888102f44530 RDI: ffff888102f43a00
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff81739c45
R10: ffffc90004767658 R11: ffffffff81ac4240 R12: 0000000000004008
R13: ffff888102f44530 R14: ffff888102f44530 R15: 0ac0d5affe09d4ff
FS:  0000555570be0500(0000) GS:ffff8882a9f36000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007febd4fa00e8 CR3: 0000000173b9e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 unwind_next_frame+0xc2/0x2390
 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: 0033:0x7fad0fbc2005
Code: Unable to access opcode bytes at 0x7fad0fbc1fdb.
RSP: 002b:00007ffe2d5060f0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: 0000000000000000 RBX: 0000000000000011 RCX: 00007fad0fbc2005
RDX: 00007ffe2d506130 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffe2d50619c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000001388
R13: 00000000000927c0 R14: 00000000000358a2 R15: 00007ffe2d5061f0
 </TASK>
