INFO: task syz.9.677:8707 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.677       state:D stack:26784 pid:8707  tgid:8706  ppid:8465   task_flags:0x400140 flags:0x00080006
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_timeout+0xc0/0x2c0
 __down_common+0x3b7/0x850
 down+0x80/0xd0
 console_lock+0x58/0x90
 con_install+0x97/0x770
 tty_init_dev+0xd7/0x4d0
 tty_open+0x7d9/0xcc0
 chrdev_open+0x4d9/0x600
 do_dentry_open+0x816/0x1380
 vfs_open+0x3b/0x340
 path_openat+0x1443/0x1d60
 do_file_open+0x23e/0x4a0
 do_sys_openat2+0x115/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fed3355ea0e
RSP: 002b:00007fed3444bb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fed3444c6c0 RCX: 00007fed3355ea0e
RDX: 0000000000000002 RSI: 00007fed3444bc00 RDI: ffffffffffffff9c
RBP: 00007fed33635888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fed33826038 R14: 00007fed33825fa0 R15: 00007ffe010f68c8
 </TASK>
INFO: task syz.8.679:8721 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.679       state:D stack:28544 pid:8721  tgid:8719  ppid:7464   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 tty_open+0x204/0xcc0
 chrdev_open+0x4d9/0x600
 do_dentry_open+0x816/0x1380
 vfs_open+0x3b/0x340
 path_openat+0x1443/0x1d60
 do_file_open+0x23e/0x4a0
 do_sys_openat2+0x115/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f434f55ea0e
RSP: 002b:00007f43504a6b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f43504a76c0 RCX: 00007f434f55ea0e
RDX: 0000000000000002 RSI: 00007f43504a6c00 RDI: ffffffffffffff9c
RBP: 00007f434f635888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f434f826128 R14: 00007f4
R13: 00007f434f826128 R14: 00007f434f826090 R15: 00007ffef4fd4e58
 </TASK>

Showing all locks held in the system:
locks held by pr/ttyS0/16: 2, last CPU#1:
 #0: ffffffff8fc362b8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60
 #1: ffffffff9bd36bd8 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0
locks held by rcu_tasks_kthre/33: 1, on CPU#1:
 #0: ffffffff8fd5d088 (rcu_tasks.tasks_gp_mutex){+.+.}-{4:4}, at: rcu_tasks_one_gp+0xb2d/0xe30
locks held by khungtaskd/36: 1, last CPU#0:
 #0: ffffffff8fd5c6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by kworker/u9:3/282: 3, last CPU#0:
 #0: ffff88810f3e1940 ((wq_completion)xfs-cil/loop9){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc9000364fc40 ((work_completion)(&ctx->push_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #2: ffffffff8fea54e0 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: fs_reclaim_acquire+0x7c/0x100
locks held by kworker/u10:5/1107: 2, on CPU#1:
 #0: ffff88816945a940 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc900074bfc40 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
locks held by getty/5423: 2, on CPU#1:
 #0: ffff8881762b00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034932e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
locks held by kworker/1:5/5672: 3, on CPU#1:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc90004fffc40 ((work_completion)(&helper->damage_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #2: ffff888109b0fa70 (&helper->lock){+.+.}-{4:4}, at: drm_fb_helper_damage_work+0x15b/0xf20
locks held by syz.4.639/8486: 6, last CPU#0:
 #0: ffffffff8fd4ea20 (console_lock){+.+.}-{0:0}, at: vt_ioctl+0x1d06/0x20e0
 #1: ffff888109b0fa70 (&helper->lock){+.+.}-{4:4}, at: drm_fb_helper_pan_display+0xbe/0xbe0
 #2: ffff888109b40128 (&dev->master_mutex){+.+.}-{4:4}, at: drm_master_internal_acquire+0x20/0x80
 #3: ffff888109b0f890 (&client->modeset_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_locked+0x4c/0x4d0
 #4: ffffc900072ff590 (crtc_ww_class_acquire){+.+.}-{0:0}, at: drm_client_modeset_commit_atomic+0x11a/0x7e0
 #5: ffffc900072ff5b8 (crtc_ww_class_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_atomic+0x11a/0x7e0
locks held by syz.9.677/8707: 2, on CPU#1:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
 #1: ffff8881be7601b0 (&tty->legacy_mutex){+.+.}-{4:4}, at: tty_init_dev+0x74/0x4d0
locks held by syz.8.679/8721: 1, on CPU#0:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
locks held by syz.3.701/9120: 1, on CPU#0:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0
locks held by syz.2.707/9172: 1, on CPU#0:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0
locks held by syz.1.738/9459: 1, on CPU#1:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0
locks held by syz.0.742/9522: 1, on CPU#0:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
locks held by syz.5.748/9539: 1, on CPU#1:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0
locks held by syz.7.750/9789: 1, on CPU#0:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
locks held by syz.4.761/9863: 1, on CPU#1:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
locks held by syz.6.778/9930: 1, on CPU#1:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
locks held by syz.8.792/10128: 1, on CPU#0:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
locks held by syz.8.792/10129: 1, on CPU#0:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
locks held by syz.8.792/10132: 1, on CPU#0:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
locks held by syz.3.795/10162: 1, on CPU#1:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
locks held by syz.2.796/10195: 1, on CPU#1:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0
locks held by syz.5.802/10412: 1, on CPU#0:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x204/0xcc0
locks held by syz.0.858/10591: 1, on CPU#0:
 #0: ffffffff90677ba0 (tty_mutex){+.+.}-{4:4}, at: ptmx_open+0xdc/0x2e0
locks held by syz.9.891/10894: 3, last CPU#0:
 #0: ffff88802234c0e8 (&type->s_umount_key#94/1){+.+.}-{4:4}, at: sget_fc+0x97c/0x1a40
 #1: ffff888118efb150 (&qinf->qi_tree_lock){+.+.}-{4:4}, at: xfs_qm_dquot_walk+0x191/0x5d0
 #2: ffff88810f41d648 (&dqp->q_qlock){+.+.}-{4:4}, at: xfs_qm_flush_one+0x9f/0x200

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 36 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17d/0x390
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 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: 16 Comm: pr/ttyS0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:io_serial_out+0x7c/0xc0
Code: 05 55 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 0c 9f c5 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 07 57 75 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90000157900 EFLAGS: 00000002
RAX: 0000000000000030 RBX: 0000000000000030 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff8572b110 R12: dffffc0000000000
R13: 0000000000000030 R14: ffffffff9bd36c00 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8882a7cd4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa413e27dac CR3: 000000016e120000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __serial8250_console_fifo_write+0x1e6/0x3e0
 serial8250_console_write+0xaa1/0x1200
 nbcon_emit_next_record+0xef5/0x1a90
 nbcon_kthread_func+0x679/0x880
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
