INFO: task syz.0.3206:23622 blocked for more than 143 s
INFO: task syz.0.3206:23622 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.0.3206      state:D stack:28464 pid:23622 tgid:23621 ppid:23469  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d4/0x5820
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 bdev_open+0xde/0xd70
 bdev_file_open_by_dev+0x1be/0x240
 setup_bdev_super+0x5a/0x680
 get_tree_bdev_flags+0x388/0x4f0
 vfs_get_tree+0x92/0x2a0
 do_new_mount+0x319/0xdc0
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f49db19e159
RSP: 002b:00007f49dc092028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f49db425fa0 RCX: 00007f49db19e159
RDX: 0000200000000200 RSI: 0000200000000300 RDI: 0000200000000040
RBP: 00007f49db23506b R08: 0000200000000400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f49db426038 R14: 00007f49db425fa0 R15: 00007ffee8d756e8
 </TASK>

Showing all locks held in the system:
locks held by pool_workqueue_/3: 1, on CPU#1:
 #0: ffffffff8ed62a68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
locks held by pr/ttyS0/16: 2, last CPU#1:
 #0: ffffffff8ec36278 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60
 #1: ffffffff9ad250d8 (&port_lock_key){-...}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0
locks held by khungtaskd/35: 1, last CPU#0:
 #0: ffffffff8ed5c6a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by udevd/5044: 1, last CPU#0:
 #0: ffffffff8ed5c6a0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550
locks held by udevd/12360: 1, on CPU#1:
 #0: ffff88810c676350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70
locks held by syz.0.3206/23622: 2, on CPU#1:
 #0: ffff8881b9c8a0e8 (&type->s_umount_key#53/1){+.+.}-{4:4}, at: sget_fc+0x97c/0x1a40
 #1: ffff88810c676350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70
locks held by syz-executor/25623: 1, on CPU#0:
 #0: ffffffff8ed62a68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
locks held by syz-executor/25655: 3, last CPU#1:
 #0: ffffffff8ee35b50 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10f/0x480
 #1: ffff8881167e7678 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0
 #2: ffff88810b2236b8 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 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: 52 57 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 4c 05 c7 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90000157900 EFLAGS: 00000002
RAX: 0000000000000061 RBX: 0000000000000061 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff85705b30 R12: dffffc0000000000
R13: 0000000000000061 R14: ffffffff9ad25100 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8882a8ce6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c384a9b CR3: 0000000026a32000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
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>
