INFO: task syz.0.954:7845 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.954       state:D stack:26536 pid:7845  tgid:7844  ppid:5599   task_flags:0x480140 flags:0x00080002
Call Trace:
 <TASK>
 __sch
 __schedule+0x17d4/0x5820
 schedule+0x164/0x2b0
 blk_mq_freeze_queue_wait+0x101/0x180
 queue_limits_commit_update_frozen+0x55/0xd0
 nbd_set_size+0x4c5/0x7d0
 nbd_genl_reconfigure+0x7e1/0x1040
 genl_family_rcv_msg_doit+0x233/0x340
 genl_rcv_msg+0x614/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 ____sys_sendmsg+0x54e/0x850
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1b1/0x290
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2a4819e159
RSP: 002b:00007f2a463f6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f2a48425fa0 RCX: 00007f2a4819e159
RDX: 0000000000004094 RSI: 0000200000000400 RDI: 0000000000000004
RBP: 00007f2a48235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2a48426038 R14: 00007f2a48425fa0 R15: 00007fff27539708
 </TASK>
INFO: task syz.1.966:7869 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.966       state:D stack:27872 pid:7869  tgid:7868  ppid:5589   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d4/0x5820
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f283d55e98e
RSP: 002b:00007f283e547e88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f283e5496c0 RCX: 00007f283d55e98e
RDX: 0000000000000020 RSI: 00007f283e548000 RDI: 0000000000000004
RBP: 0000000000000000 R08: 00007f283e547f04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00007f283e547f58 R14: 00007f283e548000 R15: 0000000000000000
 </TASK>
INFO: task syz.2.979:7896 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.979       state:D stack:27976 pid:7896  tgid:7895  ppid:5593   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d4/0x5820
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb82a75e98e
RSP: 002b:00007fb82b674e88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fb82b6766c0 RCX: 00007fb82a75e98e
RDX: 0000000000000020 RSI: 00007fb82b675000 RDI: 0000000000000004
RBP: 0000000000000000 R08: 00007fb82b674f04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00007fb82b674f58 R14: 00007fb82b675000 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:7906 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:23048 pid:7906  tgid:7906  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d4/0x5820
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1dac95e98e
RSP: 002b:00007ffff5ef7198 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000055556fef8500 RCX: 00007f1dac95e98e
RDX: 0000000000000020 RSI: 00007f1dad754670 RDI: 0000000000000005
RBP: 0000000000000001 R08: 00007ffff5ef7214 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 00007ffff5ef7268 R14: 00007f1dad754670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:7908 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22352 pid:7908  tgid:7908  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d4/0x5820
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1a4015e98e
RSP: 002b:00007ffd8ddda798 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00005555689fd500 RCX: 00007f1a4015e98e
RDX: 0000000000000020 RSI: 00007f1a40f54670 RDI: 0000000000000005
RBP: 0000000000000001 R08: 00007ffd8ddda814 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 00007ffd8ddda868 R14: 00007f1a40f54670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:7942 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:23016 pid:7942  tgid:7942  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d4/0x5820
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5897b5e98e
RSP: 002b:00007ffc4ed9fb78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555589134500 RCX: 00007f5897b5e98e
RDX: 0000000000000020 RSI: 00007f5898954670 RDI: 0000000000000005
RBP: 0000000000000001 R08: 00007ffc4ed9fbf4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 00007ffc4ed9fc48 R14: 00007f5898954670 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
locks held by pr/ttyS0/16: 2, last CPU#1:
 #0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60
 #1: ffffffff9ad2eff8 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0
locks held by khungtaskd/35: 1, last CPU#0:
 #0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by getty/5418: 2, on CPU#1:
 #0: ffff88811a2770a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034832e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
locks held by sshd/5520: 4, last CPU#0:
 #0: ffff88811948dd60 (sk_lock-AF_INET){+.+.}-{0:0}, at: inet_shutdown+0x6a/0x390
 #1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: __ip_queue_xmit+0x65/0x1b10
 #2: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5a/0x450
 #3: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3de/0x10b0
locks held by syz-executor/5528: 1, last CPU#0:
 #0: ffff88810e6c9d38 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0
locks held by udevd/5592: 1, on CPU#0:
 #0: ffff88810baeb350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70
locks held by kworker/1:9/7054: 2, last CPU#1:
 #0: ffff888100069d40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
 #1: ffffc90003f6fc40 ((gc_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630
locks held by syz.0.954/7845: 6, on CPU#0:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
 #2: ffff88810ba79a60 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_genl_reconfigure+0x4a6/0x1040
 #3: ffff88810bae47c8 (&q->limits_lock){+.+.}-{4:4}, at: nbd_set_size+0x284/0x7d0
 #4: ffff88810bae4190 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: queue_limits_commit_update_frozen+0x55/0xd0
 #5: ffff88810bae41c8 (&q->q_usage_counter(queue)#33){+.+.}-{0:0}, at: queue_limits_commit_update_frozen+0x55/0xd0
locks held by syz.1.966/7869: 2, on CPU#1:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz.2.979/7896: 2, on CPU#0:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/7906: 2, on CPU#1:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/7908: 2, on CPU#1:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/7942: 2, on CPU#0:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/7960: 2, on CPU#0:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/7978: 2, on CPU#0:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/7996: 2, on CPU#1:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/8020: 2, on CPU#0:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/8038: 2, on CPU#1:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/8056: 2, on CPU#1:
 #0: ffffffff902c07e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c0620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0

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

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+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 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:io_serial_out+0x7c/0xc0
Code: 82 56 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 ac 4a c6 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: 0000000000000020 RBX: 0000000000000020 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff85713070 R12: dffffc0000000000
R13: 0000000000000020 R14: ffffffff9ad2f020 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8882a8cdc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb8b624aefc CR3: 000000000eb48000 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>
