INFO: task syz.0.4302:27438 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.4302      state:D stack:26408 pid:27438 tgid:27437 ppid:5611   task_flags:0x480140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17dd/0x5830
 schedule+0x164/0x2b0
 blk_mq_freeze_queue_wait+0xfc/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+0x8ef/0xa80
 netlink_sendmsg+0x7f0/0xb20
 sock_sendmsg_nosec+0x14e/0x190
 ____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: 0033:0x7fe039f9f559
RSP: 002b:00007fe03aea0028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe03a225fa0 RCX: 00007fe039f9f559
RDX: 0000000000004004 RSI: 0000200000000380 RDI: 0000000000000005
RBP: 00007fe03a036b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe03a226038 R14: 00007fe03a225fa0 R15: 00007ffcafc32af8
 </TASK>
INFO: task syz.0.4302:27446 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.4302      state:D stack:27720 pid:27446 tgid:27437 ppid:5611   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17dd/0x5830
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c4/0x15a0
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x8ef/0xa80
 netlink_sendmsg+0x7f0/0xb20
 sock_sendmsg_nosec+0x14e/0x190
 ____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: 0033:0x7fe039f9f559
RSP: 002b:00007fe03ae7f028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe03a226090 RCX: 00007fe039f9f559
RDX: 0000000024044010 RSI: 0000200000000400 RDI: 0000000000000004
RBP: 00007fe03a036b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe03a226128 R14: 00007fe03a226090 R15: 00007ffcafc32af8
 </TASK>
INFO: task syz.0.4302:27450 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.4302      state:D stack:25936 pid:27450 tgid:27437 ppid:5611   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17dd/0x5830
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c4/0x15a0
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x8ef/0xa80
 netlink_sendmsg+0x7f0/0xb20
 sock_sendmsg_nosec+0x14e/0x190
 ____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: 0033:0x7fe039f9f559
RSP: 002b:00007fe03ae5e028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe03a226180 RCX: 00007fe039f9f559
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007fe03a036b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe03a226218 R14: 00007fe03a226180 R15: 00007ffcafc32af8
 </TASK>
INFO: task syz.2.4303:27442 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.4303      state:D stack:27840 pid:27442 tgid:27441 ppid:5609   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17dd/0x5830
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c4/0x15a0
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x8ef/0xa80
 netlink_sendmsg+0x7f0/0xb20
 sock_sendmsg_nosec+0x14e/0x190
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7f80b5fd8e
RSP: 002b:00007f7f81b10e88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f7f81b126c0 RCX: 00007f7f80b5fd8e
RDX: 0000000000000020 RSI: 00007f7f81b11000 RDI: 0000000000000008
RBP: 0000000000000000 R08: 00007f7f81b10f04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000008
R13: 00007f7f81b10f58 R14: 00007f7f81b11000 R15: 0000000000000000
 </TASK>
INFO: task syz.1.4304:27496 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.4304      state:D stack:27840 pid:27496 tgid:27493 ppid:5610   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17dd/0x5830
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c4/0x15a0
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x8ef/0xa80
 netlink_sendmsg+0x7f0/0xb20
 sock_sendmsg_nosec+0x14e/0x190
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5f0515fd8e
RSP: 002b:00007f5f06082e88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f5f060846c0 RCX: 00007f5f0515fd8e
RDX: 0000000000000020 RSI: 00007f5f06083000 RDI: 000000000000001e
RBP: 0000000000000000 R08: 00007f5f06082f04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000001e
R13: 00007f5f06082f58 R14: 00007f5f06083000 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
locks held by pr/ttyS0/35: 2, last CPU#1:
 #0: ffffffff8fe33dd8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60
 #1: ffffffff9bfee6d8 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0
locks held by khungtaskd/36: 1, last CPU#0:
 #0: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by getty/5446: 2, on CPU#0:
 #0: ffff8881721f70a0 (&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 syz-executor/5600: 2, last CPU#0:
 #0: ffff888112da6540 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x19c/0xa40
 #1: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: is_module_text_address+0x1d/0x1e0
locks held by udevd/19425: 1, on CPU#1:
 #0: ffff88810b12e350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70
locks held by udevd/21045: 1, on CPU#0:
 #0: ffff888105ac8350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70
locks held by syz.0.4302/27438: 6, on CPU#0:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
 #2: ffff888114c97a18 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_genl_reconfigure+0x4a6/0x1040
 #3: ffff88810b1a63b8 (&q->limits_lock){+.+.}-{4:4}, at: nbd_set_size+0x284/0x7d0
 #4: ffff88810b1a5d80 (&q->q_usage_counter(io)#71){++++}-{0:0}, at: queue_limits_commit_update_frozen+0x55/0xd0
 #5: ffff88810b1a5db8 (&q->q_usage_counter(queue)#54){+.+.}-{0:0}, at: queue_limits_commit_update_frozen+0x55/0xd0
locks held by syz.0.4302/27446: 2, on CPU#0:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz.0.4302/27450: 2, on CPU#1:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz.2.4303/27442: 2, on CPU#0:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz.1.4304/27496: 2, on CPU#0:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/27502: 2, on CPU#0:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/27505: 2, on CPU#0:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/27536: 2, on CPU#0:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/27566: 2, on CPU#1:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/27584: 2, on CPU#1:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/27602: 2, on CPU#1:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/27625: 2, on CPU#0:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/27643: 2, on CPU#1:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/27661: 2, on CPU#0:
 #0: ffffffff914f05a8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff914f03e0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 36 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+0x1073/0x10f0
 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: 35 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:native_apic_msr_write+0x39/0x50
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 cc cc cc cc cc 89 f6 31 d2 e9 d6 27 b5 03 66 0f 1f 44 00
RSP: 0018:ffffc90000ab78d0 EFLAGS: 00000046
RAX: 0000000000015a60 RBX: ffff88823c623f40 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 0000000000015a60 RDI: 0000000000000838
RBP: ffffc90000ab7988 R08: ffffffff81b5acc5 R09: 0000000000000001
R10: 0000000000000003 R11: ffffffff8175c510 R12: 0000000000015a60
R13: dffffc0000000000 R14: 000000000ffff294 R15: 0000000000000020
FS:  0000000000000000(0000) GS:ffff8882a7a20000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558f235d4528 CR3: 000000000fd48000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lapic_next_event+0x11/0x20
 clockevents_program_event+0x385/0x630
 hrtimer_start_range_ns+0x1ab/0x3e0
 hrtick_schedule_exit+0x1b3/0x2b0
 __schedule+0x1db0/0x5830
 preempt_schedule_common+0x7f/0xd0
 preempt_schedule_thunk+0x16/0x40
 _raw_spin_unlock_irqrestore+0x76/0x80
 nbcon_kthread_func+0x724/0x8d0
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
