INFO: task syz.3.19257:16638 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.19257     state:D stack:26056 pid:16638 tgid:16637 ppid:10456  task_flags:0x480140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 blk_mq_freeze_queue_wait+0x101/0x180
 queue_limits_commit_update_frozen+0x55/0xd0
 nbd_set_size+0x454/0x680
 nbd_genl_reconfigure+0x7f5/0x1ea0
 genl_family_rcv_msg_doit+0x22a/0x330
 genl_rcv_msg+0x61c/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x75c/0x8e0
 netlink_sendmsg+0x813/0xb40
 ____sys_sendmsg+0x972/0x9f0
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9b1679cdd9
RSP: 002b:00007f9b175fe028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f9b16a15fa0 RCX: 00007f9b1679cdd9
RDX: 0000000000020000 RSI: 0000200000000280 RDI: 0000000000000005
RBP: 00007f9b16832d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b16a16038 R14: 00007f9b16a15fa0 R15: 00007ffcc629d818
 </TASK>
INFO: task syz.3.19257:16639 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.19257     state:D stack:26880 pid:16639 tgid:16637 ppid:10456  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7f7/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x75c/0x8e0
 netlink_sendmsg+0x813/0xb40
 __sys_sendto+0x672/0x710
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9b1675d60e
RSP: 002b:00007f9b175dbe88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f9b175dd6c0 RCX: 00007f9b1675d60e
RDX: 0000000000000024 RSI: 00007f9b175dc000 RDI: 0000000000000004
RBP: 0000000000000000 R08: 00007f9b175dbf04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00007f9b175dbf58 R14: 00007f9b175dc000 R15: 0000000000000000
 </TASK>
INFO: task syz.3.19257:16641 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.19257     state:D stack:28216 pid:16641 tgid:16637 ppid:10456  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7f7/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x75c/0x8e0
 netlink_sendmsg+0x813/0xb40
 __sys_sendto+0x672/0x710
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9b1675d60e
RSP: 002b:00007f9b175bae88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f9b175bc6c0 RCX: 00007f9b1675d60e
RDX: 0000000000000024 RSI: 00007f9b175bb000 RDI: 000000000000000a
RBP: 0000000000000000 R08: 00007f9b175baf04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000a
R13: 00007f9b175baf58 R14: 00007f9b175bb000 R15: 0000000000000000
 </TASK>
INFO: task syz.1.19258:16644 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.19258     state:D stack:28088 pid:16644 tgid:16643 ppid:5627   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7f7/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x75c/0x8e0
 netlink_sendmsg+0x813/0xb40
 __sys_sendto+0x672/0x710
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcb0bb5d60e
RSP: 002b:00007fcb0cab7e88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fcb0cab96c0 RCX: 00007fcb0bb5d60e
RDX: 000000000000001c RSI: 00007fcb0cab8000 RDI: 0000000000000007
RBP: 0000000000000000 R08: 00007fcb0cab7f04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000007
R13: 00007fcb0cab7f58 R14: 00007fcb0cab8000 R15: 0000000000000000
 </TASK>
INFO: task syz.0.19267:16682 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.19267     state:D stack:25000 pid:16682 tgid:16680 ppid:5617   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7f7/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x75c/0x8e0
 netlink_sendmsg+0x813/0xb40
 __sys_sendto+0x672/0x710
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbcfd75d60e
RSP: 002b:00007fbcfe62fe88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fbcfe6316c0 RCX: 00007fbcfd75d60e
RDX: 0000000000000020 RSI: 00007fbcfe630000 RDI: 0000000000000010
RBP: 0000000000000000 R08: 00007fbcfe62ff04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000010
R13: 00007fbcfe62ff58 R14: 00007fbcfe630000 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5439:
 #0: ffff8881146830a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
1 lock held by udevd/30281:
 #0: ffff888195d81350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
6 locks held by syz.3.19257/16638:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
 #2: ffff8881bd284a60 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_genl_reconfigure+0x4c1/0x1ea0
 #3: ffff8881a0563528 (&q->limits_lock){+.+.}-{4:4}, at: nbd_set_size+0x263/0x680
 #4: ffff8881a0562ef0 (&q->q_usage_counter(io)#71){++++}-{0:0}, at: queue_limits_commit_update_frozen+0x55/0xd0
 #5: ffff8881a0562f28 (&q->q_usage_counter(queue)#54){+.+.}-{0:0}, at: queue_limits_commit_update_frozen+0x55/0xd0
2 locks held by syz.3.19257/16639:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz.3.19257/16641:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz.1.19258/16644:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz.0.19267/16682:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz-executor/16687:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz-executor/16690:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz-executor/16726:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz-executor/16749:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz-executor/16751:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz-executor/16784:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz-executor/16802:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz-executor/16820:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
2 locks held by syz-executor/16839:
 #0: ffffffff8fe3e7e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fe3e620 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 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+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xfd3/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 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:pv_native_safe_halt+0xf/0x20
Code: 3b 7e 02 e9 93 f6 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 13 21 21 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8e607dc0 EFLAGS: 00000206
RAX: 00000000012c5255 RBX: ffffffff819a815a RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dfa8abb RDI: ffffffff8c28abe0
RBP: ffffffff8e607eb0 R08: ffff8881210339db R09: 1ffff1102420673b
R10: dffffc0000000000 R11: ffffed102420673c R12: 0000000000000000
R13: 1ffffffff1cd25d8 R14: 0000000000000000 R15: 1ffffffff1cd25d8
FS:  0000000000000000(0000) GS:ffff88818dc90000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f984220830e CR3: 000000016c154000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 default_idle+0x9/0x20
 default_idle_call+0x72/0xb0
 do_idle+0x36a/0x5f0
 cpu_startup_entry+0x43/0x60
 rest_init+0x2de/0x300
 start_kernel+0x38a/0x3e0
 x86_64_start_reservations+0x24/0x30
 x86_64_start_kernel+0x143/0x1c0
 common_startup_64+0x13e/0x147
 </TASK>
