INFO: task syz.0.1591:11846 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1591      state:D stack:25384 pid:11846 tgid:11845 ppid:5848   task_flags:0x480140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 blk_mq_freeze_queue_wait+0xf4/0x170
 queue_limits_commit_update_frozen+0x5d/0x3e0
 nbd_set_size+0x47e/0x6a0
 nbd_genl_size_set+0x2eb/0x3c0
 nbd_genl_reconfigure+0x409/0x1870
 genl_family_rcv_msg_doit+0x215/0x300
 genl_rcv_msg+0x60e/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbd56f8eba9
RSP: 002b:00007fbd57e04038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbd571d5fa0 RCX: 00007fbd56f8eba9
RDX: 0000000020000800 RSI: 0000200000000200 RDI: 0000000000000008
RBP: 00007fbd57011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbd571d6038 R14: 00007fbd571d5fa0 R15: 00007ffdd6c04298
 </TASK>
INFO: task syz.2.1593:11853 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1593      state:D stack:25928 pid:11853 tgid:11852 ppid:5859   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 genl_rcv_msg+0x10d/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 __sys_sendto+0x3bd/0x520
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5f42b90a3c
RSP: 002b:00007f5f43939ec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f5f43939fc0 RCX: 00007f5f42b90a3c
RDX: 0000000000000020 RSI: 00007f5f4393a010 RDI: 0000000000000006
RBP: 0000000000000000 R08: 00007f5f43939f14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000006
R13: 00007f5f43939f68 R14: 00007f5f4393a010 R15: 0000000000000000
 </TASK>
INFO: task syz.2.1593:11854 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1593      state:D stack:26984 pid:11854 tgid:11852 ppid:5859   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 genl_rcv_msg+0x10d/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 __sys_sendto+0x3bd/0x520
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5f42b90a3c
RSP: 002b:00007f5f40df4ec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f5f40df4fc0 RCX: 00007f5f42b90a3c
RDX: 0000000000000020 RSI: 00007f5f40df5010 RDI: 0000000000000005
RBP: 0000000000000000 R08: 00007f5f40df4f14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000005
R13: 00007f5f40df4f68 R14: 00007f5f40df5010 R15: 0000000000000000
 </TASK>
INFO: task syz.2.1593:11855 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1593      state:D stack:28168 pid:11855 tgid:11852 ppid:5859   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 genl_rcv_msg+0x10d/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 __sys_sendto+0x3bd/0x520
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5f42b90a3c
RSP: 002b:00007f5f40dd3ec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f5f40dd3fc0 RCX: 00007f5f42b90a3c
RDX: 0000000000000024 RSI: 00007f5f40dd4010 RDI: 000000000000000a
RBP: 0000000000000000 R08: 00007f5f40dd3f14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000000a
R13: 00007f5f40dd3f68 R14: 00007f5f40dd4010 R15: 0000000000000000
 </TASK>
INFO: task syz.2.1593:11861 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1593      state:D stack:28360 pid:11861 tgid:11852 ppid:5859   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 genl_rcv_msg+0x10d/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 __sys_sendto+0x3bd/0x520
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5f42b90a3c
RSP: 002b:00007f5f409b0ec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f5f409b0fc0 RCX: 00007f5f42b90a3c
RDX: 0000000000000020 RSI: 00007f5f409b1010 RDI: 000000000000000b
RBP: 0000000000000000 R08: 00007f5f409b0f14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000000b
R13: 00007f5f409b0f68 R14: 00007f5f409b1010 R15: 0000000000000000
 </TASK>
INFO: task syz.1.1594:11857 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1594      state:D stack:27880 pid:11857 tgid:11856 ppid:5853   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 genl_rcv_msg+0x10d/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 __sys_sendto+0x3bd/0x520
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f14a9190a3c
RSP: 002b:00007f14aa012ec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f14aa012fc0 RCX: 00007f14a9190a3c
RDX: 0000000000000020 RSI: 00007f14aa013010 RDI: 0000000000000006
RBP: 0000000000000000 R08: 00007f14aa012f14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000006
R13: 00007f14aa012f68 R14: 00007f14aa013010 R15: 0000000000000000
 </TASK>
INFO: task syz.1.1594:11858 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1594      state:D stack:28616 pid:11858 tgid:11856 ppid:5853   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 genl_rcv_msg+0x10d/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 __sys_sendto+0x3bd/0x520
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f14a9190a3c
RSP: 002b:00007f14a9ff1ec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f14a9ff1fc0 RCX: 00007f14a9190a3c
RDX: 0000000000000020 RSI: 00007f14a9ff2010 RDI: 0000000000000008
RBP: 0000000000000000 R08: 00007f14a9ff1f14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000008
R13: 00007f14a9ff1f68 R14: 00007f14a9ff2010 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5680:
 #0: ffff888029b160a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by udevd/5858:
 #0: ffff888106fe0358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
6 locks held by syz.0.1591/11846:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
 #2: ffff8880226fe230 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_genl_reconfigure+0x36f/0x1870
 #3: ffff888106fc5f58 (&q->limits_lock){+.+.}-{4:4}, at: nbd_set_size+0x292/0x6a0
 #4: ffff888106fc58f8 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: queue_limits_commit_update_frozen+0x5d/0x3e0
 #5: ffff888106fc5930 (&q->q_usage_counter(queue)#33){+.+.}-{0:0}, at: queue_limits_commit_update_frozen+0x5d/0x3e0
2 locks held by syz.2.1593/11853:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz.2.1593/11854:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz.2.1593/11855:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz.2.1593/11861:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz.1.1594/11857:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz.1.1594/11858:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz-executor/11867:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz-executor/11869:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz-executor/11871:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz-executor/11894:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz-executor/11896:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz-executor/11898:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz-executor/11924:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz-executor/11926:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790
2 locks held by syz-executor/11928:
 #0: ffffffff8f59e0f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8f59df08 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790

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

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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 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+0x13/0x20
Code: 53 e7 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 f3 66 0e 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8de07d80 EFLAGS: 00000282
RAX: 9824a4387c69fb00 RBX: ffffffff819683c8 RCX: 9824a4387c69fb00
RDX: 0000000000000001 RSI: ffffffff8d9b7ff7 RDI: ffffffff8be33800
RBP: ffffffff8de07eb8 R08: ffff88804b032f9b R09: 1ffff110096065f3
R10: dffffc0000000000 R11: ffffed10096065f4 R12: ffffffff8fa38e30
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a20
FS:  0000000000000000(0000) GS:ffff8880b8618000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dcc95f63f8 CR3: 000000000df36000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 default_idle+0x13/0x20
 default_idle_call+0x74/0xb0
 do_idle+0x1e8/0x510
 cpu_startup_entry+0x44/0x60
 rest_init+0x2de/0x300
 start_kernel+0x3a9/0x410
 x86_64_start_reservations+0x24/0x30
 x86_64_start_kernel+0x143/0x1c0
 common_startup_64+0x13e/0x147
 </TASK>
