INFO: task syz.1.3942:19441 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.3942      state:D stack:25776 pid:19441 tgid:19439 ppid:16932  task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 nfsd_nl_rpc_status_get_dumpit+0xdf/0x1290
 genl_dumpit+0x10b/0x1b0
 netlink_dump+0x6e4/0xe90
 __netlink_dump_start+0x5cb/0x7e0
 genl_family_rcv_msg_dumpit+0x1e7/0x2c0
 genl_rcv_msg+0x5da/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: 0033:0x7f09bdb8ec29
RSP: 002b:00007f09beacd038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f09bddd6090 RCX: 00007f09bdb8ec29
RDX: 0000000000000000 RSI: 0000200000000180 RDI: 0000000000000004
RBP: 00007f09bdc11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f09bddd6128 R14: 00007f09bddd6090 R15: 00007ffcbb9f7b98
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:0/12:
 #0: ffff888109478148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900000f7bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f53adc8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0
1 lock held by khungtaskd/34:
 #0: ffffffff8e13a160 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5672:
 #0: ffff8880291da0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900017682f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
3 locks held by kworker/0:5/5913:
3 locks held by kworker/1:6/9967:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000412fbc0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f53adc8 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
2 locks held by syz.6.3112/16690:
 #0: ffffffff8f5a05f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8e4197c8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690
3 locks held by syz.1.3942/19441:
 #0: ffffffff8f5a05f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffff88811bbc36d8 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xfe/0x7e0
 #2: ffffffff8e4197c8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_rpc_status_get_dumpit+0xdf/0x1290
3 locks held by kworker/u10:26/21279:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90007987bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f53adc8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
5 locks held by syz.3.4943/23024:

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

NMI backtrace for cpu 0
CPU: 0 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+0x439/0x7d0
 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: 23024 Comm: syz.3.4943 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 f3 0f 1e fa 89 f6 31 d2 e9 92 a3 8f 03 66
RSP: 0018:ffffc900001df588 EFLAGS: 00000046
RAX: 000000000000031f RBX: ffff888136623900 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 000000000000031f RDI: 0000000000000838
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81ae1b4e
R10: 0000000000000003 R11: ffffffff81704490 R12: 0000000010007570
R13: dffffc0000000000 R14: 000000000000031f R15: 0000000000000020
FS:  00007fd2e5c5a6c0(0000) GS:ffff8881a3c11000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000440 CR3: 00000001256f2000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 lapic_next_event+0x11/0x20
 clockevents_program_event+0x1cf/0x360
 hrtimer_interrupt+0x620/0xaa0
 __sysvec_apic_timer_interrupt+0x10b/0x410
 sysvec_apic_timer_interrupt+0x52/0xc0
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:lock_acquire+0x175/0x360
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 3b 7b 03 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc900001df7f8 EFLAGS: 00000206
RAX: a944fc2bca597800 RBX: 0000000000000000 RCX: a944fc2bca597800
RDX: 0000000000000000 RSI: ffffffff8dbaa624 RDI: ffffffff8be34480
RBP: ffffffff8172d195 R08: 0000000000000000 R09: ffffffff8172d195
R10: ffffc900001df9b8 R11: ffffffff81ac5140 R12: 0000000000000002
R13: ffffffff8e13a160 R14: 0000000000000000 R15: 0000000000000246
 unwind_next_frame+0xc2/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kmem_cache_free+0x18f/0x400
 skb_release_data+0x62d/0x7c0
 __kfree_skb+0x55/0x70
 tcp_rcv_established+0xe9e/0x1eb0
 tcp_v4_do_rcv+0xa23/0xce0
 tcp_v4_rcv+0x26a6/0x2f40
 ip_protocol_deliver_rcu+0x221/0x440
 ip_local_deliver_finish+0x3bb/0x6f0
 NF_HOOK+0x30c/0x3a0
 ip_sublist_rcv_finish+0x221/0x2a0
 ip_sublist_rcv+0x6e7/0x9b0
 ip_list_rcv+0x3e2/0x430
 __netif_receive_skb_list_core+0x7d2/0x800
 netif_receive_skb_list_internal+0x975/0xcc0
 napi_complete_done+0x2f2/0x7c0
 e1000_clean+0xd0b/0x2b00
 __napi_poll+0xc7/0x360
 net_rx_action+0x707/0xe30
 handle_softirqs+0x286/0x870
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 common_interrupt+0xbb/0xe0
 </IRQ>
 <TASK>
 asm_common_interrupt+0x26/0x40
RIP: 0010:vprintk_emit+0x58f/0x7a0
Code: 85 32 01 00 00 e8 21 88 1f 00 41 89 df 4d 85 f6 48 8b 1c 24 75 07 e8 10 88 1f 00 eb 06 e8 09 88 1f 00 fb 48 c7 c7 00 e4 12 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 b9 35
RSP: 0018:ffffc9000292e9e0 EFLAGS: 00000283
RAX: ffffffff81a03d97 RBX: ffffffff81a03c54 RCX: 0000000000080000
RDX: ffffc90025a10000 RSI: 000000000002f93c RDI: ffffffff8e12e400
RBP: ffffc9000292eaf0 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: dffffc0000000000
R13: 1ffff92000525d40 R14: 0000000000000200 R15: 0000000000000036
 _printk+0xcf/0x120
 netdev_info+0x10a/0x160
 netif_set_allmulti+0x1b8/0x380
 dev_set_allmulti+0x12b/0x260
 del_nbp+0xae/0xa60
 br_del_if+0x146/0x320
 br_device_event+0x53e/0x910
 notifier_call_chain+0x1b6/0x3e0
 unregister_netdevice_many_notify+0x14d7/0x1ff0
 rtnl_dellink+0x488/0x710
 rtnetlink_rcv_msg+0x7cf/0xb70
 netlink_rcv_skb+0x208/0x470
 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: 0033:0x7fd2e4d8ec29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd2e5c5a038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fd2e4fd5fa0 RCX: 00007fd2e4d8ec29
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 000000000000000c
RBP: 00007fd2e4e11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd2e4fd6038 R14: 00007fd2e4fd5fa0 R15: 00007ffd4f14f938
 </TASK>
