IPVS: Unknown mcast interface: í/./ò
IPVS: Unknown mcast interface: í/./ò
IPVS: Unknown mcast interface: í/./ò
IPVS: Unknown mcast interface: í/./ò
IPVS: Unknown mcast interface: í/./ò
INFO: task syzkaller976708:3763 blocked for more than 120 seconds.
      Not tainted 4.9.84-ge7f51a5 #45
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syzkaller976708 D29216  3763   3761 0x00000000
 ffff8801d7318000 0000000000000000 ffff8801d6de8fc0 ffff8801d951e000
 ffff8801db221b98 ffff8801c2f87bc8 ffffffff838a438b 0000000000000000
 0000000000000007 00ff8801d7318000 ffff8801db222468 ffff8801db222490
Call Trace:
 [<ffffffff838a592f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3550
 [<ffffffff838a62b3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3583
 [<ffffffff838ab8c2>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff838ab8c2>] mutex_lock_nested+0x312/0x870 kernel/locking/mutex.c:621
 [<ffffffff82f1ebe5>] copy_net_ns+0x155/0x280 net/core/net_namespace.c:387
 [<ffffffff8119dd2f>] create_new_namespaces+0x37f/0x730 kernel/nsproxy.c:106
 [<ffffffff8119e6be>] unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:205
 [<ffffffff8113012d>] SYSC_unshare kernel/fork.c:2244 [inline]
 [<ffffffff8113012d>] SyS_unshare+0x3dd/0x6f0 kernel/fork.c:2194
 [<ffffffff81006504>] do_syscall_64+0x1a4/0x490 arch/x86/entry/common.c:282
 [<ffffffff838b53fd>] entry_SYSCALL_64_after_swapgs+0x47/0xc5

Showing all locks held in the system:
2 locks held by khungtaskd/514:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813730a5>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813730a5>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81238190>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3485:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d3bef>] __fdget_pos+0x9f/0xc0 fs/file.c:781
2 locks held by getty/3613:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838b3602>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8200ab14>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
1 lock held by syzkaller976708/3763:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff82f1ebe5>] copy_net_ns+0x155/0x280 net/core/net_namespace.c:387
1 lock held by syzkaller976708/3764:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff82f1ebe5>] copy_net_ns+0x155/0x280 net/core/net_namespace.c:387
1 lock held by syzkaller976708/3766:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff82f1ebe5>] copy_net_ns+0x155/0x280 net/core/net_namespace.c:387
1 lock held by syzkaller976708/3767:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff82f1ebe5>] copy_net_ns+0x155/0x280 net/core/net_namespace.c:387
1 lock held by syzkaller976708/3768:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff82f1ebe5>] copy_net_ns+0x155/0x280 net/core/net_namespace.c:387
1 lock held by syzkaller976708/3769:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff82f1ebe5>] copy_net_ns+0x155/0x280 net/core/net_namespace.c:387

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

NMI backtrace for cpu 0
CPU: 0 PID: 514 Comm: khungtaskd Not tainted 4.9.84-ge7f51a5 #45
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d859fd00 ffffffff81d956b9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810bb190 ffff8801d859fd38
 ffffffff81da07dd 0000000000000000 0000000000000000 ffff8801d7318418
Call Trace:
 [<ffffffff81d956b9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d956b9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81da07dd>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81da0917>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810bb284>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81373670>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81373670>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81373670>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81373670>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff8119a7bd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838b558c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:361
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3765 Comm: syzkaller976708 Not tainted 4.9.84-ge7f51a5 #45
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d7b81800 task.stack: ffff8801c11f0000
RIP: 0010:[<ffffffff8203aeab>] 
c [<ffffffff8203aeab>] inb arch/x86/include/asm/io.h:316 [inline]
RIP: 0010:[<ffffffff8203aeab>] 
c [<ffffffff8203aeab>] io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:414
RSP: 0018:ffff8801c11f7768  EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000005 RDI: ffffffff8627c478
RBP: ffff8801c11f7778 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8627c440
R13: 0000000000000020 R14: fffffbfff0c4f8cf R15: fffffbfff0c4f891
FS:  0000000000a76880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000471660 CR3: 00000001c12e0000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8627c440
c 0000000000002709
c ffff8801c11f77c8
c ffffffff8203cade
c
 ffffffff83a67a0d
c ffffffff8627c488
c ffffffff8627c67a
c ffffffff8627c440
c
 000000000000006e
c ffffffff8203cc20
c dffffc0000000000
c 000000000000006e
c
Call Trace:
 [<ffffffff8203cade>] serial_in drivers/tty/serial/8250/8250.h:111 [inline]
 [<ffffffff8203cade>] wait_for_xmitr+0x8e/0x1d0 drivers/tty/serial/8250/8250_port.c:1997
 [<ffffffff8203cc3f>] serial8250_console_putchar+0x1f/0x60 drivers/tty/serial/8250/8250_port.c:3103
 [<ffffffff82024f0c>] uart_console_write+0xac/0xe0 drivers/tty/serial/serial_core.c:1857
 [<ffffffff82048690>] serial8250_console_write+0x2e0/0x850 drivers/tty/serial/8250/8250_port.c:3169
 [<ffffffff82035a7f>] univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:594
 [<ffffffff81265db5>] call_console_drivers.isra.20.constprop.29+0x1a5/0x350 kernel/printk/printk.c:1589
 [<ffffffff81268a75>] console_unlock+0x425/0xb20 kernel/printk/printk.c:2445
 [<ffffffff81269652>] vprintk_emit+0x4e2/0x750 kernel/printk/printk.c:1903
 [<ffffffff812698e8>] vprintk+0x28/0x30 kernel/printk/printk.c:1913
 [<ffffffff8126990d>] vprintk_default+0x1d/0x30 kernel/printk/printk.c:1914
 [<ffffffff8143028c>] vprintk_func kernel/printk/internal.h:36 [inline]
 [<ffffffff8143028c>] printk+0xb7/0xe2 kernel/printk/printk.c:1975
 [<ffffffff8318f20f>] __ip_vs_init+0x3df/0x430 net/netfilter/ipvs/ip_vs_core.c:2243
 [<ffffffff82f1d2f9>] ops_init+0xa9/0x3a0 net/core/net_namespace.c:111
 [<ffffffff82f1d7a2>] setup_net+0x1b2/0x3e0 net/core/net_namespace.c:291
 [<ffffffff82f1ec19>] copy_net_ns+0x189/0x280 net/core/net_namespace.c:389
 [<ffffffff8119dd2f>] create_new_namespaces+0x37f/0x730 kernel/nsproxy.c:106
 [<ffffffff8119e6be>] unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:205
 [<ffffffff8113012d>] SYSC_unshare kernel/fork.c:2244 [inline]
 [<ffffffff8113012d>] SyS_unshare+0x3dd/0x6f0 kernel/fork.c:2194
 [<ffffffff81006504>] do_syscall_64+0x1a4/0x490 arch/x86/entry/common.c:282
 [<ffffffff838b53fd>] entry_SYSCALL_64_after_swapgs+0x47/0xc5
Code: 
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c