INFO: task syz-executor2:2098 blocked for more than 140 seconds.
      Not tainted 4.9.126+ #90
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor2   D27624  2098      1 0x00000004
 ffff8801cffa0000 ffff8801c5295280 ffff8801cc694780 ffff88018bf4df00
 ffff8801db721018 ffff880190a7f7b8 ffffffff8277d952 0000000000000000
 ffff8801cffa08b0 ffffed0039ff4115 00ff8801cffa0000 ffff8801db7218f0
Call Trace:
 [<ffffffff8277ee7f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff8277f803>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff82781486>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff82781486>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff823cc8ac>] xt_find_table_lock+0x3c/0x3d0 net/netfilter/x_tables.c:1027
 [<ffffffff82588c2d>] get_info+0x13d/0x510 net/ipv6/netfilter/ip6_tables.c:1012
 [<ffffffff8258ac21>] do_ipt_get_ctl+0x151/0x9d0 net/ipv4/netfilter/ip_tables.c:1717
 [<ffffffff82360890>] nf_sockopt net/netfilter/nf_sockopt.c:103 [inline]
 [<ffffffff82360890>] nf_getsockopt+0x70/0xd0 net/netfilter/nf_sockopt.c:121
 [<ffffffff8243a0a7>] ip_getsockopt+0x127/0x170 net/ipv4/ip_sockglue.c:1558
 [<ffffffff8245cba8>] tcp_getsockopt+0x88/0xe0 net/ipv4/tcp.c:3106
 [<ffffffff8222a8ea>] sock_common_getsockopt+0x9a/0xe0 net/core/sock.c:2665
 [<ffffffff82228840>] SYSC_getsockopt net/socket.c:1816 [inline]
 [<ffffffff82228840>] SyS_getsockopt+0x150/0x240 net/socket.c:1798
 [<ffffffff8100570d>] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline]
 [<ffffffff8100570d>] syscall_return_slowpath arch/x86/entry/common.c:260 [inline]
 [<ffffffff8100570d>] do_syscall_64+0x35d/0x480 arch/x86/entry/common.c:287
 [<ffffffff8278ca53>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff81309d0c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81309d0c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813e6e4c>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2017:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff8278ab22>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81cdd9a2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.126+ #90
 ffff8801d9907d08 ffffffff81af1049 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810967d0 ffff8801d9907d40
 ffffffff81afbda9 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81af1049>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81af1049>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81afbda9>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81afbd3c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff810968d4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8130a29d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8130a29d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8130a29d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8130a29d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff8113dc9d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff8278cc1c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 11189 Comm: syz-executor1 Not tainted 4.9.126+ #90
task: ffff8801ca8b2f80 task.stack: ffff88018e990000
RIP: 0010:[<ffffffff810055dd>] 
c [<ffffffff810055dd>] arch_local_save_flags arch/x86/include/asm/paravirt.h:763 [inline]
RIP: 0010:[<ffffffff810055dd>] 
c [<ffffffff810055dd>] prepare_exit_to_usermode arch/x86/entry/common.c:183 [inline]
RIP: 0010:[<ffffffff810055dd>] 
c [<ffffffff810055dd>] syscall_return_slowpath arch/x86/entry/common.c:260 [inline]
RIP: 0010:[<ffffffff810055dd>] 
c [<ffffffff810055dd>] do_syscall_64+0x22d/0x480 arch/x86/entry/common.c:287
RSP: 0018:ffff88018e997f00  EFLAGS: 00000046
RAX: 0000000000000046 RBX: ffff88018e997f58 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801ca8b37f4
RBP: ffff88018e997f48 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801ca8b2f80
R13: ffff88018e997fd0 R14: ffff8801ca8b2f80 R15: 0000000000000000
FS:  00007f2e4a346700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c44421b000 CR3: 00000001c7ec0000 CR4: 00000000001606b0
Stack:
 0000000000000000
c 0000000000000000
c 0000000000000000
c 0000000000000000
c
 0000000000000000
c 0000000000000000
c 0000000000000000
c 0000000000000000
c
 0000000000000000
c 0000000000000000
c ffffffff8278ca53
c 0000000000000000
c
Call Trace:
 [<ffffffff8278ca53>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
c30 
c00 
c41 
cf7 
cc4 
c91 
c00 
c00 
c10 
c0f 
c85 
c00 
c01 
c00 
c00 
ce8 
cda 
c40 
c30 
c00 
cfa 
c66 
c0f 
c1f 
c44 
c00 
c00 
c65 
c4c 
c8b 
c24 
c25 
c00 
c7e 
c01 
c00 
ce8 
c05 
c2e 
c1f 
c00 
c9c 
c58 
c<0f> 
c1f 
c44 
c00 
c00 
cf6 
cc4 
c02 
c0f 
c85 
ceb 
c00 
c00 
c00 
ce8 
cb0 
c40 
c30 
c00 
ce8 
c7b 
c