audit: type=1400 audit(1537686996.250:86): avc:  denied  { read } for  pid=8183 comm="syz-executor2" path="socket:[26134]" dev="sockfs" ino=26134 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1
netlink: 3 bytes leftover after parsing attributes in process `syz-executor2'.
netlink: 3 bytes leftover after parsing attributes in process `syz-executor2'.
INFO: task syz-executor4:8160 blocked for more than 140 seconds.
      Not tainted 4.9.128+ #93
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4   D28832  8160   2091 0x00000004
 ffff8801a6bbc740 0000000000000000 ffff8801d2112c00 ffff8801da6797c0
 ffff8801db721018 ffff8801a9ee7cf8 ffffffff8277ee02 0000000000000000
 ffff8801a6bbcff0 ffffed0034d779fd 00ff8801a6bbc740 ffff8801db7218f0
Call Trace:
 [<ffffffff8278032f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff82780cb3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff82782936>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff82782936>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff81fea2b2>] evdev_flush+0x72/0x120 drivers/input/evdev.c:350
 [<ffffffff814e3487>] filp_close+0xa7/0x140 fs/open.c:1129
 [<ffffffff8154c2a6>] __close_fd+0x156/0x230 fs/file.c:651
 [<ffffffff814e356c>] SYSC_close fs/open.c:1148 [inline]
 [<ffffffff814e356c>] SyS_close+0x4c/0x90 fs/open.c:1146
 [<ffffffff8100554f>] do_syscall_64+0x19f/0x480 arch/x86/entry/common.c:282
 [<ffffffff8278df13>] 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: [<ffffffff8130a0ac>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8130a0ac>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813e71ec>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2027:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff8278bfd2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81cdee72>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor4/8160:
 #0:  (&evdev->mutex){+.+.+.}, at: [<ffffffff81fea2b2>] evdev_flush+0x72/0x120 drivers/input/evdev.c:350

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.128+ #93
 ffff8801d9907d08 ffffffff81af2469 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810967d0 ffff8801d9907d40
 ffffffff81afd1c9 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81af2469>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81af2469>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81afd1c9>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81afd15c>] 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
 [<ffffffff8130a63d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8130a63d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8130a63d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8130a63d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff8113e00d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff8278e0dc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8028 Comm: syz-executor1 Not tainted 4.9.128+ #93
task: ffff8801a77697c0 task.stack: ffff8801a62e0000
RIP: 0033:[<0000000000401574>] 
c [<0000000000401574>] 0x401574
RSP: 002b:00007fe9d0b66690  EFLAGS: 00000202
RAX: 000000007436b076 RBX: 000000000000000b RCX: 0000000000457679
RDX: 0000000000000000 RSI: 00007fe9d0b666c0 RDI: 000000000000000b
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d7950 R14: 00000000004c48c6 R15: 0000000000000000
FS:  00007fe9d0b67700(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020a2f000 CR3: 00000001cea71000 CR4: 00000000001606b0