Free memory is -13468kB above reserved
lowmemorykiller: Killing 'syz-executor.0' (16804) (tgid 16792), adj 1000,
   to free 51400kB on behalf of 'rsyslogd' (1923) because
   cache 176kB is below limit 6144kB for oom_score_adj 0
   Free memory is -13468kB above reserved
INFO: task syz-executor.0:16823 blocked for more than 140 seconds.
      Not tainted 4.9.141+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D28944 16823   2128 0x20020004
 ffff8801c728c740 ffff8801d23c6e00 ffff880191c38000 ffff8801c547c740
 ffff8801db721018 ffff880101baf9f8 ffffffff828075c2 0000000000000000
 ffff8801c728cff0 ffffed0038e519fd 00ff8801c728c740 ffff8801db7218f0
Call Trace:
 [<ffffffff82808aef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff828094a3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff8280b51d>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff8280b51d>] mutex_lock_nested+0x38d/0x900 kernel/locking/mutex.c:621
 [<ffffffff822e70e5>] copy_net_ns+0x155/0x330 net/core/net_namespace.c:406
 [<ffffffff811465e1>] create_new_namespaces+0x501/0x760 kernel/nsproxy.c:106
 [<ffffffff81146acd>] copy_namespaces+0x28d/0x320 kernel/nsproxy.c:164
 [<ffffffff810d528c>] copy_process.part.8+0x240c/0x6a10 kernel/fork.c:1695
 [<ffffffff810d9d12>] copy_process kernel/fork.c:1505 [inline]
 [<ffffffff810d9d12>] _do_fork+0x1b2/0xd30 kernel/fork.c:1972
 [<ffffffff810da967>] SYSC_clone kernel/fork.c:2084 [inline]
 [<ffffffff810da967>] SyS_clone+0x37/0x50 kernel/fork.c:2078
 [<ffffffff81006311>] do_syscall_32_irqs_on arch/x86/entry/common.c:328 [inline]
 [<ffffffff81006311>] do_fast_syscall_32+0x2f1/0xa10 arch/x86/entry/common.c:390
 [<ffffffff82818de0>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fe63f>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2050:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d37362>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor.0/16804:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff822e70e5>] copy_net_ns+0x155/0x330 net/core/net_namespace.c:406
1 lock held by syz-executor.0/16823:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff822e70e5>] copy_net_ns+0x155/0x330 net/core/net_namespace.c:406
1 lock held by syz-executor.5/16841:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff822e70e5>] copy_net_ns+0x155/0x330 net/core/net_namespace.c:406

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.141+ #23
 ffff8801d9907d08 ffffffff81b42e79 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810983b0 ffff8801d9907d40
 ffffffff81b4df89 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b4df89>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b4df1c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff810984b4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c65d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c65d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c65d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c65d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff81142c3d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82817a5c>] 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: 33 Comm: kswapd0 Not tainted 4.9.141+ #23
task: ffff8801d99217c0 task.stack: ffff8801d8418000
RIP: 0010:[<ffffffff81167600>] 
c [<ffffffff81167600>] get_current arch/x86/include/asm/current.h:14 [inline]
RIP: 0010:[<ffffffff81167600>] 
c [<ffffffff81167600>] preempt_latency_start kernel/sched/core.c:3226 [inline]
RIP: 0010:[<ffffffff81167600>] 
c [<ffffffff81167600>] preempt_count_add+0xc0/0x1c0 kernel/sched/core.c:3249
RSP: 0000:ffff8801d841f868  EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8141a061 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8141a052 RDI: ffffffff8141a061
RBP: ffff8801d841f878 R08: ffff8801d99220e0 R09: 707efd6cb9f09ad1
R10: ffff8801d99217c0 R11: 0000000000000001 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff8801d2ae3740 R15: ffff8801d2ae36b8
FS:  0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f99647c0fe0 CR3: 00000001ad79a000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d2ae3740
c ffff8801d2ae2f80
c ffff8801d841f898
c ffffffff82816c06
c
 ffff8801d841f898
c ffff8801d2ae2f80
c ffff8801d841f8e0
c ffffffff8141a061
c
 ffffffff81419f70
c ffffed003a55c6d7
c ffff8801d2ae2f80
c dffffc0000000000
c
Call Trace:
 [<ffffffff82816c06>] __raw_spin_lock include/linux/spinlock_api_smp.h:143 [inline]
 [<ffffffff82816c06>] _raw_spin_lock+0x16/0x50 kernel/locking/spinlock.c:151
 [<ffffffff8141a061>] spin_lock include/linux/spinlock.h:302 [inline]
 [<ffffffff8141a061>] task_lock include/linux/sched.h:3257 [inline]
 [<ffffffff8141a061>] find_lock_task_mm+0xf1/0x270 mm/oom_kill.c:115
 [<ffffffff821effdf>] lowmem_scan+0x34f/0xaf0 drivers/staging/android/lowmemorykiller.c:134
 [<ffffffff81449cc6>] do_shrink_slab mm/vmscan.c:398 [inline]
 [<ffffffff81449cc6>] shrink_slab.part.8+0x3c6/0xa00 mm/vmscan.c:501
 [<ffffffff814557fd>] shrink_slab mm/vmscan.c:465 [inline]
 [<ffffffff814557fd>] shrink_node+0x1ed/0x740 mm/vmscan.c:2602
 [<ffffffff814570b9>] kswapd_shrink_node mm/vmscan.c:3202 [inline]
 [<ffffffff814570b9>] balance_pgdat mm/vmscan.c:3319 [inline]
 [<ffffffff814570b9>] kswapd+0x7e9/0x13b0 mm/vmscan.c:3512
 [<ffffffff81142c3d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82817a5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: 
c8f 
c80 
c00 
c00 
c00 
c65 
c8b 
c05 
caf 
c07 
ceb 
c7e 
c25 
cff 
cff 
cff 
c7f 
c41 
c39 
cc4 
c74 
c05 
c5b 
c41 
c5c 
c5d 
cc3 
c48 
c8b 
c5d 
c08 
c48 
c89 
cdf 
ce8 
c54 
c88 
c0a 
c00 
c85 
cc0 
c75 
c39 
c<65> 
c4c 
c8b 
c24 
c25 
c00 
c7e 
c01 
c00 
c49 
c8d 
cbc 
c24 
cb0 
c11 
c00 
c00 
c48 
cb8 
c00 
c00 
c