Free memory is -13336kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (27360) (tgid 27359), adj 1000,
   to free 51416kB on behalf of 'syz-fuzzer' (2043) because
   cache 240kB is below limit 6144kB for oom_score_adj 0
   Free memory is -13336kB above reserved
INFO: task syz-executor.1:27360 blocked for more than 140 seconds.
      Not tainted 4.9.141+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D
28824 27360   2107 0x00000004
 0000000000000000 ffff8801ca91b180 ffff8801c97f5f00 ffff8801db621018
 ffff8801d7f6fa08 ffffffff828075c2 0000000000000000 ffff8801da714ff0
 ffffed003b4e29fd 00ff8801da714740 ffff8801db6218f0Call 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
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82817893>] 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: [<ffffffff8131c0cc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 (tasklist_lock){.+.+..}, at: [<ffffffff813fe63f>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
 #0: 
 (&tty->ldisc_sem){++++++}, at: [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff81d37362>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
 #0: 
 ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff81130f0c>] process_one_work+0x73c/0x15f0 kernel/workqueue.c:2085
 ((addr_chk_work).work){+.+...}, at: [<ffffffff81130f44>] process_one_work+0x774/0x15f0 kernel/workqueue.c:2089
 (rtnl_mutex){+.+.+.}, at: [<ffffffff823412d7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 #0: 
 (net_mutex){+.+.+.}, at: [<ffffffff822e70e5>] copy_net_ns+0x155/0x330 net/core/net_namespace.c:406
 #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+ #1
 ffff8801d9907d08
 ffffffff81b42e79 0000000000000000 0000000000000001 0000000000000001
 0000000000000001 ffffffff810983b0 ffff8801d9907d40 ffffffff81b4df89
 0000000000000001 0000000000000000 0000000000000002Call 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: 27402 Comm: syz-executor.2 Not tainted 4.9.141+ #1
task: ffff8801c80cc740 task.stack: ffff880101360000
RIP: 0010:[<ffffffff81205ad9>] 
c [<ffffffff81205ad9>] hlock_class kernel/locking/lockdep.c:149 [inline]
RIP: 0010:[<ffffffff81205ad9>] 
c [<ffffffff81205ad9>] mark_lock+0x89/0x1290 kernel/locking/lockdep.c:3039
RSP: 0018:ffff8801013670f8  EFLAGS: 00000006
RAX: 000000000000001e RBX: ffff8801c80cd040 RCX: 1ffff10039019a0c
RDX: 0000000000000000 RSI: ffff8801c80cd040 RDI: ffff8801c80cc740
RBP: ffff880101367140 R08: ffff8801c80cd060 R09: 0000000000000000
R10: ffff8801c80cc740 R11: 1ffff10039019a07 R12: 00000000000030f0
R13: 0000000000001000 R14: 000000000000000c R15: ffff8801c80cc740
FS:  00007ff88504b700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1dbd0d2317 CR3: 000000019df5f000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 ffff8801c80cd062
c ffff8801013672b8
c 0000000000000046
c 0000000000000000
c
 ffff8801c80cd040
c 000000000000001e
c 0000000000000002
c ffff8801c80ccfdc
c
 0000000000000000
c ffff8801013672f8
c ffffffff81207a04
c ffff8801c80ccfe0
c
Call Trace:
 [<ffffffff81207a04>] __lock_acquire+0x654/0x4a10 kernel/locking/lockdep.c:3306
 [<ffffffff8120c8d0>] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756
 [<ffffffff81419fb6>] rcu_lock_acquire include/linux/rcupdate.h:493 [inline]
 [<ffffffff81419fb6>] rcu_read_lock include/linux/rcupdate.h:875 [inline]
 [<ffffffff81419fb6>] find_lock_task_mm+0x46/0x270 mm/oom_kill.c:112
 [<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
 [<ffffffff814560c7>] shrink_zones mm/vmscan.c:2749 [inline]
 [<ffffffff814560c7>] do_try_to_free_pages mm/vmscan.c:2791 [inline]
 [<ffffffff814560c7>] try_to_free_pages+0x377/0xb80 mm/vmscan.c:3002
 [<ffffffff81428a01>] __perform_reclaim mm/page_alloc.c:3324 [inline]
 [<ffffffff81428a01>] __alloc_pages_direct_reclaim mm/page_alloc.c:3345 [inline]
 [<ffffffff81428a01>] __alloc_pages_slowpath mm/page_alloc.c:3697 [inline]
 [<ffffffff81428a01>] __alloc_pages_nodemask+0x981/0x1bd0 mm/page_alloc.c:3862
 [<ffffffff814c9e8b>] __alloc_pages include/linux/gfp.h:433 [inline]
 [<ffffffff814c9e8b>] __alloc_pages_node include/linux/gfp.h:446 [inline]
 [<ffffffff814c9e8b>] alloc_pages_node include/linux/gfp.h:460 [inline]
 [<ffffffff814c9e8b>] __vmalloc_area_node mm/vmalloc.c:1644 [inline]
 [<ffffffff814c9e8b>] __vmalloc_node_range+0x25b/0x600 mm/vmalloc.c:1702
 [<ffffffff814ca71b>] __vmalloc_node mm/vmalloc.c:1745 [inline]
 [<ffffffff814ca71b>] __vmalloc_node_flags mm/vmalloc.c:1759 [inline]
 [<ffffffff814ca71b>] vmalloc+0x5b/0x70 mm/vmalloc.c:1774
 [<ffffffff82450f79>] xt_alloc_table_info+0xc9/0x100 net/netfilter/x_tables.c:997
 [<ffffffff8261e8bd>] do_replace.isra.7+0xfd/0x470 net/ipv4/netfilter/arp_tables.c:979
 [<ffffffff8261ee6f>] do_arpt_set_ctl+0xff/0x140 net/ipv4/netfilter/arp_tables.c:1469
 [<ffffffff823e290d>] nf_sockopt net/netfilter/nf_sockopt.c:105 [inline]
 [<ffffffff823e290d>] nf_setsockopt+0x6d/0xc0 net/netfilter/nf_sockopt.c:114
 [<ffffffff824c1178>] ip_setsockopt+0x88/0xa0 net/ipv4/ip_sockglue.c:1249
 [<ffffffff8256ce5a>] udp_setsockopt+0x4a/0x90 net/ipv4/udp.c:2110
 [<ffffffff826f543a>] ipv6_setsockopt+0x10a/0x130 net/ipv6/ipv6_sockglue.c:912
 [<ffffffff824deaa8>] tcp_setsockopt+0x88/0xe0 net/ipv4/tcp.c:2758
 [<ffffffff822a747a>] sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2706
 [<ffffffff822a4d76>] SYSC_setsockopt net/socket.c:1785 [inline]
 [<ffffffff822a4d76>] SyS_setsockopt+0x166/0x260 net/socket.c:1764
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82817893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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