Free memory is 43928kB above reserved
lowmemorykiller: Killing 'syz-executor376' (18395) (tgid 18395), adj 1000,
   to free 88kB on behalf of 'syz-executor376' (18546) because
   cache 1600kB is below limit 65536kB for oom_score_adj 12
   Free memory is 50820kB above reserved
INFO: task init:15544 blocked for more than 140 seconds.
      Not tainted 4.9.155+ #27
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
init            D28952 15544      1 0x00000000
 ffff8801c4cfdf00 ffff8801d4c50580 ffff8801db721000 ffff8801da5f8000
 ffff8801db721018 ffff88018c3df5a0 ffffffff82806806 ffff88018c3df5d8
 0000000000000000 0000000000000000 00ff88018c3df5b8 ffff8801db7218f0
Call Trace:
 [<ffffffff82807d92>] schedule+0x92/0x1c0 kernel/sched/core.c:3553
 [<ffffffff82813516>] schedule_timeout+0x766/0xe50 kernel/time/timer.c:1771
 [<ffffffff8280fbe0>] __down_common kernel/locking/semaphore.c:221 [inline]
 [<ffffffff8280fbe0>] __down+0x190/0x2b0 kernel/locking/semaphore.c:238
 [<ffffffff811fd2b4>] down+0x64/0x90 kernel/locking/semaphore.c:61
 [<ffffffff8122210c>] console_lock+0x2c/0x80 kernel/printk/printk.c:2217
 [<ffffffff8122752c>] console_device+0x1c/0xc0 kernel/printk/printk.c:2554
 [<ffffffff81d2e0e6>] tty_lookup_driver drivers/tty/tty_io.c:2016 [inline]
 [<ffffffff81d2e0e6>] tty_open_by_driver drivers/tty/tty_io.c:2061 [inline]
 [<ffffffff81d2e0e6>] tty_open+0x796/0xe10 drivers/tty/tty_io.c:2138
 [<ffffffff81519c40>] chrdev_open+0x230/0x630 fs/char_dev.c:392
 [<ffffffff81503cff>] do_dentry_open+0x3ef/0xc80 fs/open.c:766
 [<ffffffff81507695>] vfs_open+0x105/0x230 fs/open.c:879
 [<ffffffff8153ebd5>] do_last fs/namei.c:3457 [inline]
 [<ffffffff8153ebd5>] path_openat+0xbf5/0x2f60 fs/namei.c:3581
 [<ffffffff81543d21>] do_filp_open+0x1a1/0x280 fs/namei.c:3615
 [<ffffffff815080c0>] do_sys_open+0x2f0/0x610 fs/open.c:1072
 [<ffffffff8150840d>] SYSC_open fs/open.c:1090 [inline]
 [<ffffffff8150840d>] SyS_open+0x2d/0x40 fs/open.c:1085
 [<ffffffff810056bd>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285
 [<ffffffff82816a93>] 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: [<ffffffff8131bd9d>] rcu_read_unlock include/linux/rcupdate.h:927 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bd9d>] rcu_lock_break kernel/hung_task.c:143 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bd9d>] check_hung_uninterruptible_tasks kernel/hung_task.c:177 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bd9d>] watchdog+0x30d/0xa40 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fea8f>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1911:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff8156f2f8>] __fdget_pos+0xa8/0xd0 fs/file.c:781
2 locks held by getty/2039:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82814b83>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d3982e>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
1 lock held by init/15544:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open_by_driver drivers/tty/tty_io.c:2060 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open+0x3f9/0xe10 drivers/tty/tty_io.c:2138
1 lock held by init/15545:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open_by_driver drivers/tty/tty_io.c:2060 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open+0x3f9/0xe10 drivers/tty/tty_io.c:2138
1 lock held by init/15546:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open_by_driver drivers/tty/tty_io.c:2060 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open+0x3f9/0xe10 drivers/tty/tty_io.c:2138
1 lock held by init/15547:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open_by_driver drivers/tty/tty_io.c:2060 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open+0x3f9/0xe10 drivers/tty/tty_io.c:2138
1 lock held by init/15548:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open_by_driver drivers/tty/tty_io.c:2060 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open+0x3f9/0xe10 drivers/tty/tty_io.c:2138
1 lock held by init/15559:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open_by_driver drivers/tty/tty_io.c:2060 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81d2dd49>] tty_open+0x3f9/0xe10 drivers/tty/tty_io.c:2138

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.155+ #27
 ffff8801d9907cd0 ffffffff81b47871 0000000000000001 0000000000000000
 0000000000000001 ffffffff81097301 00000000003ff2da ffff8801d9907d08
 ffffffff81b52afc 0000000000000001 0000000000000000 0000000000000001
Call Trace:
 [<ffffffff81b47871>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b47871>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff81b52afc>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b52a84>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<ffffffff81097494>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c087>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c087>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c087>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c087>] watchdog+0x5f7/0xa40 kernel/hung_task.c:239
 [<ffffffff81142028>] kthread+0x278/0x310 kernel/kthread.c:211
 [<ffffffff82816c5c>] 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: 18680 Comm: syz-executor376 Not tainted 4.9.155+ #27
task: ffff8800114817c0 task.stack: ffff880012b48000
RIP: 0010:[<ffffffff81b63ab9>] 
c [<ffffffff81b63ab9>] memcmp+0x29/0xc0 lib/string.c:767
RSP: 0018:ffff880012b4f090  EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff880012b4f214 RCX: 0000000000000004
RDX: 00000000000000ff RSI: ffff8801c87af54c RDI: ffff880012b4f140
RBP: ffff880012b4f0b8 R08: 000000003d8ca650 R09: 00000000faba53de
R10: ffffed0002569e1b R11: ffff880012b4f0df R12: dffffc0000000000
R13: ffff880012b4f218 R14: 000000000000001b R15: 00000000000f0935
FS:  00007f4f2deca700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4f2dea8db8 CR3: 00000001d2762000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff880012b4f108
c ffffffff8107731a
c 00000000bfbf0935
c ffff8801c87af460
c
 ffff880012b4f128
c ffff880012b4f118
c ffffffff81be8c5c
c ffff880002000000
c
 00000000000000d8
c ffff880012b4f140
c 0000000000000000
c c4338a82c4bf967d
c
Call Trace:
 [<ffffffff81be8c5c>] find_stack lib/stackdepot.c:176 [inline]
 [<ffffffff81be8c5c>] depot_save_stack+0x13c/0x4a0 lib/stackdepot.c:225
 [<ffffffff814f4604>] save_stack mm/kasan/kasan.c:511 [inline]
 [<ffffffff814f4604>] set_track mm/kasan/kasan.c:517 [inline]
 [<ffffffff814f4604>] kasan_slab_free+0x104/0x190 mm/kasan/kasan.c:582
 [<ffffffff814f158b>] slab_free_hook mm/slub.c:1355 [inline]
 [<ffffffff814f158b>] slab_free_freelist_hook mm/slub.c:1377 [inline]
 [<ffffffff814f158b>] slab_free mm/slub.c:2958 [inline]
 [<ffffffff814f158b>] kfree+0xfb/0x310 mm/slub.c:3878
 [<ffffffff814caa58>] __vunmap+0x258/0x3a0 mm/vmalloc.c:1521
 [<ffffffff814cac60>] vfree+0x50/0x110 mm/vmalloc.c:1552
 [<ffffffff823c9f60>] netlink_skb_destructor+0x190/0x1e0 net/netlink/af_netlink.c:350
 [<ffffffff822bc62e>] skb_release_head_state+0xfe/0x200 net/core/skbuff.c:655
 [<ffffffff822be3c6>] skb_release_all+0x16/0x60 net/core/skbuff.c:668
 [<ffffffff822be546>] __kfree_skb net/core/skbuff.c:684 [inline]
 [<ffffffff822be546>] consume_skb+0xc6/0x340 net/core/skbuff.c:757
 [<ffffffff823d587e>] netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 [<ffffffff823d587e>] netlink_unicast+0x4ce/0x6d0 net/netlink/af_netlink.c:1311
 [<ffffffff823d62a6>] netlink_sendmsg+0x6b6/0xc80 net/netlink/af_netlink.c:1859
 [<ffffffff822a3e5e>] sock_sendmsg_nosec net/socket.c:648 [inline]
 [<ffffffff822a3e5e>] sock_sendmsg+0xbe/0x110 net/socket.c:658
 [<ffffffff822a42c4>] kernel_sendmsg+0x44/0x50 net/socket.c:666
 [<ffffffff822ae996>] sock_no_sendpage+0x116/0x150 net/core/sock.c:2335
 [<ffffffff822a3b35>] kernel_sendpage+0x95/0xf0 net/socket.c:3334
 [<ffffffff822a3c1b>] sock_sendpage+0x8b/0xc0 net/socket.c:802
 [<ffffffff815ac3ed>] pipe_to_sendpage+0x28d/0x3d0 fs/splice.c:470
 [<ffffffff815b01e1>] splice_from_pipe_feed fs/splice.c:521 [inline]
 [<ffffffff815b01e1>] __splice_from_pipe+0x351/0x790 fs/splice.c:645
 [<ffffffff815b1be8>] splice_from_pipe+0x108/0x170 fs/splice.c:680
 [<ffffffff815b1c8c>] generic_splice_sendpage+0x3c/0x50 fs/splice.c:851
 [<ffffffff815ac0e6>] do_splice_from fs/splice.c:870 [inline]
 [<ffffffff815ac0e6>] direct_splice_actor+0x126/0x1a0 fs/splice.c:1037
 [<ffffffff815ae058>] splice_direct_to_actor+0x2c8/0x820 fs/splice.c:992
 [<ffffffff815ae755>] do_splice_direct+0x1a5/0x260 fs/splice.c:1080
 [<ffffffff8150f8f3>] do_sendfile+0x503/0xc00 fs/read_write.c:1395
 [<ffffffff815118e5>] SYSC_sendfile64 fs/read_write.c:1456 [inline]
 [<ffffffff815118e5>] SyS_sendfile64+0x145/0x160 fs/read_write.c:1442
 [<ffffffff810056bd>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285
 [<ffffffff82816a93>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
c00 
c00 
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c55 
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c41 
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c10 
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c<48> 
c83 
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c01 
c48 
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cc6 
c01 
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cd8 
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c