Free memory is 1124kB above reserved
lowmemorykiller: Killing 'syz-executor.2' (28502) (tgid 28502), adj 1000,
   to free 12496kB on behalf of 'kswapd0' (28) because
   cache 8180kB is below limit 8192kB for oom_score_adj 1
   Free memory is 2484kB above reserved
INFO: task init:5684 blocked for more than 140 seconds.
      Not tainted 4.4.174+ #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
init            D ffff8801cfdc7718 29280  5684      1 0x00000000
 ffff8801cfdc7718 ffff8801d8b7df00 11effb929cf24527 ffff8801d8b7df00
 0000000000000000 ffff8801d8b7e700 ffff8801db71f180 ffff8801db71f1a8
 ffff8801db71e898 ffff8801d5b40000 ffff8801d8b7df00 ffffed0039fb8001
Call Trace:
 [<ffffffff82709b79>] schedule+0x99/0x1d0 kernel/sched/core.c:3355
 [<ffffffff8270a333>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3388
 [<ffffffff8270c492>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff8270c492>] mutex_lock_nested+0x3c2/0xb80 kernel/locking/mutex.c:621
 [<ffffffff81c8b2aa>] tty_open+0x56a/0xf50 drivers/tty/tty_io.c:2067
 [<ffffffff814a3ec0>] chrdev_open+0x230/0x630 fs/char_dev.c:388
 [<ffffffff8149154f>] do_dentry_open+0x38f/0xbd0 fs/open.c:749
 [<ffffffff81494d3b>] vfs_open+0x10b/0x210 fs/open.c:862
 [<ffffffff814c5ddf>] do_last fs/namei.c:3269 [inline]
 [<ffffffff814c5ddf>] path_openat+0x136f/0x4470 fs/namei.c:3406
 [<ffffffff814ccab1>] do_filp_open+0x1a1/0x270 fs/namei.c:3440
 [<ffffffff81495668>] do_sys_open+0x2f8/0x600 fs/open.c:1038
 [<ffffffff8149599d>] SYSC_open fs/open.c:1056 [inline]
 [<ffffffff8149599d>] SyS_open+0x2d/0x40 fs/open.c:1051
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
1 lock held by init/5684:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81c8b2aa>] tty_open+0x56a/0xf50 drivers/tty/tty_io.c:2067
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 28521 Comm: syz-executor.1 Not tainted 4.4.174+ #4
task: ffff8801d7ea8000 task.stack: ffff8801d4ca0000
RIP: 0010:[<ffffffff812063a1>]  [<ffffffff812063a1>] __lock_release kernel/locking/lockdep.c:3381 [inline]
RIP: 0010:[<ffffffff812063a1>]  [<ffffffff812063a1>] lock_release+0x141/0xcf0 kernel/locking/lockdep.c:3611
RSP: 0018:ffff8801d4ca78d0  EFLAGS: 00000097
RAX: 0000000000000003 RBX: 1ffffffff0506d10 RCX: 1ffffffff05f7178
RDX: 0000000000000004 RSI: 0000000000000001 RDI: ffff8801d7ea88c4
RBP: ffff8801d4ca7980 R08: 0000000000000002 R09: ffff8801d7ea8938
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff8288b8e0
R13: ffff8800b59efc00 R14: ffffffff82ea73a0 R15: ffffffff831a5078
FS:  00007f591c22b700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000711bb4 CR3: 000000016c05d000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000000 ffff8801d7ea8000 ffffffff82ea73a0 ffff88018963dcc0
 ffff8801d4ca7900 ffffffff8123a761 ffff8801d4ca7980 ffffffff81aba40a
 ffff8801d4ca7950 ffffffff81b0abec ffffed00312c7b70 0000000000000000
Call Trace:
 [<ffffffff813ba735>] rcu_lock_release include/linux/rcupdate.h:482 [inline]
 [<ffffffff813ba735>] rcu_read_unlock include/linux/rcupdate.h:917 [inline]
 [<ffffffff813ba735>] filemap_map_pages+0x4e5/0x960 mm/filemap.c:2155
 [<ffffffff8143b79a>] do_fault_around mm/memory.c:2987 [inline]
 [<ffffffff8143b79a>] do_read_fault mm/memory.c:3006 [inline]
 [<ffffffff8143b79a>] do_fault mm/memory.c:3177 [inline]
 [<ffffffff8143b79a>] handle_pte_fault mm/memory.c:3346 [inline]
 [<ffffffff8143b79a>] __handle_mm_fault mm/memory.c:3474 [inline]
 [<ffffffff8143b79a>] handle_mm_fault+0x1aca/0x3140 mm/memory.c:3503
 [<ffffffff8142c3c1>] faultin_page mm/gup.c:326 [inline]
 [<ffffffff8142c3c1>] __get_user_pages+0x381/0xfd0 mm/gup.c:522
 [<ffffffff8142dad8>] populate_vma_page_range+0x198/0x230 mm/gup.c:925
 [<ffffffff8142dd29>] __mm_populate+0x1b9/0x300 mm/gup.c:973
 [<ffffffff81409dde>] mm_populate include/linux/mm.h:1926 [inline]
 [<ffffffff81409dde>] vm_mmap_pgoff+0x19e/0x1c0 mm/util.c:300
 [<ffffffff81447b9d>] SYSC_mmap_pgoff mm/mmap.c:1523 [inline]
 [<ffffffff81447b9d>] SyS_mmap_pgoff+0x14d/0x1b0 mm/mmap.c:1481
 [<ffffffff81016bf6>] SYSC_mmap arch/x86/kernel/sys_x86_64.c:95 [inline]
 [<ffffffff81016bf6>] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:86
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
Code: fc ff df 48 89 45 d0 48 c7 c0 c0 8b fb 82 48 89 c1 83 e0 07 48 c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 ff 08 00 00 <44> 8b 0d 18 28 db 01 45 85 c9 0f 84 d7 03 00 00 48 8b 45 d0 48 
NMI backtrace for cpu 1
CPU: 1 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #4
task: ffff8801da6f4740 task.stack: ffff8800001d0000
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:62 [inline]
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800001d7c88  EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8800001d7cb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fef6e08e000 CR3: 00000000b7f20000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34
 000000000001b6c0 0000000000000008 ffff8800001d7cd8 ffffffff81092bee
 0000000000000008 ffffffff82924260 ffff8800001d7d30 ffffffff81ab8252
Call Trace:
 [<ffffffff81092bee>] nmi_raise_cpu_backtrace+0x5e/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81ab8252>] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae lib/nmi_backtrace.c:85
 [<ffffffff81092ca4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff813b4762>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff813b4762>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813b4762>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813b4762>] watchdog.cold+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
 [<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00 02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f1