Free memory is -13340kB above reserved
lowmemorykiller: Killing 'syz-executor.2' (28616) (tgid 28614), adj 1000,
   to free 51384kB on behalf of 'syz-executor.2' (28628) because
   cache 260kB is below limit 6144kB for oom_score_adj 0
   Free memory is -13340kB above reserved
INFO: task syz-executor.2:28641 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.2  D28968 28641   2096 0x20020004
 ffff880096755f00 0000000000000000 ffff8801d2b87900 ffff8801a85f0000
 ffff8801db721018 ffff8800285efa88 ffffffff828075c2 ffff8800285efb08
 ffff880096755f00 ffffffff810efada 00fffc0000000000 ffff8801db7218f0
Call Trace:
 [<ffffffff82808aef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff822acffc>] __lock_sock+0x13c/0x250 net/core/sock.c:2035
 [<ffffffff822ad206>] lock_sock_nested+0xf6/0x120 net/core/sock.c:2505
 [<ffffffff827d2640>] lock_sock include/net/sock.h:1404 [inline]
 [<ffffffff827d2640>] packet_setsockopt+0xc10/0x2630 net/packet/af_packet.c:3856
lowmemorykiller: Killing 'syz-executor.2' (28616) (tgid 28614), adj 1000,
   to free 51384kB on behalf of 'rs:main Q:Reg' (1907) because
   cache 260kB is below limit 6144kB for oom_score_adj 0
   Free memory is -13340kB above reserved
 [<ffffffff827d4141>] compat_packet_setsockopt+0xe1/0x140 net/packet/af_packet.c:4016
 [<ffffffff8238f7d9>] C_SYSC_setsockopt net/compat.c:399 [inline]
 [<ffffffff8238f7d9>] compat_SyS_setsockopt+0x169/0x550 net/compat.c:382
 [<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/2037:
 #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

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

lowmemorykiller: Killing 'syz-executor.2' (28616) (tgid 28614), adj 1000,
   to free 51384kB on behalf of 'syz-fuzzer' (2075) because
   cache 260kB is below limit 6144kB for oom_score_adj 0
   Free memory is -13340kB above reserved
lowmemorykiller: Killing 'syz-executor.2' (28616) (tgid 28614), adj 1000,
   to free 51384kB on behalf of 'syz-fuzzer' (2056) because
   cache 260kB is below limit 6144kB for oom_score_adj 0
   Free memory is -13340kB above reserved
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: 2075 Comm: syz-fuzzer Not tainted 4.9.141+ #23
task: ffff8801d0f4c740 task.stack: ffff8801cdfd0000
RIP: 0010:[<ffffffff81d6254b>] 
c [<ffffffff81d6254b>] io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:414
RSP: 0000:ffff8801cdfd7050  EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffffff81d624f1 RDI: ffffffff84b5bb58
RBP: ffff8801cdfd7060 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff84b5bb20
R13: 0000000000000020 R14: fffffbfff096b7ab R15: fffffbfff096b76d
FS:  000000c42005c768(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000043246a CR3: 00000001d26ee000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff84b5bb20
c 0000000000002707
c ffff8801cdfd70b0
c ffffffff81d64764
c
 ffffffff81b6cdd8
c ffffffff84b5bb68
c ffffffff84b5bd5a
c ffffffff84b5bb20
c
 0000000000000020
c ffffffff81d648b0
c dffffc0000000000
c 0000000000000020
c
Call Trace:
 [<ffffffff81d64764>] serial_in drivers/tty/serial/8250/8250.h:111 [inline]
 [<ffffffff81d64764>] wait_for_xmitr+0x94/0x1e0 drivers/tty/serial/8250/8250_port.c:1997
 [<ffffffff81d648cf>] serial8250_console_putchar+0x1f/0x60 drivers/tty/serial/8250/8250_port.c:3103
 [<ffffffff81d4cce9>] uart_console_write+0x59/0xf0 drivers/tty/serial/serial_core.c:1866
 [<ffffffff81d6fae8>] serial8250_console_write+0x528/0x820 drivers/tty/serial/8250/8250_port.c:3169
 [<ffffffff81d5d4ff>] univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:594
 [<ffffffff8122387d>] call_console_drivers.isra.0.constprop.15+0x1ad/0x360 kernel/printk/printk.c:1594
 [<ffffffff812265af>] console_unlock+0x47f/0xb50 kernel/printk/printk.c:2454
 [<ffffffff812270c8>] vprintk_emit+0x448/0x790 kernel/printk/printk.c:1908
 [<ffffffff81227438>] vprintk+0x28/0x30 kernel/printk/printk.c:1918
 [<ffffffff8122745d>] vprintk_default+0x1d/0x30 kernel/printk/printk.c:1919
 [<ffffffff81402f9f>] vprintk_func kernel/printk/internal.h:36 [inline]
 [<ffffffff81402f9f>] printk+0xaf/0xd7 kernel/printk/printk.c:1980
 [<ffffffff8222d9e8>] lowmem_scan.cold.1+0x1f9/0x35b drivers/staging/android/lowmemorykiller.c:177
 [<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
 [<ffffffff81415701>] __alloc_pages include/linux/gfp.h:433 [inline]
 [<ffffffff81415701>] __alloc_pages_node include/linux/gfp.h:446 [inline]
 [<ffffffff81415701>] alloc_pages_node include/linux/gfp.h:460 [inline]
 [<ffffffff81415701>] __page_cache_alloc include/linux/pagemap.h:208 [inline]
 [<ffffffff81415701>] page_cache_read mm/filemap.c:2007 [inline]
 [<ffffffff81415701>] filemap_fault+0xaf1/0x1110 mm/filemap.c:2192
 [<ffffffff816e7721>] ext4_filemap_fault+0x71/0xa0 fs/ext4/inode.c:5853
 [<ffffffff81492ef3>] __do_fault+0x223/0x500 mm/memory.c:2833
 [<ffffffff814a3696>] do_read_fault mm/memory.c:3180 [inline]
 [<ffffffff814a3696>] do_fault mm/memory.c:3315 [inline]
 [<ffffffff814a3696>] handle_pte_fault mm/memory.c:3516 [inline]
 [<ffffffff814a3696>] __handle_mm_fault mm/memory.c:3603 [inline]
 [<ffffffff814a3696>] handle_mm_fault+0x1326/0x2350 mm/memory.c:3640
 [<ffffffff810b2b33>] __do_page_fault+0x403/0xa60 arch/x86/mm/fault.c:1406
 [<ffffffff810b31e7>] do_page_fault+0x27/0x30 arch/x86/mm/fault.c:1469
 [<ffffffff828188b5>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:951
Code: 
c24 
cc9 
c00 
c00 
c00 
c49 
c8d 
c7c 
c24 
c38 
c48 
cb8 
c00 
c00 
c00 
c00 
c00 
cfc 
cff 
cdf 
c48 
c89 
cfa 
c48 
cc1 
cea 
c03 
cd3 
ce3 
c80 
c3c 
c02 
c00 
c75 
c17 
c41 
c03 
c5c 
c24 
c38 
c89 
cda 
cec 
c<5b> 
c0f 
cb6 
cc0 
c41 
c5c 
c5d 
cc3 
ce8 
ca8 
c0a 
c79 
cff 
ceb 
cc2 
ce8 
c01 
c0b 
c79 
cff 
ceb 
c