TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
kobject: 'loop4' (ffff8880a4a9b320): kobject_uevent_env
Modules linked in:
CPU: 0 PID: 13510 Comm: syz-executor.5 Not tainted 4.14.145 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88806214a280 task.stack: ffff88808a8f0000
kobject: 'loop4' (ffff8880a4a9b320): fill_kobj_path: path = '/devices/virtual/block/loop4'
RIP: 0010:do_tcp_sendpages+0x33d/0x18f0 net/ipv4/tcp.c:967
RSP: 0018:ffff88808a8f7918 EFLAGS: 00010202
RAX: 0000000000000010 RBX: 0000000000000000 RCX: ffffc90007a4b000
RDX: 00000000000001c4 RSI: ffffffff8523f1eb RDI: 0000000000000080
RBP: ffff88808a8f7a40 R08: 0000000000020000 R09: ffff88806214ab48
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000005555
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880604ccc40
FS:  00007f4e9b0fb700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2fc23000 CR3: 000000008f6c6000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tcp_sendpage_locked net/ipv4/tcp.c:1076 [inline]
 tcp_sendpage_locked+0x88/0x140 net/ipv4/tcp.c:1067
 tcp_sendpage+0x3f/0x60 net/ipv4/tcp.c:1086
 inet_sendpage+0x157/0x580 net/ipv4/af_inet.c:779
 kernel_sendpage+0x92/0xf0 net/socket.c:3406
 sock_sendpage+0x8b/0xc0 net/socket.c:871
 pipe_to_sendpage+0x242/0x340 fs/splice.c:451
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x348/0x780 fs/splice.c:626
 splice_from_pipe+0xf0/0x150 fs/splice.c:661
 generic_splice_sendpage+0x3c/0x50 fs/splice.c:832
 do_splice_from fs/splice.c:851 [inline]
 do_splice fs/splice.c:1147 [inline]
 SYSC_splice fs/splice.c:1402 [inline]
 SyS_splice+0xd92/0x1430 fs/splice.c:1382
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459a09
RSP: 002b:00007f4e9b0fac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000459a09
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000075bfc8 R08: 0000000000010005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4e9b0fb6d4
R13: 00000000004c9202 R14: 00000000004df800 R15: 00000000ffffffff
Code: ff ff 48 0f 44 d8 e8 13 f1 38 fc 4d 85 e4 0f 84 9b 03 00 00 e8 05 f1 38 fc 48 8d bb 80 00 00 00 44 8b 65 a8 48 89 f8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 74 08 3c 03 0f 8e 85 11 00 00 44 2b a3 80 
RIP: do_tcp_sendpages+0x33d/0x18f0 net/ipv4/tcp.c:967 RSP: ffff88808a8f7918
kobject: 'loop1' (ffff8880a49840a0): kobject_uevent_env
kobject: '0:44' (ffff8880a1b74ed0): kobject_add_internal: parent: 'bdi', set: 'devices'
kobject: 'loop1' (ffff8880a49840a0): fill_kobj_path: path = '/devices/virtual/block/loop1'
kobject: 'loop2' (ffff8880a49f89a0): kobject_uevent_env
kobject: '0:44' (ffff8880a1b74ed0): kobject_uevent_env
kobject: 'loop2' (ffff8880a49f89a0): fill_kobj_path: path = '/devices/virtual/block/loop2'
kobject: '0:44' (ffff8880a1b74ed0): fill_kobj_path: path = '/devices/virtual/bdi/0:44'
---[ end trace 4f2fadf71c30ed7f ]---