R13: 0000000000000006 R14: 0000000000000000 R15: 00007ffc4045f5a8
------------[ cut here ]------------
------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 4370 at lib/refcount.c:187 refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:187
WARNING: CPU: 0 PID: 4371 at lib/refcount.c:153 refcount_inc+0x47/0x50 lib/refcount.c:153
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4370 Comm: syzkaller542467 Not tainted 4.16.0-rc6+ #43
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x24d lib/dump_stack.c:53
 panic+0x1e4/0x41c kernel/panic.c:183
 __warn+0x1dc/0x200 kernel/panic.c:547
 report_bug+0x1f4/0x2b0 lib/bug.c:186
 fixup_bug.part.10+0x37/0x80 arch/x86/kernel/traps.c:178
 fixup_bug arch/x86/kernel/traps.c:247 [inline]
 do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296
Modules linked in:
CPU: 0 PID: 4371 Comm: syzkaller542467 Not tainted 4.16.0-rc6+ #43
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:refcount_inc+0x47/0x50 lib/refcount.c:153
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
RSP: 0018:ffff8801b97c7860 EFLAGS: 00010286
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:986
RAX: dffffc0000000008 RBX: ffff8801b91301c4 RCX: ffffffff815b423e
RDX: 0000000000000000 RSI: 1ffff100372f8ebc RDI: 1ffff100372f8e91
RIP: 0010:refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:187
RBP: ffff8801b97c7868 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801b97c7af8
RSP: 0018:ffff8801b9fdf728 EFLAGS: 00010286
R13: ffff8801bbac3513 R14: ffff8801b91301c0 R15: ffff8801bbac3501
RAX: dffffc0000000008 RBX: 0000000000000000 RCX: ffffffff815b423e
FS:  00000000016f7880(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000
RDX: 0000000000000000 RSI: 1ffff100373fbe95 RDI: 0000000000000293
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
RBP: ffff8801b9fdf7b8 R08: 0000000000000000 R09: 0000000000000000
R10: ffff8801b9fdf850 R11: 0000000000000000 R12: 1ffff100373fbee6
CR2: 00000000006dc0b0 CR3: 00000001b1b68006 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
R13: 00000000ffffffff R14: 0000000000000001 R15: ffff8801b9602084
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 get_net include/net/net_namespace.h:204 [inline]
 sk_alloc+0x3f9/0x1440 net/core/sock.c:1540
 refcount_dec_and_test+0x1a/0x20 lib/refcount.c:212
 put_net include/net/net_namespace.h:222 [inline]
 __sk_destruct+0x560/0x920 net/core/sock.c:1592
 inet_create+0x47c/0xf50 net/ipv4/af_inet.c:320
 __sock_create+0x4d4/0x850 net/socket.c:1285
 sk_destruct+0x47/0x80 net/core/sock.c:1601
 sock_create net/socket.c:1325 [inline]
 SYSC_socket net/socket.c:1355 [inline]
 SyS_socket+0xeb/0x1d0 net/socket.c:1335
 __sk_free+0xf1/0x2b0 net/core/sock.c:1612
 sk_free+0x2a/0x40 net/core/sock.c:1623
 sock_put include/net/sock.h:1664 [inline]
 tcp_close+0x967/0x1190 net/ipv4/tcp.c:2329
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 inet_release+0xed/0x1c0 net/ipv4/af_inet.c:427
 sock_release+0x8d/0x1e0 net/socket.c:594
 sock_close+0x16/0x20 net/socket.c:1149
 __fput+0x327/0x7e0 fs/file_table.c:209
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
 ____fput+0x15/0x20 fs/file_table.c:243
RIP: 0033:0x445987
 task_work_run+0x199/0x270 kernel/task_work.c:113
RSP: 002b:00007ffc4045f468 EFLAGS: 00000206
 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000445987
RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 00007ffc4045f580 R08: 0000000000000000 R09: 0000000000000001
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:166
R10: 000000000000000a R11: 0000000000000206 R12: 0000000000000002
R13: 0000000000000002 R14: 000000000000fa49 R15: 00007ffc4045f5a8
Code: 
5e 
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_64+0x6ec/0x940 arch/x86/entry/common.c:292
fe 
5b 
5d 
c3 
e8 
0a 
28 
5e 
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
fe 
RIP: 0033:0x402c30
80 
RSP: 002b:00007ffc4045f468 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
3d 
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000402c30
RDX: 00000000000000e0 RSI: 00007ffc4045fd40 RDI: 0000000000000003
6c 
RBP: 00007ffc4045f580 R08: 00007ffc4045f48c R09: 0000000000000001
R10: 00007ffc4045f580 R11: 0000000000000246 R12: 00000000006d04e0
44 
R13: 00000000006cfe60 R14: 0000000000001380 R15: 00007ffc4045f5a8
d6 05 00 75 ea e8 fc 27 5e fe 48 c7 c7 40 a7 75 87 c6 05 57 44 d6 05 01 e8 49 35 2e fe <0f> 0b eb ce 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 
---[ end trace 8191722dd821f7f7 ]---
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..