------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 1 PID: 12020 at lib/refcount.c:153 refcount_inc+0x47/0x50 lib/refcount.c:153
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 12020 Comm: syz-executor6 Not tainted 4.15.0-rc3-next-20171214+ #67
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+0xe9/0x14b lib/dump_stack.c:53
 panic+0x10e/0x2f8 kernel/panic.c:183
 __warn+0x14e/0x150 kernel/panic.c:547
 report_bug+0x11e/0x1a0 lib/bug.c:184
 fixup_bug.part.11+0x17/0x30 arch/x86/kernel/traps.c:177
 fixup_bug arch/x86/kernel/traps.c:246 [inline]
 do_error_trap+0x14a/0x180 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:1079
RIP: 0010:refcount_inc+0x47/0x50 lib/refcount.c:153
RSP: 0018:ffffc90000dc7aa8 EFLAGS: 00010292
RAX: 000000000000002b RBX: ffff8801f5c1b038 RCX: ffffffff8123dede
RDX: 00000000000047bb RSI: ffffc90004e48000 RDI: 0000000000000216
RBP: ffffc90000dc7ab0 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90000dc7a30 R11: 0000000000000000 R12: 00000000000000ff
R13: ffff8801f5c1b038 R14: 0000000000000000 R15: ffff8801f9454180
 xfrm_state_hold include/net/xfrm.h:858 [inline]
 xfrm_state_flush+0x185/0x2b0 net/xfrm/xfrm_state.c:719
 pfkey_flush+0x6f/0xd0 net/key/af_key.c:1753
 pfkey_process+0x255/0x290 net/key/af_key.c:2809
 pfkey_sendmsg+0x193/0x310 net/key/af_key.c:3648
 sock_sendmsg_nosec net/socket.c:636 [inline]
 sock_sendmsg+0x51/0x70 net/socket.c:646
 ___sys_sendmsg+0x35e/0x3b0 net/socket.c:2026
 __sys_sendmsg+0x50/0x90 net/socket.c:2060
 SYSC_sendmsg net/socket.c:2071 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2067
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a09
RSP: 002b:00007f9d00d05c58 EFLAGS: 00000212 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09
RDX: 0000000000000000 RSI: 0000000020212000 RDI: 0000000000000014
RBP: 00000000000000e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee5a0
R13: 00000000ffffffff R14: 00007f9d00d066d4 R15: 0000000000000000
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..