------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 0 PID: 3309 at lib/refcount.c:153 refcount_inc+0x47/0x50 lib/refcount.c:153
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 3309 Comm: syz-executor7 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:ffffc90002587df8 EFLAGS: 00010292
RAX: 000000000000002b RBX: ffff8802166cf800 RCX: ffffffff8123dede
RDX: 0000000000000000 RSI: ffff880207f91098 RDI: 0000000000000293
RBP: ffffc90002587e00 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90002587d80 R11: 0000000000000000 R12: ffffffff8162ef10
R13: ffff88020f764578 R14: ffff88020f764600 R15: 0000000000000000
 get_ipc_ns include/linux/ipc_namespace.h:129 [inline]
 __get_ns_from_inode ipc/mqueue.c:110 [inline]
 get_ns_from_inode ipc/mqueue.c:118 [inline]
 mqueue_evict_inode+0x69/0x340 ipc/mqueue.c:402
 evict+0x102/0x230 fs/inode.c:552
 iput_final fs/inode.c:1514 [inline]
 iput+0x32b/0x400 fs/inode.c:1541
 do_unlinkat+0x1d4/0x360 fs/namei.c:4065
 SYSC_unlink fs/namei.c:4106 [inline]
 SyS_unlink+0x26/0x30 fs/namei.c:4104
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452777
RSP: 002b:0000000000a2d888 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00000000006f65c0 RCX: 0000000000452777
RDX: 0000000000a2d890 RSI: 0000000000a2d920 RDI: 0000000000a2d920
RBP: 0000000000008041 R08: 0000000000000000 R09: 000000000000000f
R10: 0000000000000003 R11: 0000000000000206 R12: 00000000006f6618
R13: 00000000006f6618 R14: 000000000001a9d8 R15: 0000000000002710
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..