------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 0 PID: 3388 at lib/refcount.c:153 refcount_inc+0x47/0x50 lib/refcount.c:153
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 3388 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:ffffc90002a53b90 EFLAGS: 00010282
RAX: 000000000000002b RBX: ffff8801fc210800 RCX: ffffffff8123dede
RDX: 0000000000000000 RSI: ffff8801fc51ad58 RDI: 0000000000000293
RBP: ffffc90002a53b98 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90002a53b18 R11: 0000000000000000 R12: ffffffff8162ef10
R13: ffff8801fd204578 R14: ffff8801fd204600 R15: 0000000000000001
 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
 dentry_unlink_inode+0x1ab/0x1e0 fs/dcache.c:375
 __dentry_kill+0x12d/0x210 fs/dcache.c:572
 shrink_dentry_list+0x140/0x660 fs/dcache.c:1019
 shrink_dcache_parent+0x2f/0x90 fs/dcache.c:1453
 do_one_tree+0x15/0x50 fs/dcache.c:1484
 shrink_dcache_for_umount+0x37/0xb0 fs/dcache.c:1501
 generic_shutdown_super+0x2d/0x170 fs/super.c:424
 kill_anon_super fs/super.c:987 [inline]
 kill_litter_super+0x36/0x50 fs/super.c:997
 deactivate_locked_super+0x4d/0x80 fs/super.c:312
 deactivate_super+0x61/0x90 fs/super.c:343
 cleanup_mnt+0x49/0x90 fs/namespace.c:1173
 __cleanup_mnt+0x16/0x20 fs/namespace.c:1180
 task_work_run+0xa3/0xe0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x3e6/0x1050 kernel/exit.c:869
 do_group_exit+0x60/0x100 kernel/exit.c:972
 SYSC_exit_group kernel/exit.c:983 [inline]
 SyS_exit_group+0x18/0x20 kernel/exit.c:981
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a09
RSP: 002b:0000000000a2d778 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000006f5ea0 RCX: 0000000000452a09
RDX: 000000000040cc00 RSI: 0000000000a34bd0 RDI: 0000000000000045
RBP: 0000000000a2b0c0 R08: 000000000000000c R09: 0000000000000000
R10: 000000000184c940 R11: 0000000000000202 R12: 00000000004b7338
R13: 0000000000000000 R14: 0000000000007f92 R15: 0000000000000010
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..