RBP: 00007f67a180ba90 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000004b75fb
R13: 00007f67a180bbc8 R14: 00000000004b75fb R15: 0000000000000000
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(depth <= 0)
WARNING: CPU: 1 PID: 30492 at kernel/locking/lockdep.c:3766 __lock_release kernel/locking/lockdep.c:3766 [inline]
WARNING: CPU: 1 PID: 30492 at kernel/locking/lockdep.c:3766 lock_release+0x5de/0xda0 kernel/locking/lockdep.c:4023
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 30492 Comm: syz-executor2 Not tainted 4.15.0-rc2+ #149
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+0x194/0x257 lib/dump_stack.c:53
 panic+0x1e4/0x41c kernel/panic.c:183
 __warn+0x1dc/0x200 kernel/panic.c:547
 report_bug+0x211/0x2d0 lib/bug.c:184
 fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:177
 fixup_bug arch/x86/kernel/traps.c:246 [inline]
 do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:930
RIP: 0010:__lock_release kernel/locking/lockdep.c:3766 [inline]
RIP: 0010:lock_release+0x5de/0xda0 kernel/locking/lockdep.c:4023
RSP: 0018:ffff8801d304f500 EFLAGS: 00010082
RAX: dffffc0000000008 RBX: 1ffff1003a609ea5 RCX: ffffffff815a047e
RDX: 0000000000010000 RSI: ffffc900034ae000 RDI: 0000000000000000
RBP: ffff8801d304f670 R08: 0000000000000001 R09: 0000000000000000
R10: ffff8801c1eda080 R11: fffffbfff0e89663 R12: ffff8801d304f548
R13: ffff8801d304f648 R14: ffff8801c2254118 R15: ffffffff8748bd20
 up_write+0x6b/0x120 kernel/locking/rwsem.c:131
 destroy_unused_super.part.7+0x18/0xd0 fs/super.c:163
 destroy_unused_super fs/super.c:505 [inline]
 alloc_super fs/super.c:258 [inline]
 sget_userns+0x905/0xe20 fs/super.c:503
 mount_ns+0x6d/0x190 fs/super.c:1026
 mqueue_mount+0xbe/0xe0 ipc/mqueue.c:340
 mount_fs+0x66/0x2d0 fs/super.c:1219
 vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:3291 [inline]
 kern_mount_data+0x50/0xb0 fs/namespace.c:3291
 mq_init_ns+0x167/0x220 ipc/mqueue.c:1593
 create_ipc_ns ipc/namespace.c:68 [inline]
 copy_ipcs+0x3a4/0x520 ipc/namespace.c:96
 create_new_namespaces+0x278/0x880 kernel/nsproxy.c:87
 unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:206
 SYSC_unshare kernel/fork.c:2366 [inline]
 SyS_unshare+0x653/0xfa0 kernel/fork.c:2316
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a39
RSP: 002b:00007f67a180bc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f67a180baa0 RCX: 0000000000452a39
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000002c000200
RBP: 00007f67a180ba90 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000004b75fb
R13: 00007f67a180bbc8 R14: 00000000004b75fb R15: 0000000000000000
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..