WARNING: CPU: 0 PID: 3430 at fs/namespace.c:1093 cleanup_mnt+0x118/0x160 fs/namespace.c:1093
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 3430 Comm: kworker/0:2 Not tainted 4.20.0-rc7+ #360
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events proc_cleanup_work
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d3/0x2c6 lib/dump_stack.c:113
 panic+0x2ad/0x55c kernel/panic.c:188
 __warn.cold.8+0x20/0x45 kernel/panic.c:540
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:cleanup_mnt+0x118/0x160 fs/namespace.c:1093
Code: 1c 01 00 00 48 c7 c7 c0 17 85 89 e8 e2 13 03 06 48 8d 7b 38 48 c7 c6 50 0e d7 81 e8 32 15 92 ff 5b 41 5c 5d c3 e8 58 38 a7 ff <0f> 0b e9 0e ff ff ff e8 4c 38 a7 ff 48 89 df e8 64 01 07 00 e9 31
RSP: 0000:ffff8881c64af5a0 EFLAGS: 00010293
RAX: ffff8881c64be240 RBX: ffff8881c3a80200 RCX: ffffffff81d72034
RDX: 0000000000000000 RSI: ffffffff81d72128 RDI: 0000000000000005
RBP: ffff8881c64af5b0 R08: ffff8881c64be240 R09: fffffbfff12c24e5
R10: fffffbfff12c24e5 R11: ffffffff8961272b R12: 0000000000006b6c
R13: 0000000000004000 R14: dffffc0000000000 R15: ffff8881c3a80230
 mntput_no_expire+0x897/0xc00 fs/namespace.c:1177
 mntput fs/namespace.c:1187 [inline]
 kern_unmount+0xbd/0xf0 fs/namespace.c:2959
 pid_ns_release_proc+0x37/0x41 fs/proc/root.c:224
 proc_cleanup_work+0x19/0x20 kernel/pid_namespace.c:64
 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
 kthread+0x35a/0x440 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..