panic: Decrementing non-positive ref count 0xc000716f70, owned by vfs.Filesystem

goroutine 123 [running]:
panic({0x10f2ce0?, 0xc000a803e0?})
	GOROOT/src/runtime/panic.go:1017 +0x3ac fp=0xc0006bf388 sp=0xc0006bf2d8 pc=0x43a72c
gvisor.dev/gvisor/pkg/sentry/vfs.(*FilesystemRefs).DecRef(0xc000716f70, 0xc000ac0ea0?)
	bazel-out/k8-fastbuild/bin/pkg/sentry/vfs/filesystem_refs.go:126 +0x154 fp=0xc0006bf3f0 sp=0xc0006bf388 pc=0x791474
gvisor.dev/gvisor/pkg/sentry/vfs.(*Filesystem).DecRef(0x1207460?, {0x1580618?, 0xc000a4c000?})
	pkg/sentry/vfs/filesystem.go:77 +0x55 fp=0xc0006bf430 sp=0xc0006bf3f0 pc=0x790a55
gvisor.dev/gvisor/pkg/sentry/vfs.(*VirtualFilesystem).unlockMounts(0xc000210c58, {0x1580618, 0xc000a4c000})
	pkg/sentry/vfs/vfs.go:1030 +0x1df fp=0xc0006bf4e0 sp=0xc0006bf430 pc=0x7afedf
gvisor.dev/gvisor/pkg/sentry/vfs.(*Mount).destroy.func1()
	pkg/sentry/vfs/mount.go:826 +0x28 fp=0xc0006bf508 sp=0xc0006bf4e0 pc=0x79a8e8
gvisor.dev/gvisor/pkg/sentry/vfs.(*Mount).destroy(0xc00078cd10, {0x1580618, 0xc000a4c000})
	pkg/sentry/vfs/mount.go:839 +0x282 fp=0xc0006bf5a8 sp=0xc0006bf508 pc=0x79a842
gvisor.dev/gvisor/pkg/sentry/vfs.(*Mount).DecRef(0xc00078cd10, {0x1580618, 0xc000a4c000})
	pkg/sentry/vfs/mount.go:820 +0xa5 fp=0xc0006bf5d0 sp=0xc0006bf5a8 pc=0x79a585
gvisor.dev/gvisor/pkg/sentry/vfs.(*VirtualFilesystem).unlockMounts(0xc000210c58, {0x1580618, 0xc000a4c000})
	pkg/sentry/vfs/vfs.go:1030 +0x1df fp=0xc0006bf680 sp=0xc0006bf5d0 pc=0x7afedf
gvisor.dev/gvisor/pkg/sentry/vfs.(*VirtualFilesystem).UmountAt.func2()
	pkg/sentry/vfs/mount.go:578 +0x28 fp=0xc0006bf6a8 sp=0xc0006bf680 pc=0x7997a8
gvisor.dev/gvisor/pkg/sentry/vfs.(*VirtualFilesystem).UmountAt(0xc000210c58, {0x1580618, 0xc000a4c000}, 0xc000ad1800?, 0xc000ac5300?, 0xc0006bf804)
	pkg/sentry/vfs/mount.go:602 +0x342 fp=0xc0006bf778 sp=0xc0006bf6a8 pc=0x799582
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Umount2(0xc000a4c000, 0x5612634bc000?, {{0x7f59a3ff2a90}, {0xa}, {0x0}, {0xffffffff}, {0x0}, {0x0}})
	pkg/sentry/syscalls/linux/sys_mount.go:164 +0x2f7 fp=0xc0006bf910 sp=0xc0006bf778 pc=0xb94957
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc000a4c000, 0xa6, {{0x7f59a3ff2a90}, {0xa}, {0x0}, {0xffffffff}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x80b fp=0xc0006bfc50 sp=0xc0006bf910 pc=0xa2298b
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc000a4c000, 0x0?, {{0x7f59a3ff2a90}, {0xa}, {0x0}, {0xffffffff}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x4e fp=0xc0006bfcb0 sp=0xc0006bfc50 pc=0xa23f8e
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc000214238?, 0xc0006bfdf8?, {{0x7f59a3ff2a90}, {0xa}, {0x0}, {0xffffffff}, {0x0}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x74 fp=0xc0006bfd10 sp=0xc0006bfcb0 pc=0xa23b54
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc00078d130?)
	pkg/sentry/kernel/task_syscall.go:257 +0x3a8 fp=0xc0006bfe08 sp=0xc0006bfd10 pc=0xa23848
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc000a82100?, 0xc000a4c000)
	pkg/sentry/kernel/task_run.go:269 +0x1405 fp=0xc0006bff48 sp=0xc0006bfe08 pc=0xa15945
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc000a4c000, 0x6)
	pkg/sentry/kernel/task_run.go:98 +0x262 fp=0xc0006bffc0 sp=0xc0006bff48 pc=0xa13e62
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.func1()
	pkg/sentry/kernel/task_start.go:391 +0x25 fp=0xc0006bffe0 sp=0xc0006bffc0 pc=0xa20e85
runtime.goexit()
	src/runtime/asm_amd64.s:1650 +0x1 fp=0xc0006bffe8 sp=0xc0006bffe0 pc=0x471241
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start in goroutine 56
	pkg/sentry/kernel/task_start.go:391 +0xf8