panic: runtime error: index out of range [-1]

goroutine 149 [running]:
panic({0x11bd0a0, 0xc0003161c8})
	GOROOT/src/runtime/panic.go:1147 +0x3a8 fp=0xc0007ed1e8 sp=0xc0007ed128 pc=0x435148
runtime.goPanicIndex(0xffffffffffffffff, 0x0)
	GOROOT/src/runtime/panic.go:90 +0x75 fp=0xc0007ed228 sp=0xc0007ed1e8 pc=0x4324d5
gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs.parseSize({0x0, 0xc00092e690})
	pkg/sentry/fsimpl/tmpfs/tmpfs.go:951 +0x14c fp=0xc0007ed260 sp=0xc0007ed228 pc=0x8d858c
gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs.FilesystemType.GetFilesystem({}, {0x146bf60, 0xc0005df500}, 0xc0005106c0, 0xc000698540, {0xc000200bf0, 0xc0007ed528}, {{0xc000938400, 0x4}, {0x0, ...}})
	pkg/sentry/fsimpl/tmpfs/tmpfs.go:205 +0x5db fp=0xc0007ed4f0 sp=0xc0007ed260 pc=0x8d53bb
gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs.(*FilesystemType).GetFilesystem(0x1ef7fe0, {0x146bf60, 0xc0005df500}, 0xc0007ed5a8, 0xc0007ed5a8, {0xc000938200, 0xc000761400}, {{0xc000938400, 0x4}, {0x0, ...}})
	<autogenerated>:1 +0x8c fp=0xc0007ed550 sp=0xc0007ed4f0 pc=0x8de86c
gvisor.dev/gvisor/pkg/sentry/vfs.(*VirtualFilesystem).MountDisconnected(0x20003e40, {0x146bf60, 0xc0005df500}, 0xc000761400, {0xc000938200, 0x8}, {0xc000938100, 0xc0007ed678}, 0xc0007ed7c0)
	pkg/sentry/vfs/mount.go:200 +0xe3 fp=0xc0007ed5c8 sp=0xc0007ed550 pc=0x773423
gvisor.dev/gvisor/pkg/sentry/vfs.(*VirtualFilesystem).MountAt(0xc0004bed00, {0x146bf60, 0xc0005df500}, 0xc000938300, {0xc000938200, 0x1}, 0x0, {0xc000938100, 0x1}, 0xc0007ed7c0)
	pkg/sentry/vfs/mount.go:272 +0x8b fp=0xc0007ed688 sp=0xc0007ed5c8 pc=0x77384b
gvisor.dev/gvisor/pkg/sentry/syscalls/linux/vfs2.Mount(0xc0005df500, {{0x20003d40}, {0x20003d80}, {0x20003dc0}, {0x0}, {0x20003e00}, {0x0}})
	pkg/sentry/syscalls/linux/vfs2/mount.go:112 +0x5cf fp=0xc0007ed8a8 sp=0xc0007ed688 pc=0xe17d4f
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc0005df500, 0xa5, {{0x20003d40}, {0x20003d80}, {0x20003dc0}, {0x0}, {0x20003e00}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x825 fp=0xc0007edcb0 sp=0xc0007ed8a8 pc=0x9b74c5
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc0005df500, 0x0, {{0x20003d40}, {0x20003d80}, {0x20003dc0}, {0x0}, {0x20003e00}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x4d fp=0xc0007edd20 sp=0xc0007edcb0 pc=0x9b87ed
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc0005e0218, 0x5df500, {{0x20003d40}, {0x20003d80}, {0x20003dc0}, {0x0}, {0x20003e00}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x65 fp=0xc0007edd80 sp=0xc0007edd20 pc=0x9b84a5
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc0005df500)
	pkg/sentry/kernel/task_syscall.go:257 +0x31a fp=0xc0007ede48 sp=0xc0007edd80 pc=0x9b81da
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc000614180, 0xc0005df500)
	pkg/sentry/kernel/task_run.go:247 +0xe5e fp=0xc0007edf70 sp=0xc0007ede48 pc=0x9ac13e
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc0005df500)
	pkg/sentry/kernel/task_run.go:90 +0x1a2 fp=0xc0007edfc8 sp=0xc0007edf70 pc=0x9aac82
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start·dwrap·239()
	pkg/sentry/kernel/task_start.go:363 +0x26 fp=0xc0007edfe0 sp=0xc0007edfc8 pc=0x9b5c06
runtime.goexit()
	src/runtime/asm_amd64.s:1581 +0x1 fp=0xc0007edfe8 sp=0xc0007edfe0 pc=0x4692a1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:363 +0xe7