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

goroutine 294 [running]:
panic({0x11bd0a0, 0xc0002d60c0})
	GOROOT/src/runtime/panic.go:1147 +0x3a8 fp=0xc0005571e8 sp=0xc000557128 pc=0x435148
runtime.goPanicIndex(0xffffffffffffffff, 0x0)
	GOROOT/src/runtime/panic.go:90 +0x75 fp=0xc000557228 sp=0xc0005571e8 pc=0x4324d5
gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs.parseSize({0x0, 0xc0003e82d0})
	pkg/sentry/fsimpl/tmpfs/tmpfs.go:951 +0x14c fp=0xc000557260 sp=0xc000557228 pc=0x8d858c
gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs.FilesystemType.GetFilesystem({}, {0x146bf60, 0xc000758a80}, 0xc0004cacd8, 0xc0005ab0e0, {0xc0004c01f0, 0xc000557528}, {{0xc00062e600, 0x4}, {0x0, ...}})
	pkg/sentry/fsimpl/tmpfs/tmpfs.go:205 +0x5db fp=0xc0005574f0 sp=0xc000557260 pc=0x8d53bb
gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs.(*FilesystemType).GetFilesystem(0x1ef7fe0, {0x146bf60, 0xc000758a80}, 0xc0005575a8, 0xc0005575a8, {0xc00062e400, 0xc00037b800}, {{0xc00062e600, 0x4}, {0x0, ...}})
	<autogenerated>:1 +0x8c fp=0xc000557550 sp=0xc0005574f0 pc=0x8de86c
gvisor.dev/gvisor/pkg/sentry/vfs.(*VirtualFilesystem).MountDisconnected(0x20003e40, {0x146bf60, 0xc000758a80}, 0xc00037b800, {0xc00062e400, 0x8}, {0xc00062e300, 0xc000557678}, 0xc0005577c0)
	pkg/sentry/vfs/mount.go:200 +0xe3 fp=0xc0005575c8 sp=0xc000557550 pc=0x773423
gvisor.dev/gvisor/pkg/sentry/vfs.(*VirtualFilesystem).MountAt(0xc00033a400, {0x146bf60, 0xc000758a80}, 0xc00062e500, {0xc00062e400, 0x1}, 0x0, {0xc00062e300, 0x1}, 0xc0005577c0)
	pkg/sentry/vfs/mount.go:272 +0x8b fp=0xc000557688 sp=0xc0005575c8 pc=0x77384b
gvisor.dev/gvisor/pkg/sentry/syscalls/linux/vfs2.Mount(0xc000758a80, {{0x20003d40}, {0x20003d80}, {0x20003dc0}, {0x0}, {0x20003e00}, {0x0}})
	pkg/sentry/syscalls/linux/vfs2/mount.go:112 +0x5cf fp=0xc0005578a8 sp=0xc000557688 pc=0xe17d4f
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc000758a80, 0xa5, {{0x20003d40}, {0x20003d80}, {0x20003dc0}, {0x0}, {0x20003e00}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:142 +0x825 fp=0xc000557cb0 sp=0xc0005578a8 pc=0x9b74c5
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc000758a80, 0x0, {{0x20003d40}, {0x20003d80}, {0x20003dc0}, {0x0}, {0x20003e00}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:322 +0x4d fp=0xc000557d20 sp=0xc000557cb0 pc=0x9b87ed
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc00090cb60, 0xc0003a42d0, {{0x20003d40}, {0x20003d80}, {0x20003dc0}, {0x0}, {0x20003e00}, {0x0}})
	pkg/sentry/kernel/task_syscall.go:282 +0x65 fp=0xc000557d80 sp=0xc000557d20 pc=0x9b84a5
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc000758a80)
	pkg/sentry/kernel/task_syscall.go:257 +0x31a fp=0xc000557e48 sp=0xc000557d80 pc=0x9b81da
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc0004f2080, 0xc000758a80)
	pkg/sentry/kernel/task_run.go:247 +0xe5e fp=0xc000557f70 sp=0xc000557e48 pc=0x9ac13e
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc000758a80)
	pkg/sentry/kernel/task_run.go:90 +0x1a2 fp=0xc000557fc8 sp=0xc000557f70 pc=0x9aac82
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start·dwrap·239()
	pkg/sentry/kernel/task_start.go:363 +0x26 fp=0xc000557fe0 sp=0xc000557fc8 pc=0x9b5c06
runtime.goexit()
	src/runtime/asm_amd64.s:1581 +0x1 fp=0xc000557fe8 sp=0xc000557fe0 pc=0x4692a1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:363 +0xe7