panic: bad arg kind: <nil>

goroutine 36 [running]:
github.com/google/syzkaller/prog.clone({0x0?, 0x0?}, 0xc0000c7b78?)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/clone.go:94 +0x5d9
github.com/google/syzkaller/prog.cloneCall(0xc001592230, 0x12c93c0?)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/clone.go:36 +0x145
github.com/google/syzkaller/prog.cloneCalls({0xc0016434c0, 0x7, 0xc000d279a0?}, 0xc001038000?)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/clone.go:23 +0x66
github.com/google/syzkaller/prog.(*Prog).Clone(0xc001549c40)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/clone.go:14 +0x8d
github.com/google/syzkaller/prog.AssignRandomAsync(0x1?, 0xc001145560?)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/collide.go:27 +0x2d
main.(*Proc).randomCollide(0xc000a24040, 0xc00142c8a0?)
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:317 +0x98
main.(*Proc).executeAndCollide(0xc000a24040, 0xba0842?, 0xc000a4cea0?, 0xc0000c7e08?, 0xc000a24000?)
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:298 +0x50
main.(*Proc).smashInput(0xc000a24040, 0xc00156b0b0)
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:223 +0x1cb
main.(*Proc).loop(0xc000a24040)
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:78 +0xf2
created by main.main in goroutine 1
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/fuzzer.go:336 +0x1665