syz_usb_connect(0x0, 0x2d, &(0x7f0000000000)={{0x12, 0x1, 0x0, 0x79, 0x5d, 0xb8, 0x40, 0x4cb, 0x109, 0x6ff2, 0x1, 0x2, 0x3, 0x1, [{{0x9, 0x2, 0x1b, 0x1, 0x0, 0x0, 0x0, 0x0, [{{0x9, 0x4, 0x0, 0x0, 0x1, 0xc, 0xb5, 0xfc, 0x0, [], [{{0x9, 0x5, 0xc}}]}}]}}]}}, 0x0)
panic: replaceArg: group fields don't match: 2/0

goroutine 13 [running]:
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f660?}, {0xe56770?, 0xc000b2f960?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:377 +0x425
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f680?}, {0xe56770?, 0xc000b2f940?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f6a0?}, {0xe56770?, 0xc000b2f920?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f6e0?}, {0xe56770?, 0xc000b2f880?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f700?}, {0xe56770?, 0xc000b2f6e0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f720?}, {0xe56770?, 0xc000b2f6c0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f740?}, {0xe56770?, 0xc000b2e5a0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f760?}, {0xe56770?, 0xc000b2e580?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f780?}, {0xe56770?, 0xc000b2e540?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f7a0?}, {0xe56770?, 0xc000b2e520?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000b1f7c0?}, {0xe56770?, 0xc000b2e500?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.(*StructType).mutate(0x16d44a0, 0xc000b19440, 0xc00beee320, {0xe56770, 0xc000b1f7e0?}, {0xc00beee008, {0x1db72e0, 0x4, 0x4}, 0xc00beece70, ...})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:490 +0x185
github.com/google/syzkaller/prog.(*Target).mutateArg(0x0?, 0x7f942ec4b108?, 0x50?, {0xe56770, 0xc000b1f7e0}, {0xc00beee008, {0x1db72e0, 0x4, 0x4}, 0xc00beece70, ...}, ...)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:245 +0xe2
github.com/google/syzkaller/prog.(*mutator).mutateArg(0xc000865e48)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:196 +0x245
github.com/google/syzkaller/prog.(*Prog).Mutate(0xc00bdfef00, {0xe52aa8?, 0xc0016763c0}, 0x1e, 0xc001656000, 0xc00032dda0, {0xc000556000, 0x507, 0x700})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:51 +0x2ba
main.(*Proc).loop(0xc001656080)
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:95 +0x365
created by main.main in goroutine 1
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/fuzzer.go:336 +0x1665