syz_usb_ep_write$ath9k_ep1(r0, 0x82, 0x80, &(0x7f0000002100)={[{0x7a, 0x4e00, "bb2e9d9a4e89ea7412f8f2e39b8a308e25dd7b2a925815966307fa2a630fcdfd775471c6edf0f9db23378208c28013b37a04b20068a97c886cb04b57e7d543c311507465e4ea89f3d49c4e051548371834aca7f5ba93d453576f2c670f1bfa8a5bc83c6deb758278cce93bddbdd183f43433e4541744ef801501"}]})
panic: replaceArg: group fields don't match: 1/0

goroutine 26 [running]:
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc0005b0040?}, {0xe56770?, 0xc0005b02e0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:377 +0x425
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc0005b0020?}, {0xe56770?, 0xc0005b02c0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc0005b0000?}, {0xe56770?, 0xc0005b02a0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc00064bfe0?}, {0xe56770?, 0xc0005b0280?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc00064bfc0?}, {0xe56770?, 0xc0005b0260?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.(*StructType).mutate(0x16d44a0, 0xc0005b00e0, 0xc00c38d360, {0xe56770, 0xc00064bfa0?}, {0xc00c38d1d8, {0x1db72e0, 0x4, 0x4}, 0xc001186510, ...})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:490 +0x185
github.com/google/syzkaller/prog.(*Target).mutateArg(0x0?, 0xc000dd3dc8?, 0xc001183410?, {0xe56770, 0xc00064bfa0}, {0xc00c38d1d8, {0x1db72e0, 0x4, 0x4}, 0xc001186510, ...}, ...)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:245 +0xe2
github.com/google/syzkaller/prog.(*mutator).mutateArg(0xc000dd3e48)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:196 +0x245
github.com/google/syzkaller/prog.(*Prog).Mutate(0xc0010f7340, {0xe52aa8?, 0xc0010e4300}, 0x1e, 0xc001104000, 0xc0000a3ad0, {0xc000bc2000, 0x411, 0x500})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:51 +0x2ba
main.(*Proc).loop(0xc0011040c0)
	/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