sendmmsg$inet(r0, &(0x7f0000002e80)=[{{&(0x7f0000000040)={0x2, 0x4e22, @empty}, 0x10, 0x0}, 0x600}, {{&(0x7f0000000000)={0x2, 0x4e23, @multicast1}, 0x10, 0x0, 0x0, &(0x7f0000000300)=[@ip_retopts={{0x14, 0x0, 0x34, {[@timestamp={0x44, 0x4}]}}}], 0x18}}], 0x2, 0x0)
panic: replaceArg: group fields don't match: 0/1

goroutine 10 [running]:
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc01fb80fa0?}, {0xe56770?, 0xc01fb81400?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:377 +0x425
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc01fb80f20?}, {0xe56770?, 0xc01fb81380?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc01fb80ea0?}, {0xe56770?, 0xc01fb81300?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc01fb80e80?}, {0xe56770?, 0xc01fb812e0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc01fb80e60?}, {0xe56770?, 0xc01fb812c0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc01fb80e40?}, {0xe56770?, 0xc01fb812a0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc01fb80e20?}, {0xe56770?, 0xc01fb81280?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc01fb80e00?}, {0xe56770?, 0xc01fb81260?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc01fb80de0?}, {0xe56770?, 0xc01fb81240?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.(*StructType).mutate(0x16d4620, 0xc01fb81080, 0xc01faf7540, {0xe56770, 0xc01fb80dc0?}, {0xc01faf74a8, {0x1db7580, 0x4, 0x4}, 0xc01fd72f30, ...})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:490 +0x185
github.com/google/syzkaller/prog.(*Target).mutateArg(0x0?, 0xc01d7a4060?, 0xc001b61dc8?, {0xe56770, 0xc01fb80dc0}, {0xc01faf74a8, {0x1db7580, 0x4, 0x4}, 0xc01fd72f30, ...}, ...)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:245 +0xe2
github.com/google/syzkaller/prog.(*mutator).mutateArg(0xc001b61e48)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:196 +0x245
github.com/google/syzkaller/prog.(*Prog).Mutate(0xc027f72840, {0xe52aa8?, 0xc025b84a20}, 0x1e, 0xc0256d6040, 0xc000094840, {0xc02417a000, 0xf7e5, 0x11000})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:51 +0x2ba
main.(*Proc).loop(0xc0256d6180)
	/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