sendmmsg$inet6(r0, &(0x7f0000005740)=[{{0x0, 0x0, &(0x7f00000001c0)=[{&(0x7f0000000040)="f4e4d054349e7974b275ef1a814146923a69670c90b2257c3ec99cfde0ffbe62a7e6a264f3dcee82f8d42d8a6735cf789116abe599361d0507e05be290efc05da190174669cc280b39f1f8409d8671c2d87810bd3de62d5b0ac9ace4a3783e7ce540ad2b953d0a73ab34c54f9e5de973df9bf886b9a004dd1eb28003851dec2c9bcd47452ed614c7629d801b4d154213e848cfd6a57d377ce830b649afd30b49897a2af571e13765e79423b13f308244422f672c40235a", 0x7ffffff7}], 0x1}}], 0x1, 0x0)
panic: replaceArg: group fields don't match: 0/1

goroutine 33 [running]:
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc008c56ac0?}, {0xe56770?, 0xc008a900e0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:377 +0x425
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc008c569e0?}, {0xe56770?, 0xc008a90060?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc008c56960?}, {0xe56770?, 0xc008c57fe0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc008c56940?}, {0xe56770?, 0xc008c57fc0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc008c56920?}, {0xe56770?, 0xc008c57fa0?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc008c56900?}, {0xe56770?, 0xc008c57f80?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc008c568e0?}, {0xe56770?, 0xc008c57f60?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc008c568c0?}, {0xe56770?, 0xc008c57f40?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc008c568a0?}, {0xe56770?, 0xc008c57f20?})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345
github.com/google/syzkaller/prog.(*StructType).mutate(0x16d4620, 0xc008c56ba0, 0xc00a420c30, {0xe56770, 0xc008c56880?}, {0xc00a4208c8, {0x1db7580, 0x4, 0x4}, 0xc0089615c0, ...})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:490 +0x185
github.com/google/syzkaller/prog.(*Target).mutateArg(0x0?, 0x7fdad71225b8?, 0x40?, {0xe56770, 0xc008c56880}, {0xc00a4208c8, {0x1db7580, 0x4, 0x4}, 0xc0089615c0, ...}, ...)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:245 +0xe2
github.com/google/syzkaller/prog.(*mutator).mutateArg(0xc000c4dd60)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:196 +0x245
github.com/google/syzkaller/prog.(*Prog).Mutate(0xc00978b380, {0xe52aa8?, 0xc005b4c0c0}, 0x1e, 0xc007346100, 0xc0003e2840, {0xc0048ec000, 0x3279, 0x4000})
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:51 +0x2ba
main.(*Proc).smashInput(0xc0073462c0, 0xc0015e5230)
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:221 +0x165
main.(*Proc).loop(0xc0073462c0)
	/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