panic: replaceArg: group fields don't match: 1/0 goroutine 28 [running]: github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000a3a440?}, {0xe56770?, 0xc000a3c3a0?}) /syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:377 +0x425 github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000a3a420?}, {0xe56770?, 0xc000a3c380?}) /syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345 github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000a3a400?}, {0xe56770?, 0xc000a3c360?}) /syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345 github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000a3a3e0?}, {0xe56770?, 0xc000a3c340?}) /syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345 github.com/google/syzkaller/prog.replaceArg({0xe56770?, 0xc000a3a3c0?}, {0xe56770?, 0xc000a3c320?}) /syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:382 +0x345 github.com/google/syzkaller/prog.(*StructType).mutate(0x16d44a0, 0xc000a3a880, 0xc00c121270, {0xe56770, 0xc000a3a3a0?}, {0xc00c120d78, {0x1db72e0, 0x4, 0x4}, 0xc00c16a120, ...}) /syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:490 +0x185 github.com/google/syzkaller/prog.(*Target).mutateArg(0x0?, 0xc0003a3700?, 0xc000a1fdc8?, {0xe56770, 0xc000a3a3a0}, {0xc00c120d78, {0x1db72e0, 0x4, 0x4}, 0xc00c16a120, ...}, ...) /syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:245 +0xe2 github.com/google/syzkaller/prog.(*mutator).mutateArg(0xc000a1fe48) /syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:196 +0x245 github.com/google/syzkaller/prog.(*Prog).Mutate(0xc00c166e80, {0xe52aa8?, 0xc001d38840}, 0x1e, 0xc00144a000, 0xc000113e90, {0xc00013e000, 0x520, 0x700}) /syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:51 +0x2ba main.(*Proc).loop(0xc001b54000) /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