panic: broken type ref (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 56d65d052d3a add maturin as MODPY_PYBUILD backend
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=132b8467180000
kernel config: https://syzkaller.appspot.com/x/.config?x=7058272de1526588
dashboard link: https://syzkaller.appspot.com/bug?extid=4788467d2f852b1e985d

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b7257bb7a42a/disk-56d65d05.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/cdf9e1382fc9/bsd-56d65d05.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9cb9b4128349/kernel-56d65d05.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+478846...@syzkaller.appspotmail.com

panic: broken type ref

goroutine 52 [running]:
github.com/google/syzkaller/prog.ArgCommon.Type(...)
/syzkaller/gopath/src/github.com/google/syzkaller/prog/prog.go:69
github.com/google/syzkaller/prog.(*serializer).call(0xc000575170, 0xc00053ec30)
/syzkaller/gopath/src/github.com/google/syzkaller/prog/encoding.go:76 +0x1aa
github.com/google/syzkaller/prog.(*Prog).serialize(0xc0004e1800, 0x0)
/syzkaller/gopath/src/github.com/google/syzkaller/prog/encoding.go:46 +0xd8
github.com/google/syzkaller/prog.(*Prog).Serialize(...)
/syzkaller/gopath/src/github.com/google/syzkaller/prog/encoding.go:30
main.(*Proc).logProgram(0xc0000fc820, 0xc0004e1800)
/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:130 +0x4e
main.(*Proc).executeRaw(0xc0000fc820, 0xc000167ef0, 0xc0004e1800)
/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:101 +0x125
main.(*Proc).loop(0xc0000fc820)
/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:65 +0x148
created by main.main in goroutine 1
/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/fuzzer.go:256 +0x1145


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