panic: chgproccnt: procs < NUM

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6a403588e274 merge unbound 1.22.0, ok florian
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=1182fba4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7058272de1526588
dashboard link: https://syzkaller.appspot.com/bug?extid=265d5006dac2f45c9e9d

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cd7ee9c5cb7e/disk-6a403588.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/0b29ed53d388/bsd-6a403588.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2059e01e476a/kernel-6a403588.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+265d50...@syzkaller.appspotmail.com

panic: chgproccnt: procs < 0
Starting stack trace...
panic(ffffffff83330c29) at panic+0x1d0 sys/kern/subr_prf.c:229
chgproccnt(4000,ffffffff) at chgproccnt+0xcc sys/kern/kern_proc.c:171
sys_setreuid(ffff80003c0d8028,ffff8000390c8040,ffff8000390c7f90) at sys_setreuid+0x587 sys/kern/kern_prot.c:688
syscall(ffff8000390c8040) at syscall+0xb08 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff8000390c8040) at syscall+0xb08 sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x775f93dc080, count: 252
End of stack trace.


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