kern/55510: pg_jobc going negative and crashing the kernel

[n54%gmx.com@localhost]

>Number:         55510
>Category:       kern
>Synopsis:       pg_jobc going negative and crashing the kernel
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jul 21 20:40:00 +0000 2020
>Originator:     Kamil Rytarowski
>Release:        NetBSD 9.99.69 amd64
>Organization:
The NetBSD Foundation, Inc.
>Environment:
NetBSD chieftec 9.99.69 NetBSD 9.99.69 (GENERIC) #0: Tue Jul 21 21:32:24 CEST 2020  root@chieftec:/public/netbsd-root/sys/arch/amd64/compile/GENERIC amd64
>Description:
pg_jobc counts the number of processes with parent controlling terminal.

Under certain circumstances it can go negative.
>How-To-Repeat:
https://www.netbsd.org/~kamil/ptrace/pg_jobc-crash.c
>Fix:
N/A