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Date: Wed, 15 Aug 2001 20:05:15 -0700 (PDT)
From: Dave Zarzycki <zarzycki@FreeBSD.org>
To: freebsd-gnats-submit@FreeBSD.org
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Subject: kern/29741: ptrace(pid);ptrace(ppid) makes pid and ppid unkillable
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>Number:         29741
>Category:       kern
>Synopsis:       ptrace(pid);ptrace(ppid) makes pid and ppid unkillable
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Aug 15 20:10:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Dave Zarzycki
>Release:        4.3-STABLE
>Organization:
Apple Computer Inc.
>Environment:
FreeBSD freebsd.apple.com 4.3-STABLE FreeBSD 4.3-STABLE #0: Tue May 29 13:29:24 PDT 2001     creed@freebsd.apple.com:/usr/src/sys/compile/GENERIC  i386

>Description:
Running gdb against gdb and having the child gdb attach to the parent gdb seems to confuse the kernel.

Both processes seem to be unkillable.

Also each gdb's ppid is the other's pid, as seen with "ps axl".

When considering a fix for this, please also keep in mind that the following is also a problem:

/usr/libexec/elf/gdb /usr/libexec/elf/gdb
(gdb) run /usr/libexec/elf/gdb
(gdb) run
(gdb) attach $GRANDPARENTPID
>How-To-Repeat:
Run gdb against itself and have the child gdb attach to the parent.

Now try to kill either gdb.
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:

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