Bug#630104: [kfreebsd] pstree -a: /proc/19/cmdline: Bad address

[Petr Salinger <Petr.Salinger@seznam.cz>]

> Typical kfreebsd-amd64 experimental system, kernel =
> kfreebsd-image-8.2-1-amd64 8.2-1.1.  When I try to run
> "pstree -a", I get:
>
> 	$ pstree -a
> 	/proc/19/cmdline: Bad address
>
> Indeed:
>
> 	$ ps 19
> 	  PID TTY        STAT    TIME COMMAND
> 	   19 ?          S+      0:00 [flowcleaner]
> 	$ cat /proc/19/cmdline
> 	cat: /proc/19/cmdline: Bad address
>
> By contrast, getting the commandline from ordinary processes
> works okay:

It is upstream regression w.r.t 8.1 kernel.

Seems be due to
http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/compat/linprocfs/linprocfs.c.diff?r1=1.152;r2=1.153;f=h

The FreeBSD kernel 8.1 returns process name, 
the linux kernel returns empty string for kernel-only processes.

The kernel-only processes shoudl be handled specially,
the fix should go also for "environ".

Petr