kern/146436: Panic when changing profile to economy

[Demelier David]

>Number:         146436
>Category:       kern
>Synopsis:       Panic when changing profile to economy
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun May 09 17:50:04 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Demelier David
>Release:        8.0-STABLE
>Organization:
>Environment:
FreeBSD Melon.malikania.fr 8.0-STABLE FreeBSD 8.0-STABLE #8: Sun May  9 09:09:12 CEST 2010     root at Melon.malikania.fr:/usr/obj/usr/src/sys/Melon  amd64

>Description:
When changing the power profile to economy with these settings in /etc/rc.conf : 

performance_cx_lowest="HIGH"
performance_cpu_freq=${performance_cx_lowest}
economy_cx_lowest="LOW"
economy_cpu_freq=${economy_cx_lowest}

Because I wasn't capable to make a kernel dump, it just doesn't work. So I took a picture of the kernel panic and the small backtrace. Here is the mail discuss.

http://lists.freebsd.org/pipermail/freebsd-stable/2010-May/056600.html

At the beginning I thought it was a AC cable problem but not, it's only the profile state that make the panic.
>How-To-Repeat:
Change profile to economy with these settings : 

performance_cx_lowest="HIGH"
performance_cpu_freq=${performance_cx_lowest}
economy_cx_lowest="LOW"
economy_cpu_freq=${economy_cx_lowest}
>Fix:


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