amd64/153746: kernel crash with 2 X11 sessions on amd64 with radeon drm

[Patrick Mackinlay]

>Number:         153746
>Category:       amd64
>Synopsis:       kernel crash with 2 X11 sessions on amd64 with radeon drm
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jan 06 22:50:07 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Patrick Mackinlay
>Release:        8.1-RELEASE-p2 (affects 8.0 as well)
>Organization:
>Environment:
FreeBSD patrick.uknet.spacesurfer.com 8.1-RELEASE-p2 FreeBSD 8.1-RELEASE-p2 #3: Thu Jan  6 21:40:18 GMT 2011     root at patrick.uknet.spacesurfer.com:/usr/obj/usr/src/sys/PATRICK  amd64
>Description:
If I start 2 X11 sessions (startx and start -- :1). The close the sessions on display :1, when I switch to the session on display :0 the system reboots. I have an amd64 with a ATI radeon card:

drm0: <ATI Radeon HD 4650> on vgapci0

Note that if I never close either X11 session there is no problem with stability (weeks uptime), however the only graphics intensive app I use is mplayer. mplayer is the only reason I need drm, however the bug will be triggered even if I havn't used mplayer in my X11 session.

I will attach the output from dmesg with my full system setup and the output from the two xorg log files.
>How-To-Repeat:

>Fix:


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