xsrc/50093: 7.0_RC1 Xorg server gets SIGSEGV on exit

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

>Number:         50093
>Category:       xsrc
>Synopsis:       7.0_RC1 Xorg server gets SIGSEGV on exit
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    xsrc-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jul 26 16:45:00 +0000 2015
>Originator:     Izumi Tsutsui
>Release:        NetBSD 7.0_RC1
>Organization:
>Environment:
System: NetBSD mirage 7.0_RC1 NetBSD 7.0_RC1 (GENERIC.201506190427Z) i386
Architecture: i386
Machine: i386 on VirtualBox 4.3.30, but also occurs on QEMU 2.3.0 and other real machines
>Description:
NetBSD/i386 7.0_RC1 Xorg server gets SIGSEGV on exit as following:

---
# xinit

X.Org X Server 1.10.6
Release Date: 2011-07-08
X Protocol Version 11, Revision 0
Build Operating System: NetBSD/i386  - 
Current Operating System: NetBSD teokure 7.0_RC1 NetBSD 7.0_RC1 (GENERIC.201506190427Z) i386
Build Date: 01 August 2011  01:01:00AM
 
Current version of pixman: 0.32.6
        Before reporting problems, check http://wiki.X.Org
        to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Mon Jul 27 01:15:16 2015
(==) Using default built-in configuration (21 lines)
(EE) Failed to load module "vboxvideo" (module does not exist, 0)

mtrr set failed: Operation not supported by device
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Error:            Couldn't lookup keysym
>                   Symbol interpretation ignored
> Error:            Couldn't lookup keysym
>                   Symbol interpretation ignored
Errors from xkbcomp are not fatal to the X server
xinit: connection to X server lost

waiting for X server to shut down Segmentation fault at address 0xb9f9b7d9

Fatal server error:
Caught signal 11 (Segmentation fault). Server aborting


Please consult the The X.Org Foundation support 
         at http://wiki.X.Org
 for help. 
Please also check the log file at "/var/log/Xorg.0.log" for additional information.
---

/var/log/Xorg.0.log has no particular information on the exit:
---
 :
[219154.378] (II) UnloadModule: "mouse"
[219154.728] (II) Unloading mouse
[219155.468] (II) UnloadModule: "kbd"
[219155.593] (II) Unloading kbd
---

The address 0xb9f9b7d9 looks inside of some Xorg server module, and
the address depends on the video hardware. (due to loaded drivers?)

>How-To-Repeat:
- install NetBSD/i386 7.0_RC1
  (especially on QEMU or VirtualBox, which use VESA driver, to reproduce)
- start X by xinit
- exit in the default xterm to quit Xserver

>Fix:
No idea.