[Qemu-devel] Xorg 7.3 inside qemu = crash

[Qemu-devel] Xorg 7.3 inside qemu = crash

[Alexander E. Patrakov]

Hello,

when trying various Linux distributions inside qemu, I found that distributions 
using Xfce-4.4.x and Xorg-7.3 crash when attempting to run the Terminal 
application. The problem can be readily reproduced with, but is not limited to, 
  Zenwalk Live 5.0 distribution 
(http://zenlive.linuxish.net/current/zenwalk-live-5.0.iso). I have seen it also 
when trying to upgrade the Official LFS LiveCD to Xorg-7.3. It doesn't show up 
with Xorg-7.2.

The Zenwalk LiveCD has GCC and even GDB on it, so it should, in theory, allow to 
debug the problem. In practice, this is the useless backtrace obtained from GDB 
on Zenwalk:

Program received signal SIGABRT, Aborted.
[Switching to Thread -1211381552 (LWP 2140)]
0xb7d00797 in raise () from /lib/libc.so.6
(gdb) where
#0  0xb7d00797 in raise () from /lib/libc.so.6
#1  0xb7d020b8 in abort () from /lib/libc.so.6
#2  0xb7d3993b in __libc_message () from /lib/libc.so.6
#3  0xb7d45479 in free () from /lib/libc.so.6
#4  0x081ae371 in Xfree ()
#5  0xb7b06e2f in ?? () from /usr/lib/xorg/modules//libxaa.so
#6  0x08395350 in ?? ()
#7  0x0835ce70 in ?? ()
#8  0x08390298 in ?? ()
#9  0x00000004 in ?? ()
#10 0x08395334 in ?? ()
#11 0x08218070 in ?? ()
#12 0x08219e90 in ?? ()
#13 0x081cff58 in ?? ()
#14 0x00000000 in ?? ()

Could you please tell who is at fault, Xorg or Qemu? Is this bug present on 
real-hardware (as opposed to emulated) Cirrus Logic GD 5446 video cards, thus 
prompting for removal of the "cirrus" driver from the future releases of Xorg? 
The crash doesn't exist with the "vesa" driver, but the Terminal window is 
corrupted then (looks like 24/32 bpp mismatch).

-- 
Alexander E. Patrakov

[Qemu-devel] Re: Xorg 7.3 inside qemu = crash

[Alexander E. Patrakov]

I wrote:
> Could you please tell who is at fault, Xorg or Qemu? Is this bug present on 
> real-hardware (as opposed to emulated) Cirrus Logic GD 5446 video cards, thus 
> prompting for removal of the "cirrus" driver from the future releases of Xorg? 
> The crash doesn't exist with the "vesa" driver, but the Terminal window is 
> corrupted then (looks like 24/32 bpp mismatch).

Update: nether the crash nor the corruption exists at 16 bpp, which likely 
indicates a problem with color depth conversion in Xorg or maybe pixman. How to 
debug it further?

-- 
Alexander E. Patrakov