[Mesa-users] Segmentation fault in "Fake_glXUseXFont" (Mesa 10.4.3)

[Martin Knoblauch]

Hi Brian,

will have to wait two weeks. Vacation :-)

Cheers
Martin
Am 26.02.2015 16:30 schrieb "Brian Paul" <brianp at vmware.com>:

> On 02/26/2015 03:41 AM, Martin Knoblauch wrote:
>
>> On Wed, Feb 25, 2015 at 9:17 PM, Brian Paul <brianp at vmware.com
>> <mailto:brianp at vmware.com>> wrote:
>>
>>     On 02/25/2015 09:59 AM, Martin Knoblauch wrote:
>>
>>
>>
>>
>>
>>         Hi Brian,
>>
>>            so I fixed the configure option, applied the patch and
>>         rebuilt. The
>>         program is now failing even quicker in:
>>
>>         #0  XMesaGetCurrentDrawable () at xm_api.c:1324
>>
>>         This is the only useful part of the stack and I need to omit the
>>         rest to
>>         hide the innocent and incompetent ...
>>
>>
>>     I really don't see how we'd be failing at line 1324 unless the
>>     'front' pointer was garbage (which it should never be).  Can you use
>>     a debug build and gdb to try to narrow this down a little?
>>
>>     I also hacked the Mesa xfont.c demo and can't reproduce a crash in
>>     XMesaGetCurrentDrawable().
>>
>>     -Brian
>>
>>
>>
>> Hi Brian,
>>
>>   this is what gdb tells me:
>>
>> 1324             return front->drawable;
>> (gdb) list
>> 1319    {
>> 1320       XMesaBuffer xmbuffer = XMesaGetCurrentBuffer();
>> 1321       if (xmbuffer) {
>> 1322          struct xmesa_renderbuffer *front = xmbuffer->frontxrb;
>> 1323          if (front)
>> 1324             return front->drawable;
>> 1325       }
>> 1326       return 0;
>> 1327    }
>> 1328
>> (gdb) print front
>> $1 = (struct xmesa_renderbuffer *) 0x72c3800000030
>> (gdb) print front->drawable
>> Cannot access memory at address 0x72c38000000c0
>> (gdb) print *front
>> Cannot access memory at address 0x72c3800000030
>> (gdb)
>>
>> Seems the "front" pointer is not-null, but not readable.
>>
>> Any ideas ?
>>
>
> Not off-hand.
>
> Could you possibly try to hack a Mesa demo to reproduce the issue?  The
> Mesa xfont.c demo is what I was using.  I added a few calls to
> glXGetCurrentDrawable() but it didn't crash.
>
> -Brian
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/mesa-users/attachments/20150228/5b2ce85f/attachment.html>