SnappyFile::rawWrite Segfault

[José Fonseca]

Hi,

If this is happening, then that's because the user array in question,
0xbfa98ba0, is either invalid or smaller than 21960.

This could be an application bug -- passing insufficient data to the
GL application -- or an apitrace bug (over-estimating the size to be
21960)

If you have access to the source code, it should be possible to infer
where the problem lies.

Jose


On Mon, Oct 15, 2012 at 5:51 PM, Kain Osterholt
<kain.osterholt at gmail.com> wrote:
> Hi all,
>
> I have recently encountered an issue both in apitrace 3.0 and the tip of the
> source as of last friday.  I get a segmentation fault in the trace writer in
> SnappyFile::rawWrite.  From the backtrace it looks like this originates from
> a glDrawElements call.  I am attaching the partial stack here.  I still
> haven't figured out what the difference in this particular DrawElements call
> is to cause the issue.  The same rendering pipeline is traced fine for
> another game I am working on so it seems that there is some specific feature
> or mesh that isn't playing nicely with the writer.  Can anyone provide any
> insight in debugging such an issue?  I'm new to apitrace so any help in
> understanding how to report such issues better in the future would be
> welcome as well.
>
> Program terminated with signal 11, Segmentation fault.
> #0  0x40fd86af in ?? () from /lib/i386-linux-gnu/libc.so.6
> (gdb) bt
> #0  0x40fd86af in ?? () from /lib/i386-linux-gnu/libc.so.6
> #1  0x4018d7a2 in SnappyFile::rawWrite (this=0xacd3e08, buffer=0xbfa98ba0,
> length=21960)
>     at /usr/include/i386-linux-gnu/bits/string3.h:52
> #2  0x40189408 in write (this=<optimized out>, length=21960,
> buffer=0xbfa98ba0) at /apitrace/common/trace_file.hpp:119
> #3  _write (dwBytesToWrite=21960, sBuffer=0xbfa98ba0, this=<optimized out>)
> at /apitrace/common/trace_writer.cpp:82
> #4  trace::Writer::writeBlob (this=0x401fdec0, data=0xbfa98ba0, size=21960)
> at /apitrace/common/trace_writer.cpp:262
> #5  0x40165e4e in _trace_user_arrays (count=2745) at
> /apitrace/build/wrappers/glxtrace.cpp:82774
> #6  0x4016cc8b in glDrawElements (mode=4, count=3600, type=5123,
> indices=0x0)
>     at /apitrace/build/wrappers/glxtrace.cpp:2288
>
> _______________________________________________
> apitrace mailing list
> apitrace at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/apitrace
>