[postgis-users] Server crash on ST_SymDifference

[Paolo Crosato]

Hi,

I have another issue with the function in subject, however this is a bit 
nasty since it makes my postgres server crash.

This is the statement:

Select ST_SymDifference(
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
);

This will make my server crash, full version is:
"POSTGIS="2.0.2 r10789" GEOS="3.3.6-CAPI-1.7.6" PROJ="Rel. 4.8.0, 6 
March 2012" GDAL="GDAL 1.8.1, released 2011/07/09" LIBXML="2.7.6" 
LIBJSON="UNKNOWN" TOPOLOGY RASTER"

All packages are downloaded from the postgres yum repository for centos 
6, I run a centos 6.3 fully updated.

I was able to get a full backtrace from the core file, it seems the 
crash happens at this line:

#8  geos::io::WKTWriter::toLineString (p0=..., p1=...) at WKTWriter.cpp:106

#7  0x000000395aeefeb9 in operator<< (p0=..., p1=...) at 
/usr/include/c++/4.4.6/ostream:210

the last calls are system libraries, the crash happens here:

#0  0x00000035b9844293 in _IO_vfprintf_internal (s=0x7fff440123f0, 
format=0x7fff44012730 "%.*g", ap=0x7fff44012550) at vfprintf.c:232

I can provide the geometries that produced the error (results from a 
call to st_changeedgegeom), the full backtrace, core file and server 
logs, however since they are pretty big I won't post them here
in the mailing list.

For now I'll wrap the calls in a perl script and try to avoid the 
problematic edges.

Thanks,

Paolo

-- 
Paolo Crosato