[mapserver-users] Expression segmentation fault
Stephen Woodbridge
woodbri at swoodbridge.com
Thu Sep 5 07:30:07 PDT 2013
Hi,
This is a great idea. Regardless we should try to identify the case that
is causing the crash and trap that. Mapserver should never crash as a
general rule so finding the specific case is important so Thomas can
reproduce it.
If you have (or can load) the data in a database table, then it should
be fairly easy to do a manual binary search to find the offending object
by adding " where gid between <lower> and <upper>" to your query and
adjusting the value of lower and upper to narrow the search to the
problem object.
Thanks,
-Steve W
On 9/5/2013 10:11 AM, Rahkonen Jukka wrote:
> Hi,
>
> Osm2pgsql can create invalid polygons with self-intersections and/or
> three-vertex A-B-A rings. It might be good to run MakeValid or simply
> find possibly invalid features with IsValid and delete them and then
> see if Mapserver gets happy. Actually, run IsValid and save the
> faulty geometries somewhere before correcting or deleting them. It
> would be nice to catch them if they happen to be the reason for the
> crash.
>
> -Jukka Rahkonen-
>
> Frank Broniewski wrote:
>>
>> Ok, this is weird. It is, as I know now, data source related. I was
>> poking in the layer configuration to find out why the core dump
>> happens. Reinstalling didn't solve the issue, btw.
>>
>> So first I converted the data to shapefile with ogr2ogr (as always
>> very handy!) and changed the layer accordingly. And no core dump
>> happened! Then I tried several versions of the data and filter
>> statements without success. Since this is a osm2pgsql database I
>> swapped finally the table from planet_osm_polygon to
>> planet_osm_line (same table schema apart from the geometry) - and
>> voilà - no core dump.
>>
>> So I can relate the problem to the planet_osm_polygon table - but
>> I'm not sure what difference actually is responsible for the crash
>> ...
>>
>> The most apparent difference is of course the geometry type:
>> planet_osm_line is linestring, planet_osm_polygon is geometry ...
>>
>> I will investigate the attributes further tomorrow, but now I need
>> to earn some money. It's always the deadlines ...
>>
>>
>> Frank
>>
>>
>> Am 2013-09-05 09:47, schrieb thomas bonfort:
>>> Frank, This is such a simple use-case that I doubt it's a bug in
>>> the code per-se. Can you make sure that you are using a clean
>>> build (make clean && make && make install) as I suspect this
>>> could be happening due to a compilation problem (as a rule of
>>> thumb, with mapserver <6.4, always run make clean after
>>> re-running configure)
>>>
>>> -- thomas
>>>
>>>
>>> On Wed, Sep 4, 2013 at 2:39 PM, Frank Broniewski
>>> <brfr at metrico.lu> wrote:
>>>> Am 2013-09-04 14:33, schrieb thomas bonfort:
>>>>
>>>>> Frank, please supply a backtrace of the crash (`bt` in gdb
>>>>> once it has halted at the segfault)
>>>>>
>>>>> -- thomas
>>>>>
>>>>> On Wed, Sep 4, 2013 at 2:25 PM, Frank Broniewski
>>>>> <brfr at metrico.lu>
>> wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I just updated my mapserver installation to the latest
>>>>>> version (6.2.1). I'm running FreeBSD 9.1 and I'm getting a
>>>>>> segmentation fault related to expression usage in my
>>>>>> mapfile. I've already compiled mapserver with debug symbols
>>>>>> and I loaded the core file into gdb:
>>>>>>
>>>>>>> gdb /usr/local/www/apache22/cgi-bin/mapserv mapserv.core
>>>>>>
>>>>>> <snip> Reading symbols from /lib/libc.so.7...done. Loaded
>>>>>> symbols for /lib/libc.so.7 Reading symbols from
>>>>>> /usr/local/lib/libintl.so.9...done. Loaded symbols for
>>>>>> /usr/local/lib/libintl.so.9 Reading symbols from
>>>>>> /usr/lib/libsupc++.so.1...done. Loaded symbols for
>>>>>> /usr/lib/libsupc++.so.1 Reading symbols from
>>>>>> /libexec/ld-elf.so.1...done. Loaded symbols for
>>>>>> /libexec/ld-elf.so.1 #0 0x00000008008e2520 in yylex
>>>>>> (lvalp=0x7fffffffd250, p=0x7fffffffd3b0) at
>>>>>> mapparser.y:649 649 mapparser.y: No such file or
>>>>>> directory. in mapparser.y [New Thread 809007400 (LWP
>>>>>> 101134/mapserv)]
>>>>>>
>>>>>> So apparently there seems to be a file missing!? Looking at
>>>>>> the source code (git), line 649 is a blank line, so I'm not
>>>>>> sure what's missing exactly. I've got yacc, bison and flex
>>>>>> installed. For testing purposes I'm using the mapserver cgi
>>>>>> on the command line:
>>>>>>
>>>>>> /usr/local/www/apache22/cgi-bin/mapserv -nh
>>>>>>
>>>>>>
>> "QUERY_STRING=map=/data/web/mapserver/cnra/cnra.map&mode=map&laye
>> r=boundaries"
>>>>>>
>>>>>> The boundaries layer:
>>>>>>
>>>>>> Layer
>>>>>>
>>>>>> # Classitem "level" Connection "host=10.0.0.2 dbname=osm
>>>>>> user=user
>> password=guessme"
>>>>>> Connectiontype Postgis Data "geom FROM (SELECT osm_id, way
>>>>>> AS geom, name, admin_level
>> AS
>>>>>> level, tags FROM planet_osm_polygon) AS foo USING UNIQUE
>>>>>> osm_id USING
>> SRID=3857"
>>>>>> Filter "tags ?& ARRAY['boundary', 'admin_level']" Name
>>>>>> "boundaries" Processing "CLOSE_CONNECTION=DEFER" Status on
>>>>>> Type line Units meters
>>>>>>
>>>>>> Metadata "ows_title" "Boundary Map" "ows_abstract"
>>>>>> "Boundary map - data from OpenStreetMap, ODbl licensed"
>>>>>> End
>>>>>>
>>>>>> Projection "init=epsg:3857" End
>>>>>>
>>>>>> Class
>>>>>>
>>>>>> Expression ("[level]" = "6") # Expression "6" Name
>>>>>> "communes"
>>>>>>
>>>>>> Style Color 10 10 10 Opacity 50 Width 2 End
>>>>>>
>>>>>> End End
>>>>>>
>>>>>>
>>>>>> The classitem / simple expression (Expression "6") works
>>>>>> with the mapserver cgi, but python mapscript throws an
>>>>>> error: _mapscript.MapServerError: msEvalExpression():
>>>>>> General error message. Invalid item index.
>>>>>>
>>>>>> I've read the mapserver expressions documentation [1] and
>>>>>> the note that says something about the working environment
>>>>>> might be linked to more than
>> one
>>>>>> expression library. But my operating system skills are not
>>>>>> high enough to turn this paragraph into something useful
>>>>>> for me.
>>>>>>
>>>>>> So any help is greatly appreciated.
>>>>>>
>>>>>> Frank
>>>>>>
>>>>>>
>>>>>> Frank BRONIEWSKI
>>>>>>
>>>>>> METRICO s.à r.l. géomètres technologies d'information
>>>>>> géographique rue des Romains 36 L-5433 NIEDERDONVEN
>>>>>>
>>>>>> tél.: +352 26 74 94 - 28 fax.: +352 26 74 94 99
>>>>>> http://www.metrico.lu
>>>>>> _______________________________________________
>>>>>> mapserver-users mailing list
>>>>>> mapserver-users at lists.osgeo.org
>>>>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>>>>
>>>>>
>>>>>
>>>>
>>>> Hi Thomas,
>>>>
>>>> thanks for the fast response! Here's the bt:
>>>>
>>>> (gdb) bt
>>>>
>>>> #0 0x00000008008e2520 in yylex (lvalp=0x7fffffffd250,
>>>> p=0x7fffffffd3b0) at mapparser.y:649 #1 0x00000008008e0146 in
>>>> yyparse (p=0x7fffffffd3b0) at mapparser.c:1500 #2
>>>> 0x00000008009239b2 in msEvalExpression (layer=0x809009000,
>>>> shape=0x7fffffffd4e0, expression=0x8090a0280, itemindex=-1) at
>>>> maputil.c:478 #3 0x0000000800923f03 in msShapeGetClass
>>>> (layer=0x809009000, map=0x8090bd800, shape=0x7fffffffd4e0,
>>>> classgroup=0x0, numclasses=1) at maputil.c:581 #4
>>>> 0x0000000800980ab2 in msDrawVectorLayer (map=0x8090bd800,
>>>> layer=0x809009000, image=0x8090a91c0) at mapdraw.c:989 #5
>>>> 0x00000008009800ed in msDrawLayer (map=0x8090bd800,
>> layer=0x809009000,
>>>> image=0x8090a91c0) at mapdraw.c:808 #6 0x000000080097ed18 in
>>>> msDrawMap (map=0x8090bd800, querymap=0)
>> at
>>>> mapdraw.c:437 #7 0x0000000800a16e6e in
>>>> msCGIDispatchImageRequest
>> (mapserv=0x8090b2300) at
>>>> mapservutil.c:1448 #8 0x0000000800a179c2 in
>>>> msCGIDispatchRequest (mapserv=0x8090b2300)
>> at
>>>> mapservutil.c:1690 #9 0x00000000004012c1 in main (argc=3,
>>>> argv=0x7fffffffd9f0) at mapserv.c:259 (gdb)
>>>>
>>>>
>>>>
>>>>
>>>> -- Frank BRONIEWSKI
>>>>
>>>> METRICO s.à r.l. géomètres technologies d'information
>>>> géographique rue des Romains 36 L-5433 NIEDERDONVEN
>>>>
>>>> tél.: +352 26 74 94 - 28 fax.: +352 26 74 94 99
>>>> http://www.metrico.lu
>>>
>>>
>>
>>
>> -- Frank BRONIEWSKI
>>
>> METRICO s.à r.l. géomètres technologies d'information géographique
>> rue des Romains 36 L-5433 NIEDERDONVEN
>>
>> tél.: +352 26 74 94 - 28 fax.: +352 26 74 94 99
>> http://www.metrico.lu
>> _______________________________________________ mapserver-users
>> mailing list mapserver-users at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
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