[mapserver-users] PHP MapScript request handling gives seg fault error in libgdal

Jeff McKenna jmckenna at gatewaygeomatics.com
Mon Oct 12 10:17:43 PDT 2020


Hi Rob,

Next I would remove the ECW support/reliance and try to trigger the 
error without ECW data (yes with a local mapfile called from shp2img).

Maybe others have ideas.

-jeff



-- 
Jeff McKenna
MapServer Consulting and Training Services
co-founder of FOSS4G
http://gatewaygeo.com/



On 2020-10-12 2:11 p.m., Rob Marjot wrote:
> Hi Jeff, all,
> 
> Thank you for your thoughts on this. Can you elaborate on the PROJ<6 
> remark; serious performance hits?
> 
> Indeed, I am on the NG (SWIG) MapScript. Trying with shp2img and mapserv 
> -nh will require to have the equivalent .map file on disk; I will work 
> on that soon.
> 
> Taking a complete different approach, I have been able to reproduce the 
> same problem by:
> 1. Installing *binaries* for MapServer 7.6.1, GDAL 3.1.3 and PROJ 7.1.1 
> from UbuntuGIS Unstable
> 2. Add ECW support through compiling the simple GDAL-plugin (tested: 
> gdal_translate from ECW to GTiff works brilliantly)
> 3. Configured this to run in the context of 7.4 PHP-FPM
> 
> Again the seg fault. Connecting to PHP-FPM from either Apache or NGINX 
> does not make a difference, but that's no surprise.
> 
> Rob
> 
> Op ma 12 okt. 2020 om 15:38 schreef Jeff McKenna 
> <jmckenna at gatewaygeomatics.com <mailto:jmckenna at gatewaygeomatics.com>>:
> 
>     Hi Rob,
> 
>     I'm not sure what is happening in your case, but make sure that you are
>     using the recommended PHP SWIG MapScript in your build
>     (-DWITH_PHPNG=1),
>     as the old PHP MapScript is unmaintained.
> 
>     Some other thoughts:
> 
>     - can you trigger this with shp2img at the commandline? (this will
>     remove MapScript/Apache/WMS from the equation)
>     https://mapserver.org/utilities/shp2img.html
> 
>     - also, try your GetMap request at the commandline with:
> 
>           mapserv -nh
>     "QUERY_STRING=map=/ms4w/apps/local-demo/local-demo.map&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&..."
> 
>       > ttt.png
> 
>     But if I can speak openly here, I believe most production instances are
>     still running PROJ<6, so everyone is beginning to experiment with
>     settings of FCGI/PHP-FPM for GDAL3+PROJ7 (as there is a noticeable
>     performance hit with the new PROJ).
> 
>     In other words, keep us posted here on your testing and configuration;
>     also, do consider documenting your configuration and workaround on the
>     MapServer wiki, so others can follow:
>     https://github.com/MapServer/MapServer/wiki
> 
>     Thanks Rob!
> 
>     -jeff
> 
> 
> 
>     -- 
>     Jeff McKenna
>     MapServer Consulting and Training Services
>     co-founder of FOSS4G
>     http://gatewaygeo.com/
> 
> 
> 
>     On 2020-10-09 9:44 p.m., Rob Marjot wrote:
>      > Hi All,
>      >
>      > I am running latest MapServer 7.6.1 compiled from source on
>     Ubuntu 20.04
>      > with (also from source):
>      > - proj-7.1.0
>      > - gdal-3.1.2
>      >
>      > Using the ppa:ondrej/php repo, I installed the following PHP
>     packages:
>      > php7.4 php7.4-fpm php7.4-dev
>      > Apache/2.4.41 proxies into the FPM over unix socket
>      >
>      > Compiling MapServer went smoothly and through the configuration
>     of the
>      > extension in PHP, MapScript is available. When I call (HTTP GET)
>     my PHP
>      > script to handle a WMS-formatted request [ OWSDispatch() ], the
>     first 2
>      > requests are handled fine (returns a rendered map image), but the
>     next
>      > two make the PHP-FPM crash:
>      > /var/log/syslog:
>      > Oct 10 01:59:25 as02 kernel: [3663532.034251] php-fpm7.4[1260175]:
>      > segfault at 28 ip 00007fbce21fb3eb sp 00007ffe87f600e0 error 6 in
>      > libgdal.so.27.0.2[7fbce152e000+d50000]
>      > Oct 10 01:59:25 as02 kernel: [3663532.034262] Code: 8b 15 81 de
>     56 00 e9
>      > 24 2d 38 ff 0f 1f 40 00 f3 0f 1e fa 41 54 49 89 f4 55 48 89 d5 53
>     89 fb
>      > 48 89 cf e8 e8 f0 ff ff 48 63 fb <4c> 89 24 f8 48 89 ac f8 00 01
>     00 00
>      > 5b 5d 41 5c c3 0f 1f 40 00 f3
>      >
>      > What could be the problem? Any help is much appreciated.
>      >
>      > Best,
>      > Rob Marjot
>      >
>      >
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