Debug-Hints with Tomcat

[Umberto Nicoletti]

Newer glibc have internal checks that are probably turned on by
default on some distros.
Try to play with the MALLOC_CHECK_ variable and read this (it is about
fedora core, but should apply to suse too):

    glibc
      The version of glibc provided with Fedora Core 3 performs
      additional internal sanity checks to prevent and detect data
      corruption as early as possible. By default, should corruption
      be detected, a message similar to the following will be displayed
      on standard error (or logged via syslog if stderr is not open):

      *** glibc detected *** double free or corruption: 0x0937d008 ***

      By default, the program that generated this error will also be
      killed; however, this (and whether or not an error message is
      generated) can be controlled via the MALLOC_CHECK_ environment
      variable. The following settings are supported:

            0 -- Do not generate an error message, and do not kill the program
            1 -- Generate an error message, but do not kill the program
            2 -- Do not generate an error message, but kill the program
            3 -- Generate an error message and kill the program

      Note

      If MALLOC_CHECK_ is explicitly set a value other than 0, this
      causes glibc to perform more tests that are more extensive than
      the default, and may impact performance.

      Should you have a program from a third party ISV that triggers
      these corruption checks and displays a message, you should
      file a defect report with the application's vendor, since this
      indicates a serious bug.

Best regards,
Umberto

On 11/2/05, Benedikt Rothe <umn-ms at hydrotec.de> wrote:
>
> Dear Mapserver-Users
>
> We developed a Tomcat/Mapserver-Site using Mapscript on
> Linux/SUSE 9.3.
>
> Many things run fine. On a test-machine we made successfully
> some stress-testing and Tomcat runs for weeks.
>
> Unfortunately Tomcat crashes on the customers production-machine
> approximately once a day. It runs for several hours,
> passes stress-tests successfully but crashes unpredictable after
> 12-20hours.
>
> The crash occurs in Mapserver-Code. Message in the Tomcat-log
> is
> *** glibc detected *** double free or corruption (top): 0x0xf99950"
>
> Question: Can I do something to make this error-message more helpful?
> I'd like to have the stack and the line-numbers in the sourcecode.
> (I mean the C-stack and C-linenumber and not the Java-Stack...)
>
> I looked through the gcc-man-page, but I coudn't find anything helpful.
>
> Thanks
> Benedikt Rothe