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  1. Harmony
  2. HARMONY-3117

[db2] IBM DB2 JDBC "sample apps" crash on exit


    • Type: Bug
    • Status: Closed
    • Priority: Critical
    • Resolution: Won't Fix
    • Affects Version/s: None
    • Fix Version/s: 5.0M4
    • Labels:
    • Environment:
      EM64T -- RedHat Enterprise Linux 4 - U4
      IBM DB2 Express-C version9.1
      Latest Harmony JRE binary download (vn = r487452, (Dec 15 2006), Linux/em64t/gcc 4.0.3, release build)
    • Estimated Complexity:


      Putting critical because critical is defined as "Crashes, loss of data, severe memory leak."

      I was experimenting with whether DB2 JDBC connection will work with Harmony. I am using the sample apps that come with DB2. The JDBC layer appears to connect to the database successfully (which is good for Harmony) and queries appear to work (data comes thru). However, during shutdown of the sample apps, the process regularly segfaults when using Harmony and exits cleanly using the BEA JRE and Sun JRE.

      crash behavior is consistent with both "java DbConn" (basic connection test) and "java TbSel" (basic sql select test) sample apps that come with the "free" version of DB2.

      unfortunately, the core file provides little insight.
      (gdb) bt
      #0 0x0000002aaf5898fa in ?? ()
      #1 0x0000000000000000 in ?? ()
      (gdb) info threads

      • 1 process 22262 0x0000002aaf5898fa in ?? ()

      Attaching with debugger gives a possible hint:
      Program received signal SIGSEGV, Segmentation fault.
      0x0000002aaf5898fa in OSSHLibrary::unload ()
      from /home/db2inst/sqllib/lib64/libdb2osse.so.1
      (gdb) bt
      #0 0x0000002aaf5898fa in OSSHLibrary::unload ()
      from /home/db2inst/sqllib/lib64/libdb2osse.so.1
      #1 0x0000002aacce93de in sqlexPluginUnload ()
      from /home/db2inst/sqllib/lib64/libdb2.so.1
      #2 0x0000002aad1dd080 in sqlexAppLibTerm ()
      from /home/db2inst/sqllib/lib64/libdb2.so.1
      #3 0x0000002aacc41afa in sqlmStreamFlagsAction ()
      from /home/db2inst/sqllib/lib64/libdb2.so.1
      #4 0x0000002aacc41b83 in _ZN10appLibInitD9Ev ()
      from /home/db2inst/sqllib/lib64/libdb2.so.1
      #5 0x0000002aacc41b73 in appLibInit::~appLibInit ()
      from /home/db2inst/sqllib/lib64/libdb2.so.1
      #6 0x000000380df30c45 in exit () from /lib64/tls/libc.so.6
      #7 0x000000380df1c402 in __libc_start_main () from /lib64/tls/libc.so.6
      #8 0x000000000040096a in _start () at ../sysdeps/x86_64/elf/start.S:113

      It looks to me that the C++ destructors registered by some presumably JNI components are being invoked by the C runtime at process exit. At this time there are no other threads remaining (i.e., java looks like it is done and gone) and presumably during the cleanup process something gets out of control.

      In contrast with the Sun Java5 JRE, there are 13 other threads remaining when the destructor runs and 12 other threads with the BEA Java5 JRE.

      I'm not sure if this is a compatibility issue with the reference implementation or if is simply a hole in the JNI support that Harmony currently provides. It appears to be 100% reproducable.


        1. db2-setup.zip
          131 kB
          Chris Elford
        2. db2admin.png
          19 kB
          Gregory Shimansky

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              • Assignee:
                gshimansky Gregory Shimansky
                elford Chris Elford
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