PH48383: PLUGIN SHOULDN'T CRASH IF WEBSPHERE RETURNS NULL DWLM INFORMATION AND CAUSED IBM HTTP SERVER CRASHED

APAR status

• Closed as program error.

Error description

• Env:
  Web server version: 8.5.5.19
  Available local GSKit version: 8.0.55.19
  plugin Bld version: 8.5.5.19
  
  Description:
  The customer encountered the ihs crashed.
  From the crash mustgather log and report:
  Program terminated with signal 11, Segmentation fault.
  #0  0x00002b1e05f66e71 in __strlen_sse2 () from /lib64/libc.so.6
  
  
  #0  0x00002b1e05f66e71 in __strlen_sse2 () from /lib64/libc.so.6
  
  #1  0x00002b1e05f66b7e in strdup () from /lib64/libc.so.6
  #2  0x00002b1e079782e5 in dwlmUpdateTable (serverGroup=0xd78c80,
  dwlmTableHeader=0x2b1e140206a8 "-1R38TJO:1bth2p6hs;-1QQ1TT9:1bt
  h2p6hs;-1O71S3H:1bth2p6hs;-1O41V2U:1bth2p6hs;-1NG9ROE:1bth2p6hs
  ;-1N01RH9:1bth2p6hs;-1MB1V5M:1bth2s0i6;-1KG3USQ:1bth2p6hs;-1KA0
  RLA:1bth2p6hs;-1IIGPBA:1bth2pu8v;-1I08P0O:1"...,dwlmTableVersion
  ns.http/src/common/ws_server_group.c:2404
  #3  0x00002b1e0795e958 in websphereExecute
  (wsRequest=0x2b1e0a5ffba0, waitForContinue=0, connectTimeout=0,
  serverIOTimeout=0, useExtendedHandshake=0, keepaliveTimeout=28,
  useExistingStream=0, lastServer=0) at /blddir/WAS855.NATV/NATV/
  ws/code/plugins.http/src/common/ws_common.c:3445
  #4  0x00002b1e07961a07 in websphereWriteRequestReadResponse
  (request=0x2b1e0a5ffba0, force_serverio_timeout=-1,
  useExistingStream=0) at /blddir/WAS855.NATV/NATV/ws/code/plugin
  s.http/src/common/ws_common.c:4699
  #5  0x00002b1e0797fdfc in esiResponseCreate
  (request=0x2b1e14017100, includeDepth=0, hasAlt=0 '\000',
  rc=0x2b1e0a5ffb24) at /blddir/WAS855.NATV/NATV/ws/code/plugins.
  http/src/common/esi/esiResponse.c:697
  #6  0x00002b1e0798197f in esiResponseGet
  (request=0x2b1e14017100, includeDepth=0, hasAlt=0 '\000',
  rc=0x2b1e0a5ffb24) at /blddir/WAS855.NATV/NATV/ws/code/plugins.
  http/src/common/esi/esiResponse.c:1510
  
  
  1 thread: __strlen_sse2<__strlen_sse2<strdup<dwlmUpdateTable<we
  bsphereExecute<websphereWriteRequestReadResponse<esiResponseCre
  ate<esiResponseGet<esiHandleRequest<websphereHandleRequest<as_h
  andler<ihs_run_handler<ap_invoke_handler<ap_process_request<ap_
  process_http_connection<ap_run_process_connection<process_socke
  t<worker_thread<start_thread<clone
     (WebSphere plug-in handling request on IHS thread)
  
  Based on the stack trace, the crash occurred within the function
  that updates the DWLM table values.  This data is provided
  within the WebSphere response.  The plugin needs this data to
  maintain a table of which clones were used when memory to memory
  replication on WebSphere's side is in use.
  
  Within the plugin code, it needs  to have better checks of the
  DWLM response data before attempting a table update. The plugin
  should handle the null condition gracefully instead of causing a
  crash.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server                                      *
  ****************************************************************
  * PROBLEM DESCRIPTION: Plugin may crash if WebSphere returns   *
  *                      a null value for DWLM information       *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  On rare occasions, WebSphere might return a null value for
  the DWLM table version value.  When plugin gets this value, it
  doesn't handle the null correctly causing the plugin to crash.
  

Problem conclusion

• The plugin code has been corrected so that it won't crash if a
  null is returned for the DWLM table version.
  
  The fix for this APAR is targeted for inclusion in fix pack
  8.5.5.23 & 9.0.5.14. For more information, see 'Recommended
  Updates for WebSphere Application Server':
  https://www.ibm.com/support/pages/node/715553
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WEBSPHERE APP S

• Fixed component ID

  5724J0800

Applicable component levels