Fix (APAR):  PH44114

Status:  Fix

Release:  9.0.5.11

Operating System:  Linux

Supersedes Fixes:  

CMVC Defect:  xxxxxx

Byte size of APAR:  26505605

Date: 2022-04-07

Abstract:  ibm http server on Windows may hang during shutdown or restart

Description/symptom of problem:  
PH44114 resolves the following problem:

ERROR DESCRIPTION:
The reinitialization of the parent process may hang on Windows, 
which is triggered by MaxRequestsPerChild and graceful restarts.
                                                                
This prevents a new child process from being started, so new    
connections cannot be accepted.                                 

LOCAL FIX:

PROBLEM SUMMARY:

USERS AFFECTED:
 All users of IBM HTTP Server on Windows
with
mod_mpmstats loaded

PROBLEM DESCRIPTION:
IHS may appear to hang if
MaxRequestsPerChild is non-zero,
because a
replacement process will not be
launched.

RECOMMENDATION:
None

On Windows, mod_mpmstats runs in the IHS parent process and
MaxRquestsPerChild causes the parent to gracefully reload.
An unknown problem may block the delivery of the restart signal
to the mod_mpmstats thread, which will cause the
reinitialization of the parent process to hang indefinitely.
If the parent process cannot reinitialize, it cannot spawn a
replacement connection-handling child process.

PROBLEM CONCLUSION:
mod_mpmstats was updated to use a fallback mechanism to get     
notified of restarts. This backup mechanism is enabled by defaul
                                                                
The fix for this APAR is targeted for inclusion in IBM HTTP     
Server fix packs 8.5.5.22 and 9.0.5.12. For more information, se
'Recommended Updates for WebSphere Application Server':         
https://www.ibm.com/support/pages/node/715553                   


Directions to apply fix:  
1) Stop IBM HTTP Server. AIX Only: run "slibclean" as root.
2) Backup your IBM HTTP Server installation directory
3) Extract this interim fix with your IBM HTTP Server installation as your working directory
4) Start IBM HTTP Server

Directions to remove fix:  
1) Stop IBM HTTP Server. AIX Only: run "slibclean" as root.
2) Restore earlier IBM HTTP Server installation root from backup. Or, extract a previous maintenance level archive install on top of current installation
2) Start IBM HTTP Server

Directions to re-apply fix:  
1) Stop IBM HTTP Server.
2) Follow the directions to apply the fix.
3) Restart IBM HTTP Server.


Additional Information: