PK00856; 5.1.1.4: WebSphere Application Server
hang
Downloadable files
Abstract
Deadlock when httpconnection class tries to log a message
whose text cannot be found and RAS attempts to log message too.
Download Description
PK00856 resolve the following problem:
ERROR DESCRIPTION:
The HttpConnection class attempts to log an error message. Its message
text can not be found so the RAS code attempts to log a message to the
System.out stream, informing about the missing message. However, just
before that, the HttpConnection in another thread has started a write to
the System.out stream which is redirected to the RAS code.
This causes a deadlock as neither of these threads will be able to
continue because they each hold a lock on an object the other one needs.
PROBLEM SUMMARY:
USERS AFFECTED:
IBM® WebSphere® Application Server users of the Http Transport.
PROBLEM DESCRIPTION:
The WebSphere Application Server hangs due to a deadlock between threads
in the server process. The deadlock occurs while trying to write an error
message and a stack trace.
RECOMMENDATION:
The problem occurs when one thread in HttpConnection tries to write an
error message via the RAS component and another thread in HttpConnection
tries to write exception to System.out which is redirected thru RAS.
Neither of these threads will be able to continue because they each hold a
lock on an object the
other one needs.
PROBLEM CONCLUSION:
HttpConnection will be changed to use FFDC to log the exception. This
should prevent the deadlock from occurring.
The fix for this APAR is currently targeted for inclusion in V5.0.2.11 and
V5.1.1.5.