AIX

periodically my oracle 11.2.0.1 listener process 'tnslsnr' seems to crash and disappear ( I am using an AIX 6.1 unix platform ). When this happens I am able to restart my listener ok. However when this happens there is is no stop recorded in my listener log (as there normally would be - hence why I believe the listener process is crashing ).

However I am having difficulty finding any trace information at Oracle level or AIX OS level.

There are no errors recorded in the loracle istener log, nor is there anything recorded in the OS level syslog or error report ( errpt ) that relates to the time the listener crashes.

Any advice on how to track doem why a process dies ( I have the exact time the process seems to die ) ?

If there are neither entries in the listener log, nor sqlnet.log or trace files that could be useful
(search your <diag_dest> for sqlnet.log files and your <diag_dest>/tnslsnr/ for trace files),
you should open an SR (a service request) with OSS (Oracle Support Services).