ERROR: "XCOMU0602E unable to lock queue" XCOM for Linux process hung

Products

• XCOM Data Transport - Linux PC
• XCOM Data Transport
• XCOM Data Transport - z/OS

Issue/Introduction

XCOM for z/OS to XCOM for Linux file transfer hangs with this message at the z/OS side:
XCOMM0780E Txpi  226: Select timed out with no data available

Further review of the XCOM for Linux xcom.log file shows repeated messages:
#XCOMU0602E unable to lock queue

Environment

XCOM™ Data Transport® for z/OS
XCOM™ Data Transport® for UNIX/Linux PC

Cause

The above message "XCOMU0602E unable to lock queue" has been previously reported when the XCOM shared memory semaphore has been blocked and there is a fix in later 11.6 SP01 PTFs for XCOM for Linux and UNIX that should prevent it.

Resolution

To resolve the immediate problem the xcomd was restarted i.e. commands
xcomd -s
xcomd

In this case, an old "r11.6 16061 SP00 64bit" version of XCOM for Linux was being used.

First, upgrade to 11.6 SP01 and then apply the latest 11.6 SP01 PTF to pick up the shared memory semaphore fix (XCOM fixes are cumulative so only need to install the latest PTF).
Alternatively, if Linux is being used then there is an option to upgrade to version 12.0 and apply the latest PTF (again XCOM fixes are cumulative so only need to install the latest PTF).

Additional Information

This message "XCOMU0602E unable to lock queue" has also been reported with XCOM for Linux 11.6 SP00 when there is no impact on XCOM transfers and continues to occur after a normal xcomd stop/start using the commands "xcomd -s" and "xcomd" which should also clear the shared memory.
Also in the system file /var/log/messages  there are corresponding messages:
xcomtcp: *** glibc detected *** xcomtcp: double free or corruption

This old solution for XCOM 3.1 QI76440 may still apply for 11.6 SP00:

Sporadic XCOMU0602E: Unable to lock queue errors may occur when numerous transfers are running and access to the queue (shared memory) was simultaneously attempted by a transfer, the xcomd deamon, or the xcomqm command. The error message is
now a retryable error condition and the semop() system function retries a second time.

So if the volume of simultaneous transfers has increased that could explain the messages and because it is a retryable condition there is no impact on the transfers.

Useful Links
11.6
a. Product Downloads: XCOM Data Transport for Linux (PC) LINUX -ALL 11.6
NOTE: Download "CA XCOM Data Transport for Linux PC r11.6 SP01 - Product Package" file DVD10172026E.iso
b. Solution Downloads: XCOM Data Transport for Linux (PC) LINUX -ALL 11.6
c. Documentation steps for upgrading 11.6 (11.6 SP00) to 11.6.1 (11.6 SP01): XCOM Data Transport for UNIX/Linux 11.6.1 > Installing > Install Using ISO Conventional Method > Upgrade Using ISO Conventional Method

12.0
a. Product Downloads: XCOM Data Transport for Linux (PC) LINUX -ALL 12.0
NOTE: Download "CA XCOM Data Transport for Linux PC 12.0 0000 - Product Package" file DVDLinux120.iso.
b. Solution Downloads: XCOM Data Transport for Linux (PC) LINUX -ALL 12.0
c. Documentation steps for upgrading 11.6 (11.6 SP00) to 11.6.1 (11.6 SP01): XCOM Data Transport for UNIX/Linux 12.0 > Installing > Install Using ISO Conventional Method > Upgrade from a Previous Release > Upgrade from a Supported Release


NOTE: To check Operating System (OS) version compatibility please review the relevant Information Solution on the XCOM Distributed Platform Compatibilities page.