zfcp_san_disc terminated with Crtl-C leaves WLUN in use

This document (7017518) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 11 Service Pack 3 (SLES 11 SP3)
SUSE Linux Enterprise Server 11 Service Pack 4 (SLES 11 SP4)
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server 12 Service Pack 1 (SLES 12 SP1)

Situation

If zfcp_san_disc is interrupted by a Ctrl-C it can leave the "REPORT LUNS Well-Known-LUN" (WLUN) in use and the WLUN will be inaccessible to other z/VM guests.

*** Not in use***:
# lszfcp -D -l 0xc101000000000000
#

# zfcp_san_disc -b 0.0.4000 -p 0x5005076801206950 -L | grep 0027
^C

*** Now in use:***
# lszfcp -D -l 0xc101000000000000
0.0.4000/0x5005076801206950/0xc101000000000000 0:0:3:49409

*** 'zfcp_san_disc" on another z/VM Guest:***

zfcp_san_disc:Unable to activate LUN 0
and
zfcp.747e7d: 0.0.4000: LUN 0xc101000000000000 on port 0x50050763040355b6 is already in use by CSS1, MIF Image ID 3

The same situation can happen when the output of zfcp_san_disc is piped to a non-existent command. When the command fails or doesn't process stdin properly, WLUN will be left in use (active) and inaccessible to other guests:

# lszfcp -D
Error: No fcp devices found.

# zfcp_san_disc -b 0.0.1e16 -p 0x500507630808c65f -L | a
-bash: a: command not found

# lszfcp -D
0.0.1e16/0x500507630808c65f/0xc101000000000000 1:0:1:49409

Resolution

SUSE Linux Enterprise Server 11 Service Pack 3: A future s390-tools update will include the corrected script to resolve the problem. Customers with a long term support contract (LTSS) affected by this issue can contact SUSE Technical Support to request a PTF (temporary fix).

SUSE Linux Enterprise Server 12 and SUSE Linux Enterprise Server 12 Service Pack 1: The s390-tools updates released May 2016 include the solution to resolve this problem.

SUSE Linux Enterprise Server 11 Service Pack 4: The s390-tools update released July 2016, s390-tools-1.15.0-0.161.6, includes the patches to resolve the problem.

Please install the recommended updates.

Cause

The two problems are caused by inaccurate signal handling. Cleanup after activating WLUN and terminating zfcp_san_disk wasn't handled properly.

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.