A fix is available
APAR status
Closed as program error.
Error description
z/VM systems in an ISFC collection may hang during shutdown or (on rare occasions) update obsolete message storage, leading to unpredictable behavior (potentially including an abend). (1) HCPCMSRD and HCPCMRCM may launch tasks that depend on user VMDBK being dispatched to obtain and release locks. During System Shutdown this can result in a ISFC Global Lock hang during system SHUTDOWN (preventing or delaying re-IPL). (2) In a rare timing sequence, SSI messages sent via HCPKCCTX and HCPKCWTX may be sent successfully and released before HCPKCWTX can return to HCPKCCTX (where HCPKCCTX clears error status on an MBHBK which may no longer belong to that task). If that storage has already been reassigned the alteration could cause unpredictable behavior.
Local fix
Apply PTF
Problem summary
**************************************************************** * USERS AFFECTED: z/VM systems connected via ISFC links. * **************************************************************** * PROBLEM DESCRIPTION: * **************************************************************** * RECOMMENDATION: APPLY PTF * **************************************************************** This update addresses the following problems: (1) SSI client traffic sometimes hangs with no explanation. (2) CP SHUTDOWN hangs (usually after system services are already showing signs of a hang).
Problem conclusion
This update provides: (1) HCPKCCTX (a transmit function for SSI traffic) is modified to avoid altering the outbound message (represented by an MBHBK) after a successful return from HCPKCWTX (a low-level transmit function). Some diagnostic code is added as well. (2) HCPWRP is modified to invoke a new function (HCPBINSP) to alert the ISFC subsystem that Shutdown is Pending. This allows ISFC to set a flag to prevent certain tasks from being started (tasks like IUCV functions that depend on a VM user being dispatched so ISFC can complete its shutdown operations). Otherwise SYSUHOLD can be set while ISFC is waiting for a user to be dispatched.
Temporary fix
FOR RELEASE VM/ESACP/ESAR710 : PREREQ: NONE CO-REQ: NONE IF-REQ: NONE
Comments
APAR Information
APAR number
VM66308
Reported component name
VM CP
Reported component ID
568411202
Reported release
710
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
YesSpecatt / New Function / Xsystem
Submitted date
2019-07-25
Closed date
2019-09-27
Last modified date
2020-01-23
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UM35541
Modules/Macros
HCPACQ HCPBIN HCPBUU HCPCMR HCPCMS HCPKCC HCPKCD HCPKCW HCPWRP
Fix information
Fixed component name
VM CP
Fixed component ID
568411202
Applicable component levels
R710 PSY UM35541
UP19/09/30 P 2001
Fix is available
Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.
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Document Information
Modified date:
23 January 2020