A fix is available
APAR status
Closed as program error.
Error description
A small window exists in HCPXLKAL that could cause the cross- system lock to stay held on a device for a guest that requested it. This could prevent the guest from ever logging off and any other process requiring that lock for this XDISK structure to hang.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All z/VM Users * **************************************************************** * PROBLEM DESCRIPTION: * **************************************************************** * RECOMMENDATION: APPLY PTF * **************************************************************** It appears possible that a call to acquire the cross-system lock can end up acquiring the lock for a RDEV other than the one the XLKAL code was called with. When HCPXLKAL gets control and that RDEV happens to get deleted at the same time, we can end up exiting HCPXLKAL with the cross-system lock held on another RDEV. This can only happen if the XLKBK structure has a pointer to a XLK-ASS-Lite chain(XLKASSLT field). Since this field can point to another RDEV, we exit with the cross-system lock held on that RDEV. This will result in the cross-system lock never being released since the caller of HCPXLKAL checks the RDEV it entered XLKAL on to determine if the cross-system lock was held or not.
Problem conclusion
HCPXLKAL has been updated to only acquire the cross-system lock on the RDEV the code was entered with.
Temporary fix
********* * HIPER * ********* FOR RELEASE VM/ESA CP/ESA R720 : PREREQ: NONE CO-REQ: NONE IF-REQ: NONE
Comments
APAR Information
APAR number
VM66437
Reported component name
VM CP
Reported component ID
568411202
Reported release
720
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2020-08-18
Closed date
2020-09-04
Last modified date
2021-03-30
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UM35728
Modules/Macros
HCPIOJ HCPLND HCPLNS HCPMNO HCPVDS HCPXLK
Fix information
Fixed component name
VM CP
Fixed component ID
568411202
Applicable component levels
R720 PSY UM35728
UP20/09/16 P 2101 ¢
Fix is available
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Document Information
Modified date:
31 March 2021