A fix is available
APAR status
Closed as unreproducible in next release.
Error description
A listener is using FRCA. A connection is completed to the FRCA listener, then reset without sending in any requests. EZBTCRDG will obtain the listener lock exclusive while processing the reset on the connected socket. The lock is not released, causing EZBITKRA to abend during destruction of the unit of work. EZBTCRDG is clearing the TCB pointer when returning to EZBTCRD, causing the lock to not be released. . KEYWORDS: 4C5 ABEND4C5 http was ABENDS4C5 . VERIFICATION STEPS: 1) Dump will show exclusive listen on TCB lock 2) DUCB holding lock will have call back structure RSA 7F288668 Prev 1757B2A0 Next 7F288758 Mod EZBIFRC1 RSA 7F288760 Prev 7F288668 Next 7F2888B0 Mod EZBITKRA . ADDITIONAL SYMPTOMS: If there are multiple batches to be processed, processing the next packet will fail with an abend obtaining the TCB lock: EZBITKOB(HIP61B0 09.077)+000BF2 S4C5/74F52002 74F52002 . This is because the listener TCB lock of a FRCA listener is already held by the DUCB.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of the IBM Communications Server * * for z/OS Version 1 Release(s) 10, 11, and 12 * * IP: FRCA * **************************************************************** * PROBLEM DESCRIPTION: Abend S4C5 RSN74F62301 in EZBITKRA when * * a client connection is reset while in * * the backlog of a FRCA enabled listener. * **************************************************************** * RECOMMENDATION: * **************************************************************** Abend S4C5 RSN74F62301 in EZBITKRA when a client connection is reset while in the backlog of a FRCA enabled listener. The listener lock is obtained while processing the RST packet on the child connection. The code path in EZBTCRDG fails to release the listener lock before exiting. When the thread processing the RST exits the residual lock is detected, forcing the abend S4C5. The listener lock is released during recovery processing with no residual side effects. +-------------------------------------------------------------+ + Please check our Communications Server for OS/390 homepages + + for common networking tips and fixes. The URL for these + + homepages can be found in Informational APAR II11334. + +-------------------------------------------------------------+
Problem conclusion
Temporary fix
Comments
EZBTCRDG has been amended to release the listener lock while processing a RST for a connection in the backlog.
APAR Information
APAR number
PM26736
Reported component name
TCP/IP V3 MVS
Reported component ID
5655HAL00
Reported release
1B0
Status
CLOSED UR1
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2010-11-15
Closed date
2010-12-14
Last modified date
2011-03-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK63089 UK63090 UK63091
Modules/Macros
EZBTCRDG
Fix information
Fixed component name
TCP/IP V3 MVS
Fixed component ID
5655HAL00
Applicable component levels
R1A0 PSY UK63089
UP11/02/10 P F102
R1B0 PSY UK63090
UP11/02/10 P F102
R1C0 PSY UK63091
UP11/02/10 P F102
Fix is available
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Document Information
Modified date:
02 March 2011