What it means
U4083 is raised by Language Environment (LE) when the chain of save areas, which links each routine's stack frame back to its caller, is found to be broken. LE then ends the enclave, so the program stops.
The reason code, shown in hex, is what narrows the cause. Most reason codes point to a loop in the chain or to a save area that is misaligned or cannot be addressed. Others mean the chain was never set up correctly, or was broken while a condition was being handled. This page covers z/OS Language Environment only, not z/VSE.
Typical causes
- 01, 08, 10: a save area loop, including one that points to itself or to a higher area wrongly
- 13, 14: the module delete (13) or module load (14) service found a save area loop
- 15, 16: the AMODE 31 (15) or AMODE 64 (16) dynamic dump routine found a save area loop
- 02: walking the back chain caused a program check
- 03: the chain ended on a zero back pointer instead of the expected start
- 04, 09: a misaligned save area, or a linkage stack found where a save area should be
- 05: a condition raised before the main stack frame existed or after the main routine ended
- 06: the save-area format was not set to up or down
- 07, 0F: the chain is missing, unreachable or not intact
- 11: pthread_exit found a chain ending on a zero stack frame pointer
- 12: the GPR fix-up routine found save-area corruption
How to fix it
- Match the hex reason code to the causes above before changing anything.
- If your program builds its own save areas, make sure they are linked together properly and can all be reached in 31-bit addressing.
- Take a system dump of the original error by setting TERMTHDACT(UAIMM) and TRAP(ON,NOSPIE).
- For other programs, suspect something overwrote storage it did not own; look for code that writes past its own area.
Example
Illustrative only; names and values are invented.
IEF450I PAYJOB01 STEP030 - ABEND=S000 U4083 REASON=00000008