[pups] 2.11BSD "make unix" aborts Error 141

[sms@2BSD.COM (Steven M. Schultz)]

Hi -

> From: "Jonathan Engdahl" <j.r.engdahl at adelphia.net>
> I'm running essentially the CURLY 2.11BSD system with networking on a

	Ah, yes - the 'master reference 2.11BSD system' ('SHEMP' is a virtual
	pdp-11 running under P11 ;)).

> PDP-11/53. When I go to rebuild unix with "make all", the build will run for
> a while, then quit with "Error 141". If I type "make all" again, it keeps on

	Yep, I've been seeing that for years and aside from some kernel
	hackery to assist in the debugging I haven't done much other than
	to come up with a workaround.

> going for a while. After several iterations of this, eventually the make
> completes, and the system will boot the result. What is this "Error 141"
> business?

	It's the exit status of the assembler.   On _some_ modules, the 
	assembler ('as') jumps off into the weeds and executes an 'exit'
	system call with a non-zero value in R0.   141 is a lower case 'a'
	as I recall.

	Now for the interesting part.  If you do something like

		setenv FOOBAR abcdef

	and run the make the assembler won't "exit 'a".   ALSO, if you run
	the pipeline of the failing command manually, using temp files, it
	won't fail.  Makes it very hard to debug.
	
> I've not looked for the cause of this yet. I'm being lazy, and hoping
> someone has seen this before and can give me a quick answer, before I go

	I'm lazy too (I hear that being lazy is a virtue in programmers ;))
	so I just pad the environment with "FOO abc" or something and the
	make works.

	The only idea I've come up with to try and track the problem down
	is a hack to the 'exit' logic in the kernel to create a coredump
	of a program that exits with 'non-zero' status.  Then at least
	there'd be something to postmortem.   An added complication is that
	the assembler has this nasty habit of using 'jmp' to move around
	rather than 'jsr' so it's hard to find out where the program was
	at times.   A long time ago I did make a few changes to 'as' to reduce
	the usage of 'jmp' in an attempt to track this down but then, when
	even I ran the program under the debugger it never failed - a typical
	Heisenberg type of bug ;(

	Good Luck.

	Steven Schultz