bin/51405: core dump from make (amd64 current as of 2016-08-11)

[kre%munnari.OZ.AU@localhost]

>Number:         51405
>Category:       bin
>Synopsis:       core dump from make (amd64 current as of 2016-08-11)
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Aug 11 10:45:00 +0000 2016
>Originator:     Robert Elz
>Release:        NetBSD 7.99.35
>Organization:
>Environment:
System: NetBSD onyx.coe.psu.ac.th 6.99.30 NetBSD 6.99.30 (ONYX-Dom0) #0: Mon Feb 3 19:26:44 ICT 2014 kre%onyx.coe.psu.ac.th@localhost:/usr/obj/current/kernels/amd64/ONYX-Dom0 amd64
Architecture: x86_64
Machine: amd64
>Description:
	I was doing a complete (except X) build of NetBSD currentm
	when that finishes, I use the tools it constructed, to compile
	my local kernels (for reasons not important here, I don't
	use build.sh for that).   The kernels that build correctly
	were fine.   But one of them I have a config problem with
	(have had for a while - the link fails - undefined symbols - why
	is also not important right now).

	Immediately after the link failed make printed the very
	long command line it had been executing, said "*** Error code 1".
	"Stop." and "nbmake: stopped in ..." all of which was normal.

	Then it dumped core (seg fault).

	Traceback:

Core was generated by `nbmake'.
Program terminated with signal 11, Segmentation fault.
#0  0x0000000000418c2e in Var_Append ()
(gdb) where
#0  0x0000000000418c2e in Var_Append ()
#1  0x000000000040c058 in addErrorCMD ()
#2  0x000000000040bcc8 in Lst_ForEachFrom ()
#3  0x000000000040bc5f in Lst_ForEach ()
#4  0x000000000040cd36 in PrintOnError ()
#5  0x0000000000403d1b in Compat_Make ()
#6  0x000000000040bcc8 in Lst_ForEachFrom ()
#7  0x000000000040bc5f in Lst_ForEach ()
#8  0x0000000000403b2a in Compat_Make ()
#9  0x0000000000404512 in Compat_Run ()
#10 0x000000000040efd3 in main ()

	Since this was a normal tools build, there ar eno debug symbols,
	but I could re-build make with -g, and run it again if the
	problem doesn't turn out to be obvious.

	This is new in the past day or so.

>How-To-Repeat:

	Probably not easy - or it might be.   Perhaps purposely mis-configure
	a kernel in a way that "config" doesn't object to, and see what
	happens, or perhaps config a kernel, then edit the Makefile and
	remove one of the object files from the list, so linking cannot
	possibly work.   It is only because I don't really need a new Dom0
	kernel anytime soon that I had been ignoring the link error on my
	past few (well, more than a few) builds...

>Fix:
	??