David M. MacMillan - 2011-07-13

Varkon 1.19D running under Kubuntu 10.10 seems consistently to crash on certain
uses of sur_sweep().  I presume that these are incorrect uses (I'm just trying to
understand the function, so I'm not sure of this yet; a "_Surf_Error.DAT file is
generated).   Even if incorrect, though, these uses of a function shouldn't crash
the entire Varkon program.  The module shown below will on my
system crash Varkon consistently (on a Run if you call it as a part, or right at
startup if you try to run its .MBO directly).

Regards,
David M. MacMillan
dmm@Lemur.com

! demonstrate failure in Varkon 1.19D with sur_sweep
global module test3a();
beginmodule

! make profile curve
mode_basic();
lin_free(#1,vec(30,0,0),vec(30,50,0));
mode_global();

! make spine
lin_free(#2,vec(0,0,0),vec(0,0,50): width=1);

! correct invocation works:
!sur_sweep(#3, #1,#2,1,vec(0,1,0));

! incorrect invocation crashes Varkon instantly
sur_sweep(#3, #1,#2,1,vec(0,0,1));

! The dump/backtrace starts with:
! "*** buffer overflow detected ***"
! /lib/libc.so.6(__fortify_fail+0x37)
!
! … and ends with:
!7ff56f918000-7ff56f919000 r-xp 00000000 08:01 22154816                   /usr/lib/nvidia-current/tls/libnvidia-tls.so.260.19.06Aborted

endmodule