Steps to reproduce the problem:
$ echo -e '#include<stdio.h>\nint main(void){printf("hello world\\n");return 0;}' > test.c
$ clang test.c -o test
$ ./test
hello world
$ ~/Downloads/upx-3.91-src/src/upx.out test -o test-compressed
Ultimate Packer for eXecutables
Copyright (C) 1996 - 2013
UPX 3.91 Markus Oberhumer, Laszlo Molnar & John Reiser Sep 30th 2013
File size Ratio Format Name
-------------------- ------ ----------- -----------
8432 -> 4096 48.58% Mach/AMD64 test-compressed
Packed 1 file.
$ ./test-compressed
Killed: 9
For those who are just looking:
There is no answer posted for
http://stackoverflow.com/questions/30358184/taskgated-no-signature-for-pid
There is some recent activity on:
https://community.apachefriends.org/f/viewtopic.php?f=29&t=73971
Chrome has a similar problem:
https://productforums.google.com/forum/#!topic/chrome/fMuGXrIgzxU
Looks like this was fixed on https://github.com/upx/upx/issues/4. UPX 3.92 works for me. Thanks!