what you really need is a fresher vim. Compiled a vim from git master, and it seems to work now with cscope master. Thanks for the tip.
Can confirm that this happens here on macOS with the following steps: Clone cscope git master at https://git.code.sf.net/p/cscope/cscope export EDITOR=vim Run cscope -R to generate an index. Here, I used the root of the ffmpeg git repo. Open ffmpeg.c file via "Find this file:" Run ":cs f s <undefined-symbol>" within vim.</undefined-symbol> Vim freezes / becomes unresponsive and has to be killed. Was able to bisect and narrow it down to this commit: 6d646e7528f499d6df559cffc43ee11dd424c501 $ git show...