macOS – How to Determine What is Hanging Git

I'm trying to do a git pull on my Mac from a local repo. It is hanging. My question is, why is it hanging and how can I stop it? That is, I'm in a repo where the "remotes" are on the local filesystem:

rcook@mymachine (paraDIS_lib (master)): git remote -v
origin  /Users/rcook/gitrepos/paraDIS_lib (fetch)
origin  /Users/rcook/gitrepos/paraDIS_lib (push)

And if I do a git pull then it just hangs, no progress, nothing. It seems to be stuck doing something called "git-upload-pack":

rcook@RichCookHomeMac (~ (BARE:master)): psfind git
root            15840     1   0.0  0.0 git              git fetch
rcook           23160 22699   0.0  0.0 git              git pull -v --progress
rcook           23161 23160   0.0  0.0 git              git fetch --update-head-ok -v --progress
rcook           23162 23161   0.0  0.0 git-upload-pack  git-upload-pack /Users/rcook/gitrepos/paraDIS_lib

And if run with GIT_TRACE, it looks like I'm hung on "git rev-list":

rcook@RichCookHomeMac (paraDIS_lib.local (master)):    GIT_TRACE=1 git pull
16:51:50.002029 git.c:348               trace: built-in: git 'pull'
16:51:50.002479 run-command.c:335       trace: run_command: 'fetch' '--update-head-ok'
16:51:50.003491 exec_cmd.c:128          trace: exec: 'git' 'fetch' '--update-head-ok'
16:51:50.016960 git.c:348               trace: built-in: git 'fetch' '--update-head-ok'
16:51:50.017949 run-command.c:335       trace: run_command: 'git-upload-pack '\''/Users/rcook/gitrepos/paraDIS_lib'\'''
16:51:50.018872 run-command.c:195       trace: exec: '/bin/sh' '-c' 'git-upload-pack '\''/Users/rcook/gitrepos/paraDIS_lib'\''' 'git-upload-pack '\''/Users/rcook/gitrepos/paraDIS_lib'\'''
16:51:50.038192 run-command.c:335       trace: run_command: 'rev-list' '--objects' '--stdin' '--not' '--all' '--quiet'

Indeed, I can induce a hang with:

GIT_TRACE=1 git rev-list --objects --stdin --not --all

Pulling from the same repo but from a remote machine via ssh works fine. I.e.,

rcook@rzhasgpu18 (paraDIS_lib (master)): git remote -v
origin  mymachine.net:/Users/rcook/gitrepos/paraDIS_lib (fetch)
origin  mymachine.net:/Users/rcook/gitrepos/paraDIS_lib (push)

There, git pull works great, although it's still very slow.

My question is, shouldn't the local version be way way faster? How can I figure out what is slowing this down? On linux, I would run it under strace, but on OS X this is very hard to do it seems, especially in El Capitan with all its weird security stuff.