mock: chroot proc busy when unmounting

[Alan Franzoni]

Hello, I'm experiencing a rather strange error with mock. This happens
almost every time, hence I'd like to find out what's happening.

Build host machine: Fedora 12, 64 bit
Build target: Centos 5 64 bit, using some additional repos in the
config, otherwise the config is the stock epel-5-x86_64.cfg
Mock version: 1.0.2
Running mock as root.

After building (either with success or without) I get this problem:

DEBUG: Executing command: umount -n
/var/lib/mock/rhel5-unstable-x86_64/root/proc
DEBUG: umount: /var/lib/mock/rhel5-unstable-x86_64/root/proc: device is
busy.
DEBUG:         (In some cases useful info about processes that use
DEBUG:          the device is found by lsof(8) or fuser(1))

I tried modifying mock's backend.py in order to run lsof before and
after running umount and grepping for proc, but without success - there
seems to be no open file there. I tried running orphanskill before
umounting, I tried sleeping before umount, but nothing changed.

While that error has no great impact, that one and some subsequent
(involving some failing chattr calls) really get my build logs messed up
and hard to crawl when something goes wrong.

Has anybody had similar issues? Can I provide you with any other useful
debugging data?



-- 
Alan Franzoni
contact me at public@[mysurname].eu