[CRIU] [PATCH 2/2] tests: prevent zdtm_mount_cgroups from failing w/ EBUSY

[Tycho Andersen]

On Mon, Feb 01, 2016 at 10:13:14PM -0800, Andrew Vagin wrote:
> On Tue, Feb 02, 2016 at 09:56:41AM +1100, Tycho Andersen wrote:
> > Sometimes I get:
> > 
> > sudo ./zdtm.py run -t zdtm/live/static/cgroup03
> > umount: /home/tycho/packages/criu/test/zdtm.qPwsoO: target is busy
> >         (In some cases useful info about processes that
> >          use the device is found by lsof(8) or fuser(1).)
> > Traceback (most recent call last):
> >   File "./zdtm.py", line 1401, in <module>
> >     tst.available()
> >   File "./zdtm.py", line 435, in available
> >     subprocess.check_call(["flock", "zdtm_mount_cgroups", "./zdtm_mount_cgroups"])
> >   File "/usr/lib/python2.7/subprocess.py", line 540, in check_call
> >     raise CalledProcessError(retcode, cmd)
> > subprocess.CalledProcessError: Command '['flock', 'zdtm_mount_cgroups', './zdtm_mount_cgroups']' returned non-zero exit status 1
> > 
> > let's use a lazy unmount so we avoid this.
> 
> Maybe we need to find who uses it in this moment?

Unfortunately I can't seem to reliably reproduce it, and by the time I
can lsof when it happens whoever is using the mount is done. We can
drop this one for now if you want until I can figure that out.

Tycho

> > 
> > Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> > ---
> >  test/zdtm_mount_cgroups | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/test/zdtm_mount_cgroups b/test/zdtm_mount_cgroups
> > index d7bc142..34e0e85 100755
> > --- a/test/zdtm_mount_cgroups
> > +++ b/test/zdtm_mount_cgroups
> > @@ -11,6 +11,6 @@ for i in "zdtmtst" "zdtmtst.defaultroot"; do
> >  	mount -t cgroup -o none,name=$i zdtm $tdir &&
> >  	# a fake group prevents destroying of a controller
> >  	mkdir -p $tdir/holder &&
> > -	umount $tdir || exit 1
> > +	umount -l $tdir || exit 1
> >  done
> >  rmdir $tdir
> > -- 
> > 2.5.0
> > 
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