[LTP] [PATCH v4, 2/2] cgroup/cgroup_regression_test: Fix umount failure

[Leo Liang <ycliang@andestech.com>]

Hi Petr,
On Wed, Jul 21, 2021 at 10:37:27PM +0800, Petr Vorel wrote:
> Hi Leo,
> 
> Reviewed-by: Petr Vorel <pvorel@suse.cz>
> 
> >  	rmdir cgroup/0 cgroup/1
> > -	umount cgroup/
> > +	tst_umount cgroup/	# Avoid possible EBUSY error
> >  }
> 
> >  #---------------------------------------------------------------------------
> > @@ -193,7 +193,7 @@ test3()
> >  	wait $pid2 2>/dev/null
> 
> >  	rmdir $cpu_subsys_path/0 2> /dev/null
> > -	umount cgroup/ 2> /dev/null
> > +	tst_umount cgroup/ 2> /dev/null		# Avoid possible EBUSY error
> I'd prefer: # keep "/" to avoid possible EBUSY error
> But that can be changed before merge.
> 
> More I'm interested if other maintainers agree with me about this approach.
> (keep / here instead of in tst_umount())
> 
> >  	check_kernel_bug
> >  }
> 
> > @@ -222,7 +222,7 @@ test4()
> >  	mount -t cgroup -o none,name=foo cgroup cgroup/
> >  	mkdir cgroup/0
> >  	rmdir cgroup/0
> > -	umount cgroup/
> > +	tst_umount cgroup/		# Avoid possible EBUSY error
> 
> >  	if dmesg | grep -q "MAX_LOCKDEP_SUBCLASSES too low"; then
> >  		tst_res TFAIL "lockdep BUG was found"
> > @@ -254,7 +254,7 @@ test5()
> >  	mount -t cgroup none cgroup 2> /dev/null
> >  	mkdir cgroup/0
> >  	rmdir cgroup/0
> > -	umount cgroup/ 2> /dev/null
> > +	tst_umount cgroup/ 2> /dev/null		# Avoid possible EBUSY error
> I'd drop stderr redirection here. It was here originally, but I suppose it's not
> needed when using tst_umount. But that can be done during merge.
> 

OK got it.
Thanks for the review!
Let's wait for other maintainer's comment on the aaproach for keeping '/' here or not.

Best regards,
Leo
> ...
> 
> Kind regards,
> Petr