[CRIU] [PATCH] cg: don't leak properties when cg dir exists

[Tycho Andersen]

On Thu, Oct 02, 2014 at 06:00:17PM +0400, Andrew Vagin wrote:
> On Wed, Oct 01, 2014 at 08:57:28PM +0000, Tycho Andersen wrote:
> > We're using NULL as a sentinel here to indicate that we shouldn't restore any
> > cgroup properties. We should make sure that we don't leak this information and
> > instead check the n_properties field, which we should also set correctly.
> 
> Tycho, I beg you to run tests before sending patches.

I thought I did :)

> It's like brushing teeth before bedtime.

One thing that makes it harder than brushing your teeth is that it
chmods a lot of files to root in the process. This means I have to
fix a whole bunch of things manually before using git again, or it
gets really confused.

> [root at avagin-fc19-cr criu]# bash test/zdtm.sh static/cgroup00
> ================================= CRIU CHECK =================================
> Looks good.
> Execute zdtm/live/static/cgroup00
> ./cgroup00 --pidfile=cgroup00.pid --outfile=cgroup00.out --dirname=cgroup00.test
> Dump 1457
> Executing pre-restore hook
> Cleaning cgclean.OkAnTX
> Left there is:
> cgroup.clone_children  cgroup.procs  cgroup.sane_behavior  notify_on_release  release_agent  tasks
> Restore
> Test: zdtm/live/static/cgroup00, Result: FAIL
> ==================================== ERROR ====================================
> Test: zdtm/live/static/cgroup00, Namespace: 
> Dump log   : /root/git/criu/test/dump/static/cgroup00/1457/1/dump.log
> --------------------------------- grep Error ---------------------------------
> ------------------------------------- END -------------------------------------
> Restore log: /root/git/criu/test/dump/static/cgroup00/1457/1/restore.log
> --------------------------------- grep Error ---------------------------------
> (00.032275)   1457: Error (cgroup.c:943): cg: copying property cpuset.cpus to cpuset////cpuset.cpus failed
> (00.032319)   1457: Error (cgroup.c:968): cg: copying prop cpuset.cpus failed
> (00.032336)   1457: Error (cgroup.c:1005): cg: Couldn't copy special cgroup properties
> (00.032373) Error (cr-restore.c:1820): Restoring FAILED.
> (00.039606) Error (cr-restore.c:1177): 1457 exited, status=1
> ------------------------------------- END -------------------------------------
> ================================= ERROR OVER =================================

For me this test passes, can you paste the entire log file? (really
just the next line, there was a \n in my perror message)

Tycho

> Thanks,
> Andrey
> 
> > 
> > Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> > ---
> >  cgroup.c | 15 +++++++--------
> >  1 file changed, 7 insertions(+), 8 deletions(-)
> > 
> > diff --git a/cgroup.c b/cgroup.c
> > index 26b0a17..ce49d04 100644
> > --- a/cgroup.c
> > +++ b/cgroup.c
> > @@ -1114,12 +1114,7 @@ static int prepare_cgroup_dir_properties(char *path, int off, CgroupDirEntry **e
> >  		size_t off2 = off;
> >  
> >  		off2 += sprintf(path + off, "/%s", e->dir_name);
> > -		/*
> > -		 * Check to see if we made e->properties NULL during restore
> > -		 * because directory already existed and as such we don't want to
> > -		 * change its properties
> > -		 */
> > -		if (e->properties) {
> > +		if (e->n_properties > 0) {
> >  			for (j = 0; j < e->n_properties; ++j) {
> >  				if (restore_cgroup_prop(e->properties[j], path, off2) < 0)
> >  					return -1;
> > @@ -1168,7 +1163,7 @@ static int prepare_cgroup_dirs(char *paux, size_t off, CgroupDirEntry **ents, si
> >  		/*
> >  		 * Checking to see if file already exists. If not, create it. If
> >  		 * it does exist, prevent us from overwriting the properties
> > -		 * later by setting the CgroupDirEntry's properties pointer to NULL
> > +		 * later by removing the CgroupDirEntry's properties.
> >  		 */
> >  		if (access(paux, F_OK) < 0) {
> >  			if (errno != ENOENT) {
> > @@ -1181,7 +1176,11 @@ static int prepare_cgroup_dirs(char *paux, size_t off, CgroupDirEntry **ents, si
> >  			}
> >  			pr_info("Created dir %s\n", paux);
> >  		} else {
> > -			e->properties = NULL;
> > +			if (e->n_properties > 0) {
> > +				xfree(e->properties);
> > +				e->properties = NULL;
> > +				e->n_properties = 0;
> > +			}
> >  			pr_info("Determined dir %s already existed\n", paux);
> >  		}
> >  
> > -- 
> > 1.9.1
> > 
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