[CRIU] [PATCH 1/2] cgroup: don't look up existing mount point

[Pavel Emelyanov]

On 07/16/2014 05:46 PM, Andrew Vagin wrote:
> A mount point, which is mounted by someone else, may be umounted in
> any moment.
> 
> For example the test system executes tests concurrently and sometimes
> one test looks up a mount point, which has been mounted by another test.
> 
> ==================================== ERROR ====================================
> Test: zdtm/live/static/inotify00, Namespace: 1
> Dump log   : /var/lib/jenkins/jobs/CRIU-dump/workspace/test/dump/inotify00/15535/1/dump.log
> --------------------------------- grep Error ---------------------------------
> (00.021951) Error (cgroup.c:409): cg: failed walking /var/lib/jenkins/jobs/CRIU-dump/workspace/test/dump/signalfd00/15538/1/.criu.cgmounts.UGj28v/ for empty cgroups
> (00.021967) Error (cr-dump.c:1601): Dump core (pid: 15535) failed with -1
> (00.025509) Error (cr-dump.c:1914): Dumping FAILED.
> ------------------------------------- END -------------------------------------
> ================================= ERROR OVER =================================
> 
> In the previous patch I suggested to open a mount point, but it brought
> other problems. We may open a directory where a cgroup mount has been
> umounted and an owner will get EBUSY on attempt to remove this
> directory.
> 
> Reported-by: Jenkins Criuovich
> Acked-by: Tycho Andersen <tycho.andersen at canonical.com>
> Signed-off-by: Andrew Vagin <avagin at openvz.org>

Applied, thanks