CVE request: kernel: vfs: refcount issues during unmount on symlink

[Vasily Averin <vvs () parallels com>]

https://bugzilla.redhat.com/show_bug.cgi?id=1122472
"
A flaw was found in the way reference counting was handled in the Linux kernel's
VFS subsystem when unmount on symlink was performed.

On Red Hat Enterprise Linux 6 an unprivileged local user could use this flaw to
cause OOM conditions leading to denial of service or, potentially, trigger
use-after-free error.

On Red Hat Enterprise Linux 7 a privileged local user with CAP_SYS_ADMIN
capability (also in a container) could use this flaw to cause OOM conditions
leading to denial of service or, potentially, trigger use-after-free error.

Acknowledgements:
Red Hat would like to thank Vasily Averin of Parallels for reporting this issue.
"
https://lkml.org/lkml/2014/7/21/98

Problem was fixed in OpenVZ kernel 2.6.32-042stab092.3
https://openvz.org/Download/kernel/rhel6/042stab092.3/changes

Also I would like to add that KernelCare project (http://kernelcare.com) have released
a live hot update for this issue, both for affected OpenVZ and RHEL6 kernels.
http://www.cloudlinux.com/blog/clnews/kernelcare-update-for-openvz-pcs-and-centosrhel-6-kernels-psbm28104.php

Thank you,
        Vasily Averin