Article ID: 116284, created on Jun 14, 2013, last review on Apr 25, 2014

  • Applies to:
  • Virtuozzo hypervisor 5.0

Synopsis:          New Parallels Server Bare Metal 5.0 kernel provides
                   an update with performance and stability fixes.
Product:           Parallels Server Bare Metal 5.0
Keywords:          "bugfix" "stability"


This document provides information on the new Parallels Server Bare Metal 5.0
kernel, version 2.6.32-042stab078.22.


1. About This Release
2. Updates Description
3. Obtaining New Kernel
4. References



The current update for the Parallels Server Bare Metal 5.0 kernel provides a new
kernel based on the Red Hat Enterprise Linux 6.4 kernel (2.6.32-358.6.1.el6).
The updated kernel includes a number of performance and stability fixes.



This update resolves the following issues:

* Posix timer TID preserve support during checkpoint/restore has been
  implemented. (PSBM-19073)

* A kernel panic could occur while resuming a Container due to an 
  unexpected empty task signal handler. (PSBM-19177, PCLIN-31850)

* A number of issues found in the Trinity test have been fixed. (PSBM-18611)

* A potential file system corruption has been eliminated by preventing
  pipe writes and fsyncs on a frozen file system. Those writes-after-freeze
  were accompanied by kernel warnings:
   "WARNING: at fs/ext4/super.c:248 ext4_journal_start_sb"
   (PSBM-19255, PSBM-19460)

* The CBQ-based traffic shaping algorithm has been corrected to properly limit the
  bandwidth when the limit is greater than 50 percent of the total bandwidth.

* Checkpoint functionality has been enhanced to operate on
  systems with the /tmp directory mounted with the "noexec" mount option.

* Fixed NFS vzquota bug that caused random memory corruptions.
  (PSBM-17619, OVZ 2506)

* Ubuntu 12.04 LTS syslog-ng may fail to log kernel messages due to the internal
  capability CAP_FS_FREEZE, which was introduced in the previous kernel update.
  (PSBM-17503, OVZ 2567)

* A memory leak (struct file object) has been fixed. (PCLIN-31738)

* VEFS dentry alias for disconnected private dentry handling has been corrected.
  Previously, this defect could lead to a kernel BUG trigger at
  include/linux/dcache.h:375. (PCLIN-31714)

* A kernel BUG in try_to_release_page() could be triggered by the memory shrinker
  on an attempt to strip buffer heads from swap-backed pages. (PCLIN-31748)

* The quota sync operation has been protected by a mutex, preventing
  possible NFS quota corruptions. (PCLIN-31715)

* fsync locking has been reworked in order to prevent possible Node lockups.

* The memory management algorithm has been enhanced to give higher priority to
  Containers with an unlimited memory barriers set.

* The NFS volume unmount operation issued inside a Container could cause
  a kernel panic if the NFS volume was mounted on a Hardware Node.

* Resolves an issue with umask not being ignored in a file or directory create operation
  inside a directory with default ACL rights set. This issue only affected 
  Containers using the vzfs filesystem. (PCLIN-31394)

* /proc/stat:btime values are now corrected on a Container restore operation
  after the online migration. This should also fix glitches with process start
  time reports. (OVZ 2572)

* Under certain circumstances, the Container checkpoint/restore cycle could
  break process capabilities. (PSBM-18649)

* Under certain conditions, direct memory reclaiming could trigger fs-related
  activity and could cause a Node deadlock in the event of high
  memory pressure. (PSBM-20210)

* Checkpointing a Container with a tty under inotify watch could trigger
  a kernel panic. (PCLIN-31849)



You can download and install this kernel update using the "vzup2date" utility
included in the Parallels Server Bare Metal 5.0 distribution set.



Copyright (c) 1999-2013 Parallels Holdings, Ltd. and its affiliates. All rights

c662da62f00df94fd77ba7a2c9eff4b4 2897d76d56d2010f4e3a28f864d69223 a26b38f94253cdfbf1028d72cf3a498b

Email subscription for changes to this article
Save as PDF