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9. Known Issues

9.1. All Architectures

  • When using the new disk encryption feature to encrypt the root filesystem, the following error message will be reported on the console when shutting down the system: 
    Stopping disk encryption [FAILED]
    This message can safely be ignored, the shutdown process will complete successfully.
  • When using an encrypted device, the following error message may be reported during bootup: 
    insmod: error inserting '/lib/aes_generic.ko': -1 File exists
    This message can safely be ignored.
  • Installation using a Multiple Device (MD) RAID on top of multipath will result in a machine that cannot boot. Multipath to Storage Area Network (SAN) devices which provide RAID internally are not affected.
  • When a large number of LUNs are added to a node, multipath can significantly increase the time it takes for udev to create device nodes for them. If you experience this problem, you can correct it by deleting the following line in /etc/udev/rules.d/40-multipath.rules: 
    KERNEL!="dm-[0-9]*", ACTION=="add", PROGRAM=="/bin/bash -c '/sbin/lsmod | /bin/grep ^dm_multipath'", RUN+="/sbin/multipath -v0 %M:%m"
    This line causes udev to run multipath every time a block device is added to the node. Even with this line removed, multipathd will still automatically create multipath devices, and multipath will still be called during the boot process, for nodes with multipathed root filesystems. The only change is that multipath devices will not be automatically created when multipathd is not running, which should not be a problem for the vast majority of multipath users.
  • When upgrading from an earlier version of Red Hat Enterprise Linux to 5.3, you may encounter the following error: 
    Updating  : mypackage                 ################### [ 472/1655]
rpmdb: unable to lock mutex: Invalid argument
    The cause of the locking issue is that the shared futex locking in glibc was enhanced with per-process futexes between 5.2 and 5.3. As a result, programs running against the 5.2 glibc can not properly perform shared futex locking against programs running with the 5.3 glibc.
    This particular error message is a side effect of a package calling rpm as part of its install scripts. The rpm instance performing the upgrade is using the prior glibc throughout the upgrade, but the rpm instance launched from within the script is using the new glibc.
    To avoid this error, upgrade glibc first in a separate run: 
    # yum update glibc
# yum update
    You will also see this error if you downgrade glibc to an earlier version on an installed 5.3 system.
  • mvapich and mvapich2 in Red Hat Enterprise Linux 5 are compiled to support only InfiniBand/iWARP interconnects. Consequently, they will not run over ethernet or other network interconnects.
  • On systems with more than two encrypted block devices, anaconda has a option to provide a global passphrase. The init scripts, however, do not support this feature. When booting the system, entering each individual passphrase for all encrypted devices will be required.
  • When upgrading openmpi using yum, the following warning may be returned: 
    cannot open `/tmp/openmpi-upgrade-version.*' for reading: No such file or directory
    The message is harmless and can be safely ignored.
  • Configuring IRQ SMP affinity has no effect on some devices that use message signalled interrupts (MSI) with no MSI per-vector masking capability. Examples of such devices include Broadcom NetXtreme Ethernet devices that use the bnx2 driver.
    If you need to configure IRQ affinity for such a device, disable MSI by creating a file in /etc/modprobe.d/ containing the following line: 
    		  options bnx2 disable_msi=1
    Alternatively, you can disable MSI completely using the kernel boot parameter pci=nomsi.
  • A bug in the updated /etc/udev/rules.d/50-udev.rules file prevents the creation of persistent names for tape devices with numbers higher than 9 in their names. For example, a persistent name will not be created for a tape device with a name of nst12.
    To work around this, add an asterisk (*) after each occurrence of the string nst[0-9] in /etc/udev/rules.d/50-udev.rules.
  • The smartctl tool cannot properly read SMART parameters from SATA devices.
  • A bug in previous versions of openmpi and lam may prevent you from upgrading these packages. This bug manifests in the following error (when attempting to upgrade openmpi or lam: 
    error: %preun(openmpi-[version]) scriptlet failed, exit status 2
    As such, you need to manually remove older versions of openmpi and lam in order to install their latest versions. To do so, use the following rpm command:
    rpm -qa | grep '^openmpi-\|^lam-' | xargs rpm -e --noscripts --allmatches
  • When using dm-multipath, if features "1 queue_if_no_path" is specified in /etc/multipath.conf then any process that issues I/O will hang until one or more paths are restored.
    To avoid this, set no_path_retry [N] in /etc/multipath.conf (where [N] is the number of times the system should retry a path). When you do, remove the features "1 queue_if_no_path" option from /etc/multipath.conf as well.
    If you need to use "1 queue_if_no_path" and experience the issue noted here, use dmsetup to edit the policy at runtime for a particular LUN (i.e. for which all the paths are unavailable).
    To illustrate: run dmsetup message [device] 0 "fail_if_no_path", where [device] is the multipath device name (e.g. mpath2; do not specify the path) for which you want to change the policy from "queue_if_no_path" to "fail_if_no_path".
  • Enabling multiple installed versions of the same kernel module is not supported. In addition to this, a bug in the way kernel module versions are parsed can sometimes result in enabling an older version of the same kernel module.
    Red Hat recommends that when you install a newer version of an installed kernel module, you should delete the older one first.
  • Executing kdump on an IBM Bladecenter QS21 or QS22 configured with NFS root will fail. To avoid this, specify an NFS dump target in /etc/kdump.conf.
  • IBM T60 laptops will power off completely when suspended and plugged into a docking station. To avoid this, boot the system with the argument acpi_sleep=s3_bios.
  • The QLogic iSCSI Expansion Card for the IBM Bladecenter provides both ethernet and iSCSI functions. Some parts on the card are shared by both functions. However, the current qla3xxx and qla4xxx drivers support ethernet and iSCSI functions individually. Both drivers do not support the use of ethernet and iSCSI functions simultaneously.
    Because of this limitation, successive resets (via consecutive ifdown/ifup commands) may hang the device. To avoid this, allow a 10-second interval after an ifup before issuing an ifdown. Also, allow the same 10-second interval after an ifdown before issuing an ifup. This interval allows ample time to stabilize and re-initialize all functions when an ifup is issued.
  • Laptops equipped with the Cisco Aironet MPI-350 wireless may hang trying to get a DHCP address during any network-based installation using the wired ethernet port.
    To work around this, use local media for your installation. Alternatively, you can disable the wireless card in the laptop BIOS prior to installation (you can re-enable the wireless card after completing the installation).
  • Boot-time logging to /var/log/boot.log is not available in Red Hat Enterprise Linux 5.3.
  • The system may not successfully reboot into a kexec/kdump kernel if X is running and using a driver other than vesa. This problem only exists with ATI Rage XL graphics chipsets.
    If X is running on a system equipped with ATI Rage XL, ensure that it is using the vesa driver in order to successfully reboot into a kexec/kdump kernel.
  • When using Red Hat Enterprise Linux 5.2 on a machine with an nVidia CK804 chipset installed, the following kernel messages may appear: 
    kernel: assign_interrupt_mode Found MSI capability
kernel: pcie_portdrv_probe->Dev[005d:10de] has invalid IRQ. Check vendor BIOS
    These messages indicate that certain PCI-E ports are not requesting IRQs. They do not, however, affect the operation of the machine in any way.
  • Removable storage devices (such as CDs and DVDs) do not automatically mount when you are logged in as root. As such, you will need to manually mount the device through the graphical file manager.
    Alternatively, you can run the following command to mount a device to /media: 
    mount /dev/[device name] /media
  • When a LUN is deleted on a configured storage system, the change is not reflected on the host. In such cases, lvm commands will hang indefinitely when dm-multipath is used, as the LUN has now become stale.
    To work around this, delete all device and mpath link entries in /etc/lvm/.cache specific to the stale LUN.
    To find out what these entries are, run the following command:
    ls -l /dev/mpath | grep [stale LUN]
    For example, if [stale LUN] is 3600d0230003414f30000203a7bc41a00, the following results may appear: 
    lrwxrwxrwx 1 root root 7 Aug  2 10:33 /3600d0230003414f30000203a7bc41a00 -> ../dm-4
lrwxrwxrwx 1 root root 7 Aug  2 10:33 /3600d0230003414f30000203a7bc41a00p1 -> ../dm-5
    This means that 3600d0230003414f30000203a7bc41a00 is mapped to two mpath links: dm-4 and dm-5.
    As such, the following lines should be deleted from /etc/lvm/.cache: 
    /dev/dm-4 
/dev/dm-5 
/dev/mapper/3600d0230003414f30000203a7bc41a00
/dev/mapper/3600d0230003414f30000203a7bc41a00p1
/dev/mpath/3600d0230003414f30000203a7bc41a00
/dev/mpath/3600d0230003414f30000203a7bc41a00p1
  • Running the multipath command with the -ll option can cause the command to hang if one of the paths is on a blocking device. Note that the driver does not fail a request after some time if the device does not respond.
    This is caused by the cleanup code, which waits until the path checker request either completes or fails. To display the current multipath state without hanging the command, use multipath -l instead.
  • Upgrading pm-utils from a Red Hat Enterprise Linux 5.2 Beta version of pm-utils will fail, resulting in the following error: 
    error: unpacking of archive failed on file /etc/pm/sleep.d: cpio: rename
    To prevent this from occurring, delete the /etc/pm/sleep.d/ directory prior to upgrading. If /etc/pm/sleep.d contains any files, move those files to /etc/pm/hooks/.
  • Hardware testing for the Mellanox MT25204 has revealed that an internal error occurs under certain high-load conditions. When the ib_mthca driver reports a catastrophic error on this hardware, it is usually related to an insufficient completion queue depth relative to the number of outstanding work requests generated by the user application.
    Although the driver will reset the hardware and recover from such an event, all existing connections at the time of the error will be lost. This generally results in a segmentation fault in the user application. Further, if opensm is running at the time the error occurs, then you need to manually restart it in order to resume proper operation.
  • When installing Red Hat Enterprise Linux 5 on a guest, the guest is configured to explicitly use a temporary installation kernel provided by dom0. Once installation finishes, it can then use its own bootloader. However, this can only be achieved by forcing the guest's first reboot to be a shutdown.
    As such, when the Reboot button appears at the end of the guest installation, clicking it shuts down the guest, but does not reboot it. This is an expected behavior.
    Note that when you boot the guest after this it will then use its own bootloader.
  • Running rpmbuild on the compiz source RPM will fail if any KDE or qt development packages (for example, qt-devel) are installed. This is caused by a bug in the compiz configuration script.
    To work around this, remove any KDE or qt development packages before attempting to build the compiz package from its source RPM.
  • If your system has either ATI Radeon R500 or R600 graphics card equipped, firstboot will not run after installation. The system will go directly to the graphical login screen and skip firstboot altogether. If you attempt to run firstboot manually (i.e. from a failsafe terminal), the X session will crash.
    This issue is caused by the driver used by the ATI Radeon R500/R600 hardware. The default driver used by these graphics cards are still in technology preview. To work around this, backup your /etc/X11/xorg.conf file; then, configure X to use the supported vesa driver instead using the following command:
    system-config-display --reconfig --set-driver=vesa
    You can now run firstboot. To switch back to your old settings, restore your original /etc/X11/xorg.conf.
  • If your system uses the TSC timer, the gettimeofday system call may move backwards. This is because of an overflow issue that causes the TSC timer to jump forward significantly in some cases; when this occurs, the TSC timer will correct itself, but will ultimately register a movement backwards in time.
    This issue is particularly critical for time-sensitive systems, such as those used for transaction systems and databases. As such, if your system needs precision timing, Red Hat strongly recommends that you set the kernel to use another timer (for example, HPET).
  • Attempting to run sniff may result in an error. This is because some required packages are not installed with dogtail.
    To prevent this from occurring, install the following packages manually:
    • librsvg2
    • ghostscript-fonts
    • pygtk2-libglade
  • Thin Provisioning (also known as "virtual provisioning") will be first released with EMC Symmetrix DMX3 and DMX4. Please refer to the EMC Support Matrix and Symmetrix Enginuity code release notes for further details.
  • In /etc/multipath.conf, setting max_fds to unlimited will prevent the multipathd daemon from starting up properly. As such, you should use a sufficiently high value instead for this setting.
  • SystemTap currently uses GCC to probe user-space events. GCC is, however, unable to provide debuggers with precise location list information for parameters. In some cases, GCC also fails to provide visibility on some parameters. As a consequence, SystemTap scripts that probe user-space may return inaccurate readings.
  • The IBM T41 laptop model does not enter Suspend Mode properly; as such, Suspend Mode will still consume battery life as normal. This is because Red Hat Enterprise Linux 5 does not yet include the radeonfb module.
    To work around this, add a script named hal-system-power-suspend to /usr/share/hal/scripts/ containing the following lines: 
    	
chvt 1
radeontool light off
radeontool dac off
    This script will ensure that the IBM T41 laptop enters Suspend Mode properly. To ensure that the system resumes normal operations properly, add the script restore-after-standby to the same directory as well, containing the following lines: 
    	
radeontool dac on
radeontool light on
chvt 7
  • If the edac module is loaded, BIOS memory reporting will not work. This is because the edac module clears the register that the BIOS uses for reporting memory errors.
    The current Red Hat Enterprise Linux Driver Update Model instructs the kernel to load all available modules (including the edac module) by default. If you wish to ensure BIOS memory reporting on your system, you need to manually blacklist the edac modules. To do so, add the following lines to /etc/modprobe.conf: 
    	
blacklist edac_mc
blacklist i5000_edac
blacklist i3000_edac
blacklist e752x_edac
  • Red Hat Enterprise Linux 5.3 can detect online growing or shrinking of an underlying block device. However, there is no method to automatically detect that a device has changed size, so manual steps are required to recognize this and resize any file systems which reside on the given device(s). When a resized block device is detected, a message like the following will appear in the system logs: 
    VFS: busy inodes on changed media or resized disk sdi
    If the block device was grown, then this message can be safely ignored. However, if the block device was shrunk without shrinking any data set on the block device first, the data residing on the device may be corrupted.
    It is only possible to do an online resize of a filesystem that was created on the entire LUN (or block device). If there is a partition table on the block device, then the file system will have to be unmounted to update the partition table.
  • If your system has a GFS2 file system mounted, a node may hang if a cached inode is accessed in one node and unlinked on a different node. When this occurs, the hung node will be unavailable until you fence and recover it via the normal cluster recovery mechanism. The function calls gfs2_dinode_dealloc and shrink_dcache_memory will also appear in the stack traces of any processes stuck in the hung node.
    This issue does not affect single-node GFS2 file systems.
  • The following message may be encountered during system boot: 
    Could not detect stabilization, waiting 10 seconds.
Reading all physical volumes.  This may take a while...
    This delay (which may be up to 10 seconds, dependant on the hardware configuration) is necessary to ensure that the kernel has completed scanning the disks.
  • The current implementation of User Payload Access in ipmitool allows you to configure devices, but does not allow you to retrieve the current settings for those devices.
  • Using the swap --grow parameter in a kickstart file without setting the --maxsize parameter at the same time makes anaconda impose a restriction on the maximum size of the swap partition. It does not allow it to grow to fill the device.
    For systems with less than 2GB of physical memory, the imposed limit is twice the amount of physical memory. For systems with more than 2GB, the imposed limit is the size of physical memory plus 2GB.
  • The gfs2_convert program may not free up all blocks from the GFS metadata that are no longer used under GFS2. These unused metadata blocks will be discovered and freed the next time gfs2_fsck is run on the file system. It is recommended that gfs2_fsck be run after the filesystem has been converted to free the unused blocks. These unused blocks will be flagged by gfs2_fsck with messages such as: 
    Ondisk and fsck bitmaps differ at block 137 (0x89) 
Ondisk status is 1 (Data) but FSCK thinks it should be 0 (Free)
Metadata type is 0 (free)
    These messages do not indicate corruption in the GFS2 file system, they indicate blocks that should have been freed, but were not. The number of blocks needing to be freed will vary depending on the size of the file system and block size. Many file systems will not encounter this issue at all. Large file systems may have a small number of blocks (typically less than 100).

9.2. x86 Architectures

  • When running the bare-metal (non-Virtualized) kernel, the X server may not be able to retrieve EDID information from the monitor. When this occurs, the graphics driver will be unable to display resolutions highers than 800x600.
    To work around this, add the following line to the ServerLayout section of /etc/X11/xorg.conf: 
    Option "Int10Backend" "x86emu"
  • Recording needs to be manually enabled on Dell M4300 and M6300. To do this, perform the following steps:
    1. Open alsamixer.
    2. Press Tab to toggle [Capture] in the View field (located at the upper left part of the menu).
    3. Press the Space bar.
    4. To verify that recording is enabled, the text above the ADCMux field should display L R CAPTUR.
  • If encryption is enabled on the boot device during system installation, the following message will be logged during system boot: 
    padlock: VIA PadLock not detected.
    This message can safely be ignored.

9.3. x86_64 Architectures

  • Some machines that use NVIDIA graphics cards may display corrupted graphics or fonts when using the graphical installer or during a graphical login. To work around this, switch to a virtual console and back to the original X host.
  • On an IBM T61 laptop, Red Hat recommends that you refrain from clicking the glxgears window (when glxgears is run). Doing so can lock the system.
    To prevent this from occurring, disable the tiling feature. To do so, add the following line in the Device section of /etc/X11/xorg.conf: 
    Option "Tiling" "0"
  • Recording needs to be manually enabled on Dell M4300 and M6300. To do this, perform the following steps:
    1. Open alsamixer.
    2. Press Tab to toggle [Capture] in the View field (located at the upper left part of the menu).
    3. Press the Space bar.
    4. To verify that recording is enabled, the text above the ADCMux field should display L R CAPTUR.
  • If your system uses an Intel 945GM graphics card, do not use the i810 driver. You should use the default intel driver instead.
  • On dual-GPU laptops, if one of the graphics chips is Intel-based, the Intel graphics mode cannot drive any external digital connections (including HDMI, DVI, and DisplayPort). This is a hardware limitation of the Intel GPU. If you require external digital connections, configure the system to use the discrete graphics chip (in the BIOS).

9.4. PowerPC Architectures

  • When using Alt-SysRq-W to debug, the following warning message will appear: 
    Badness in smp_call_function at arch/powerpc/kernel/smp.c:223
    Afterwards, the system will also warn that it will hang. This message should be ignored as it will not cause the system to hang.
  • Recording needs to be manually enabled on Dell M4300 and M6300. To do this, perform the following steps:
    1. Open alsamixer.
    2. Press Tab to toggle [Capture] in the View field (located at the upper left part of the menu).
    3. Press the Space bar.
    4. To verify that recording is enabled, the text above the ADCMux field should display L R CAPTUR.
  • The size of the PPC kernel image is too large for OpenFirmware to support. Consequently, network booting will fail, resulting in the following error message: 
    Please wait, loading kernel...
/pci@8000000f8000000/ide@4,1/disk@0:2,vmlinux-anaconda: No such file or directory
boot:
    To work around this:
    1. Boot to the OpenFirmware prompt, by pressing the '8' key when the IBM splash screen is displayed.
    2. Run the following command: 
      setenv real-base 2000000
    3. Boot into System Managment Services (SMS) with the command: 
      0> dev /packages/gui obe

9.5. s390x Architectures

  • When running Red Hat Enterprise Linux 5.2 on a z/VM that has more than 2GB of guest storage defined, invalid data can be read from and written to any FCP and OSA device attached in QDIO mode with the Queued-I/O assist (QIOASSIST) option enabled. If your system has any such devices attached, Red Hat recommends that you download and install the corresponding z/VM Program Temporary Fix (PTF) from the following link:
    http://www-1.ibm.com/support/docview.wss?uid=isg1VM64306
  • It is not possible to directly read and convert a z/VM dump into a file. Instead, you should first copy the dump from the z/VM reader into a Linux file system using vmur and convert the dump into a Linux-readable file using vmconvert.
  • The IBM System z does not provide a traditional Unix-style physical console. As such, Red Hat Enterprise Linux 5.2 for the IBM System z does not support the firstboot functionality during initial program load.
    To properly initialize setup for Red Hat Enterprise Linux 5.2 on the IBM System z, run the following commands after installation:
    • /usr/bin/setup — provided by the setuptool package.
    • /usr/bin/rhn_register — provided by the rhn-setup package.

9.6. ia64 Architecture

  • Some Itanium systems cannot properly produce console output from the kexec purgatory code. This code contains instructions for backing up the first 640k of memory after a crash.
    While purgatory console output can be useful in diagnosing problems, it is not needed for kdump to properly function. As such, if your Itanium system resets during a kdump operation, disable console output in purgatory by adding --noio to the KEXEC_ARGS variable in /etc/sysconfig/kdump.
  • Running perftest will fail if different CPU speeds are detected. As such, you should disable CPU speed scaling before running perftest.
  • When the kdump kernel is booted, the following error will appear in the boot log: 
    mknod: /tmp/initrd.[numbers]/dev/efirtc: No such file or directory
    This error results from a malformed request to create the efirtc in an incorrect path. However, the device path in question is also created statically in the initramfs when the kdump service is started. As such, the run-time creation of the device node is redundant, harmless, and should not affect the performance of kdump.
  • Some systems may be unable to boot the kdump kernel properly. In such cases, use the machvec=dig kernel parameter.
  • Recording needs to be manually enabled on Dell M4300 and M6300. To do this, perform the following steps:
    1. Open alsamixer.
    2. Press Tab to toggle [Capture] in the View field (located at the upper left part of the menu).
    3. Press the Space bar.
    4. To verify that recording is enabled, the text above the ADCMux field should display L R CAPTUR.
  • On Intel Itanium-based systems running SELinux in enforcing mode, either the allow_unconfined_execmem_dyntrans or allow_execmem Booleans must be turned on to allow the IA-32 Execution Layer (the ia32el service) to operate correctly. If the allow_unconfined_execmem_dyntrans Boolean is off, but the allow_execmem Boolean is on, which it is by default in Red Hat Enterprise Linux 5, the ia32el service supports 32-bit emulation; however, if both Booleans are off, emulation fails.