I successfully upgraded desktops using the CR repo and 'yum update'.
However after installing the CR repo on 2 VPS's running C 5.6 and doing a reboot I got a load of Kernel messages, for the first time ever.
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--------------------- Kernel Begin ------------------------
WARNING: Kernel Errors Present rtc_cmos: probe of rtc_cmos failed with error -16 ...: 1 Time(s)
1 Time(s): RCU-based detection of stalled CPUs is disabled. 1 Time(s): Verbose stalled-CPUs detection is disabled. 1 Time(s): 0: 0x00000001 -> 0x000000a0 1 Time(s): 0: 0x00000100 -> 0x00010000 1 Time(s): #1 [0001a7b000 - 0001a8c000] XEN PAGETABLES 1 Time(s): #10 [00019ed000 - 00019ee000] BOOTMEM 1 Time(s): #11 [00019ee000 - 00019ef000] BOOTMEM 1 Time(s): #12 [00019ef000 - 00019f0000] BOOTMEM 1 Time(s): #13 [00019f0000 - 00019f1000] BOOTMEM 1 Time(s): #14 [0002400000 - 0002780000] MEMMAP 0 1 Time(s): #15 [0001a8c000 - 0001aa4000] BOOTMEM 1 Time(s): #16 [0001aa4000 - 0001abc000] BOOTMEM 1 Time(s): #17 [00019f1000 - 00019f2000] BOOTMEM 1 Time(s): #18 [00019f2000 - 00019f3000] BOOTMEM 1 Time(s): #19 [00019f3000 - 00019f4000] BOOTMEM 1 Time(s): #2 [0001000000 - 00019d70c0] TEXT DATA BSS 1 Time(s): #20 [00019ec0c0 - 00019ec1a0] BOOTMEM 1 Time(s): #21 [00019ec1c0 - 00019ec228] BOOTMEM 1 Time(s): #22 [00019ec240 - 00019ec2a8] BOOTMEM 1 Time(s): #23 [00019ec2c0 - 00019ec328] BOOTMEM 1 Time(s): #24 [00019ec340 - 00019ec360] BOOTMEM 1 Time(s): #25 [00019ec380 - 00019ec3a0] BOOTMEM 1 Time(s): #26 [00019ec3c0 - 00019ec3e0] BOOTMEM 1 Time(s): #27 [0001abc000 - 0001ad9000] BOOTMEM 1 Time(s): #28 [00019ec400 - 00019ec408] BOOTMEM 1 Time(s): #29 [00019ec440 - 00019ec448] BOOTMEM 1 Time(s): #3 [00019f8000 - 0001a7b000] XEN START INFO 1 Time(s): #30 [00019ec480 - 00019ec484] BOOTMEM 1 Time(s): #31 [00019ec4c0 - 00019ec4c8] BOOTMEM 1 Time(s): #32 [00019ec500 - 00019ec600] BOOTMEM 1 Time(s): #33 [00019ec600 - 00019ec648] BOOTMEM 1 Time(s): #34 [00019ec680 - 00019ec6c8] BOOTMEM 1 Time(s): #35 [00019f4000 - 00019f6000] BOOTMEM 1 Time(s): #4 [0000001000 - 0000003000] TRAMPOLINE 1 Time(s): #5 [0000003000 - 0000007000] ACPI WAKEUP 1 Time(s): #6 [0000008000 - 0000076000] PGTABLE 1 Time(s): #7 [00019d70c0 - 00019eb0c0] NODE_DATA 1 Time(s): #8 [00019eb0c0 - 00019ec0c0] BOOTMEM 1 Time(s): #9 [0000007000 - 0000007030] BOOTMEM 1 Time(s): DMA 0x00000001 -> 0x00001000 1 Time(s): DMA32 0x00001000 -> 0x00100000 1 Time(s): Magic number: 1:252:3141 1 Time(s): NODE_DATA [00000000019d70c0 - 00000000019eb0bf] 1 Time(s): Normal empty 1 Time(s): Xen: 0000000000000000 - 00000000000a0000 (usable) 1 Time(s): Xen: 00000000000a0000 - 0000000000100000 (reserved) 1 Time(s): Xen: 0000000000100000 - 0000000010000000 (usable) 1 Time(s): ACPI in unprivileged domain disabled 1 Time(s): ACPI: Interpreter disabled. 1 Time(s): APIC: disable apic facility 1 Time(s): APIC: switched to apic NOOP 1 Time(s): Adding 524284k swap on /dev/xvda2. Priority:-1 extents:1 across:524284k SS 1 Time(s): Allocating PCI resources starting at 10000000 (gap: 10000000:f0000000) 1 Time(s): BIOS-provided physical RAM map: 1 Time(s): Block layer SCSI generic (bsg) driver version 0.4 loaded (major 253) 1 Time(s): Booting paravirtualized kernel on Xen 1 Time(s): Brought up 1 CPUs 1 Time(s): Built 1 zonelists in Node order, mobility grouping on. Total pages: 64543 1 Time(s): CONFIG_NF_CT_ACCT is deprecated and will be removed soon. Please use 1 Time(s): CPU: Unsupported number of siblings 4 1 Time(s): Calibrating delay loop (skipped), value calculated using timer frequency.. 4999.99 BogoMIPS (lpj=2499996) 1 Time(s): Checking aperture... 1 Time(s): Command line: root=/dev/xvda1 ro selinux=0 ro 1 Time(s): Console: colour dummy device 80x25 1 Time(s): DMI not present or invalid. 1 Time(s): Dentry cache hash table entries: 32768 (order: 6, 262144 bytes) 1 Time(s): Detected 2499.996 MHz processor. 1 Time(s): Dquot-cache hash table entries: 512 (order 0, 4096 bytes) 1 Time(s): EXT3-fs (xvda1): mounted filesystem with ordered data mode 1 Time(s): EXT3-fs (xvda1): using internal journal 1 Time(s): EXT3-fs: barriers not enabled 1 Time(s): Faking a node at 0000000000000000-0000000010000000 1 Time(s): Fixed MDIO Bus: probed 1 Time(s): Freeing SMP alternatives: 20k freed 1 Time(s): Freeing unused kernel memory: 892k freed 1 Time(s): Grant table initialized 1 Time(s): Hierarchical RCU implementation. 1 Time(s): HugeTLB registered 2 MB page size, pre-allocated 0 pages 1 Time(s): IMA: No TPM chip found, activating TPM-bypass! 1 Time(s): IP route cache hash table entries: 2048 (order: 2, 16384 bytes) 1 Time(s): Initalizing network drop monitor service 1 Time(s): Initialising Xen virtual ethernet driver. 1 Time(s): Initializing XFRM netlink socket 1 Time(s): Initializing cgroup subsys cpu 1 Time(s): Initializing cgroup subsys cpuacct 1 Time(s): Initializing cgroup subsys cpuset 1 Time(s): Initializing cgroup subsys devices 1 Time(s): Initializing cgroup subsys freezer 1 Time(s): Initializing cgroup subsys memory 1 Time(s): Initializing cgroup subsys net_cls 1 Time(s): Initializing cgroup subsys ns 1 Time(s): Initmem setup node 0 0000000000000000-0000000010000000 1 Time(s): Inode-cache hash table entries: 16384 (order: 5, 131072 bytes) 1 Time(s): Kernel command line: root=/dev/xvda1 ro selinux=0 ro 1 Time(s): Kernel log daemon terminating. 1 Time(s): Kernel logging (proc) stopped. 1 Time(s): Linux agpgart interface v0.103 1 Time(s): Linux version 2.6.35.4 (dfn@localhost.localdomain) (gcc version 4.4.4 20100630 (Red Hat 4.4.4-10) (GCC) ) #2 SMP Thu Sep 16 18:27:27 EDT 2010 1 Time(s): Memory: 246604k/262144k available (4193k kernel code, 388k absent, 15152k reserved, 3589k data, 892k init) 1 Time(s): Mount-cache hash table entries: 256 1 Time(s): Movable zone start PFN for each node 1 Time(s): NET: Registered protocol family 1 1 Time(s): NET: Registered protocol family 10 1 Time(s): NET: Registered protocol family 16 1 Time(s): NET: Registered protocol family 17 1 Time(s): NET: Registered protocol family 2 1 Time(s): NR_IRQS:16640 nr_irqs:256 1 Time(s): NX (Execute Disable) protection: active 1 Time(s): NetLabel: domain hash size = 128 1 Time(s): NetLabel: protocols = UNLABELED CIPSOv4 1 Time(s): NetLabel: unlabeled traffic allowed by default 1 Time(s): NetLabel: Initializing 2 Time(s): No AGP bridge found 1 Time(s): No NUMA configuration found 1 Time(s): No local APIC present 1 Time(s): Non-volatile memory driver v1.3 1 Time(s): PCI: Fatal: No config space access function found 2 Time(s): PCI: System does not support PCI 1 Time(s): PERCPU: Embedded 29 pages/cpu @ffff880001abc000 s90112 r8192 d20480 u118784 1 Time(s): PID hash table entries: 1024 (order: 1, 8192 bytes) 1 Time(s): PM: Registered nosave memory: 00000000000a0000 - 0000000000100000 1 Time(s): PNP: No PS/2 controller found. Probing ports directly. 1 Time(s): Performance Events: unsupported p6 CPU model 23 no PMU driver, software events only. 1 Time(s): Policy zone: DMA32 1 Time(s): SCSI subsystem initialized 1 Time(s): SELinux: Disabled at boot. 1 Time(s): SFI: Simple Firmware Interface v0.81 http://simplefirmware.org 1 Time(s): SLUB: Genslabs=14, HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1 1 Time(s): SMP alternatives: switching to UP code 1 Time(s): SMP: Allowing 1 CPUs, 0 hotplug CPUs 1 Time(s): Security Framework initialized 1 Time(s): Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled 1 Time(s): Subtract (36 early reservations) 1 Time(s): Switching to clocksource xen 1 Time(s): TCP bind hash table entries: 8192 (order: 5, 131072 bytes) 1 Time(s): TCP cubic registered 1 Time(s): TCP established hash table entries: 8192 (order: 5, 131072 bytes) 1 Time(s): TCP reno registered 1 Time(s): TCP: Hash tables configured (established 8192 bind 8192) 1 Time(s): Time: 165:165:165 Date: 165/165/65 1 Time(s): UDP hash table entries: 128 (order: 0, 4096 bytes) 1 Time(s): UDP-Lite hash table entries: 128 (order: 0, 4096 bytes) 1 Time(s): VFS: Disk quotas dquot_6.5.2 1 Time(s): VFS: Mounted root (ext3 filesystem) readonly on device 202:1. 1 Time(s): XENBUS: Device with no driver: device/console/0 1 Time(s): Xen version: 3.3.0 (preserve-AD) 1 Time(s): Xen: using vcpu_info placement 1 Time(s): Zone PFN ranges: 1 Time(s): acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5 1 Time(s): alg: No test for stdrng (krng) 1 Time(s): allocated 2621440 bytes of page_cgroup 1 Time(s): audit: initializing netlink socket (disabled) 1 Time(s): bio: create slab <bio-0> at 0 1 Time(s): blkfront: xvda1: barriers enabled 1 Time(s): blkfront: xvda2: barriers enabled 1 Time(s): brd: module loaded 1 Time(s): console [hvc0] enabled 1 Time(s): console [tty0] enabled 1 Time(s): cpuidle: using governor ladder 1 Time(s): cpuidle: using governor menu 1 Time(s): device-mapper: ioctl: 4.17.0-ioctl (2010-03-05) initialised: dm-devel@redhat.com 1 Time(s): device-mapper: multipath: version 1.1.1 loaded 1 Time(s): device-mapper: uevent: version 1.0.3 1 Time(s): devtmpfs: initialized 1 Time(s): devtmpfs: mounted 1 Time(s): drivers/rtc/hctosys.c: unable to open rtc device (rtc0) 1 Time(s): early_node_map[2] active PFN ranges 1 Time(s): ftrace: allocating 19525 entries in 77 pages 1 Time(s): ftrace: converting mcount calls to 0f 1f 44 00 00 1 Time(s): i8042.c: No controller found. 1 Time(s): init_memory_mapping: 0000000000000000-0000000010000000 1 Time(s): input: PC Speaker as /devices/platform/pcspkr/input/input0 1 Time(s): installing Xen timer for CPU 0 1 Time(s): io scheduler cfq registered (default) 1 Time(s): io scheduler deadline registered 1 Time(s): io scheduler noop registered 1 Time(s): ip_tables: (C) 2000-2006 Netfilter Core Team 1 Time(s): kjournald starting. Commit interval 5 seconds 1 Time(s): klogd 1.4.1, log source = /proc/kmsg started. 1 Time(s): last_pfn = 0x10000 max_arch_pfn = 0x400000000 1 Time(s): lo: Disabled Privacy Extensions 2 Time(s): md: ... autorun DONE. 2 Time(s): md: Autodetecting RAID arrays. 1 Time(s): md: If you don't use raid, use raid=noautodetect 2 Time(s): md: Scanned 0 and added 0 devices. 1 Time(s): md: Waiting for all devices to be available before autodetect 2 Time(s): md: autorun ... 1 Time(s): mice: PS/2 mouse device common for all mice 1 Time(s): msgmni has been set to 481 1 Time(s): nf_conntrack version 0.5.0 (1926 buckets, 7704 max) 1 Time(s): nf_conntrack.acct=1 kernel parameter, acct=1 nf_conntrack module option or 1 Time(s): pci-stub: invalid id string "" 1 Time(s): pci_hotplug: PCI Hot Plug PCI Core version: 0.5 1 Time(s): pciehp: PCI Express Hot Plug Controller Driver version: 0.4 1 Time(s): pcpu-alloc: [0] 0 1 Time(s): pcpu-alloc: s90112 r8192 d20480 u118784 alloc=29*4096 1 Time(s): pid_max: default: 32768 minimum: 301 1 Time(s): platform rtc_cmos: registered platform RTC device (no PNP device found) 1 Time(s): please try 'cgroup_disable=memory' option if you don't want memory cgroups 1 Time(s): pnp: PnP ACPI: disabled 1 Time(s): registered taskstats version 1 1 Time(s): regulator: core version 0.5 1 Time(s): setup_percpu: NR_CPUS:256 nr_cpumask_bits:256 nr_cpu_ids:1 nr_node_ids:1 1 Time(s): sysctl net.netfilter.nf_conntrack_acct=1 to enable it. 1 Time(s): type=2000 audit(1313617098.849:1): initialized 1 Time(s): vgaarb: loaded 1 Time(s): warning: `dbus-daemon' uses 32-bit capabilities (legacy support in use) 1 Time(s): warning: process `kudzu' used the deprecated sysctl system call with 1.23. 1 Time(s): xen_balloon: Initialising balloon driver.