[Bug 930447] Re: Unable to start Ubuntu 12.04 live CD with syslinux loader on Pentium M x86 Laptop due to bug in PAE kernel, initramfs or syslinux

[sudodus]

On 2013-11-24 11:13, roland aus köln wrote:
> i did a comparison of the installer`s kernel .config with the kernel
> .config of my working system - and they appear nearly identical:
> 
> 3c3
> < # Linux/i386 3.11.0-12-generic Kernel Configuration
> ---
>> # Linux/i386 3.11.0-13-generic Kernel Configuration
> 68c68
> < CONFIG_VERSION_SIGNATURE="Ubuntu 3.11.0-12.19-generic 3.11.3"
> ---
>> CONFIG_VERSION_SIGNATURE="Ubuntu 3.11.0-13.20-generic 3.11.6"
> 5435c5435
> < CONFIG_USB_OTG=y
> ---
>> # CONFIG_USB_OTG is not set
> 5703d5702
> < CONFIG_USB_ZERO_HNPTEST=y
> 6717a6717
>> CONFIG_DM_RAID45=m
> 
> so i would confirm the suspicion that the problem must be related to the
> bootloader somehow.
> 
> but the question is if syslinux makes the kernel fail boot or if grub
> has something "inside" which avoids the kernel fail to boot.
> 
> if PAE cpu flag is not available in some processor`s CPUID, i wonder why
> the kernel can boot. does linux kernel not check for cpu flags and does
> it detect pae capability differently (i.e. more reliable?)
> 
The flag is only an indicator, that is used by other programs to decide
what to do. Most Celeron M and Pentium M computers have PAE capability,
at least they can manage to run PAE kernels without problems. But there
is no PAE flag.

There are at least two checks,

- in syslinux that prevents installation if there is no PAE flag

- in the system for upgrading, that prevents upgrading to a new kernel.
I guess more precisely it prevents upgrading to a PAE kernel, if there
is no PAE flag.

But there is no check in grub, so that way we can boot the kernel.

-o-

If you have the time and insight to fix these issues, we are many people
who would be happy :-)

Best regards
Nio

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https://bugs.launchpad.net/bugs/930447

Title:
  Unable to start Ubuntu 12.04 live CD with syslinux loader on Pentium M
  x86 Laptop due to bug in PAE kernel, initramfs or syslinux

Status in “syslinux” package in Ubuntu:
  Confirmed
Status in Baltix GNU/Linux:
  Triaged

Bug description:
  Ubuntu 12.04 doesn't start from Desktop CD or USB with syslinux boot
  loader on Pentium M 1.6Ghz or faster Pentium M CPU - displays error
  message about missing PAE feature in CPU, but *the same* *Ubuntu
  12.04* Desktop CD/LiveUSB starts fine on *the same CPU* (and same PAE
  kernel) if GRUB boot loader is used, for example when WUBI or LiveUSB
  with GRUB boot loader, like Multisystem
  (http://liveusb.info/dotclear/index.php?pages/install ) is used!

  The error message is:
  "This kernel requires the following features not present on the CPU: pae.
  Unable to boot - please use a kernel appropriate for you CPU."

  THIS IS AN IMPORTANT REGRESSION! People are able to install and successfully use Ubuntu 12.04 on such pretty new hardware, like IBM Thinkpad T42 laptop with Pentium M 1700Mhz processor, but the bug in syslinux (or something related) forbids Ubuntu 12.04 installation.
  This bug is reproducible on lots of computers, there are several log files and /proc/cpuinfo file attached to this bugreport, AFAIK it's enough to reopen this bug.

  ---
  ApportVersion: 1.23-0ubuntu4
  Architecture: i386
  CurrentDmesg: Error: command ['sh', '-c', 'dmesg | comm -13 --nocheck-order /var/log/dmesg -'] failed with exit code 1: comm: /var/log/dmesg: Permission denied
  MachineType: IBM 2373PPU
  dmi.bios.date: 06/18/2007
  dmi.bios.vendor: IBM
  dmi.bios.version: 1RETDRWW (3.23 )
  dmi.board.name: 2373PPU
  dmi.board.vendor: IBM
  dmi.board.version: Not Available
  dmi.chassis.asset.tag: No Asset Information
  dmi.chassis.type: 10
  dmi.chassis.vendor: IBM
  dmi.chassis.version: Not Available
  dmi.modalias: dmi:bvnIBM:bvr1RETDRWW(3.23):bd06/18/2007:svnIBM:pn2373PPU:pvrThinkPadT42:rvnIBM:rn2373PPU:rvrNotAvailable:cvnIBM:ct10:cvrNotAvailable:
  dmi.product.name: 2373PPU
  dmi.product.version: ThinkPad T42
  dmi.sys.vendor: IBM

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