[syslinux] Linux boot hangs after/during read of initrd.img

[Thomas Schmitt]

Hi,

Didier Spaier wrote:
> I am CCing Thomas Schmitt, xorriso mantainer who could shed more light.

I saw Paul Smith's report already, but did not feel in charge because
he reports to see messages from fully running SYSLINUX.

Paul Smith wrote:
> > ‘Loading vmlinux…ok’ and ‘loading initrd.img…ok’

Problems specific to ISO 9660 boot entries should rather appear earlier.
(E.g. we had the failure of isohybrid MBR on C/H/S addressing BIOS to
 properly start the isolinux.bin program. That's about the limit how far
 i can reach with my experience.)


>   *   SYS/ISOLINUX seems to crash/hang in an fread() of the initrd.img file;

But why then does it say ‘loading initrd.img…ok’ ?

With that "ok", i did put the blame on the booted Linux or on the way how
SYSLINUX tries to start it.


It would be helpful for me to have the exact URL of the affected ISO.


Didier Spaier wrote:
> xorriso -as mkisofs \
> ...

Repacking a CentOS ISO should be doable by xorriso.
My youngest image is from august 2015.
It is prepared for BIOS and EFI from CD-ROM.
But for booting from USB stick it only is prepared for BIOS.

  $ xorriso -indev CentOS-6.7-x86_64-minimal.iso -report_el_torito plain -report_system_area plain
  ...
  El Torito images   :   N  Pltf  B   Emul  Ld_seg  Hdpt  Ldsiz         LBA
  El Torito boot img :   1  BIOS  y   none  0x0000  0x00      4          82
  El Torito boot img :   2  UEFI  y   none  0x0000  0x00    744          94
  El Torito img path :   1  /isolinux/isolinux.bin
  El Torito img opts :   1  boot-info-table isohybrid-suitable
  El Torito img path :   2  /images/efiboot.img
  ...
  MBR partition table:   N Status  Type        Start       Blocks
  MBR partition      :   1   0x80  0x17            0       808960

No MBR partition of type 0xef, no GPT which would point to file
/images/efiboot.img.

To add an EFI System Partition of type 0xef to the MBR you may run

  isohybrid --uefi CentOS-6.7-x86_64-minimal.iso


Maybe you did already that and it was the trigger to get further with
booting.
But if in this case really the EFI System Partition was used, then you'd
have ended up in GRUB-Legacy:

  # mount CentOS-6.7-x86_64-minimal.iso /mnt/iso
  # mount /mnt/iso/images/efiboot.img /mnt/fat
  # strings /mnt/fat/EFI/BOOT/BOOTX64.efi | grep '^GNU GRUB'
  GNU GRUB 0.97

The situation stays riddling.


Have a nice day :)

Thomas