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Hi there! I was just wondering if any of you might suggest a solution to a little linux problem I have? You see, I recently decided to compile a later ...
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  1. #1
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    Linux compiling woes


    Hi there!
    I was just wondering if any of you might suggest a solution to a little linux problem I have? You see, I recently decided to compile a later version of the kernel, with added grsecurity patch. However, when I re-booted, horror of horrors, the kernel panicked with:
    Code:
    VFS: Cannot open root device "304" or unknow-block(3,4)
    Please append a correct "root=" boot option; here are the availab
    le partitions:
    Kernel panic - not syncing: VFS: Unable to mount root fs on unkno
    wn-block(3,4)


    However, not to be dettered, I (after a little google searching) loaded up knoppix and made an initrd, only to find next time I tried to boot:
    Code:
    Decompressing Linux... Parsing ELF... done.
    Booting the kernel.

    ...
    Code:
    BUG: Int 14: CR2 ffffb0f0

    With a dump of registers and stack to follow.

    So, now I'm completely out of ideas on what to try next! Any suggestion? And, more importantly what did I do wrong? (it wasn't an important computer)

    Thanks in advance!
    OScoder

    P.S Sorry if this is in the wrong section of the forum

  2. #2
    Linux Engineer Segfault's Avatar
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    So, now I'm completely out of ideas on what to try next! Any suggestion? And, more importantly what did I do wrong?
    You did not include support for your root filesystem. You probably had it as module, but to load modules kernel has to read the root filesystem.
    I'd try again and spend a little more time with make menuconfig. Initrd should not be used with custom kernel, it is meant for generic we-support-everything setups.

  3. #3
    Linux User vickey_20's Avatar
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    boot into the system with a live cd and post the o/p of grub.conf here.
    Only if I could understand the man pages
    Registered Linux user #492640
    OS: RHEL4,5 ,RH 9,Ubuntu

  4. #4
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    You did not include support for your root filesystem. You probably had it as module, but to load modules kernel has to read the root filesystem.
    I'd try again and spend a little more time with make menuconfig. Initrd should not be used with custom kernel, it is meant for generic we-support-everything setups.
    Thanks - I did that, but to no avail! All filesystem drivers are *not* modules, and I re-built with all the ones I could need selected. I still get the 'cannot open root device' thing though, seemingly even when I boot the old kernel!

    boot into the system with a live cd and post the o/p of grub.conf here
    I'm using lilo, so here's my lilo.conf:
    Code:
    # LILO configuration file
    # generated by 'liloconfig'
    #
    # Start LILO global section
    # Append any additional kernel parameters:
    append=" vt.default_utf8=0"
    boot = /dev/hda
    default = test-4
    
    # Boot BMP Image.
    # Bitmap in BMP format: 640x480x8
      bitmap = /boot/slack.bmp
    # Menu colors (foreground, background, shadow, highlighted
    # foreground, highlighted background, highlighted shadow):
      bmp-colors = 255,0,255,0,255,0
    # Location of the option table: location x, location y, number of
    # columns, lines per column (max 15), "spill" (this is how many
    # entries must be in the first column before the next begins to
    # be used.  We don't specify it here, as there's just one column.
      bmp-table = 60,6,1,16
    # Timer location x, timer location y, foreground color,
    # background color, shadow color.
      bmp-timer = 65,27,0,255
    
    # Standard menu.
    # Or, you can comment out the bitmap menu above and 
    # use a boot message with the standard menu:
    #message = /boot/boot_message.txt
    
    # Wait until the timeout to boot (if commented out, boot the
    # first entry immediately):
    prompt
    # Timeout before the first entry boots.
    # This is given in tenths of a second, so 600 for every minute:
    timeout = 300
    # Override dangerous defaults that rewrite the partition table:
    change-rules
      reset
    # Normal VGA console
    vga = normal
    # VESA framebuffer console @ 1024x768x64k
    # vga=791
    # VESA framebuffer console @ 1024x768x32k
    # vga=790
    # VESA framebuffer console @ 1024x768x256
    # vga=773
    # VESA framebuffer console @ 800x600x64k
    # vga=788
    # VESA framebuffer console @ 800x600x32k
    # vga=787
    # VESA framebuffer console @ 800x600x256
    # vga=771
    # VESA framebuffer console @ 640x480x64k
    # vga=785
    # VESA framebuffer console @ 640x480x32k
    # vga=784
    # VESA framebuffer console @ 640x480x256
    # vga=769
    # End LILO global section
    # Linux bootable partition config begins
    image=/boot/bzImage-3
      root=/dev/hda4
      label=test-3
      read-only
    
    image=/boot/bzImage-4
      root=/dev/hda4
      label=test-4
      read-only
    
    # Linux bootable partition config ends
    # Windows bootable partition config begins
    other = /dev/hda1
      label = Windows
      table = /dev/hda
    # Windows bootable partition config ends
    Thanks for your help so far,
    OScoder

  5. #5
    Linux User vickey_20's Avatar
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    I dont see an initrd entry in your lilo.conf file?
    Only if I could understand the man pages
    Registered Linux user #492640
    OS: RHEL4,5 ,RH 9,Ubuntu

  6. #6
    Linux Engineer Segfault's Avatar
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    VFS: Cannot open root device "304" or unknow-block(3,4)
    Do you still get exactly this error or it's different now? You may have missed HDD controller support this time.

  7. #7
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    Do you still get exactly this error or it's different now? You may have missed HDD controller support this time.
    Ah - that'd be it! I've gone through the menuconfig a fourth time, and yep - another driver I needed was unticked! System now boots fine.

    Thanks alot!
    OScoder

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