RedHat: VFS: Cannot open root device - Help

This is a discussion on RedHat: VFS: Cannot open root device - Help ; I have RedHat 9, kernel 2.4.20-31.9. I have rebuild the kernel to increase the VMALLOC_RESERVE to 256MB. Here are the steps I have followed: make mrproper cp config-2.4.20-31.1 /usr/src/linux/.config make oldconfig make dep make bzImage make modules make modules_install make ...

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Thread: RedHat: VFS: Cannot open root device

  1. RedHat: VFS: Cannot open root device

    I have RedHat 9, kernel 2.4.20-31.9.
    I have rebuild the kernel to increase the VMALLOC_RESERVE to 256MB. Here are
    the steps I have followed:

    make mrproper
    cp config-2.4.20-31.1 /usr/src/linux/.config
    make oldconfig
    make dep
    make bzImage
    make modules
    make modules_install
    make install

    Now I have a new kernel 2.4.20-31.9custom. When I boot this kernel I get the
    following error:

    VFS: Cannot open root device "LABEL=/" or 00:00
    Please append a correct "root=" boot option
    Kernel panic: VFS: Unable to mount root fs on 00:00

    I use grub as bootloader. Here is my grub.conf file:

    # grub.conf generated by anaconda
    #
    # Note that you do not have to rerun grub after making changes to this file
    # NOTICE: You have a /boot partition. This means that
    # all kernel and initrd paths are relative to /boot/, eg.
    # root (hd0,0)
    # kernel /vmlinuz-version ro root=/dev/hda3
    # initrd /initrd-version.img
    #boot=/dev/hda
    default=0
    timeout=10
    splashimage=(hd0,0)/grub/splash.xpm.gz
    title Red Hat Linux (2.4.20-31.9custom)
    root (hd0,0)
    kernel /vmlinuz-2.4.20-31.9custom ro root=LABEL=/ hdd=ide-scsi
    initrd /initrd-2.4.20-31.9custom.img
    title Red Hat Linux (2.4.20-31.9)
    root (hd0,0)
    kernel /vmlinuz-2.4.20-31.9 ro root=LABEL=/ hdd=ide-scsi
    initrd /initrd-2.4.20-31.9.img


    If I change the following line like this (replace root=LABEL=/ with
    root=/dev/hdc3):
    kernel /vmlinuz-2.4.20-31.9custom ro root=/dev/hdc3 hdd=ide-scsi

    It works!
    Why the boot option "root=LABEL=/" works for my kernel 2.4.20-31.9 and not
    for my kernel 2.4.20-31.9custom?

    Thank you.




  2. Re: RedHat: VFS: Cannot open root device

    Presuming you know how to edit at grub prompt
    I would suggest you do the following
    Instead of
    kernel /vmlinuz-2.4.20-31.9custom ro root=LABEL=/ hdd=ide-scsi
    specify
    kernel /vmlinuz-2.4.20-31.9custom
    Good luck! This shud work
    Somu
    ************************************************** ***********************
    "I've never understood how God could expect his creatures
    to pick the one true religion by faith - it strikes me as a
    sloppy way to run a universe."
    Robert A. Heinlein
    STRANGER IN A STRANGE LAND
    ************************************************** ***********************

    On Mon, 17 Oct 2005, CÚdric Pillonel wrote:

    > I have RedHat 9, kernel 2.4.20-31.9.
    > I have rebuild the kernel to increase the VMALLOC_RESERVE to 256MB. Here are
    > the steps I have followed:
    >
    > make mrproper
    > cp config-2.4.20-31.1 /usr/src/linux/.config
    > make oldconfig
    > make dep
    > make bzImage
    > make modules
    > make modules_install
    > make install
    >
    > Now I have a new kernel 2.4.20-31.9custom. When I boot this kernel I get the
    > following error:
    >
    > VFS: Cannot open root device "LABEL=/" or 00:00
    > Please append a correct "root=" boot option
    > Kernel panic: VFS: Unable to mount root fs on 00:00
    >
    > I use grub as bootloader. Here is my grub.conf file:
    >
    > # grub.conf generated by anaconda
    > #
    > # Note that you do not have to rerun grub after making changes to this file
    > # NOTICE: You have a /boot partition. This means that
    > # all kernel and initrd paths are relative to /boot/, eg.
    > # root (hd0,0)
    > # kernel /vmlinuz-version ro root=/dev/hda3
    > # initrd /initrd-version.img
    > #boot=/dev/hda
    > default=0
    > timeout=10
    > splashimage=(hd0,0)/grub/splash.xpm.gz
    > title Red Hat Linux (2.4.20-31.9custom)
    > root (hd0,0)
    > kernel /vmlinuz-2.4.20-31.9custom ro root=LABEL=/ hdd=ide-scsi
    > initrd /initrd-2.4.20-31.9custom.img
    > title Red Hat Linux (2.4.20-31.9)
    > root (hd0,0)
    > kernel /vmlinuz-2.4.20-31.9 ro root=LABEL=/ hdd=ide-scsi
    > initrd /initrd-2.4.20-31.9.img
    >
    >
    > If I change the following line like this (replace root=LABEL=/ with
    > root=/dev/hdc3):
    > kernel /vmlinuz-2.4.20-31.9custom ro root=/dev/hdc3 hdd=ide-scsi
    >
    > It works!
    > Why the boot option "root=LABEL=/" works for my kernel 2.4.20-31.9 and not
    > for my kernel 2.4.20-31.9custom?
    >
    > Thank you.
    >
    >
    >
    >


  3. Re: RedHat: VFS: Cannot open root device

    I know that replacing LABEL with /dev/hdc3 works.
    My question is why do I need to replace "root=LABEL=/" with
    "root=/dev/hdc3"?

    The option "root=LABEL=/" works with my old kernel but not with the new one.


    wrote in message
    news:1129695884.573279.191610@g47g2000cwa.googlegr oups.com...
    CÚdric Pillonel wrote:

    > I have RedHat 9, kernel 2.4.20-31.9.
    > I have rebuild the kernel to increase the VMALLOC_RESERVE to 256MB. Here

    are
    > the steps I have followed:
    >
    > make mrproper
    > cp config-2.4.20-31.1 /usr/src/linux/.config
    > make oldconfig
    > make dep
    > make bzImage
    > make modules
    > make modules_install
    > make install
    >
    > Now I have a new kernel 2.4.20-31.9custom. When I boot this kernel I get

    the
    > following error:
    >
    > VFS: Cannot open root device "LABEL=/" or 00:00
    > Please append a correct "root=" boot option
    > Kernel panic: VFS: Unable to mount root fs on 00:00


    Copy paste this error in google and you will get all possible solutions
    even for the problems that you wouldn't have faced!! ;-)
    I think replacing the LABEL with the image name.I think it should work!

    Sagar



  4. Re: RedHat: VFS: Cannot open root device

    > I know that replacing LABEL with /dev/hdc3 works.
    > My question is why do I need to replace "root=LABEL=/" with
    > "root=/dev/hdc3"?
    > The option "root=LABEL=/" works with my old kernel but not with the new one.


    You are likely missing a module in the initrd or you didn't create one.
    Referring to the partition by its /dev name avoids the offending
    module.

  5. Re: RedHat: VFS: Cannot open root device

    CÚdric Pillonel wrote:
    > I know that replacing LABEL with /dev/hdc3 works.
    > My question is why do I need to replace "root=LABEL=/" with
    > "root=/dev/hdc3"?
    >
    > The option "root=LABEL=/" works with my old kernel but not with thenew one.


    Maybe this excerpt from Documentation/filesystems/devfs/README will help:

    In general, a kernel built with CONFIG_DEVFS_FS=y but without mounting
    devfs onto /dev is completely safe, and requires no
    configuration changes. One exception to take note of is when
    LABEL= directives are used in /etc/fstab. In this
    case you will be unable to boot properly. This is because the
    mount(8) programme uses /proc/partitions as part of
    the volume label search process, and the device names it finds are not
    available, because setting CONFIG_DEVFS_FS=y changes the names in
    /proc/partitions, irrespective of whether devfs is mounted.

    There's another section there that describes what happens and how to
    resolve.

    Josef
    --
    Josef M÷llers (Pinguinpfleger bei FSC)
    If failure had no penalty success would not be a prize
    -- T. Pratchett


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