Guest VM kernel panic with VIRTIO_BLK with KVM

Discussion in 'General Server' started by saurabh agarwal, Apr 1, 2014.

  1. saurabh agarwal

    saurabh agarwal New Member

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    We have compiled a new linux kernel for a guest VM with CONFIG_VIRTIO_BLK=y. But it doesn't boot and kernel panics. To kernel command line I tried passing root=/dev/vda and root=/dev/vda1 but same kernel panic comes every time. VIRTIO_NET worked fine.
    But with VIRTIO_BLK we see the below kernel panic. Can someone suggest what could be going wrong?

    Kernel command line is
    kernel /boot/bzImage root=/dev/vda1 early_printk=serial console=hvc0 console=tty0 console=ttyS0,115200n8 divider=10 e1000.disable_vlan_offload=1 initrd /boot/initramfs.cpio

    Below is a portion of GuestVM Kernel Console logs while booting up
    brd: module loaded^M
    vda: vda1 vda2 vda3 vda4^M
    scsi0 : ata_piix^M
    scsi1 : ata_piix^M
    ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc180 irq 14^M
    ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc188 irq 15^M
    ................
    ...................
    ...............


    VFS: Cannot open root device "vda" or unknown-block(253,0)^M
    Please append a correct "root=" boot option; here are the available partitions:^M
    fd00 8388608 vda driver: virtio_blk^M
    fd01 7340032 vda1 00000000-0000-0000-0000-000000000000^M
    fd02 512000 vda2 00000000-0000-0000-0000-000000000000^M
    fd03 535552 vda3 00000000-0000-0000-0000-000000000000^M
    Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(253,0)^M

    Can someone suggest what could be wrong?

    Regards,
    Saurabh
  2. Niemi

    Niemi New Member

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    Hi, what kernel version fo you use on VM and why "divider=10" in use? What version of KVM?
  3. saurabh agarwal

    saurabh agarwal New Member

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    You can ignore divider=10. It is a custom parameter for me. Kernel version in VM is 3.0.76

    kvm --version gives me this output
    "QEMU emulator version 1.3.0, Copyright (c) 2003-2008 Fabrice Bellard"
  4. ryanvade

    ryanvade Administrator Staff Member Staff Writer

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    Have you double checked the initrd and the file systems?
  5. saurabh agarwal

    saurabh agarwal New Member

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    Can you please tell what do you mean by "double checked the initrd and the file systems"? The initrd and the filesystems are the same as when i was using ide and not vitrio_blk. This time I have compiled VIRTIO_BLK into the kernel.
  6. ryanvade

    ryanvade Administrator Staff Member Staff Writer

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    Did you rebuild the initrd file for the new kernel? I think the image file is the issue.

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