Re: Kernel panics (in QEMU) when booting with GRUB2 + OVMF + QEMU.

[Andrei Borzenkov]

On 14.08.2015 09:45, Mark Lee wrote:
> To all,
>
> I've encountered a bug when using GRUB2 + OVMF + QEMU on Arch Linux 64 bit.
> The issue can be reproduced when running the latest git code from grub as
> well.
>
> ISSUE: Kernel panics (in QEMU) when booting with GRUB2 + OVMF + QEMU.

Once kernel is loaded, GRUB task is over. Why do you think it is GRUB issue?

> ------
>      When booting using OVMF (ovmf_x64.bin) + QEMU, GRUB2 manages to load but
> kernel panics when loading its menu entry. This issue is not observed in
> hardware or via bios boot.
>
> DOWNLOADS: test.img
> ----------
>      To speed up testing, one can skip reproducing test.img and grab a copy at
> <https://drive.google.com/file/d/0Bx2cO4TT8XjeSEt2aEVkNEVsZUk/view?usp=sharing>
>
> REPRODUCE test.img:
> -------------------
> # fallocate -l 3G test.img
> # gdisk test.img <<<(
> o
> y
> n
> 1
>
> +1M
> ef02
>
> n
> 2
>
> +100M
> ef00
>
> n
> 3
>
>
>
>
> w
> y
> )
> # kpartx -l test.img      /* Get the name of loop device <loop> */
> # kpartx -a test.img
> # mkfs.fat /dev/mapper/<loop>p2
> # mkfs.ext4 /dev/mapper/<loop>p3
> # mount /dev/mapper/<loop>p3 /mnt
> # mkdir /mnt/boot
> # mount /dev/mapper/<loop>p2 /mnt/boot
>
> /* This part is Arch Linux specific */
> # pacstrap /mnt base grub
> /* End Arch Linux specific */
>
> # grub-install --target=i386-pc --boot-directory=/mnt/boot /dev/<loop>
> # grub-install --target=x86_64-efi --efi-directory=/mnt/boot --boot-
> directory=/mnt/boot --removable
> # echo "
> insmod all_video
> menuentry "Arch Linux" {
>    linux /vmlinuz-linux rw root=/dev/sda3
>    initrd /initramfs-linux-fallback.img
> }
> " > /mnt/boot/grub/grub.cfg
> # umount -R /mnt
> # kpartx -d test.img
>
> REPRODUCE QEMU ERROR:
> ---------------------
> /* Bios works */
> # qemu-system-x86_64 -enable-kvm -cpu host test.img
>
> /* UEFI doesn't */
> # qemu-system-x86_64 -enable-kvm -cpu host -bios /usr/share/ovmf/ovmf_x64.bin
> test.img
>
> /* I get the following error */
> Kernel panic - not syncing : VFS: Unable to mount root fs on Unknown-
> block(0,0)
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.1.4-1-ARCH #1
> Hardware name : QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> 0000000000000000 000000007fac344c ffff880006527db8 ffffffff815865be
> 0000000000000000 ffffffff816f61b0 ffff880006527e38 ffffffff81585453
> ffff880000000010 ffff880006527e48 ffff880006527de8 000000007fac344c
> Call Trace:
> [<ffffffff815865be>] dump_stack+0x4c/0x6e
> [<ffffffff81585453>] panic+0xd0/0x203
> [<ffffffff818fa621>] mount_block_root+0x297/0x2a6
> [<ffffffff818fa684>] mount_root+0x54/0x58
> [<ffffffff818fa7c0>] prepare_namespace+0x138/0x171
> [<ffffffff818fa22e>] kernel_init_freeable+0x1ec/0x215
> [<ffffffff8157cbb0>] ? rest_init+0x90/0x90
> [<ffffffff8157cbbe>] kernel_init+0xe/0xf0
> [<ffffffff8157c2a2>] ret_fromt_fork+0x42/0x70
> [<ffffffff8157cbb0>] ? rest_init+0x90/0x90
> Kernel Offset: disabled
> ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-
> block(0,0)
>
>
>
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