[yocto] Can't boot to initramfs

Thu Jul 11 00:24:06 PDT 2019

Hello Moritz,

I need here some help from you. I'll try to reconstruct the parts of
the local.conf you are using, so I (and Jupiter) can understand what
should we do to also bundle kernel image with initramfs, to end up in
Dracut/rescue shell.

Here is what I anticipate after reading several YOCTO @ threads:

IMAGE_FSTYPES_append = " cpio.gz"
INITRAMFS_IMAGE = "core-image-minimal-initramfs"
INITRAMFS_IMAGE_BUNDLE = "1"
# debug: adds debug boot parameters like 'shell' and 'debug', see
# meta/recipes-core/initrdscripts/initramfs-framework/debug for details
# Could be removed in more minimal product image
PACKAGE_INSTALL += "initramfs-module-debug"

Could you, please, review these lines and fix, if something is not correct?

I what I understood, this does the magic, but you could not stop in
initramfs shell? Still, this problem is not solved?

> I was following this site: https://wiki.debian.org/InitramfsDebug
> Rescue shell (also known as initramfs shell)
> Read man initramfs-tools to learn about the break=something kernel
> parameter (where valid arguments for something are: top, modules,
> premount, mount, mountroot, bottom, init), which starts a debug shell.
> You can try, for example, break=premount. You can edit /boot/grub/grub.cfg
> to add this to the end of the kernel line, or you can do it interactively
> from the grub boot menu: "e" to edit, and "b" to boot once you've edited
> the kernel line.

Now, as my understanding is, you solved this problem actually adding
to grub.cfg in command kernel line break=premount, and was able to
stop in rescue shell?! Am I correct here?

Thank you,
Zoran
_______

On Mon, Jul 1, 2019 at 4:33 PM Moritz Porst <moritz.porst at gmx.de> wrote:
>
> Hello,
> I think I found the issue. ( see below )
>
> On 01.07.19 15:57, Zoran Stojsavljevic wrote:
>
> Hello Moritz,
>
> Too hot here, in Belgrade... Where I am resting for the Time being
> (actually, this message given to my invisible spying security "angels"
> on this list)...  :-) Projected +38C degrees today. Too hot for this
> too old Siberian untouchable bobcat!
>
> Luckily it's a rather cold day in germany, thanks that you still take the time to answer !
>
> I started from the core-image-minimal to have a small image and
> extended it with the features I need, which is e.g. a graphical system.
> The console=[...] part in the kernel command line is probably a
> remnant but my image boots into the GUI. Is this a problem ?
>
> Nope, it is not. If you need to do it correctly, you should use
> bitbake -k core-image-sato build command (my best educated guess).
> Then, I do not feel comfortable seeing in your kernel command line
> serial interface, do you agree?
>
> Yes that is true.
>
> YOCTO maintainers, any additional
> advices?
>
> My bootloader is currently grub, the EFI is AM.
>
> Nope. Eeeeeeeeek. Wrong. Currently, your boot-loader is UEFI AMI. Your
> OS (Linux probably, U name it) boot-loader is GRUB2. Let us keep it
> contained, sane and sober.
>
> Sorry but I can't find this info in the EFI.
>
> Could you, please try the following command being root: dmesg | grep
> MCU. or grep mcu, or grep CPUID or grep cpuid?? Please, post results
> to this list (to me).
>
> No luck unfortunately (used grep -i)
>
> Could you, also, send to YOCTO list/me attached file:
> /boot/microcode.cpio so I can somehow (?) inspect it? ;-)
>
> I send it to you directly, so I don't spam the list with a large attachment.
>
> 2GB, single channel.
>
> All Cool. E3825 by HW/silicon design could/does NOT support multiple
> memory channels. ONLY single... But even YOCTO primes (INTEL ones from
> this list) are not gonna tell this to you. Not 'cause they are nasty.
> They are NOT aware/they are ignorant (with the purpose)! ;-))
>
> No, the boot does not stop. Even if I do issue "break=premount" I
> end up in my graphical interface with the rootfs mounted. This is the
> last message in the log: EXT4-fs (sdb2): re-mounted. Opts: (null)
> The rootfs partition is always 2, so either /dev/sda2 or /dev/sdb2
> (when booting from stick)
>
> Yes, from https://pastebin.com/ya7iCtq7, so it is remounted rw, not
> read only. So, it seems that you have passed dracut phase. and mounted
> SD or flash rootfs. So, initramfs is NOT your true problem, is it???
>
> The thing is that the boot works but I want an initramfs that can be used for updating (in case the rootfs is broken). However I need to be able to intercept the boot process there because otherwise I can't deploy an update mechanism, that's what I was trying.
>
> Zoran
> _______
>
>
> No, the boot does not stop. Even if I do issue "break=premount" I end up
> in my graphical interface with the rootfs mounted. This is  the last message
> in the log: EXT4-fs (sdb2): re-mounted. Opts: (null) The rootfs partition is
> always 2, so either /dev/sda2 or /dev/sdb2 (when booting from stick)
>
>
> So for the issue...
> I expected yocto to put the bundled bzImage onto my rootfs. This was not the case. My image directory contains 2x bzImage, one bundled and one unbundled. Apparently yocto puts the >un<bundled image onto my /boot partition and uses it for boot. So of course I couldn't access initramfs in this case. Now I get to the initramfs statement "dropping to shell" if I intentionally boot with wrong rootfs.
> Still I don't get the interactive shell.
> On the github ostroproject site I found this:
>
> # debug: adds debug boot parameters like 'shell' and 'debug', see
> #        meta/recipes-core/initrdscripts/initramfs-framework/debug for details
> # Could be removed in more minimal product image.
> PACKAGE_INSTALL += "initramfs-module-debug"
>
> including the module-debug still does not enable me to get an interactive shell.
> I was following this site: https://wiki.debian.org/InitramfsDebug
> I am aware that yocto is no debian but I expected that kernel parameters (like 'break') would be independent of the distribution.
>
> Lastly I do not really need the interactive shell, it is enough if I can deploy a custom init script in the initramfs. Still I think that getting an initramfs shell should be as simple as stating the name of the initramfs image and setting the "INITRAMFS_DO_BUNDLE" variable.
>
> Best regards
> Moritz
>
>
> On Mon, Jul 1, 2019 at 11:20 AM Moritz Porst <moritz.porst at gmx.de> wrote:
>
> Hello Zoran,
> thanks for your answer
>
> On 28.06.19 14:26, Zoran Stojsavljevic wrote:
>
> INITRAMFS_IMAGE = "core-image-minimal-initramfs"
> INITRAMFS_IMAGE_BUNDLE = "1"
>
> ...
>
> You can find the /var/log/dmesg here: https://pastebin.com/ya7iCtq7I
>
> Some hints...
>
> [1] Kernel command line: BOOT_IMAGE=/bzImage root=PARTUUID=71d1d94a-83e8-4895-98eb-35309f58119f
> break=premount quiet rootwait rootwait rootfstype=ext4 console=ttyS0,115200 console=tty0
>
> input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/LNXVIDEO:00/input/input7
> fbcon: inteldrmfb (fb0) is primary device
> Console: switching to colour frame buffer device 128x48
> i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
> snd_hda_intel 0000:00:1b.0: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
>
> Hmmmmm... You are using console and serial, but full i915 GFX kernel driver is still included in the build???
>
> I started from the core-image-minimal to have a small image and extended it with the features I need, which is e.g. a graphical system. The console=[...] part in the kernel command line is probably a remnant but my image boots into the GUI. Is this a problem ?
>
>
> [2] efi: EFI v2.31 by American Megatrends
>
> Using AMI BIOS as boot loader FW... OK?! Am I correct?
>
> My bootloader is currently grub, the EFI is AM.
>
>
> [3] smpboot: CPU0: Intel(R) Atom(TM) CPU  E3825  @ 1.33GHz (family: 0x6, model: 0x37, stepping: 0x9)
>
> This is CPUID ID 0x30679, which uses MCU... Which MicroCodeUnit? M0130679xxx (info from AMI BIOS)?
>
> Sorry but I can't find this info in the EFI
>
>
> [4] Using INTEL ATOM BYT E3825 dual core (sans Hyper-threading), implies that you are using
> 4GB (e820 messages) as single channel (one memory module DDR3 as 4GB)! Am I correct (important)?
>
> 2GB, single channel.
>
>
> [5] Dracut phase?!
>
> To my understanding the initramfs should be embedded in /boot/bzImage.
> However since I use an intel platform I also have a /boot/microcode.cpio
> which gets loaded via "initrd /microcode.cpio". Removing this line in
> grub does not enable me to get an initramfs prompt either (again, using
> break as option).
>
> You are obviously stopping in boot phase called dracut. Please, try to mount by hand
> /dev/sda(whatever)... You should use fdisk -l command, or do ls -al /dev | grep sda to
> dig out which partition you need to mount to /tmp dir to see rootfstype=ext4 (HDD/SSD)
>
> No, the boot does not stop. Even if I do issue "break=premount" I end up in my graphical interface with the rootfs mounted. This is the last message in the log:
> EXT4-fs (sdb2): re-mounted. Opts: (null)
> The rootfs partition is always 2, so either /dev/sda2 or /dev/sdb2 (when booting from stick)
>
> _______
>
> Just thinking loud... .. .
>
> Hope this helps (has very little to do with YOCTO build system, BTW) . ;-)
>
> Zoran
> _______
>
>
> On Fri, Jun 28, 2019 at 11:22 AM Moritz Porst <moritz.porst at gmx.de> wrote:
>
> Hello,
> I currently try to deploy a single rootfs update mechanism for my
> embedded device. I can't boot to initramfs using either "break" or
> "break=premount" (without quotes...). I tried this in systemd-boot and
> grub-efi (always efi boot) but the boot process just continues normally.
> If I insert at the same point e.g. "quiet" this argument is recognised.
> I boot the .wic image with a separate boot partition from a USB stick.
> in local.conf I have set:
> INITRAMFS_IMAGE = "core-image-minimal-initramfs"
> INITRAMFS_IMAGE_BUNDLE = "1"
>
> In order to reduce complexity I now use the standard
> core-image-minimal-initramfs without .bbappend. I can confirm (from
> seeing the task) that bitbake bundled the kernel with the initramfs.
>
> You can find the /var/log/dmesg here: https://pastebin.com/ya7iCtq7
>
> To my understanding the initramfs should be embedded in /boot/bzImage.
> However since I use an intel platform I also have a /boot/microcode.cpio
> which gets loaded via "initrd /microcode.cpio". Removing this line in
> grub does not enable me to get an initramfs prompt either (again, using
> break as option).
>
> Did I forget some configuration or do I have to put the break statement
> at a very specific position within the "linux ..." boot command ? Do you
> know which bitbake variables to check ? (both set in local.conf do not
> get overwritten, already checked this). I got the thud branch checked
> out in all my meta-layers except for meta-qt which is currently on
> master branch.
>
> Help is much appreciated !
>
> Best regards
> Moritz
>
> --
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