initramfs and system logs

initramfs and system logs

[jguittet.opensource]

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Dear community,

I'm currently building a professional yocto project.
There are 2 variants of the image I'm building: the first one is using classical rootfs on SD card (dev and test purpose). The other one is building an initramfs fitImage (production). I'm using INITRAMFS_IMAGE to indicate the name of the recipe building the initramfs + INITRAMFS_IMAGE_BUNDLE = "1".

Problem I get is that the initramfs image produces no logs (except kernel logs) in the console while the dev with the rootfs on the SD card have logs printed in the console. I don't understand why and where I should patch to have logs. The wanted logs are logs from init.d scripts for example (creating ssh keys, setting hwclock etc) + logs from my own applications that are properly output on the serial console with the "classic" image.

Thanks for any feedbacks!
Joel

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Re: [yocto] initramfs and system logs

[Khem Raj]

On Wed, Jan 17, 2024 at 5:43 AM jguittet.opensource via
lists.yoctoproject.org
<jguittet.opensource=witekio.com@lists.yoctoproject.org> wrote:
>
> Dear community,
>
> I'm currently building a professional yocto project.
> There are 2 variants of the image I'm building: the first one is using classical rootfs on SD card (dev and test purpose). The other one is building an initramfs fitImage (production). I'm using INITRAMFS_IMAGE to indicate the name of the recipe building the initramfs + INITRAMFS_IMAGE_BUNDLE = "1".
>
> Problem I get is that the initramfs image produces no logs (except kernel logs) in the console while the dev with the rootfs on the SD card have logs printed in the console. I don't understand why and where I should patch to have logs. The wanted logs are logs from init.d scripts for example (creating ssh keys, setting hwclock etc) + logs from my own applications that are properly output on the serial console with the "classic" image.

check if /dev/console is created in the initramfs init script which
runs as /sbin/init

>
> Thanks for any feedbacks!
> Joel
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Re: [yocto] initramfs and system logs

[Mauro Salvini]

On 17/01/24 18:49, Khem Raj wrote:
> On Wed, Jan 17, 2024 at 5:43 AM jguittet.opensource via
> lists.yoctoproject.org
> <jguittet.opensource=witekio.com@lists.yoctoproject.org> wrote:
>>
>> Dear community,
>>
>> I'm currently building a professional yocto project.
>> There are 2 variants of the image I'm building: the first one is using classical rootfs on SD card (dev and test purpose). The other one is building an initramfs fitImage (production). I'm using INITRAMFS_IMAGE to indicate the name of the recipe building the initramfs + INITRAMFS_IMAGE_BUNDLE = "1".
>>
>> Problem I get is that the initramfs image produces no logs (except kernel logs) in the console while the dev with the rootfs on the SD card have logs printed in the console. I don't understand why and where I should patch to have logs. The wanted logs are logs from init.d scripts for example (creating ssh keys, setting hwclock etc) + logs from my own applications that are properly output on the serial console with the "classic" image.
> 
> check if /dev/console is created in the initramfs init script which
> runs as /sbin/init
> 
>>
>> Thanks for any feedbacks!
>> Joel

Hi Joel,

how many console= arguments do you have on the kernel cmdline?
Kernel logs are shown on all of the declared consoles, but userspace 
logs (initrd script logs, init manager logs) are shown only on last 
console= specified in kernel cmdline.

Regards

-- 
Mauro Salvini | KOAN sas | Bergamo - Italia
embedded software engineering
http://KoanSoftware.com

Re: [yocto] initramfs and system logs

[Joel GUITTET]

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Thanks for the answers.

- /sbin/init is a symlink to /sbin/init.sysvinit and it's a binary file, not a script. Maybe I should look at the sources that build this ? Will do in parallel.

- console= arguments is the same for both my images, eg "console=ttyS0,115200n8".
The difference between the 2 images on the cmdline are only the options related to the rootfs:
* distro with the rootfs on the sdcard: "mem=128M console=ttyS0,115200n8 root=/dev/mmcblk0p4 rw rootfstype=ext4 rootwait"
* distro with the initramfs: "mem=128M console=ttyS0,115200n8"

I have done a check of /proc/consoles for both (don't know if this is really important, this returns "ttyS0                -W- (EC p a)    4:64" for both distro.

Joel

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Re: [yocto] initramfs and system logs

[Joel GUITTET]

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Hello all,

Checked init process and build option, don't find any relevant information.

Anybody getting the same issue (no output on the console at the initialization) while building an initramfs ??

Thanks!
Joel

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Re: [yocto] initramfs and system logs

[Joel GUITTET]

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Hello community!

Finally got a solution to my issue.

I created a busybox_%.bbappend file in my layer with the following content, to create the /dev/console node during the build:

> 
> # Install
> do_install:append() {
> # init process needs the console created before running
> # If the console is not available, no logs are displayed in the terminal
> install -d ${D}/dev
> mknod -m 622 ${D}/dev/console c 5 1
> }
> FILES:${PN}:append = " \
> /dev/console \
> "
> 

I also found a relevant discussion here that seems still to be up to date: https://busybox.busybox.narkive.com/Erf4teRC/modifying-init-to-create-dev-console

I hope this will help others reading this message in the future :-)

Joel

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Re: [yocto] initramfs and system logs

[Khem Raj]

On Thu, Feb 8, 2024 at 7:12 AM Joel GUITTET via lists.yoctoproject.org
<jguittet.opensource=witekio.com@lists.yoctoproject.org> wrote:
>
> Hello community!
>
> Finally got a solution to my issue.
>
> I created a busybox_%.bbappend file in my layer with the following content, to create the /dev/console node during the build:
>
> # Install
> do_install:append() {
>     # init process needs the console created before running
>     # If the console is not available, no logs are displayed in the terminal
>     install -d ${D}/dev
>     mknod -m 622 ${D}/dev/console c 5 1
> }
> FILES:${PN}:append = " \
>     /dev/console \
> "
>
> I also found a relevant discussion here that seems still to be up to date: https://busybox.busybox.narkive.com/Erf4teRC/modifying-init-to-create-dev-console
>
> I hope this will help others reading this message in the future :-)

busybox would not be appropriate recipe to create this device, since
it is also used in main rootfs, however a separate recipe or init
script would be a better place see
meta/recipes-core/initrdscripts/initramfs-framework/init

>
> Joel
>
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Re: [yocto] initramfs and system logs

[Joel GUITTET]

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Not bad to have a separated recipe as well. I added this to busybox because init is provided by busybox in my case.
I'm not using the initramfs-framework, so the init script you indicated there doesn't help me at all.

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