Hi Matti,

On Wed, Sep 24, 2014 at 9:20 AM, Martti Kühne mysatyre@gmail.com wrote:

Thanks for the pointer. I just removed the init= setting from /etc/default/grub and added the systemd hook to mkinitcpio.conf. I generated both the bootloader config and the initcpio.

Yeap, that part works fine for me, too. Make sure to use the "sd-*" variant of the HOOKS if available. The arch wiki is unfortunately a bit lacking wrt. mkinitcpio and systemd:-/

It e.g. suggests to add the "base" hook before "systemd", to get a debug environment... That will indeed install some binaries, but then the systemd hook will overwrite the init script with systemd and thus remove the normal options to trigger a debug shell in the initrd.

However, I still wonder, because my machine boots just fine this way.

So does mine till I start to tinker with it:-)

Thinking more closely about the issue as you present it, usually, if things go wrong in the inticpio stage you get thrown to a shell to fix stuff manually.

That is no longer the case once I enable the "systemd" hook (I do have the "base" hook before the "systemd" one).

As it does not looks like this seems to be the case, your new_root appears to get mounted and the issue appears to be somewhere else...

You are correct, but how did you gather that from my original mail? :-)

Systemd claims to have mounted / and /usr. It then proceeds to tear down services it started as part of the initrd and tries to pivot root. Everything perfectly normal up to that point.

Then it fails with "/bin/sh not found".

Most likely either / or /usr is not mounted properly. A quick "ls" should point me into the right direction, but how do I get a debug shell?

You also did not provide any error message or other pointer which would lead us to the source of your problem, and I think you should add anything you have (eg. remove the "quiet" boot option).

I have to admit that I did not think about removing "quiet" this morning:-/ Shame on me.

My question is basically how to get the a debug shell in an initrd created by mkinitcpio with the "systemd" hook enabled?

The long and involved way is most likely to make sure the systemd-debug-generator will be added to the initrd by the "systemd" hook, together with a modified debug-shell.service that actually is started during the initrd (and not only afterwards).

Then I should be able to enable that debug shell with the kernel parameters documented for the systemd-debug-generator.

Is there a simpler way, involving less hacking?

Best Regards, Tobias

On Wed, Sep 24, 2014 at 1:02 PM, Martti Kühne mysatyre@gmail.com wrote:

On Wed, Sep 24, 2014 at 9:51 AM, Tobias Hunger tobias.hunger@gmail.com wrote:

...

Then it fails with "/bin/sh not found".

As new_root is mounted (/bin/sh is there in the initrd), where /bin is a symlink to /usr/bin, this should be obvious...

Yeap. I just need to check what ended up being mounted where and what the .mount units that got generated actually look like.

That is why I am asking wether somebody knows how to get a debug shell.

<snip>

With /usr not correctly mounted, you might want to check fstab and arch-chroot to the current setup and try mount -a?

There is no /usr in fstab:-) Getting /usr mounted based on /proc/cmdline is what I am experimenting with and I might just have ended up messing up the mount options, getting me something else on /usr than whatever I expect.

My C-foo is a bit rusty, so who knows what I actually put into my patched version of systemd-fstab-generator that I have on that initrd;-)

Maybe somehow pull busybox into / before you chroot, so you have everything you need while in the dark ages...

chroot works fine, once I manually mounted the root and /usr FS to some directory.

I guess the next stop is getting a debug shell into the initrd. "man systemd-debug-generator" should have all the information I need for that, I hope.

But first I need to check whether removing "quiet" has any useful effect.

Best Regards, Tobias

On Wed, Sep 24, 2014 at 1:47 PM, Tobias Hunger tobias.hunger@gmail.com wrote:

My C-foo is a bit rusty, so who knows what I actually put into my patched version of systemd-fstab-generator that I have on that initrd;-)

I was planning to complain already. Try not to insult people trying to help you like that...

cheers! mar77i

hi tobias,

I wasn't taking you rude. But implying you were using custom packages while we're trying to debug an issue is generally seen as a serious undermining of any help... Such things are to be mentioned beforehand, since the basic assumption is a repo install.

cheers! mar77i

On Thu, Sep 25, 2014 at 7:21 PM, Tobias Hunger tobias.hunger@gmail.com wrote:

Hi Martti,

I did mention that I have been playing with the hooks and systemd in my initial mail. At least I thought that would be clear. Sorry if it was not. I will try to make that more clear next time. Was my first post here, I only joined this list recently.

My question about how to open a debug shell is not effected by my changes in any way.

That said, I'm sorry. I should have just told you to test without your changes and been done with it.

cheers! mar77i