# System frozen -- can't boot [UDEV] -- urgent

## Xploderman90

Hi all.

After last system-update ( udev updated too ) i'm unable to boot up my system.

It's frozen during booting on line : "cannot start udev as udev-mount would not start".

Some lines above there is "CONFIG_DEVTMPFS=y is required in your kernel configuration".

The problem is i can't use rescue shell because mounts file system in read only mode and i can't do anything.

Please help me because i use this pc for job and today i have to do a heavy task, now i'm in panic!! (2:25 AM here)

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## 666threesixes666

take another system and get unetbootin....  install gentoo image or ubuntu...

chroot, recompile kernel with old config....  find devtmpfs line and change it from not set to =y

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## Xploderman90

Ok, it was my last resort..i see there is nothing else to do!!

Thanks, now i'll try and i'll let you know!!

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## Jaglover

Yea, you can remount rw and fix it.

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## albright

yes, I had the same problem and luckily had a system rescue

cd so I could chroot in and recompile kernel

but what I didn't see is the WARNING about this when

the udev upgrade happened.

Can someone please point out the eselect news or udev

build message that reminded users *before* upgrading

udev that a kernel recompile would be necessary if

the until now unnecessary kernel option was not selected?

Because I would really like to think this was MY fault

and not some other moron's

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## 666threesixes666

ill expand on what i said, ubuntu would be easiest....  as it has tools like gedit and a gui to work with....

mkdir /mnt/gentoo

mount /dev/$YOURROOT /mnt/gentoo

mkdir /mnt/gentoo/boot

mount /dev/$YOURBOOT /mnt/gentoo/boot

mount -t proc none /mntgentoo/proc

mount --rbind /dev /mnt/gentoo/dev

chroot /mnt/gentoo /bin/bash

now your ready to start fixing....

cd /usr/src/linux

make clean && make distclean && make mrproper

#copy old config to clean kernel sources

cp /boot/config-3.7.1 /usr/src/linux/.config

nano /usr/src/linux/.config

scroll down to #DEV_TMP_FS OR WHAT EVER

its line 934 for me

CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"

CONFIG_DEVTMPFS=y

CONFIG_DEVTMPFS_MOUNT=y

CONFIG_STANDALONE=y

CONFIG_PREVENT_FIRMWARE_BUILD=y

set to look like that....

then....

make menuconfig

make && make modules_install

then copy your new kernel to where your old one was.....

cp arch/x86_64/boot/bzImage /boot/kernel-3.7.1

run lilo....  or grub (see the wiki script i just posted yesterday) to get your boot loader to install the new kernel....

reboot

&& god speed man

update to add grub2 automated installs via "grub" command

https://wiki.gentoo.org/wiki/GRUB2_Quick_Start#Automating_Installs

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## Xploderman90

Phew, problem solved!!

Edited .config and added the param requested, then rebuilded kernel.

Now i have another problem with mysql (it seems something strange during update) but i'll open another thread for that!

Albright, i remember that there was a warning in messages after emerge world.

Thanks to all!

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## 666threesixes666

ls /usr/portage/distfiles | grep mysql....

revert your version back....  or version completely forward.... 

see

https://forums.gentoo.org/viewtopic-t-948592-highlight-.html

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## Xploderman90

Yeah, i was reading that thread!! Hehe you're anticipating me in all solutions!!now i'll get back to the last working version!!

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## tryn

I emerged udev today and this showed up at the end of the emerge.

*   DEVTMPFS is not set in this kernel. Udev will not run.

 * Please check to make sure these options are set correctly.

 * Failure to do so may cause unexpected problems.

 So I rebuilt the kernel before restarting the computer.

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## VoidMage

Editing kernel config manually is one of the worse ideas you could get.

It might work every now and then, but you'll get bitten by it eventually.

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## modnaruved

Ive get these rakes too and success solve it with chrooting by gentoo liveDVD "EOWE 2012"

This is very strange that emerge system not show any warning messages about post-install steps and requirements. After emerging many packages important summary messages not show. This is not normal behaviour.

Why emerge cant detect automatically necessary options in kernel?

At this moment many "noob-users" choice gentoo as very good and friendly distro. Perhaps, these rakes is awaiting new members...

I understand that nobody can provide stable system - but from other side some parts of gentoo system needs to be some improving.

Many beginnings from "noob" level but human factor is forever. More tests before stabilization is quite.

my make.conf options:

PORTAGE_ELOG_SYSTEM="save"

PORTAGE_ELOG_CLASSES="save_summary:log,warn,error,qa echo"

this is correct for display all warnings and post-install messages after emerge many packages?

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## BasketCase

I had a similar issue when switching to devtmpfs.  I am going to post it in here because this is the thread I found when I searched and because I have the answer....

I got some cryptic messages about device not found, /dev/tty* not being a character device, and urandom failing to start then the system just hung during bootup.

Turns out the problem was that I had defined /dev in /etc/fstab as a tmpfs so that I could restrain the size of it with the size= mount option.  If you have such an entry in /etc/fstab it must be either removed or converted to devtmpfs.

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## Aiken

At least the fix for me was easy enough. Add init=/bin/bash to the kernel line in grub, mount / rw then recompile the kernel. The message had long scrolled off the screen and I would have expected if there was an update that would stop the computer from booting to either refuse to install or have a warning that a person could not miss.

What I don't get is with a populated /dev from when building the initial system image why the computer could not continue booting. Even without udev and devtmpfs my /dev already had all nodes needed to boot the computer normally.

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## Jaglover

 *Aiken wrote:*   

> At least the fix for me was easy enough. Add init=/bin/bash to the kernel line in grub, mount / rw then recompile the kernel. 

 

Nah, too easy, look at this! (You gotta learn how to do stuff the hard way, borking the config by editing it by hand is a good idea, too.)

 *666threesixes666 wrote:*   

> ill expand on what i said, ubuntu would be easiest....  as it has tools like gedit and a gui to work with....
> 
> mkdir /mnt/gentoo
> 
> mount /dev/$YOURROOT /mnt/gentoo
> ...

 

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## Duncan Mac Leod

 *BasketCase wrote:*   

> Turns out the problem was that I had defined /dev in /etc/fstab as a tmpfs so that I could restrain the size of it with the size= mount option.  If you have such an entry in /etc/fstab it must be either removed or converted to devtmpfs.

 

What's the correct entry for /etc/fstab ??

I had this entry for a while:

udev                   /dev            tmpfs           size=10M,nr_inodes=4k   0 0

Unfortunately, the portage output says that I need to edit /etc/fstab - but it tells not WHAT to edit ???

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## 666threesixes666

my fstab does not have a /dev or /udev rule.....

/dev/sda1		/boot		jfs		noauto,noatime	1 2

/dev/sda5		/		xfs		noatime		0 1

/dev/sda6		none		swap		sw		0 0

/dev/sda7		/home		xfs		noatime		0 0

#/dev/cdrom		/mnt/cdrom	auto		noauto, ro	0 0

#/dev/fd0		/mnt/floppy	auto		noauto		0 0

&&

some people use syslinux or lilo, thats a very specific solve for grub users....

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## SamuliSuominen

 *Duncan Mac Leod wrote:*   

>  *BasketCase wrote:*   Turns out the problem was that I had defined /dev in /etc/fstab as a tmpfs so that I could restrain the size of it with the size= mount option.  If you have such an entry in /etc/fstab it must be either removed or converted to devtmpfs. 
> 
> What's the correct entry for /etc/fstab ??
> 
> I had this entry for a while:
> ...

 

It does now. The warning got adjusted in Portage. It can't be "tmpfs" as it must be "devtmpfs". Or you can simply delete whole line -- works fine here without any /dev line.

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## Duncan Mac Leod

During boot it says that CONFIG_DEVTMPFS is not set, BUT IT IS !!! DEFINTELY!!

Using Kernel 3.3.8 gentoo-sources - what went wrong ??

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## SamuliSuominen

 *Duncan Mac Leod wrote:*   

> During boot it says that CONFIG_DEVTMPFS is not set, BUT IT IS !!! DEFINTELY!!
> 
> Using Kernel 3.3.8 gentoo-sources - what went wrong ??

 

I guess you should run something like 'make clean' in the kernel source tree before building it after setting CONFIG_DEVTMPFS using 'make menuconfig'

Then you verify you are actually using the correct kernel, like using `ls -l` and checking the time in /boot and then grub's config

It's something simple you did wrong, if the boot is telling it's missing, it most certainly is missing

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## Duncan Mac Leod

It's the correct kernel, properly built!

It boots up, but with errors -> http://www.f-mail.eu/images/gentoo_error.jpg

and Network eth0 is missing!

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## Duncan Mac Leod

devfs, udev and udev-mount are in runlevel sysinit - is this correct ?

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## 666threesixes666

eth0 is missing because its /DEV/eth0.....  your kernels not installed, or you changed your /boot/config and not your /usr/src/linux/.config  or you edited your /usr/src/linux/.config and make clean && make depclean && make mrproper to remove the .config........  rebuild your kernel again....  if it fails, roll back your udev version using /etc/portage/package.accept_keywords file as described on the mysql problem link a few posts up i posted.....

your correct...  the 3 are sysinit run levelsLast edited by 666threesixes666 on Tue Jan 22, 2013 12:56 am; edited 1 time in total

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## SamuliSuominen

 *Duncan Mac Leod wrote:*   

> devfs, udev and udev-mount are in runlevel sysinit - is this correct ?

 

Yes, it's correct.

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## SamuliSuominen

 *Duncan Mac Leod wrote:*   

> It's the correct kernel, properly built!
> 
> It boots up, but with errors -> http://www.f-mail.eu/images/gentoo_error.jpg
> 
> and Network eth0 is missing!

 

eth* would go away if you don't have the /etc/udev/rules.d/80-net-name-slot.rules, otherwise you propably just have wrongly configured kernel

and the CONFIG_DEVTMPFS check is reading /proc/filesystems of the running kernel, so it really can't be wrongLast edited by SamuliSuominen on Tue Jan 22, 2013 1:00 am; edited 2 times in total

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## 666threesixes666

id suggest going to kernel.org and getting 3.7.4 and running uname -a to verify your running the kernel your installing....

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## SamuliSuominen

 *666threesixes666 wrote:*   

> id suggest going to kernel.org and getting 3.7.4 and running uname -a to verify your running the kernel your installing....

 

Kernel's menuconfig:

General setup ---> <*> Kernel .config support

Then you have /proc/config.gz available in the running kernel and you can:

```

# zgrep DEVTMPFS /proc/config.gz 

CONFIG_DEVTMPFS=y

CONFIG_DEVTMPFS_MOUNT=y

```

It's much more reliable than reading /usr/src/linux/.config. I don't understand why people don't use it more.

Also:

```

# grep devtmpfs /proc/filesystems

nodev   devtmpfs

```

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## 666threesixes666

its .config built into your kernel....  i dont use it as i keep hard records of it in /boot  i have used it and did advocate it in the past, just ive found other methods to the same ends, easier to cat than zcat...  copy once and be done with it....  i actually have 2 records of it /boot/config.kernel-3.6.7 for kernel-3.6.7 and /usr/src/linux-3.6.7/.config  1s generally unmounted and 1s hidden, 3rd copy is a bit excessive, but i do agree, its the .config that the kernel is running, and known working....  i do keep a stale 3.5.4 and 3.6.2 kernel & config set around too incase 3.7.4 makes my old dv9000 hardware flip out and unbootable.....  lol after re reading your post i realized your directing that to the other posters on the thread.....

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## Duncan Mac Leod

udev-197 is up and running! sorry, for bothering you with my problems.

It was my fault!!!

Building Gentoo kernels since 2004 with genkernel, but it seems that something has changed in the past.

I always used "genkernel --menuconfig all", made my config and saved the config file to my home-directory using the save-option in the kernel menu (for later use, if I have to rebuild the kernel). This has worked in the past. But if I load the config file via the kernel menu and start compiling, my loaded config file is not used. Instead it uses the .config in /usr/src/linux !

Now, kernel is compiled properly and everything works  :Cool:  !

Sorry, again!

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## 666threesixes666

so gedit $HOME/.config

ctrl + f (or alt+ f) to find "DEVTMPFS" set =y....

then

sudo cp $HOME/.config /usr/src/linux

or if your system is totally voodoo and doesnt have sudo

su -c 'cp $HOME/.config /usr/src/linux'

for future references   :Twisted Evil: 

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## aCOSwt

 *666threesixes666 wrote:*   

> so gedit $HOME/.config

 

Warning 666threesixes666, editing the kernel config file is not a good practice at all!

 *Quote:*   

> acoswt@PrimaPratica /usr/src/linux $ more .config
> 
> #
> 
> # Automatically generated file; DO NOT EDIT.
> ...

 

You are... not under FreeBSD !   :Wink: 

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## iandoug

hi

I was able to fix this problem without going the rescue-disk way ... during boot  I switched to Interactive boot, did not let udev load, and let the rest proceed normally. Then I used make menuconfig to fix the option and proceeded as per normal after such editing.

cheers, Ian

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## modnaruved

 *iandoug wrote:*   

> hi
> 
> I was able to fix this problem without going the rescue-disk way ... during boot  I switched to Interactive boot, did not let udev load, and let the rest proceed normally. Then I used make menuconfig to fix the option and proceeded as per normal after such editing.
> 
> cheers, Ian

 

In my case I tried npress "I" before start init but this not help. But will be good If you post some steps how you resolve this.

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## iandoug

 *devurandom wrote:*   

>  *iandoug wrote:*   hi
> 
> I was able to fix this problem without going the rescue-disk way ... during boot  I switched to Interactive boot, did not let udev load, and let the rest proceed normally. Then I used make menuconfig to fix the option and proceeded as per normal after such editing.
> 
> cheers, Ian 
> ...

 

I found out the hard way (when my OTHER box would not boot) that there is a setting in  /etc/conf.d/rc  which enables this ... if it is set to no then you can't .... 

Still trying to fix broken box ... the Live DVD fails to complete booting ( total waste of a 4GB download ... we need a small rescue disk please...) so trying with a minimal install CD which did complete booting ...

Think the live DVD fails because it doesn't like my LG blu-ray writer drive.

Cheers, Ian

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## 666threesixes666

the huge post i was using a usb flash rescue disk, my usb flash rescue disk was generated using these isos (only if your 64 will they work for you)

http://distfiles.gentoo.org/releases/amd64/autobuilds/current-iso/

i generated documentation by hand in a note book so i could do gentoo installs with no net to see documentation (ie terminal only) and just a flash thumb drive.  i still have links in terminal but its a pain to try to read the handbook as it has too many explanations and is far too verbose to do that.  well i had net but was only using it to pull sources for emerge --sync and emerging goodies.

fair warning, these iso images are TERMINAL ONLY...  so generate a notebook of documentation if you intend to use them.  i use unetbootin if you go through the thread again you can find links to this to generate flash thumb drive rescue boot disks.

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## Chiitoo

 *iandoug wrote:*   

> Still trying to fix broken box ... the Live DVD fails to complete booting ( total waste of a 4GB download ... we need a small rescue disk please...) so trying with a minimal install CD which did complete booting ...

 

I do believe that neither the LiveDVDs nor the Minimal Installation CDs are intended to be used as a 'rescue disk'.

Correct me if I'm wrong.  ^^;

If you have not before, you might like to take a peek at the SystemRescueCd.  That's what I always recommend at least, sometimes even for doing the initial installation of Gentoo.  I used the Minimal Installation CD myself (which, I think, gives the realer experience, and that is an important part to include in the recommendation).  Not that I even knew about the sysresccd existing back when I was taking my first steps...

It's very easy to put into a USB-stick, too!

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## boyan7640

Hi all,

I decided to upgrade to sys-fs/udev-200, so as usually happens I broke my system. So, fun   :Very Happy: , I lost 3 hours to fix it   :Mad: .

I was very careful following the instructions on http://www.gentoo.org/doc/en/udev-guide.xml . The following part of it broke my system ending with "kernel panic - not syncing: VFS: Unable to mount root fs on unknown block (0,0) Pid 1, comm: swapper Not tainted...":

 *Quote:*   

> Code Listing 2.2: Required kernel options
> 
> Device Drivers --->
> 
>   (Make sure the following item is *not* enabled)
> ...

 

It seems that the root cause is my old system and especially my old IBM ATA 30.7 GB hard disk (IC35L030AVVN07-0).

So, I set both CONFIG_DEVTMPFS=y and CONFIG_DEVTMPFS_MOUNT=y + CONFIG_IDE (ATA/ATAPI/MFM/RLL support (DEPRECATED)) was not set as advised above. Unfortunately my system ended with kernel panic.

I was not able to boot my old non-devtmpfs kernel with sys-fs/udev-200 as well. Finally, thanks to this topic I succeed to boot the old kernel like that:

```
root (hd0,0)

kernel /boot/vmlinuz.old root=/dev/hda3 init=/bin/bash rw
```

Afterwards I rebuilt the kernel with CONFIG_IDE=y (+other sub parameters, see below) and CONFIG_DEVTMPFS=y and CONFIG_DEVTMPFS_MOUNT=y:

 *Quote:*   

> [hostname] boot # diff config-3.8.13-gentoo_bad config-3.8.13-gentoo
> 
> 682c682,748
> 
> < # CONFIG_IDE is not set
> ...

 

I changed only tmpfs to devtmpfs in /etc/fstab:

```
shm         /dev/shm   devtmpfs   nodev,nosuid,noexec   0 0
```

Reboot and my kernel and my system became live again, luckily   :Very Happy:   :Exclamation:  .

Just wanted to share that. I hope that it can help somebody.

Best Regards,

Boyan Boychev

Bulgaria

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## boyan7640

Hi all,

That's a continuation of my previous thread (see above). The package >=sys-fs/udev-200 recommends to unset CONFIG_IDE (ATA/ATAPI/MFM/RLL support (DEPRECATED)) as it's deprecated. In its place I should use CONFIG_ATA (Serial ATA and Parallel ATA drivers) kernel parameters as I use ATA disk and Intel IDE Controller (82801BA IDE U100 Controller). So, I disabled CONFIG_IDE (ATA/ATAPI/MFM/RLL support (DEPRECATED)) and enabled CONFIG_ATA (Serial ATA and Parallel ATA drivers) and "SCSI device support" kernel parameters.

Here are the details:

 *Quote:*   

> 
> 
> Device Drivers --->
> 
> 	< > ATA/ATAPI/MFM/RLL support (DEPRECATED)
> ...

 

Do not forget to set SCSI device support  ---> SCSI disk support otherwise you will end with kernel panic.

Do not forget to change /boot/grub/menu.lst - from hda* to sda* (especially root parameter), e.g.

```
title=Gentoo Linux (3.8.13-gentoo)

root (hd0,0)

kernel /boot/vmlinuz root=/dev/sda3 gentoo=udev ro quiet splash
```

Do not forget to change /etc/fstab - from hda* to sda*, e.g.

```
/dev/sda1               /boot           ext3            noauto,noatime  1 2

/dev/sda3               /               ext3            noatime         0 1

/dev/sda2               none            swap            sw              0 0

```

Reboot and my kernel and my system became live again, luckily  :Very Happy:   :Exclamation:  .

Just wanted to share that. I hope that it can help somebody.

Best Regards,

Boyan Boychev

Bulgaria

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## jecepede

Aloha ! 

I can't believe I fell for this issue. I read about but BANG.... did it wrong never the less...

So I did what is described in this thread and it solvend my problem.

I Booted from my live CD and compiled a new kernel.

I did however use make menuconfig. Like lots of you, I'm lazy to edit .config directly.

Besides, in my humble opinion is it safer...

Cheeeeeeeeeeeeers and thank you for the help everyone.

Jecepede

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