Root Device Problem on boot [SOLVED]

[filteredbygentoo]

On Bootup the problems begin here.

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>>Genkernel 4.2.6. Linux kernel 5.15.11-gentoo-x86_64
>>Activating udev ...
>>Dtermining root device (trying UUID= (Bunch of random #'s)
!! Block device UUID=(random nums from above)    is not a valid root device
!! Could not find root block device in UUID =(Random nums from above)
!!please specify another value or:
!!-press Enter for the same
!!type shell for a shell
!!type q to skip
Root block device UUID:(Random nums) ::

I have tried to enter /dev/sda4 (my root device) and nothing happens, it says it is not a valid root device. Everything should be mounted and my kernel has ext4 included . No it is not as a module. I had it as a module and recompiled my kernel to include it and this still happens. Unsure of where to go from here. Thanks for any and all assistance.

[Moderator edit: added [code] tags to preserve output layout. -Hu]

[grknight]

If you drop to the shell of the initramfs, does 'blkid' show the sda4?

If not, then the disk controller or other driver is not loading.

[filteredbygentoo]

If you drop to the shell of the initramfs, does 'blkid' show the sda4?

If not, then the disk controller or other driver is not loading.

blkid shows nothing when I type it, so I have to go looking for disk controller stuff in the kernel?

Also I figure I should add my knowledge of the necessity of an initramfs is extremely limited / nill. I think I need one but don't know, anyways, that's a question for another forum on another day.

[grknight]

If you drop to the shell of the initramfs, does 'blkid' show the sda4?

If not, then the disk controller or other driver is not loading.

blkid shows nothing when I type it, so I have to go looking for disk controller stuff in the kernel?

Also I figure I should add my knowledge of the necessity of an initramfs is extremely limited / nill. I think I need one but don't know, anyways, that's a question for another forum on another day.

1. Yes, a kernel piece is missing. Often this is a disk controller or missing SCSI disk support (SATA is run via Linux SCSI) or missing NVMe block support.

2. You need an initramfs when modules or other programs are required to prepare the rootfs (LVM, mdadm, cryptsetup, etc). You can also use an initramfs as an emergency shell to fix things without a live media.

[filteredbygentoo]

If you drop to the shell of the initramfs, does 'blkid' show the sda4?

If not, then the disk controller or other driver is not loading.

blkid shows nothing when I type it, so I have to go looking for disk controller stuff in the kernel?

Also I figure I should add my knowledge of the necessity of an initramfs is extremely limited / nill. I think I need one but don't know, anyways, that's a question for another forum on another day.

1. Yes, a kernel piece is missing. Often this is a disk controller or missing SCSI disk support (SATA is run via Linux SCSI) or missing NVMe block support.

2. You need an initramfs when modules or other programs are required to prepare the rootfs (LVM, mdadm, cryptsetup, etc). You can also use an initramfs as an emergency shell to fix things without a live media.

I have all of the SCSI stuff supported in my kernel. Everything is the same. As for the disk controller support, I cannot tell what the disk controller is when using lspci, nothing explicitly says disk controller. I also don't know where to look for it in the kernel. I am sorry that I am such a noob.

[NeddySeagoon]

filteredbygentoo,

To use root=UUID= you must have an an initrd as the kernel does not understand that.

The kernel can use root=PARTUUID=, /dev/... or major:minor device number. Nobody uses that any more.
If you don't have an initrd you won't have the rescue shell it provides either.

We need to see your kernel .config file. Use wgetpaste to put it onto a pastebin site and post the link and your

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lspci -nnk

-- edit --

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!!type shell for a shell 

you do have an initrd.

We need the same information as I requested above.

[filteredbygentoo]

filteredbygentoo,

To use root=UUID= you must have an an initrd as the kernel does not understand that.

The kernel can use root=PARTUUID=, /dev/... or major:minor device number. Nobody uses that any more.
If you don't have an initrd you won't have the rescue shell it provides either.

We need to see your kernel .config file. Use wgetpaste to put it onto a pastebin site and post the link and your

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lspci -nnk

-- edit --

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!!type shell for a shell 

you do have an initrd.

We need the same information as I requested above.

https://dpaste.com/DH5X77ELP - CONFIG
https://dpaste.com/E6YNBDHYT -lspci

There is likely a mass of unnecessary garbage in the kernel. I have been essentially remedying a horrifying genkernel config

[pietinger]

There is likely a mass of unnecessary garbage in the kernel. [...]

Yes. You have enabled as module as much as possible. I dont recommend this. You will usually never have an X25 connection and also never need this:

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CONFIG_OSF_PARTITION=y
CONFIG_AMIGA_PARTITION=y
CONFIG_MAC_PARTITION=y
CONFIG_BSD_DISKLABEL=y
CONFIG_MINIX_SUBPARTITION=y
CONFIG_SOLARIS_X86_PARTITION=y
CONFIG_UNIXWARE_DISKLABEL=y
CONFIG_LDM_PARTITION=y
CONFIG_SGI_PARTITION=y
CONFIG_SUN_PARTITION=y
CONFIG_KARMA_PARTITION=y

But this is another story. Hint: If you miss something in the kernel you will see it immediatly (because something doesnt work; as now ), If you enable something you will never use, you will never know about. So: Configure as less as possible. Now your problem:

Your hd-controller is:

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00:1f.2 RAID bus controller [0104]: Intel Corporation 82801 Mobile SATA Controller [RAID mode] [8086:282a] (rev 04)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: ahci
	Kernel modules: ahci

and therefore this must be static in the kernel and not as module:

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CONFIG_SATA_AHCI=m

See more here: https://wiki.gentoo.org/wiki/HDD

If you have a NVMe SSD you also need this:

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# NVME Support
#
# CONFIG_BLK_DEV_NVME is not set
# CONFIG_NVME_RDMA is not set
# CONFIG_NVME_FC is not set
# CONFIG_NVME_TCP is not set
# CONFIG_NVME_TARGET is not set
# end of NVME Support

See more here: https://wiki.gentoo.org/wiki/NVMe

May I recommend you the usual steps for configuring the kernel:
0. Read this:
https://wiki.gentoo.org/wiki/Kernel/Gen ... tion_Guide
https://wiki.gentoo.org/wiki/Kernel/Configuration#Usage
1. Boot with gentoo minimal CD
2. Do a "lsmod" and write down all modules used.
3. Configure your kernel with this list and some links:
https://wiki.gentoo.org/wiki/Handbook:A ... ion/Kernel
https://wiki.gentoo.org/wiki/Intel
- or -
https://wiki.gentoo.org/wiki/Nouveau
- or -
https://wiki.gentoo.org/wiki/AMDGPU
https://wiki.gentoo.org/wiki/Intel_microcode
- or-
https://wiki.gentoo.org/wiki/AMD_microcode
https://wiki.gentoo.org/wiki/Libinput
https://wiki.gentoo.org/wiki/USB/Guide
-> enable also "USB Mass Storage support"
https://wiki.gentoo.org/wiki/ALSA
https://wiki.gentoo.org/wiki/Power_management/Guide
https://wiki.gentoo.org/wiki/System_time
KDE Vaults needs https://wiki.gentoo.org/wiki/Encfs
Optional: https://wiki.gentoo.org/wiki/CDROM

Good luck.

[filteredbygentoo]

There is likely a mass of unnecessary garbage in the kernel. [...]

Yes. You have enabled as module as much as possible. I dont recommend this. You will usually never have an X25 connection and also never need this:

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CONFIG_OSF_PARTITION=y
CONFIG_AMIGA_PARTITION=y
CONFIG_MAC_PARTITION=y
CONFIG_BSD_DISKLABEL=y
CONFIG_MINIX_SUBPARTITION=y
CONFIG_SOLARIS_X86_PARTITION=y
CONFIG_UNIXWARE_DISKLABEL=y
CONFIG_LDM_PARTITION=y
CONFIG_SGI_PARTITION=y
CONFIG_SUN_PARTITION=y
CONFIG_KARMA_PARTITION=y

But this is another story. Hint: If you miss something in the kernel you will see it immediatly (because something doesnt work; as now ), If you enable something you will never use, you will never know about. So: Configure as less as possible. Now your problem:

Your hd-controller is:

Code: Select all

00:1f.2 RAID bus controller [0104]: Intel Corporation 82801 Mobile SATA Controller [RAID mode] [8086:282a] (rev 04)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: ahci
	Kernel modules: ahci

and therefore this must be static in the kernel and not as module:

Code: Select all

CONFIG_SATA_AHCI=m

See more here: https://wiki.gentoo.org/wiki/HDD

If you have a NVMe SSD you also need this:

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# NVME Support
#
# CONFIG_BLK_DEV_NVME is not set
# CONFIG_NVME_RDMA is not set
# CONFIG_NVME_FC is not set
# CONFIG_NVME_TCP is not set
# CONFIG_NVME_TARGET is not set
# end of NVME Support

See more here: https://wiki.gentoo.org/wiki/NVMe

May I recommend you the usual steps for configuring the kernel:
0. Read this:
https://wiki.gentoo.org/wiki/Kernel/Gen ... tion_Guide
https://wiki.gentoo.org/wiki/Kernel/Configuration#Usage
1. Boot with gentoo minimal CD
2. Do a "lsmod" and write down all modules used.
3. Configure your kernel with this list and some links:
https://wiki.gentoo.org/wiki/Handbook:A ... ion/Kernel
https://wiki.gentoo.org/wiki/Intel
- or -
https://wiki.gentoo.org/wiki/Nouveau
- or -
https://wiki.gentoo.org/wiki/AMDGPU
https://wiki.gentoo.org/wiki/Intel_microcode
- or-
https://wiki.gentoo.org/wiki/AMD_microcode
https://wiki.gentoo.org/wiki/Libinput
https://wiki.gentoo.org/wiki/USB/Guide
-> enable also "USB Mass Storage support"
https://wiki.gentoo.org/wiki/ALSA
https://wiki.gentoo.org/wiki/Power_management/Guide
https://wiki.gentoo.org/wiki/System_time
KDE Vaults needs https://wiki.gentoo.org/wiki/Encfs
Optional: https://wiki.gentoo.org/wiki/CDROM

Good luck.

This was a super resourceful post for a beginner like me. I ditched my old kernel config, and took your advice. Surprise. My machine works. I sincerely thank you, hard to believe a custom config works better than genkernel garbage for a complete newbie who doesn't really know much(although i think im using a genkernel'd initramfs). My network card fails to start on bootup but i'm sure that is a simple kernel issue and I will figure it out myself. You fellows @grknight @NeddySeagoon and @pietinger have provided me with invaluable assistance and I appreciate your patience with a newbie like me. I doubt this will be the last time I am asking for help on this forum, but I will try to learn more about gentoo so that I can contribute and help the community as you guys have done for me. Thanks again

[pietinger]

[...] I appreciate your patience with a newbie like me. [...]

We all started with a poor knowledge and had help from others. Thanks to this excellent community. No one knows all. We have many specialists for some aspects of Linux and Gentoo and together we are strong ...

[...] I doubt this will be the last time I am asking for help on this forum, but I will try to learn more about gentoo [...]

Ask whenever you need help.

[...] so that I can contribute and help the community as you guys have done for me. Thanks again

This is a very noble approach and I want to encourage you to read this forum furthermore (yes, also newbies have some special knowhow and have answered here). Experience needs time to grow.

Many greetings,
Peter (pietinger)

[NeddySeagoon]

filteredbygentoo,

I'll quote your entire lspci -nnk because we may want to refer to it after its gone from the pastebin.

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00:00.0 Host bridge [0600]: Intel Corporation 3rd Gen Core processor DRAM Controller [8086:0154] (rev 09)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: ivb_uncore
00:01.0 PCI bridge [0604]: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port [8086:0151] (rev 09)
	Kernel driver in use: pcieport
00:02.0 VGA compatible controller [0300]: Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09)
	DeviceName:  Onboard IGD
	Subsystem: Dell Device [1028:0535]
	Kernel modules: i915
00:14.0 USB controller [0c03]: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller [8086:1e31] (rev 04)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: xhci_hcd
	Kernel modules: xhci_pci
00:16.0 Communication controller [0780]: Intel Corporation 7 Series/C216 Chipset Family MEI Controller #1 [8086:1e3a] (rev 04)
	Subsystem: Dell Device [1028:0535]
00:19.0 Ethernet controller [0200]: Intel Corporation 82579LM Gigabit Network Connection (Lewisville) [8086:1502] (rev 04)
	DeviceName:  Onboard LAN
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: e1000e
	Kernel modules: e1000e
00:1a.0 USB controller [0c03]: Intel Corporation 7 Series/C216 Chipset Family USB Enhanced Host Controller #2 [8086:1e2d] (rev 04)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: ehci-pci
00:1b.0 Audio device [0403]: Intel Corporation 7 Series/C216 Chipset Family High Definition Audio Controller [8086:1e20] (rev 04)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: snd_hda_intel
	Kernel modules: snd_hda_intel
00:1c.0 PCI bridge [0604]: Intel Corporation 7 Series/C216 Chipset Family PCI Express Root Port 1 [8086:1e10] (rev c4)
	Kernel driver in use: pcieport
00:1c.1 PCI bridge [0604]: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 2 [8086:1e12] (rev c4)
	Kernel driver in use: pcieport
00:1c.2 PCI bridge [0604]: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 3 [8086:1e14] (rev c4)
	Kernel driver in use: pcieport
00:1c.3 PCI bridge [0604]: Intel Corporation 7 Series/C216 Chipset Family PCI Express Root Port 4 [8086:1e16] (rev c4)
	Kernel driver in use: pcieport
00:1c.5 PCI bridge [0604]: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 6 [8086:1e1a] (rev c4)
	Kernel driver in use: pcieport
00:1d.0 USB controller [0c03]: Intel Corporation 7 Series/C216 Chipset Family USB Enhanced Host Controller #1 [8086:1e26] (rev 04)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: ehci-pci
00:1f.0 ISA bridge [0601]: Intel Corporation QM77 Express Chipset LPC Controller [8086:1e55] (rev 04)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: lpc_ich
	Kernel modules: lpc_ich
00:1f.2 RAID bus controller [0104]: Intel Corporation 82801 Mobile SATA Controller [RAID mode] [8086:282a] (rev 04)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: ahci
	Kernel modules: ahci
00:1f.3 SMBus [0c05]: Intel Corporation 7 Series/C216 Chipset Family SMBus Controller [8086:1e22] (rev 04)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: i801_smbus
	Kernel modules: i2c_i801
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GF108GLM [NVS 5200M] [10de:0dfc] (rev a1)
	Subsystem: Dell Device [1028:1535]
01:00.1 Audio device [0403]: NVIDIA Corporation GF108 High Definition Audio Controller [10de:0bea] (rev a1)
	Kernel driver in use: snd_hda_intel
	Kernel modules: snd_hda_intel
03:00.0 Network controller [0280]: Intel Corporation Centrino Advanced-N 6205 [Taylor Peak] [8086:0082] (rev 34)
	Subsystem: Intel Corporation Centrino Advanced-N 6205 AGN [8086:1321]
	Kernel driver in use: iwlwifi
	Kernel modules: iwlwifi
0c:00.0 SD Host controller [0805]: O2 Micro, Inc. OZ600FJ0/OZ900FJ0/OZ600FJS SD/MMC Card Reader Controller [1217:8221] (rev 05)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: sdhci-pci
	Kernel modules: sdhci_pci

All those lowest lever hardware drivers listed there may as well be built into the kernel, with the exception of those that need firmware. The firmware must be available when the code is initalised. That means if the code is built in, the firmware must be too. When the code is a loadable module, the firmware is read from /lib/fimware. That makes life easier.
It looks like only iwlwifi is affected by firmware.

snd_hda_intel has a wart. It loads its CODECs when it is initalised, so snd_hda_intel and its codecs, which are all kernel options, all need to be set the same way, either <M> or <*>.

That's the easy bit. The lowest level things are identified there.
The kernel is designed as a number of software 'stacks'. A stack is like the layers of a cake. Its done this way fore ease of maintenance. The layers all have a consistent interface between them. The makes it easy to write a replacement for a layer or at the bottom, add a new hardware interface, as it has a well defined interface to the layer above.

Lets look at one device at the bottom (lowest level) on one such stack.

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00:1f.2 RAID bus controller [0104]: Intel Corporation 82801 Mobile SATA Controller [RAID mode] [8086:282a] (rev 04)
	Subsystem: Dell Device [1028:0535]
	Kernel driver in use: ahci
	Kernel modules: ahci

This is your HDD hardware controller. Its at the bottom of the SCSI stack in your system and its set as

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CONFIG_SATA_AHCI=m

That means it has to be in the initrd so it can be loaded before root is mouted as its needed to be able to see the HDD at all to be able to mount root.
Set it as <*> in menuconfig.

Now the rest of the SCSI stack above it.
Its on the

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CONFIG_ATA=y

menu, that's already <*>

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CONFIG_BLK_DEV_SD=y
CONFIG_BLK_DEV_SR=y
CONFIG_CHR_DEV_SG=y

Good. on SD is needed to boot. SR the the optical driver and SG is everything else that uses the SCSI protocol.

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CONFIG_SCSI=y

Good. That takes care of the SCSI stack but we are not done yet.

SCSI is a type of block device. Thare are others, so

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CONFIG_BLOCK=y

is correct.

That lets the kernel read the HDD. Now it needs to understand what it finds there.

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CONFIG_MSDOS_PARTITION=y
CONFIG_EFI_PARTITION=y

is enough for a PC.
The kernel needs to read the partition table on the drive that holds the root filesystem so it can locate the filesystem on the disk.
If you have followed the handbook you will have an ext4 root filesystem, so

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CONFIG_EXT4_FS=y
CONFIG_EXT4_USE_FOR_EXT2=y
CONFIG_EXT4_FS_POSIX_ACL=y
CONFIG_EXT4_FS_SECURITY=y

is correct.

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CONFIG_EXT4_DEBUG=y

should be off. Debug kernel options always lead to a lot of logspam. They are also permitted to interfere with normal operation of the kernel to help with debugging.
So all debug options should be off unless you understand what they do.
Oh, one or two debug options log keystrokes - including passwords, so they are a major security risk too.

Use the search in menuconfig to find and change those two options, then rebuild the kernel and initrd.
If you don't want to use an initrd, the kernel command line must not contain root=UUID=...