[SOLVED] Cannot initialize device-mapper.

[Rainer06]

I have updated my Gentoo installation for the first time after several months, and now I cannot read my encrypted Raid array any more.

When I am trying to access the Raid array with

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cryptsetup luksOpen /dev/md1 raid

I am getting the following error message:

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Cannot initialize device-mapper. Is dm_mod kernel module loaded?

I have tried to downgrade the version of cryptsetup, compiled a new kernel version, downgraded the version of udev, downgraded the version of lvm2,
but nothing was resolving the error. I am getting a little desperate now....

Let me try to provide some more background information:

1) The kernel configuration has not changed, and it was working previously with the kernel that is used.
In particular, device mapper is compiled into the kernel and available.
In /proc/misc, there is an entry "236 device-mapper".

2) The node /dev/md1 is visible.

3) The problem is with the device mapper itself.
Commands such as

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cryptsetup luksDump -v /dev/md1

are successful.

4) dmraid is not installed. Maybe this has been uninstalled with the update?
However, after an emerge of dmraid, the problem persists.

5)

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 dmsetup targets 

returns

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crypt            v1.12.1
striped          v1.5.1
linear           v1.2.1
error            v1.1.0

6) device mapper from lvm2 is started:

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# /etc/init.d/device-mapper status
 * status: started
# /etc/init.d/dmeventd status
 * status: started

Do you have any idea what I could do?
Maybe I could compile a new kernel with a device mapper module dm_mod and load that module.
But I am a little hesitant to do so because I think that this is not the problem, the
device mapper compiled into the kernel was working previously.

[khayyam]

Rainer06 ...

somewhat of a guess really, but did you perhaps also update udev during this update?

>=udev-197 had a soname change, so perhaps your cryptsetup is linked to an older library:

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# ldd /sbin/cryptsetup
	linux-gate.so.1 (0xb775c000)
	libcryptsetup.so.4 => /usr/lib/libcryptsetup.so.4 (0xb7730000)
	libpopt.so.0 => /usr/lib/libpopt.so.0 (0xb7724000)
	libc.so.6 => /lib/libc.so.6 (0xb759b000)
	libuuid.so.1 => /lib/libuuid.so.1 (0xb7595000)
	libdevmapper.so.1.02 => /lib/libdevmapper.so.1.02 (0xb7556000)
	libgcrypt.so.11 => /usr/lib/libgcrypt.so.11 (0xb74db000)
	/lib/ld-linux.so.2 (0xb775d000)
	libudev.so.1 => /lib/libudev.so.1 (0xb749e000)
	libgpg-error.so.0 => /usr/lib/libgpg-error.so.0 (0xb7499000)
	librt.so.1 => /lib/librt.so.1 (0xb7490000)
	libpthread.so.0 => /lib/libpthread.so.0 (0xb7475000)

A 'revdep-rebuild' should fix this ... and any other packages linked to a libudev.so.{N}.

best ... khay

[Rainer06]

Khay,

Thank you for the suggestion.
I have run revdep-rebuild before,
and I have emerged cryptsetup newly.
But that did not solve the problem.

Regards,
Rainer

[Rainer06]

I have now compiled the kernel with device mapper as a module.

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modprobe dm_mod

and subsequent

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cryptsetup luksOpen /dev/md1 raid

yields the same error though.

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Cannot initialize device-mapper. Is dm_mod kernel module loaded?

I have no more idea what else I could do to resolve the issue.

[ulenrich]

Newer cryptsetup has wider encryption keys by default. Current~unstable cryptsetup needs a hint to decrypt with older kind of key. Lazily I stabled this ebuild with package.accept_keywords.

[jamatik]

Problem: =dev-libs/libgcrypt-1.5.2

Solution:

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USE="-caps" emerge -av libgcrypt

[ulenrich]

Yeah, but we are just wild guessing, because we know nothing about Rainers system

[jamatik]

@ulenrich
Maybe u r doing "wild guessing", I do not.
If u don't know the problem and not have a "not confusing answer" to rainer06, then don't post anything in first place;-).

[Rainer06]

Thank you very much!

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USE="-caps" emerge -av libgcrypt

is resolving the problem!

There should be a big warning about this for everybody updating libgcrypt.
I just checked the emerge logs, but there is no info about this.
Please add this information for the benefit of everybody else
using encryption.